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Sample records for variability hrv analysis

  1. gHRV: Heart rate variability analysis made easy.

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    Rodríguez-Liñares, L; Lado, M J; Vila, X A; Méndez, A J; Cuesta, P

    2014-08-01

    In this paper, the gHRV software tool is presented. It is a simple, free and portable tool developed in python for analysing heart rate variability. It includes a graphical user interface and it can import files in multiple formats, analyse time intervals in the signal, test statistical significance and export the results. This paper also contains, as an example of use, a clinical analysis performed with the gHRV tool, namely to determine whether the heart rate variability indexes change across different stages of sleep. Results from tests completed by researchers who have tried gHRV are also explained: in general the application was positively valued and results reflect a high level of satisfaction. gHRV is in continuous development and new versions will include suggestions made by testers. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  2. Effect of spontaneous saliva swallowing on short-term heart rate variability (HRV) and reliability of HRV analysis.

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    Yildiz, Metin; Doma, Serian

    2017-09-26

    The effects of effortful swallowing and solid meal ingestions on heart rate variability (HRV) have been examined previously. The effects of spontaneous saliva swallowing on short-term HRV and reliability of HRV analysis have not been studied before. The effect of saliva swallowing on HRV analyses parameters [meanRRI, SDNN (standard deviation of normal-to-normal), LF (low frequency), HF (high frequency) powers, LH/HF] and the reliability of LF and HF powers were investigated by frequency, time-frequency and intraclass correlation coefficient (ICC) analyses. Electrocardiogram and swallowing signal that obtained from an electronic stethoscope placed on the necks of subjects were recorded simultaneously from 30 healthy and young volunteers in sitting position during 15 min. Spontaneous swallowing has been shown to significantly alter some HRV parameters (SDNN, LF power and LF/HF ratio). Time-frequency analysis results showed that the contribution of saliva swallowing to LF (1-58%) and HF (2-42%) powers could change significantly depending on the number of swallowing. The ICC of the LF and HF powers for the successive 5-min signal segments were found 0·89, 0·92, respectively. These values decreased to 0·73 and 0·90 in the subjects with more swallowing rate. When the analyses were made for 2-min signal periods, these values decreased to 0·63 and 0·67. We concluded that spontaneous saliva swallowing can change HRV parameters. We have also seen that changes in swallowing rate and use of short signal segments may reduce the reliability of HRV analyses. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  3. Heart rate variability (HRV): an indicator of stress

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    Kaur, Balvinder; Durek, Joseph J.; O'Kane, Barbara L.; Tran, Nhien; Moses, Sophia; Luthra, Megha; Ikonomidou, Vasiliki N.

    2014-05-01

    Heart rate variability (HRV) can be an important indicator of several conditions that affect the autonomic nervous system, including traumatic brain injury, post-traumatic stress disorder and peripheral neuropathy [3], [4], [10] & [11]. Recent work has shown that some of the HRV features can potentially be used for distinguishing a subject's normal mental state from a stressed one [4], [13] & [14]. In all of these past works, although processing is done in both frequency and time domains, few classification algorithms have been explored for classifying normal from stressed RRintervals. In this paper we used 30 s intervals from the Electrocardiogram (ECG) time series collected during normal and stressed conditions, produced by means of a modified version of the Trier social stress test, to compute HRV-driven features and subsequently applied a set of classification algorithms to distinguish stressed from normal conditions. To classify RR-intervals, we explored classification algorithms that are commonly used for medical applications, namely 1) logistic regression (LR) [16] and 2) linear discriminant analysis (LDA) [6]. Classification performance for various levels of stress over the entire test was quantified using precision, accuracy, sensitivity and specificity measures. Results from both classifiers were then compared to find an optimal classifier and HRV features for stress detection. This work, performed under an IRB-approved protocol, not only provides a method for developing models and classifiers based on human data, but also provides a foundation for a stress indicator tool based on HRV. Further, these classification tools will not only benefit many civilian applications for detecting stress, but also security and military applications for screening such as: border patrol, stress detection for deception [3],[17], and wounded-warrior triage [12].

  4. Promising effects of xanthine oxidase inhibition by allopurinol on autonomic heart regulation estimated by heart rate variability (HRV analysis in rats exposed to hypoxia and hyperoxia.

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    Stanisław Zajączkowski

    Full Text Available It has long been suggested that reactive oxygen species (ROS play a role in oxygen sensing via peripheral chemoreceptors, which would imply their involvement in chemoreflex activation and autonomic regulation of heart rate. We hypothesize that antioxidant affect neurogenic cardiovascular regulation through activation of chemoreflex which results in increased control of sympathetic mechanism regulating heart rhythm. Activity of xanthine oxidase (XO, which is among the major endogenous sources of ROS in the rat has been shown to increase during hypoxia promote oxidative stress. However, the mechanism of how XO inhibition affects neurogenic regulation of heart rhythm is still unclear.The study aimed to evaluate effects of allopurinol-driven inhibition of XO on autonomic heart regulation in rats exposed to hypoxia followed by hyperoxia, using heart rate variability (HRV analysis.16 conscious male Wistar rats (350 g: control-untreated (N = 8 and pretreated with Allopurinol-XO inhibitor (5 mg/kg, followed by 50 mg/kg, administered intraperitoneally (N = 8, were exposed to controlled hypobaric hypoxia (1h in order to activate chemoreflex. The treatment was followed by 1h hyperoxia (chemoreflex suppression. Time-series of 1024 RR-intervals were extracted from 4kHz ECG recording for heart rate variability (HRV analysis in order to calculate the following time-domain parameters: mean RR interval (RRi, SDNN (standard deviation of all normal NN intervals, rMSSD (square root of the mean of the squares of differences between adjacent NN intervals, frequency-domain parameters (FFT method: TSP (total spectral power as well as low and high frequency band powers (LF and HF. At the end of experiment we used rat plasma to evaluate enzymatic activity of XO and markers of oxidative stress: protein carbonyl group and 8-isoprostane concentrations. Enzymatic activity of superoxide dismutase (SOD, catalase (CAT and glutathione peroxidase (GPx were measures in erythrocyte

  5. Promising effects of xanthine oxidase inhibition by allopurinol on autonomic heart regulation estimated by heart rate variability (HRV) analysis in rats exposed to hypoxia and hyperoxia

    Science.gov (United States)

    Ziółkowski, Wiesław; Badtke, Piotr; Zajączkowski, Miłosz A.; Flis, Damian J.; Figarski, Adam; Smolińska-Bylańska, Maria; Wierzba, Tomasz H.

    2018-01-01

    Background It has long been suggested that reactive oxygen species (ROS) play a role in oxygen sensing via peripheral chemoreceptors, which would imply their involvement in chemoreflex activation and autonomic regulation of heart rate. We hypothesize that antioxidant affect neurogenic cardiovascular regulation through activation of chemoreflex which results in increased control of sympathetic mechanism regulating heart rhythm. Activity of xanthine oxidase (XO), which is among the major endogenous sources of ROS in the rat has been shown to increase during hypoxia promote oxidative stress. However, the mechanism of how XO inhibition affects neurogenic regulation of heart rhythm is still unclear. Aim The study aimed to evaluate effects of allopurinol-driven inhibition of XO on autonomic heart regulation in rats exposed to hypoxia followed by hyperoxia, using heart rate variability (HRV) analysis. Material and methods 16 conscious male Wistar rats (350 g): control-untreated (N = 8) and pretreated with Allopurinol-XO inhibitor (5 mg/kg, followed by 50 mg/kg), administered intraperitoneally (N = 8), were exposed to controlled hypobaric hypoxia (1h) in order to activate chemoreflex. The treatment was followed by 1h hyperoxia (chemoreflex suppression). Time-series of 1024 RR-intervals were extracted from 4kHz ECG recording for heart rate variability (HRV) analysis in order to calculate the following time-domain parameters: mean RR interval (RRi), SDNN (standard deviation of all normal NN intervals), rMSSD (square root of the mean of the squares of differences between adjacent NN intervals), frequency-domain parameters (FFT method): TSP (total spectral power) as well as low and high frequency band powers (LF and HF). At the end of experiment we used rat plasma to evaluate enzymatic activity of XO and markers of oxidative stress: protein carbonyl group and 8-isoprostane concentrations. Enzymatic activity of superoxide dismutase (SOD), catalase (CAT) and glutathione

  6. Validity of the Elite HRV Smartphone Application for Examining Heart Rate Variability in a Field-Based Setting.

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    Perrotta, Andrew S; Jeklin, Andrew T; Hives, Ben A; Meanwell, Leah E; Warburton, Darren E R

    2017-08-01

    Perrotta, AS, Jeklin, AT, Hives, BA, Meanwell, LE, and Warburton, DER. Validity of the elite HRV smartphone application for examining heart rate variability in a field-based setting. J Strength Cond Res 31(8): 2296-2302, 2017-The introduction of smartphone applications has allowed athletes and practitioners to record and store R-R intervals on smartphones for immediate heart rate variability (HRV) analysis. This user-friendly option should be validated in the effort to provide practitioners confidence when monitoring their athletes before implementing such equipment. The objective of this investigation was to examine the relationship and validity between a vagal-related HRV index, rMSSD, when derived from a smartphone application accessible with most operating systems against a frequently used computer software program, Kubios HRV 2.2. R-R intervals were recorded immediately upon awakening over 14 consecutive days using the Elite HRV smartphone application. R-R recordings were then exported into Kubios HRV 2.2 for analysis. The relationship and levels of agreement between rMSSDln derived from Elite HRV and Kubios HRV 2.2 was examined using a Pearson product-moment correlation and a Bland-Altman Plot. An extremely large relationship was identified (r = 0.92; p smartphone HRV application may offer a reliable platform when assessing parasympathetic modulation.

  7. The use of historical range and variability (HRV) in landscape management

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    Robert E. Keane; Paul F. Hessburg; Peter B. Landres; Fred J. Swanson

    2009-01-01

    This paper examines the past, present, and future use of the concept of historical range and variability (HRV) in land management. The history, central concepts, benefits, and limitations of HRV are presented along with a discussion on the value of HRV in a changing world with rapid climate warming, exotic species invasions, and increased land development. This paper...

  8. EFFECT OF SPIRONOLACTONE ON HEART RATE VARIABILITY (HRV IN DIABETIC PATIENTS

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    Ramin Heydari

    2010-12-01

    Full Text Available Abstract  INTRODUCTION: Diabetes mellitus is the most common metabolic and endocrine disease. Depressed Heart Rate Variability (HRV is an early warning sign of diabetic neuropathy. In numerous studies, spironolactone improved HRV and decreased mortality in Congestive Heart Failure (CHF. This study was performed to assess the effect of spironolactone on HRV in diabetic patients. methods: This prospective, randomized, double-blind clinical trial was performed on 62 diabetic patients with autonomic neuropathy at Isfahan Cardiovascular Research Center. Baseline HRV was measured with time domain and frequency domain methods using a Valiance system manufactured by US Biomedical Systems Inc. (2000. The patients were then randomly placed in case and control groups. The control group was given placebo and the case group was given 25mg spironolactone twice daily for two months. HRV was measured at the end of this period and data were analyzed using SPSS. HRV before and after medication was compared with t-test, paired t-test, Wilcoxon test, and Mann-Whitney test. results: Twenty-nine patients in the control group and thirty-three patients in the case group were assessed. HRV was measured before and after the study. T-test and Mann-Whitney test revealed no significant difference between HRV in the two groups. Paired t-test and Wilcoxon test did not show any significant difference of HRV within the two groups. Discussion: In this study, spironolactone did not improve HRV in diabetic patients. 

  9. CameraHRV: robust measurement of heart rate variability using a camera

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    Pai, Amruta; Veeraraghavan, Ashok; Sabharwal, Ashutosh

    2018-02-01

    The inter-beat-interval (time period of the cardiac cycle) changes slightly for every heartbeat; this variation is measured as Heart Rate Variability (HRV). HRV is presumed to occur due to interactions between the parasym- pathetic and sympathetic nervous system. Therefore, it is sometimes used as an indicator of the stress level of an individual. HRV also reveals some clinical information about cardiac health. Currently, HRV is accurately measured using contact devices such as a pulse oximeter. However, recent research in the field of non-contact imaging Photoplethysmography (iPPG) has made vital sign measurements using just the video recording of any exposed skin (such as a person's face) possible. The current signal processing methods for extracting HRV using peak detection perform well for contact-based systems but have poor performance for the iPPG signals. The main reason for this poor performance is the fact that current methods are sensitive to large noise sources which are often present in iPPG data. Further, current methods are not robust to motion artifacts that are common in iPPG systems. We developed a new algorithm, CameraHRV, for robustly extracting HRV even in low SNR such as is common with iPPG recordings. CameraHRV combined spatial combination and frequency demodulation to obtain HRV from the instantaneous frequency of the iPPG signal. CameraHRV outperforms other current methods of HRV estimation. Ground truth data was obtained from FDA-approved pulse oximeter for validation purposes. CameraHRV on iPPG data showed an error of 6 milliseconds for low motion and varying skin tone scenarios. The improvement in error was 14%. In case of high motion scenarios like reading, watching and talking, the error was 10 milliseconds.

  10. Heart Rate Variability (HRV biofeedback: A new training approach for operator’s performance enhancement

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    Auditya Purwandini Sutarto

    2010-06-01

    Full Text Available The widespread implementation of advanced and complex systems requires predominantly operators’ cognitive functions and less importance of human manual control. On the other hand, most operators perform their cognitive functions below their peak cognitive capacity level due to fatigue, stress, and boredom. Thus, there is a need to improve their cognitive functions during work. The goal of this paper is to present a psychophysiology training approach derived from cardiovascular response named heart rate variability (HRV biofeedback. Description of resonant frequency biofeedback - a specific HRV training protocol - is discussed as well as its supported researches for the performance enhancement. HRV biofeedback training works by teaching people to recognize their involuntary HRV and to control patterns of this physiological response. The training is directed to increase HRV amplitude that promotes autonomic nervous system balance. This balance is associated with improved physiological functioning as well as psychological benefits. Most individuals can learn HRV biofeedback training easily which involves slowing the breathing rate (around six breaths/min to each individual’s resonant frequency at which the amplitude of HRV is maximized. Maximal control over HRV can be obtained in most people after approximately four sessions of training. Recent studies have demonstrated the effectiveness of HRV biofeedback to the improvement of some cognitive functions in both simulated and real industrial operators.

  11. Accuracy of the Garmin 920 XT HRM to perform HRV analysis.

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    Cassirame, Johan; Vanhaesebrouck, Romain; Chevrolat, Simon; Mourot, Laurent

    2017-12-01

    Heart rate variability (HRV) analysis is widely used to investigate autonomous cardiac drive. This method requires periodogram measurement, which can be obtained by an electrocardiogram (ECG) or from a heart rate monitor (HRM), e.g. the Garmin 920 XT device. The purpose of this investigation was to assess the accuracy of RR time series measurements from a Garmin 920 XT HRM as compared to a standard ECG, and to verify whether the measurements thus obtained are suitable for HRV analysis. RR time series were collected simultaneously with an ECG (Powerlab system, AD Instruments, Castell Hill, Australia) and a Garmin XT 920 in 11 healthy subjects during three conditions, namely in the supine position, the standing position and during moderate exercise. In a first step, we compared RR time series obtained with both tools using the Bland and Altman method to obtain the limits of agreement in all three conditions. In a second step, we compared the results of HRV analysis between the ECG RR time series and Garmin 920 XT series. Results show that the accuracy of this system is in accordance with the literature in terms of the limits of agreement. In the supine position, bias was 0.01, - 2.24, + 2.26 ms; in the standing position, - 0.01, - 3.12, + 3.11 ms respectively, and during exercise, - 0.01, - 4.43 and + 4.40 ms. Regarding HRV analysis, we did not find any difference for HRV analysis in the supine position, but the standing and exercise conditions both showed small modifications.

  12. Physical activity as a health factor modifying heart rate variability (HRV

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    Nowosielska-Swadzba Danuta

    2015-03-01

    Full Text Available Purpose: The aim of the research was the evaluation of the selected HRV factors of the training volleyball players in two training periods and non-training people. Materials and methods : The study involved 8 leading volleyball players aged 20-23 and 13 non-training persons aged 19-26. The study of the training players was conducted twice: in the pre-competition and in the competition period. The study for the non-training persons was conducted once. The selected factors of the spectral analysis have been evaluated: TP [ms 2], share of LF and HF power [n.u], LF/HF indicator and time analysis factors: RR [ms], HR [1/min], RMSSD [ms]. Results : Statistically significant differences appeared only in the selected time analysis factors (RR, HR, between the group of the training and non-training persons. Other differences in the evaluated parameters were not statistically significant. Conclusions : Physical activity influences on the HRV growth. HRV measurement may serve for the control of the changes taking place in the AUN under the influence of the physical activity.

  13. Validation of PC-based Sound Card with Biopac for Digitalization of ECG Recording in Short-term HRV Analysis.

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    Maheshkumar, K; Dilara, K; Maruthy, K N; Sundareswaren, L

    2016-07-01

    Heart rate variability (HRV) analysis is a simple and noninvasive technique capable of assessing autonomic nervous system modulation on heart rate (HR) in healthy as well as disease conditions. The aim of the present study was to compare (validate) the HRV using a temporal series of electrocardiograms (ECG) obtained by simple analog amplifier with PC-based sound card (audacity) and Biopac MP36 module. Based on the inclusion criteria, 120 healthy participants, including 72 males and 48 females, participated in the present study. Following standard protocol, 5-min ECG was recorded after 10 min of supine rest by Portable simple analog amplifier PC-based sound card as well as by Biopac module with surface electrodes in Leads II position simultaneously. All the ECG data was visually screened and was found to be free of ectopic beats and noise. RR intervals from both ECG recordings were analyzed separately in Kubios software. Short-term HRV indexes in both time and frequency domain were used. The unpaired Student's t-test and Pearson correlation coefficient test were used for the analysis using the R statistical software. No statistically significant differences were observed when comparing the values analyzed by means of the two devices for HRV. Correlation analysis revealed perfect positive correlation (r = 0.99, P < 0.001) between the values in time and frequency domain obtained by the devices. On the basis of the results of the present study, we suggest that the calculation of HRV values in the time and frequency domains by RR series obtained from the PC-based sound card is probably as reliable as those obtained by the gold standard Biopac MP36.

  14. Smart ECG Monitoring Patch with Built-in R-Peak Detection for Long-Term HRV Analysis.

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    Lee, W K; Yoon, H; Park, K S

    2016-07-01

    Since heart rate variability (HRV) analysis is widely used to evaluate the physiological status of the human body, devices specifically designed for such applications are needed. To this end, we developed a smart electrocardiography (ECG) patch. The smart patch measures ECG using three electrodes integrated into the patch, filters the measured signals to minimize noise, performs analog-to-digital conversion, and detects R-peaks. The measured raw ECG data and the interval between the detected R-peaks can be recorded to enable long-term HRV analysis. Experiments were performed to evaluate the performance of the built-in R-wave detection, robustness of the device under motion, and applicability to the evaluation of mental stress. The R-peak detection results obtained with the device exhibited a sensitivity of 99.29%, a positive predictive value of 100.00%, and an error of 0.71%. The device also exhibited less motional noise than conventional ECG recording, being stable up to a walking speed of 5 km/h. When applied to mental stress analysis, the device evaluated the variation in HRV parameters in the same way as a normal ECG, with very little difference. This device can help users better understand their state of health and provide physicians with more reliable data for objective diagnosis.

  15. Paroxysmal atrial fibrillation prediction based on HRV analysis and non-dominated sorting genetic algorithm III.

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    Boon, K H; Khalil-Hani, M; Malarvili, M B

    2018-01-01

    This paper presents a method that able to predict the paroxysmal atrial fibrillation (PAF). The method uses shorter heart rate variability (HRV) signals when compared to existing methods, and achieves good prediction accuracy. PAF is a common cardiac arrhythmia that increases the health risk of a patient, and the development of an accurate predictor of the onset of PAF is clinical important because it increases the possibility to electrically stabilize and prevent the onset of atrial arrhythmias with different pacing techniques. We propose a multi-objective optimization algorithm based on the non-dominated sorting genetic algorithm III for optimizing the baseline PAF prediction system, that consists of the stages of pre-processing, HRV feature extraction, and support vector machine (SVM) model. The pre-processing stage comprises of heart rate correction, interpolation, and signal detrending. After that, time-domain, frequency-domain, non-linear HRV features are extracted from the pre-processed data in feature extraction stage. Then, these features are used as input to the SVM for predicting the PAF event. The proposed optimization algorithm is used to optimize the parameters and settings of various HRV feature extraction algorithms, select the best feature subsets, and tune the SVM parameters simultaneously for maximum prediction performance. The proposed method achieves an accuracy rate of 87.7%, which significantly outperforms most of the previous works. This accuracy rate is achieved even with the HRV signal length being reduced from the typical 30 min to just 5 min (a reduction of 83%). Furthermore, another significant result is the sensitivity rate, which is considered more important that other performance metrics in this paper, can be improved with the trade-off of lower specificity. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. The effect of the number of consecutive night shifts on diurnal rhythms in cortisol, melatonin and heart rate variability (HRV)

    DEFF Research Database (Denmark)

    Jensen, Marie Aarrebo; Garde, Anne Helene; Kristiansen, Jesper

    2016-01-01

    PURPOSE: The purpose of this review is to summarize the current knowledge from field studies on how many consecutive night shifts are required for adaptation of diurnal rhythms in cortisol, melatonin and heart rate variability (HRV) to night work. METHODS: A systematic search of the databases Pub...... recordings for HRV. Most of the studies in the review were small studies with less than 30 participants, and most studies evaluated diurnal rhythms after only two consecutive night shifts whereas only six studies used seven or more consecutive night shifts. The majority of studies found that adaptation...... to night work had not occurred after two consecutive night shifts, whereas a small number found evidence for full adaptation after seven consecutive night shifts based on diurnal rhythms in cortisol and melatonin. CONCLUSION: There are methodological differences in the field studies analyzing diurnal...

  17. Heart rate variability analysis with the R package RHRV

    CERN Document Server

    García Martínez, Constantino Antonio; Vila, Xosé A; Lado Touriño, María José; Rodríguez-Liñares, Leandro; Rodríguez Presedo, Jesús María; Méndez Penín, Arturo José

    2017-01-01

    This book introduces readers to the basic concepts of Heart Rate Variability (HRV) and its most important analysis algorithms using a hands-on approach based on the open-source RHRV software. HRV refers to the variation over time of the intervals between consecutive heartbeats. Despite its apparent simplicity, HRV is one of the most important markers of the autonomic nervous system activity and it has been recognized as a useful predictor of several pathologies. The book discusses all the basic HRV topics, including the physiological contributions to HRV, clinical applications, HRV data acquisition, HRV data manipulation and HRV analysis using time-domain, frequency-domain, time-frequency, nonlinear and fractal techniques. Detailed examples based on real data sets are provided throughout the book to illustrate the algorithms and discuss the physiological implications of the results. Offering a comprehensive guide to analyzing beat information with RHRV, the book is intended for masters and Ph.D. students in v...

  18. Negative Affectivity, Depression, and Resting Heart Rate Variability (HRV as Possible Moderators of Endogenous Pain Modulation in Functional Somatic Syndromes

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    Maaike Van Den Houte

    2018-03-01

    Full Text Available Background: Several studies have shown that patients with functional somatic syndromes (FSS have, on average, deficient endogenous pain modulation (EPM, as well as elevated levels of negative affectivity (NA and high comorbidity with depression and reduced resting heart rate variability (HRV compared to healthy controls (HC. The goals of this study were (1 to replicate these findings and (2 to investigate the moderating role of NA, depression, and resting HRV in EPM efficiency within a patient group with fibromyalgia and/or chronic fatigue syndrome (CFS. Resting HRV was quantified as the root mean square of successive differences between inter-beat intervals (RMSSD in rest, a vagally mediated time domain measure of HRV.Methods: Seventy-eight patients with fibromyalgia and/or CFS and 33 HC completed a counter-irritation paradigm as a measure of EPM efficiency. Participants rated the painfulness of electrocutaneous stimuli (of individually calibrated intensity on the ankle before (baseline phase, during (counter-irritation phase and after (recovery phase the application of a cold pain stimulus on the forearm. A larger reduction in pain in the counter-irritation phase compared to the baseline phase reflects a more efficient EPM.Results: In contrast to our expectations, there was no difference between pain ratings in the baseline compared to counter-irritation phase for both patients and HC. Therefore, reliable conclusions on the moderating effect of NA, depression, and RMSSD could not be made. Surprisingly, patients reported more pain in the recovery compared to the counter-irritation and baseline phase, while HC did not. This latter effect was more pronounced in patients with comorbid depression, patients who rated the painfulness of the counter-irritation stimulus as high and patients who rated the painfulness of the electrocutaneous stimuli as low. We did not manage to successfully replicate the counter-irritation effect in HC or FSS patients

  19. A method for continuously assessing the autonomic response to music-induced emotions through HRV analysis.

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    Orini, Michele; Bailón, Raquel; Enk, Ronny; Koelsch, Stefan; Mainardi, Luca; Laguna, Pablo

    2010-05-01

    Interest in therapeutic applications of music has recently increased, as well as the effort to understand the relationship between music features and physiological patterns. In this study, we present a methodology for characterizing music-induced effects on the dynamics of the heart rate modulation. It consists of three steps: (i) the smoothed pseudo Wigner-Ville distribution is performed to obtain a time-frequency representation of HRV; (ii) a parametric decomposition is used to robustly estimate the time-course of spectral parameters; and (iii) statistical population analysis is used to continuously assess whether different acoustic stimuli provoke different dynamic responses. Seventy-five healthy subjects were repetitively exposed to pleasant music, sequences of Shepard tones with the same tempo as the pleasant music and unpleasant sounds overlaid with the same sequences of Shepard tones. Results show that the modification of HRV parameters are characterized by an early fast transient phase (15-20 s), followed by an almost stationary period. All kinds of stimuli provoked significant changes compared to the resting condition, while during listening to pleasant music the heart and respiratory rates were higher (for more than 80% of the duration of the stimuli, p < 10(-5)) and the power of the HF modulation was lower (for more than 70% of the duration of the stimuli, p < 0.05) than during listening to unpleasant stimuli.

  20. An adaptive technique for multiscale approximate entropy (MAEbin) threshold (r) selection: application to heart rate variability (HRV) and systolic blood pressure variability (SBPV) under postural stress.

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    Singh, Amritpal; Saini, Barjinder Singh; Singh, Dilbag

    2016-06-01

    Multiscale approximate entropy (MAE) is used to quantify the complexity of a time series as a function of time scale τ. Approximate entropy (ApEn) tolerance threshold selection 'r' is based on either: (1) arbitrary selection in the recommended range (0.1-0.25) times standard deviation of time series (2) or finding maximum ApEn (ApEnmax) i.e., the point where self-matches start to prevail over other matches and choosing the corresponding 'r' (rmax) as threshold (3) or computing rchon by empirically finding the relation between rmax, SD1/SD2 ratio and N using curve fitting, where, SD1 and SD2 are short-term and long-term variability of a time series respectively. None of these methods is gold standard for selection of 'r'. In our previous study [1], an adaptive procedure for selection of 'r' is proposed for approximate entropy (ApEn). In this paper, this is extended to multiple time scales using MAEbin and multiscale cross-MAEbin (XMAEbin). We applied this to simulations i.e. 50 realizations (n = 50) of random number series, fractional Brownian motion (fBm) and MIX (P) [1] series of data length of N = 300 and short term recordings of HRV and SBPV performed under postural stress from supine to standing. MAEbin and XMAEbin analysis was performed on laboratory recorded data of 50 healthy young subjects experiencing postural stress from supine to upright. The study showed that (i) ApEnbin of HRV is more than SBPV in supine position but is lower than SBPV in upright position (ii) ApEnbin of HRV decreases from supine i.e. 1.7324 ± 0.112 (mean ± SD) to upright 1.4916 ± 0.108 due to vagal inhibition (iii) ApEnbin of SBPV increases from supine i.e. 1.5535 ± 0.098 to upright i.e. 1.6241 ± 0.101 due sympathetic activation (iv) individual and cross complexities of RRi and systolic blood pressure (SBP) series depend on time scale under consideration (v) XMAEbin calculated using ApEnmax is correlated with cross-MAE calculated using ApEn (0.1-0.26) in steps of 0

  1. Hypothesis: Low frequency heart rate variability (LF-HRV) is an input for undisclosed yet biological adaptive control, governing the cardiovascular regulations to assure optimal functioning.

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    Gabbay, Uri; Bobrovsky, Ben Zion

    2012-02-01

    Cardiovascular regulation is considered today as having three levels: autoregulations, neural regulations and hormonal regulations. We hypothesize that the cardiovascular regulation has an additional (fourth) control level which is outer, hierarchical (adaptive) loop where LF-HRV amplitude serves as a reference input which the neural cardiovascular center detects and responses in order to maintain LF-HRV around some prescribed level. Supporting evidences: LF-HRV absence during artificial cardiac pacing may be associated with "pacemaker syndrome" which had not been sufficiently understood regardless of apparently unimpaired cardiovascular performance. The hypothesis may provide an essential basis for understanding several cardiovascular morbidities and insight toward diagnostic measures and treatments (including but not limited to adding variability to the pulse generator of artificial pacemakers to eliminate "pace maker syndrome"). Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Application of HRV-CD for estimation of life expectancy in various clinical disorders.

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    Almoznino-Sarafian, Dorit; Sarafian, Gideon; Zyssman, Itzhak; Shteinshnaider, Miriam; Tzur, Irma; Kaplan, Ben-Zion; Berman, Sylvia; Cohen, Natan; Gorelik, Oleg

    2009-12-01

    Low heart rate variability (HRV) was found in various medical conditions including heart failure and acute myocardial infarction. Decreased HRV in these conditions predicted poor prognosis. HRV was estimated in 133 unselected inpatients with relevant clinical bedside conditions by non-linear analysis derived from chaos theory, which calculates the correlation dimension (CD) of the cardiac electrophysiologic system (HRV-CD). Mean HRV-CD in the entire group was 3.75+/-0.45. Heart failure, coronary artery disease, cardiac arrhythmia, low serum potassium, renal dysfunction, and diabetes mellitus were significantly associated with reduced HRV-CD compared to their counterparts [3.6 vs. 3.9 (P3.75) was associated with lower survival (P=.01). Mortality of diabetic patients with HRV-CD 3.75 (P=.02). Heart failure, renal dysfunction or age over 70 combined with HRV-CD < or =3.75 also appeared to be associated with augmented mortality. Diminished HRV-CD is associated with heart failure, coronary artery disease, cardiac arrhythmia, renal dysfunction, diabetes mellitus and low serum potassium. Among the latter, heart failure is most significantly associated with decreased HRV-CD. Decreased HRV-CD values, especially in diabetics, are also associated with lower survival.

  3. Toward Capturing Momentary Changes of Heart Rate Variability by a Dynamic Analysis Method.

    Directory of Open Access Journals (Sweden)

    Haoshi Zhang

    Full Text Available The analysis of heart rate variability (HRV has been performed on long-term electrocardiography (ECG recordings (12~24 hours and short-term recordings (2~5 minutes, which may not capture momentary change of HRV. In this study, we present a new method to analyze the momentary HRV (mHRV. The ECG recordings were segmented into a series of overlapped HRV analysis windows with a window length of 5 minutes and different time increments. The performance of the proposed method in delineating the dynamics of momentary HRV measurement was evaluated with four commonly used time courses of HRV measures on both synthetic time series and real ECG recordings from human subjects and dogs. Our results showed that a smaller time increment could capture more dynamical information on transient changes. Considering a too short increment such as 10 s would cause the indented time courses of the four measures, a 1-min time increment (4-min overlapping was suggested in the analysis of mHRV in the study. ECG recordings from human subjects and dogs were used to further assess the effectiveness of the proposed method. The pilot study demonstrated that the proposed analysis of mHRV could provide more accurate assessment of the dynamical changes in cardiac activity than the conventional measures of HRV (without time overlapping. The proposed method may provide an efficient means in delineating the dynamics of momentary HRV and it would be worthy performing more investigations.

  4. Heart rate variability in bipolar disorder

    DEFF Research Database (Denmark)

    Faurholt-Jepsen, Maria; Kessing, Lars Vedel; Munkholm, Klaus

    2017-01-01

    Background Heart rate variability (HRV) has been suggested reduced in bipolar disorder (BD) compared with healthy individuals (HC). This meta-analysis investigated: HRV differences in BD compared with HC, major depressive disorder or schizophrenia; HRV differences between affective states; HRV...

  5. ENVIRONMENTAL CHANGES ANALYSIS IN BUCHAREST CITY USING CORONA, SPOT HRV AND IKONOS IMAGES

    Directory of Open Access Journals (Sweden)

    I. Noaje

    2012-08-01

    Full Text Available Bucharest, capital of Romania, deals with serious difficulties as a result of urban politics: influx of people due to industrialization and development of dormitory areas, lack of a modern infrastructure, absence of coherent and long term urban development politics, continuous depletion of environment. This paper presents a multisensor study relying on multiple data sets, both analogical and digital: satellite images (Corona – 1964 panchromatic, SPOT HRV – 1994 multispctral and panchromatic, IKONOS – 2007 multispectral, aerial photographs – 1994, complementary products (topographic and thematic maps. Georeferenced basis needs to be generated to highlight changes detection. The digital elevation model is generated from aerial photography 1:5,000 scaled, acquired in 1994. First a height correction is required followed by an affine transformation to the ground control points identified both in aerial photographs and IKONOS image. SPOT-HRV pansharpened satellite image has been rectified on georeferenced IKONOS image, by an affine transformation method. The Corona panoramic negative film was scanned and rubber sheeting method is used for rectification. The first 25 years of the study period (1964–1989 are characterized by growth of industrial areas, high density apartment buildings residential areas and leisure green areas by demolition of cultural heritage areas (hundred years old churches and architectural monuments. Changes between the imagery were determined partially through visual interpretation, using elements such as location, size, shape, shadow, tone, texture, and pattern (Corona image, partially using unsupervised classification (SPOT HRV and IKONOS. The second period of 18 years (1989–2007 highlighted considerable growth of residential areas in the city neighborhood, simultaneously with the diminish of green areas and massive deforestation in confiscated areas before and returned to the original owners.

  6. Monitoring Fatigue Status with HRV Measures in Elite Athletes: An Avenue Beyond RMSSD?

    Science.gov (United States)

    Schmitt, Laurent; Regnard, Jacques; Millet, Grégoire P.

    2015-01-01

    Among the tools proposed to assess the athlete's “fatigue,” the analysis of heart rate variability (HRV) provides an indirect evaluation of the settings of autonomic control of heart activity. HRV analysis is performed through assessment of time-domain indices, the square root of the mean of the sum of the squares of differences between adjacent normal R-R intervals (RMSSD) measured during short (5 min) recordings in supine position upon awakening in the morning and particularly the logarithm of RMSSD (LnRMSSD) has been proposed as the most useful resting HRV indicator. However, if RMSSD can help the practitioner to identify a global “fatigue” level, it does not allow discriminating different types of fatigue. Recent results using spectral HRV analysis highlighted firstly that HRV profiles assessed in supine and standing positions are independent and complementary; and secondly that using these postural profiles allows the clustering of distinct sub-categories of “fatigue.” Since, cardiovascular control settings are different in standing and lying posture, using the HRV figures of both postures to cluster fatigue state embeds information on the dynamics of control responses. Such, HRV spectral analysis appears more sensitive and enlightening than time-domain HRV indices. The wealthier information provided by this spectral analysis should improve the monitoring of the adaptive training-recovery process in athletes. PMID:26635629

  7. Detailed heart rate variability analysis in athletes.

    Science.gov (United States)

    Kiss, Orsolya; Sydó, Nóra; Vargha, Péter; Vágó, Hajnalka; Czimbalmos, Csilla; Édes, Eszter; Zima, Endre; Apponyi, Györgyi; Merkely, Gergő; Sydó, Tibor; Becker, Dávid; Allison, Thomas G; Merkely, Béla

    2016-08-01

    Heart rate variability (HRV) analysis has been used to evaluate patients with various cardiovascular diseases. While the vast majority of HRV studies have focused on pathological states, our study focuses on the less explored area of HRV analysis across different training intensity and sports. We aimed to measure HRV in healthy elite and masters athletes and compare to healthy, but non-athletic controls. Time-domain HRV analysis was applied in 138 athletes (male 110, age 28.4 ± 8.3) and 100 controls (male 56, age 28.3 ± 6.9) during Holter monitoring (21.3 ± 3.0 h). All studied parameters were higher in elite athletes compared to controls [SDNN (CI) 225.3 (216.2-234.5) vs 158.6 (150.2-167.1) ms; SDNN Index (CI) 99.6 (95.6-103.7) vs 72.4 (68.7-76.2) ms; pNN50 (CI) 24.2 (22.2-26.3) vs 14.4 (12.7-16.3) %; RMSSD (CI) 71.8 (67.6-76.2) vs 50.8 (46.9-54.8) ms; p HRV values than controls, but no significant differences were found between elite athletes and masters athletes. Some parameters were higher in canoeists-kayakers and bicyclists than runners. Lower cut-off values in elite athletes were SDNN: 147.4 ms, SDNN Index: 66.6 ms, pNN50: 9.7 %, RMSSD: 37.9 ms. Autonomic regulation in elite athletes described with HRV is significantly different than in healthy controls. Sports modality and level of performance, but not age- or sex-influenced HRV. Our study provides athletic normal HRV values. Further investigations are needed to determine its role in risk stratification, optimization of training, or identifying overtraining.

  8. Effects of HRV-Guided vs. Predetermined Block Training on Performance, HRV and Serum Hormones.

    Science.gov (United States)

    Nuuttila, Olli-Pekka; Nikander, Aku; Polomoshnov, Dmitry; Laukkanen, Jari Antero; Häkkinen, Keijo

    2017-11-01

    The aim of this study was to compare heart rate variability -guided (HRVG) and predetermined (PD) block periodization of high intensity aerobic training (HIT). Endurance performance, neuromuscular performance, heart rate variability (HRV) and serum hormone concentrations were measured before, in the middle and after the 8-week training period in 24 endurance trained males. Both groups improved significantly maximal treadmill velocity (V max ) (pHRV (RMSSD, LF and TP) increased significantly only in HRVG (pHRV and serum testosterone levels observed in HRVG, individually HRV -guided block training may be more optimal compared to predetermined training. © Georg Thieme Verlag KG Stuttgart · New York.

  9. Toward Hypertension Prediction Based on PPG-Derived HRV Signals: a Feasibility Study.

    Science.gov (United States)

    Lan, Kun-Chan; Raknim, Paweeya; Kao, Wei-Fong; Huang, Jyh-How

    2018-04-21

    Heart rate variability (HRV) is often used to assess the risk of cardiovascular disease, and data on this can be obtained via electrocardiography (ECG). However, collecting heart rate data via photoplethysmography (PPG) is now a lot easier. We investigate the feasibility of using the PPG-based heart rate to estimate HRV and predict diseases. We obtain three months of PPG-based heart rate data from subjects with and without hypertension, and calculate the HRV based on various forms of time and frequency domain analysis. We then apply a data mining technique to this estimated HRV data, to see if it is possible to correctly identify patients with hypertension. We use six HRV parameters to predict hypertension, and find SDNN has the best predictive power. We show that early disease prediction is possible through collecting one's PPG-based heart rate information.

  10. Real-time spectral analysis of HRV signals: an interactive and user-friendly PC system.

    Science.gov (United States)

    Basano, L; Canepa, F; Ottonello, P

    1998-01-01

    We present a real-time system, built around a PC and a low-cost data acquisition board, for the spectral analysis of the heart rate variability signal. The Windows-like operating environment on which it is based makes the computer program very user-friendly even for non-specialized personnel. The Power Spectral Density is computed through the use of a hybrid method, in which a classical FFT analysis follows an autoregressive finite-extension of data; the stationarity of the sequence is continuously checked. The use of this algorithm gives a high degree of robustness of the spectral estimation. Moreover, always in real time, the FFT of every data block is computed and displayed in order to corroborate the results as well as to allow the user to interactively choose a proper AR model order.

  11. Heart rate variability (HRV) and muscular system activity (EMG) in cases of crash threat during simulated driving of a passenger car.

    Science.gov (United States)

    Zużewicz, Krystyna; Roman-Liu, Danuta; Konarska, Maria; Bartuzi, Paweł; Matusiak, Krzysztof; Korczak, Dariusz; Lozia, Zbigniew; Guzek, Marek

    2013-10-01

    The aim of the study was to verify whether simultaneous responses from the muscular and circulatory system occur in the driver's body under simulated conditions of a crash threat. The study was carried out in a passenger car driving simulator. The crash was included in the driving test scenario developed in an urban setting. In the group of 22 young male subjects, two physiological signals - ECG and EMG were continuously recorded. The length of the RR interval in the ECG signal was assessed. A HRV analysis was performed in the time and frequency domains for 1-minute record segments at rest (seated position), during undisturbed driving as well as during and several minutes after the crash. For the left and right side muscles: m. trapezius (TR) and m. flexor digitorum superficialis (FDS), the EMG signal amplitude was determined. The percentage of maximal voluntary contraction (MVC) was compared during driving and during the crash. As for the ECG signal, it was found that in most of the drivers changes occurred in the parameter values reflecting HRV in the time domain. Significant changes were noted in the mean length of RR intervals (mRR). As for the EMG signal, the changes in the amplitude concerned the signal recorded from the FDS muscle. The changes in ECG and EMG were simultaneous in half of the cases. Such parameters as mRR (ECG signal) and FDS-L amplitude (EMG signal) were the responses to accident risk. Under simulated conditions, responses from the circulatory and musculoskeletal systems are not always simultaneous. The results indicate that a more complete driver's response to a crash in road traffic is obtained based on parallel recording of two physiological signals (ECG and EMG).

  12. Exercise effects on HRV in cancer patients.

    Science.gov (United States)

    Niederer, D; Vogt, L; Thiel, C; Schmidt, K; Bernhörster, M; Lungwitz, A; Jäger, E; Banzer, W

    2013-01-01

    The present study evaluated the effects of physical exercise on heart rate variability (HRV) in cancer patients. 3 matched groups of each 15 tumour patients (60.4±8.9 years, 27 male, 18 female) were recruited: Physical exercise group 1 (acute treatment), Physical exercise group 2 (post treatment) and non-intervention group (acute treatment, no exercise). Exercise group patients received counselling for exercise and participated in a Nordic-Walking program. Short-term HRV-recordings, assessments of fatigue and quality of life (QoL) were performed prior to and 16 weeks after the exercise program initiation. MANCOVA revealed group × time differences in total power frequency domain of HRV and QoL (pHRV-parameters and prolonged survival in cancer patients, improvement in autonomic control may be an important goal of exercise. © Georg Thieme Verlag KG Stuttgart · New York.

  13. Relative influence of age, resting heart rate and sedentary life style in short-term analysis of heart rate variability

    Directory of Open Access Journals (Sweden)

    E.R. Migliaro

    2001-04-01

    Full Text Available In order to assess the relative influence of age, resting heart rate (HR and sedentary life style, heart rate variability (HRV was studied in two different groups. The young group (YG consisted of 9 sedentary subjects aged 15 to 20 years (YG-S and of 9 nonsedentary volunteers (YG-NS also aged 15 to 20. The elderly sedentary group (ESG consisted of 16 sedentary subjects aged 39 to 82 years. HRV was assessed using a short-term procedure (5 min. R-R variability was calculated in the time-domain by means of the root mean square successive differences. Frequency-domain HRV was evaluated by power spectrum analysis considering high frequency and low frequency bands. In the YG the effort tolerance was ranked in a bicycle stress test. HR was similar for both groups while ESG showed a reduced HRV compared with YG. Within each group, HRV displayed a negative correlation with HR. Although YG-NS had better effort tolerance than YG-S, their HR and HRV were not significantly different. We conclude that HRV is reduced with increasing HR or age, regardless of life style. The results obtained in our short-term study agree with others of longer duration by showing that age and HR are the main determinants of HRV. Our results do not support the idea that changes in HRV are related to regular physical activity.

  14. Relative influence of age, resting heart rate and sedentary life style in short-term analysis of heart rate variability.

    Science.gov (United States)

    Migliaro, E R; Contreras, P; Bech, S; Etxagibel, A; Castro, M; Ricca, R; Vicente, K

    2001-04-01

    In order to assess the relative influence of age, resting heart rate (HR) and sedentary life style, heart rate variability (HRV) was studied in two different groups. The young group (YG) consisted of 9 sedentary subjects aged 15 to 20 years (YG-S) and of 9 nonsedentary volunteers (YG-NS) also aged 15 to 20. The elderly sedentary group (ESG) consisted of 16 sedentary subjects aged 39 to 82 years. HRV was assessed using a short-term procedure (5 min). R-R variability was calculated in the time-domain by means of the root mean square successive differences. Frequency-domain HRV was evaluated by power spectrum analysis considering high frequency and low frequency bands. In the YG the effort tolerance was ranked in a bicycle stress test. HR was similar for both groups while ESG showed a reduced HRV compared with YG. Within each group, HRV displayed a negative correlation with HR. Although YG-NS had better effort tolerance than YG-S, their HR and HRV were not significantly different. We conclude that HRV is reduced with increasing HR or age, regardless of life style. The results obtained in our short-term study agree with others of longer duration by showing that age and HR are the main determinants of HRV. Our results do not support the idea that changes in HRV are related to regular physical activity.

  15. Facial Video-Based Photoplethysmography to Detect HRV at Rest.

    Science.gov (United States)

    Moreno, J; Ramos-Castro, J; Movellan, J; Parrado, E; Rodas, G; Capdevila, L

    2015-06-01

    Our aim is to demonstrate the usefulness of photoplethysmography (PPG) for analyzing heart rate variability (HRV) using a standard 5-min test at rest with paced breathing, comparing the results with real RR intervals and testing supine and sitting positions. Simultaneous recordings of R-R intervals were conducted with a Polar system and a non-contact PPG, based on facial video recording on 20 individuals. Data analysis and editing were performed with individually designated software for each instrument. Agreement on HRV parameters was assessed with concordance correlations, effect size from ANOVA and Bland and Altman plots. For supine position, differences between video and Polar systems showed a small effect size in most HRV parameters. For sitting position, these differences showed a moderate effect size in most HRV parameters. A new procedure, based on the pixels that contained more heart beat information, is proposed for improving the signal-to-noise ratio in the PPG video signal. Results were acceptable in both positions but better in the supine position. Our approach could be relevant for applications that require monitoring of stress or cardio-respiratory health, such as effort/recuperation states in sports. © Georg Thieme Verlag KG Stuttgart · New York.

  16. smRithm: Graphical user interface for heart rate variability analysis.

    Science.gov (United States)

    Nara, Sanjeev; Kaur, Manvinder; Datta, Saurav

    2015-01-01

    Over the past 25 years, Heart rate variability (HRV) has become a non-invasive research and clinical tool for indirectly carrying out investigation of both cardiac and autonomic system function in both healthy and diseased. It provides valuable information about a wide range of cardiovascular disorders, pulmonary diseases, neurological diseases, etc. Its primary purpose is to access the functioning of the nervous system. The source of information for HRV analysis is the continuous beat to beat measurement of inter-beat intervals. The electrocardiography (ECG or EKG) is considered as the best way to measure inter-beat intervals. This paper proposes an open source Graphical User Interface (GUI): smRithm developed in MATLAB for HRV analysis that will apply effective techniques on the raw ECG signals to process and decompose it in a simpler manner to obtain more useful information out of signals that can be utilized for more powerful and efficient applications in the near future related to HRV.

  17. ARTiiFACT: a tool for heart rate artifact processing and heart rate variability analysis.

    Science.gov (United States)

    Kaufmann, Tobias; Sütterlin, Stefan; Schulz, Stefan M; Vögele, Claus

    2011-12-01

    The importance of appropriate handling of artifacts in interbeat interval (IBI) data must not be underestimated. Even a single artifact may cause unreliable heart rate variability (HRV) results. Thus, a robust artifact detection algorithm and the option for manual intervention by the researcher form key components for confident HRV analysis. Here, we present ARTiiFACT, a software tool for processing electrocardiogram and IBI data. Both automated and manual artifact detection and correction are available in a graphical user interface. In addition, ARTiiFACT includes time- and frequency-based HRV analyses and descriptive statistics, thus offering the basic tools for HRV analysis. Notably, all program steps can be executed separately and allow for data export, thus offering high flexibility and interoperability with a whole range of applications.

  18. Clinical Characteristics and Genetic Variability of Human Rhinovirus in Mexico

    Directory of Open Access Journals (Sweden)

    Hilda Montero

    2012-01-01

    Full Text Available Human rhinovirus (HRV is a leading cause of acute respiratory infection (ARI in young children and infants worldwide and has a high impact on morbidity and mortality in this population. Initially, HRV was classified into two species: HRV-A and HRV-B. Recently, a species called HRV-C and possibly another species, HRV-D, were identified. In Mexico, there is little information about the role of HRV as a cause of ARI, and the presence and importance of species such as HRV-C are not known. The aim of this study was to determine the clinical characteristics and genetic variability of HRV in Mexican children. Genetic characterization was carried out by phylogenetic analysis of the 5′-nontranslated region (5′-NTR of the HRV genome. The results show that the newly identified HRV-C is circulating in Mexican children more frequently than HRV-B but not as frequently as HRV-A, which was the most frequent species. Most of the cases of the three species of HRV were in children under 2 years of age, and all species were associated with very mild and moderate ARI.

  19. Permutation entropy analysis of heart rate variability for the assessment of cardiovascular autonomic neuropathy in type 1 diabetes mellitus.

    Science.gov (United States)

    Carricarte Naranjo, Claudia; Sanchez-Rodriguez, Lazaro M; Brown Martínez, Marta; Estévez Báez, Mario; Machado García, Andrés

    2017-07-01

    Heart rate variability (HRV) analysis is a relevant tool for the diagnosis of cardiovascular autonomic neuropathy (CAN). To our knowledge, no previous investigation on CAN has assessed the complexity of HRV from an ordinal perspective. Therefore, the aim of this work is to explore the potential of permutation entropy (PE) analysis of HRV complexity for the assessment of CAN. For this purpose, we performed a short-term PE analysis of HRV in healthy subjects and type 1 diabetes mellitus patients, including patients with CAN. Standard HRV indicators were also calculated in the control group. A discriminant analysis was used to select the variables combination with best discriminative power between control and CAN patients groups, as well as for classifying cases. We found that for some specific temporal scales, PE indicators were significantly lower in CAN patients than those calculated for controls. In such cases, there were ordinal patterns with high probabilities of occurrence, while others were hardly found. We posit this behavior occurs due to a decrease of HRV complexity in the diseased system. Discriminant functions based on PE measures or probabilities of occurrence of ordinal patterns provided an average of 75% and 96% classification accuracy. Correlations of PE and HRV measures showed to depend only on temporal scale, regardless of pattern length. PE analysis at some specific temporal scales, seem to provide additional information to that obtained with traditional HRV methods. We concluded that PE analysis of HRV is a promising method for the assessment of CAN. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Analysis of degree of nonlinearity and stochastic nature of HRV signal during meditation using delay vector variance method.

    Science.gov (United States)

    Reddy, L Ram Gopal; Kuntamalla, Srinivas

    2011-01-01

    Heart rate variability analysis is fast gaining acceptance as a potential non-invasive means of autonomic nervous system assessment in research as well as clinical domains. In this study, a new nonlinear analysis method is used to detect the degree of nonlinearity and stochastic nature of heart rate variability signals during two forms of meditation (Chi and Kundalini). The data obtained from an online and widely used public database (i.e., MIT/BIH physionet database), is used in this study. The method used is the delay vector variance (DVV) method, which is a unified method for detecting the presence of determinism and nonlinearity in a time series and is based upon the examination of local predictability of a signal. From the results it is clear that there is a significant change in the nonlinearity and stochastic nature of the signal before and during the meditation (p value > 0.01). During Chi meditation there is a increase in stochastic nature and decrease in nonlinear nature of the signal. There is a significant decrease in the degree of nonlinearity and stochastic nature during Kundalini meditation.

  1. Influence of heart rate in nonlinear HRV indices as a sampling rate effect evaluated on supine and standing

    Directory of Open Access Journals (Sweden)

    Juan Bolea

    2016-11-01

    Full Text Available The purpose of this study is to characterize and attenuate the influence of mean heart rate (HR on nonlinear heart rate variability (HRV indices (correlation dimension, sample and approximate entropy as a consequence of being the HR the intrinsic sampling rate of HRV signal. This influence can notably alter nonlinear HRV indices and lead to biased information regarding autonomic nervous system (ANS modulation.First, a simulation study was carried out to characterize the dependence of nonlinear HRV indices on HR assuming similar ANS modulation. Second, two HR-correction approaches were proposed: one based on regression formulas and another one based on interpolating RR time series. Finally, standard and HR-corrected HRV indices were studied in a body position change database.The simulation study showed the HR-dependence of non-linear indices as a sampling rate effect, as well as the ability of the proposed HR-corrections to attenuate mean HR influence. Analysis in a body position changes database shows that correlation dimension was reduced around 21% in median values in standing with respect to supine position (p < 0.05, concomitant with a 28% increase in mean HR (p < 0.05. After HR-correction, correlation dimension decreased around 18% in standing with respect to supine position, being the decrease still significant. Sample and approximate entropy showed similar trends.HR-corrected nonlinear HRV indices could represent an improvement in their applicability as markers of ANS modulation when mean HR changes.

  2. Continuous multi-parameter heart rate variability analysis heralds onset of sepsis in adults.

    Directory of Open Access Journals (Sweden)

    Saif Ahmad

    Full Text Available BACKGROUND: Early diagnosis of sepsis enables timely resuscitation and antibiotics and prevents subsequent morbidity and mortality. Clinical approaches relying on point-in-time analysis of vital signs or lab values are often insensitive, non-specific and late diagnostic markers of sepsis. Exploring otherwise hidden information within intervals-in-time, heart rate variability (HRV has been documented to be both altered in the presence of sepsis, and correlated with its severity. We hypothesized that by continuously tracking individual patient HRV over time in patients as they develop sepsis, we would demonstrate reduced HRV in association with the onset of sepsis. METHODOLOGY/PRINCIPAL FINDINGS: We monitored heart rate continuously in adult bone marrow transplant (BMT patients (n = 21 beginning a day before their BMT and continuing until recovery or withdrawal (12+/-4 days. We characterized HRV continuously over time with a panel of time, frequency, complexity, and scale-invariant domain techniques. We defined baseline HRV as mean variability for the first 24 h of monitoring and studied individual and population average percentage change (from baseline over time in diverse HRV metrics, in comparison with the time of clinical diagnosis and treatment of sepsis (defined as systemic inflammatory response syndrome along with clinically suspected infection requiring treatment. Of the 21 patients enrolled, 4 patients withdrew, leaving 17 patients who completed the study. Fourteen patients developed sepsis requiring antibiotic therapy, whereas 3 did not. On average, for 12 out of 14 infected patients, a significant (25% reduction prior to the clinical diagnosis and treatment of sepsis was observed in standard deviation, root mean square successive difference, sample and multiscale entropy, fast Fourier transform, detrended fluctuation analysis, and wavelet variability metrics. For infected patients (n = 14, wavelet HRV demonstrated a 25% drop from

  3. Characterization of structural proteins of hirame rhabdovirus, HRV

    Science.gov (United States)

    Nishizawa, Toyohiko; Yoshimizu, Mamoru; Winton, James; Ahne, Winfried; Kimura, Takahisa

    1991-01-01

    Structural proteins of hirame rhabdovirus (HRV) were analyzed by SDS-polyacrylarnide gel electrophoresis, western blotting, 2-dimensional gel electrophoresis, and Triton X-100 treatment. Purified HRV virions were composed of: polymerase (L), glycoprotein (G), nucleoprotein (N), and 2 matrix proteins (M1 and M2). Based upon their relative mobilities, the estimated molecular weights of the proteins were: L, 156 KDa; G, 68 KDa; N, 46.4 KDa; M1, 26.4 KDa; and M2, 19.9 KDa. The electrophorehc pattern formed by the structural proteins of HRV was clearly different from that formed by pike fry rhabdovirus, spring viremia of carp virus, eel virus of America, and eel virus European X which belong to the Vesiculovirus genus; however, it resembled the pattern formed by structural proteins of viral hemorrhagic septicemia virus (VHSV) and infectious hematopoietic necrosis virus (IHNV) which are members of the Lyssavirus genus. Among HRV, IHNV, and VHSV, differences were observed in the relative mobilities of the G, N, M1, and M2 proteins. Western blot analysis revealed that the G. N, and M2 proteins of HRV shared antigenic determinants with IHNV and VHSV, but not with any of the 4 fish vesiculoviruses tested. Cross-reactions between the M1 proteins of HRV, IHNV, or VHSV were not detected in this assay. Two-dimensional gel electrophoresis was used to show that HRV differed from IHNV or VHSV in the isoelectric point (PI) of the M1 and M2 proteins. In this system, 2 forms of the M1 protein of HRV and IHNV were observed.These subspecies of M1 had the same relative mobility but different p1 values. Treatment of purified virions with 2% Triton X-100 in Tris buffer containing NaCl removed the G, M1, and M2 proteins of IHNV, but HRV virions were more stable under these conditions.

  4. Heart rate variability analysis in acute poisoning by cholinesterase inhibitors

    OpenAIRE

    JEONG, JINWOO; KIM, YONGIN

    2017-01-01

    Heart rate variability (HRV) has been associated with a variety of clinical situations. However, few studies have examined the association between HRV and acute poisoning. Organophosphate (OP) and carbamate inhibit esterase enzymes, particularly acetylcholinesterase, resulting in an accumulation of acetylcholine and thereby promoting excessive activation of corresponding receptors. Because diagnosis and treatment of OP and carbamate poisoning greatly depend on...

  5. Heart Rate Variability Density Analysis (Dyx) and Prediction of Long-Term Mortality after Acute Myocardial Infarction

    DEFF Research Database (Denmark)

    Jørgensen, Rikke Mørch; Abildstrøm, Steen Z; Levitan, Jacob

    2016-01-01

    AIMS: The density HRV parameter Dyx is a new heart rate variability (HRV) measure based on multipole analysis of the Poincaré plot obtained from RR interval time series, deriving information from both the time and frequency domain. Preliminary results have suggested that the parameter may provide...... new predictive information on mortality in survivors of acute myocardial infarction (MI). This study compares the prognostic significance of Dyx to that of traditional linear and nonlinear measures of HRV. METHODS AND RESULTS: In the Nordic ICD pilot study, patients with an acute MI were screened...... with 2D echocardiography and 24-hour Holter recordings. The study was designed to assess the power of several HRV measures to predict mortality. Dyx was tested in a subset of 206 consecutive Danish patients with analysable Holter recordings. After a median follow-up of 8.5 years 70 patients had died...

  6. Anxiety disorders are associated with reduced heart rate variability: A meta-analysis

    Directory of Open Access Journals (Sweden)

    John eChalmers

    2014-07-01

    Full Text Available Background: Anxiety disorders increase risk of future cardiovascular disease (CVD and mortality, even after controlling for confounds including smoking, lifestyle, and socioeconomic status, and irrespective of a history of medical disorders. While impaired vagal function, indicated by reductions in heart rate variability (HRV, may be one mechanism linking anxiety disorders to CVD, prior studies have reported inconsistent findings highlighting the need for meta-analysis.Method: Studies comparing resting state HRV recordings in patients with an anxiety disorder as a primary diagnosis and healthy controls were considered for meta-analysis. Results: Meta-analyses were based on 36 articles, including 2086 patients with an anxiety disorder and 2294 controls. Overall, anxiety disorders were characterised by lower HRV (high frequency: Hedges’ g = -.29. 95%CI: -.41 to -.17, p < 0.001; time domain: Hedges’ g = -0.45, 95%CI: -0.57 to -0.33, p < .001 than controls. Panic Disorder (n=447, Post-Traumatic Stress Disorder (n=192, Generalized Anxiety Disorder (n=68, and Social anxiety disorder (n=90, but not Obsessive Compulsive Disorder (n=40, displayed reductions in high frequency HRV relative to controls (all ps < .001. Conclusions: Anxiety disorders are associated with reduced HRV, findings associated with a small to moderate effect size. Findings have important implications for future physical health and wellbeing of patients, highlighting a need for comprehensive cardiovascular risk reduction.

  7. Historic range of variability for upland vegetation in the Medicine Bow National Forest, Wyoming

    Science.gov (United States)

    Gregory K. Dillon; Dennis H. Knight; Carolyn B. Meyer

    2005-01-01

    An approach for synthesizing the results of ecological research pertinent to land management is the analysis of the historic range of variability (HRV) for key ecosystem variables that are affected by management activities. This report provides an HRV analysis for the upland vegetation of the Medicine Bow National Forest in southeastern Wyoming. The variables include...

  8. Cardiac arrhythmia detection using combination of heart rate variability analyses and PUCK analysis.

    Science.gov (United States)

    Mahananto, Faizal; Igasaki, Tomohiko; Murayama, Nobuki

    2013-01-01

    This paper presents cardiac arrhythmia detection using the combination of a heart rate variability (HRV) analysis and a "potential of unbalanced complex kinetics" (PUCK) analysis. Detection performance was improved by adding features extracted from the PUCK analysis. Initially, R-R interval data were extracted from the original electrocardiogram (ECG) recordings and were cut into small segments and marked as either normal or arrhythmia. HRV analyses then were conducted using the segmented R-R interval data, including a time-domain analysis, frequency-domain analysis, and nonlinear analysis. In addition to the HRV analysis, PUCK analysis, which has been implemented successfully in a foreign exchange market series to characterize change, was employed. A decision-tree algorithm was applied to all of the obtained features for classification. The proposed method was tested using the MIT-BIH arrhythmia database and had an overall classification accuracy of 91.73%. After combining features obtained from the PUCK analysis, the overall accuracy increased to 92.91%. Therefore, we suggest that the use of a PUCK analysis in conjunction with HRV analysis might improve performance accuracy for the detection of cardiac arrhythmia.

  9. Orthostatic Dysregulation during Postural Change on the Dental Chair and Intraoperative Monitoring by Heart Rate Variability Analysis

    Directory of Open Access Journals (Sweden)

    Yukihiro Momota

    2014-01-01

    Full Text Available This is the first case report of orthostatic dysregulation (OD manifested during postural change on the dental chair and intraoperatively monitored by heart rate variability (HRV analysis. OD-associated autonomic dysfunction is induced by postural changes and easily leads to disturbance in circulatory dynamics; however, most dental practices have not yet realized the importance of managing OD. We measured autonomic activity in a patient with OD during dental therapy and assessed the clinical significance of HRV analysis for OD. The patient was a 17-year-old Japanese female. She was diagnosed with impacted wisdom teeth and had no previous history of a distinct systemic disease. A surgical procedure to extract the teeth was safely performed under both local anesthesia and sedation with nitrous oxide and midazolam. After the surgery, her postural change to sitting induced orthostatic hypotension. HRV variables showed parasympathetic dominance due to the upright position. Subsequently, her posture was returned to supine, and atropine sulfate administration for the immediate treatment of OD returned her blood pressure to normal levels. HRV variables showed relative sympathetic dominance due to an atropine-derived parasympathetic blockade. HRV analysis revealed OD-associated autonomic dysfunction and should become a standard tool for safe and secure dental management of OD.

  10. Heart rate variability in newborns.

    Science.gov (United States)

    Javorka, K; Lehotska, Z; Kozar, M; Uhrikova, Z; Kolarovszki, B; Javorka, M; Zibolen, M

    2017-09-22

    Heart rate (HR) and heart rate variability (HRV) in newborns is influenced by genetic determinants, gestational and postnatal age, and other variables. Premature infants have a reduced HRV. In neonatal HRV evaluated by spectral analysis, a dominant activity can be found in low frequency (LF) band (combined parasympathetic and sympathetic component). During the first postnatal days the activity in the high frequency (HF) band (parasympathetic component) rises, together with an increase in LF band and total HRV. Hypotrophy in newborn can cause less mature autonomic cardiac control with a higher contribution of sympathetic activity to HRV as demonstrated by sequence plot analysis. During quiet sleep (QS) in newborns HF oscillations increase - a phenomenon less expressed or missing in premature infants. In active sleep (AS), HRV is enhanced in contrast to reduced activity in HF band due to the rise of spectral activity in LF band. Comparison of the HR and HRV in newborns born by physiological vaginal delivery, without (VD) and with epidural anesthesia (EDA) and via sectio cesarea (SC) showed no significant differences in HR and in HRV time domain parameters. Analysis in the frequency domain revealed, that the lowest sympathetic activity in chronotropic cardiac chronotropic regulation is in the VD group. Different neonatal pathological states can be associated with a reduction of HRV and an improvement in the health conditions is followed by changes in HRV what can be use as a possible prognostic marker. Examination of heart rate variability in neonatology can provide information on the maturity of the cardiac chronotropic regulation in early postnatal life, on postnatal adaptation and in pathological conditions about the potential dysregulation of cardiac function in newborns, especially in preterm infants.

  11. Correlating multidimensional fetal heart rate variability analysis with acid-base balance at birth

    International Nuclear Information System (INIS)

    Frasch, Martin G; Durosier, Lucien D; Xu, Yawen; Wang, Xiaogang; Gao, Xin; Stampalija, Tamara; Herry, Christophe; Seely, Andrew JE; Casati, Daniela; Ferrazzi, Enrico; Alfirevic, Zarko

    2014-01-01

    Fetal monitoring during labour currently fails to accurately detect acidemia. We developed a method to assess the multidimensional properties of fetal heart rate variability (fHRV) from trans-abdominal fetal electrocardiogram (fECG) during labour. We aimed to assess this novel bioinformatics approach for correlation between fHRV and neonatal pH or base excess (BE) at birth. We enrolled a prospective pilot cohort of uncomplicated singleton pregnancies at 38–42 weeks’ gestation in Milan, Italy, and Liverpool, UK. Fetal monitoring was performed by standard cardiotocography. Simultaneously, with fECG (high sampling frequency) was recorded. To ensure clinician blinding, fECG information was not displayed. Data from the last 60 min preceding onset of second-stage labour were analyzed using clinically validated continuous individualized multiorgan variability analysis (CIMVA) software in 5 min overlapping windows. CIMVA allows simultaneous calculation of 101 fHRV measures across five fHRV signal analysis domains. We validated our mathematical prediction model internally with 80:20 cross-validation split, comparing results to cord pH and BE at birth. The cohort consisted of 60 women with neonatal pH values at birth ranging from 7.44 to 6.99 and BE from −0.3 to −18.7 mmol L −1 . Our model predicted pH from 30 fHRV measures (R 2 = 0.90, P < 0.001) and BE from 21 fHRV measures (R 2 = 0.77, P < 0.001). Novel bioinformatics approach (CIMVA) applied to fHRV derived from trans-abdominal fECG during labor correlated well with acid-base balance at birth. Further refinement and validation in larger cohorts are needed. These new measurements of fHRV might offer a new opportunity to predict fetal acid-base balance at birth. (fast track communication)

  12. Hypnosis in the Treatment of Major Depression: An Analysis of Heart Rate Variability.

    Science.gov (United States)

    Chen, Xiuwen; Yang, Rongqian; Ge, Lulu; Luo, Jie; Lv, Ruixue

    2017-01-01

    Hypnosis is an adjuvant treatment of major depression (MD). Heart rate variability (HRV) can assess the autonomic nervous system, which is associated with MD, and HRV is decreased in MD patients. There is a lack of research on HRV changes before, during, and after the use of hypnosis in MD patients. A total of 21 MD patients participated in this study, and 5-minute electrocardiograms were recorded before, during, and after hypnosis. Compared with the prehypnotic condition, HRV parameters significantly (p hypnosis treatment should bring some functional improvement to the autonomic nervous system. HRV is potentially a useful tool that quantifies the physiological impact of hypnosis treatment in MD patients.

  13. Continuous measurement of heart rate variability following carbon ...

    African Journals Online (AJOL)

    Background: Previous studies of autonomic nervous system activity through analysis of heart rate variability (HRV) have demonstrated increased sympathetic activity during positive-pressure pneumoperitoneum. We employed an online, continuous method for rapid HRV analysis (MemCalc™, Tarawa, Suwa Trust, Tokyo, ...

  14. Continuous measurement of heart rate variability following carbon ...

    African Journals Online (AJOL)

    2010-07-16

    Jul 16, 2010 ... Power spectral analysis of the electrocardiographic R-R interval [heart rate variability: (HRV)] is a well known, non- invasive method for assessing autonomic nervous activity.1. Studies using HRV analysis during positive-pressure pneumoperitoneum (PPP) have demonstrated increased sympathetic ...

  15. Detection of Driver Drowsiness Using Wavelet Analysis of Heart Rate Variability and a Support Vector Machine Classifier

    Directory of Open Access Journals (Sweden)

    Gang Li

    2013-12-01

    Full Text Available Driving while fatigued is just as dangerous as drunk driving and may result in car accidents. Heart rate variability (HRV analysis has been studied recently for the detection of driver drowsiness. However, the detection reliability has been lower than anticipated, because the HRV signals of drivers were always regarded as stationary signals. The wavelet transform method is a method for analyzing non-stationary signals. The aim of this study is to classify alert and drowsy driving events using the wavelet transform of HRV signals over short time periods and to compare the classification performance of this method with the conventional method that uses fast Fourier transform (FFT-based features. Based on the standard shortest duration for FFT-based short-term HRV evaluation, the wavelet decomposition is performed on 2-min HRV samples, as well as 1-min and 3-min samples for reference purposes. A receiver operation curve (ROC analysis and a support vector machine (SVM classifier are used for feature selection and classification, respectively. The ROC analysis results show that the wavelet-based method performs better than the FFT-based method regardless of the duration of the HRV sample that is used. Finally, based on the real-time requirements for driver drowsiness detection, the SVM classifier is trained using eighty FFT and wavelet-based features that are extracted from 1-min HRV signals from four subjects. The averaged leave-one-out (LOO classification performance using wavelet-based feature is 95% accuracy, 95% sensitivity, and 95% specificity. This is better than the FFT-based results that have 68.8% accuracy, 62.5% sensitivity, and 75% specificity. In addition, the proposed hardware platform is inexpensive and easy-to-use.

  16. Minimal Window Duration for Accurate HRV Recording in Athletes

    Science.gov (United States)

    Bourdillon, Nicolas; Schmitt, Laurent; Yazdani, Sasan; Vesin, Jean-Marc; Millet, Grégoire P.

    2017-01-01

    Heart rate variability (HRV) is non-invasive and commonly used for monitoring responses to training loads, fitness, or overreaching in athletes. Yet, the recording duration for a series of RR-intervals varies from 1 to 15 min in the literature. The aim of the present work was to assess the minimum record duration to obtain reliable HRV results. RR-intervals from 159 orthostatic tests (7 min supine, SU, followed by 6 min standing, ST) were analyzed. Reference windows were 4 min in SU (min 3–7) and 4 min in ST (min 9–13). Those windows were subsequently divided and the analyses were repeated on eight different fractioned windows: the first min (0–1), the second min (1–2), the third min (2–3), the fourth min (3–4), the first 2 min (0–2), the last 2 min (2–4), the first 3 min (0–3), and the last 3 min (1–4). Correlation and Bland & Altman statistical analyses were systematically performed. The analysis window could be shortened to 0–2 instead of 0–4 for RMSSD only, whereas the 4-min window was necessary for LF and total power. Since there is a need for 1 min of baseline to obtain a steady signal prior the analysis window, we conclude that studies relying on RMSSD may shorten the windows to 3 min (= 1+2) in SU or seated position only and to 6 min (= 1+2 min SU plus 1+2 min ST) if there is an orthostatic test. Studies relying on time- and frequency-domain parameters need a minimum of 5 min (= 1+4) min SU or seated position only but require 10 min (= 1+4 min SU plus 1+4 min ST) for the orthostatic test. PMID:28848382

  17. Minimal Window Duration for Accurate HRV Recording in Athletes

    Directory of Open Access Journals (Sweden)

    Nicolas Bourdillon

    2017-08-01

    Full Text Available Heart rate variability (HRV is non-invasive and commonly used for monitoring responses to training loads, fitness, or overreaching in athletes. Yet, the recording duration for a series of RR-intervals varies from 1 to 15 min in the literature. The aim of the present work was to assess the minimum record duration to obtain reliable HRV results. RR-intervals from 159 orthostatic tests (7 min supine, SU, followed by 6 min standing, ST were analyzed. Reference windows were 4 min in SU (min 3–7 and 4 min in ST (min 9–13. Those windows were subsequently divided and the analyses were repeated on eight different fractioned windows: the first min (0–1, the second min (1–2, the third min (2–3, the fourth min (3–4, the first 2 min (0–2, the last 2 min (2–4, the first 3 min (0–3, and the last 3 min (1–4. Correlation and Bland & Altman statistical analyses were systematically performed. The analysis window could be shortened to 0–2 instead of 0–4 for RMSSD only, whereas the 4-min window was necessary for LF and total power. Since there is a need for 1 min of baseline to obtain a steady signal prior the analysis window, we conclude that studies relying on RMSSD may shorten the windows to 3 min (= 1+2 in SU or seated position only and to 6 min (= 1+2 min SU plus 1+2 min ST if there is an orthostatic test. Studies relying on time- and frequency-domain parameters need a minimum of 5 min (= 1+4 min SU or seated position only but require 10 min (= 1+4 min SU plus 1+4 min ST for the orthostatic test.

  18. The effect of heart rate variability biofeedback training on stress and anxiety: a meta-analysis.

    Science.gov (United States)

    Goessl, V C; Curtiss, J E; Hofmann, S G

    2017-11-01

    Some evidence suggests that heart rate variability (HRV) biofeedback might be an effective way to treat anxiety and stress symptoms. To examine the effect of HRV biofeedback on symptoms of anxiety and stress, we conducted a meta-analysis of studies extracted from PubMed, PsycINFO and the Cochrane Library. The search identified 24 studies totaling 484 participants who received HRV biofeedback training for stress and anxiety. We conducted a random-effects meta-analysis. The pre-post within-group effect size (Hedges' g) was 0.81. The between-groups analysis comparing biofeedback to a control condition yielded Hedges' g = 0.83. Moderator analyses revealed that treatment efficacy was not moderated by study year, risk of study bias, percentage of females, number of sessions, or presence of an anxiety disorder. HRV biofeedback training is associated with a large reduction in self-reported stress and anxiety. Although more well-controlled studies are needed, this intervention offers a promising approach for treating stress and anxiety with wearable devices.

  19. Hyperthyroidism is characterized by both increased sympathetic and decreased vagal modulation of heart rate: evidence from spectral analysis of heart rate variability.

    Science.gov (United States)

    Chen, Jin-Long; Chiu, Hung-Wen; Tseng, Yin-Jiun; Chu, Woei-Chyn

    2006-06-01

    The clinical manifestations of hyperthyroidism resemble those of the hyperadrenergic state. This study was designed to evaluate the impact of hyperthyroidism on the autonomic nervous system (ANS) and to investigate the relationship between serum thyroid hormone concentrations and parameters of spectral heart rate variability (HRV) analysis in hyperthyroidism. Thirty-two hyperthyroid Graves' disease patients (mean age 31 years) and 32 sex-, age-, and body mass index (BMI)-matched normal control subjects were recruited to receive one-channel electrocardiogram (ECG) recording. The cardiac autonomic nervous function was evaluated by the spectral analysis of HRV, which indicates the autonomic modulation of the sinus node. The correlation coefficients between serum thyroid hormone concentrations and parameters of the spectral HRV analysis were also computed. The hyperthyroid patients revealed significant differences (P hyperthyroidism in 28 patients, all of the above parameters were restored to levels comparable to those of the controls. In addition, serum thyroid hormone concentrations showed significant correlations with spectral HRV parameters. Hyperthyroidism is in a sympathovagal imbalanced state, characterized by both increased sympathetic and decreased vagal modulation of the heart rate. These autonomic dysfunctions can be detected simultaneously by spectral analysis of HRV, and the spectral HRV parameters could reflect the disease severity in hyperthyroid patients.

  20. Heart rate variability analysis in postural orthostatic tachycardia syndrome: a case report

    Directory of Open Access Journals (Sweden)

    Raffaele Calabrò

    2006-09-01

    Full Text Available The authors present a case of 36 year old male patient with idiopathic postural orthostatic tachycardia syndrome (POTS diagnosed during head-up tilt testing. Power spectral analysis of heart rate variability (HRV during the tilt test revealed that the ratio of low and high frequency powers (LF/HF increased with the onset of orthostatic intolerance. This analysis confirmed in our patient a strong activation in sympathetic tone.

  1. Heart rate variability analysis in sheep affected by transmissible spongiform encephalopathies

    Directory of Open Access Journals (Sweden)

    Konold Timm

    2011-12-01

    Full Text Available Abstract Background The function of the autonomic nervous system can be assessed by determining heart rate variability (HRV, which is impaired in some brainstem diseases in humans. Transmissible spongiform encephalopathies (TSEs in sheep are diseases characterised by accumulation of disease-associated prion protein in the brainstem, including nuclei of the parasympathetic nervous system. This study was undertaken to assess whether analysis of HRV can be used as an aid in the diagnosis of TSEs in clinically affected, naturally or experimentally infected sheep. Findings When HRV indices were compared between 41 clinical TSE cases (18 sheep infected with scrapie and 23 sheep infected with bovine spongiform encephalopathy, 11 control sheep and six sheep reported as scrapie suspects or dosed with BSE brain homogenate, which were not confirmed as TSE cases by postmortem tests, no significant differences were found between the groups. Median heart rate was significantly different but only when sheep were grouped by gender: it was higher in female TSE cases than in control sheep and higher in female than castrated male ovine classical BSE cases. Conclusions HRV analysis was not useful as a diagnostic aid for TSEs of sheep.

  2. Increasing sensitivity in the measurement of heart rate variability: the method of non-stationary RR time-frequency analysis.

    Science.gov (United States)

    Melkonian, D; Korner, A; Meares, R; Bahramali, H

    2012-10-01

    A novel method of the time-frequency analysis of non-stationary heart rate variability (HRV) is developed which introduces the fragmentary spectrum as a measure that brings together the frequency content, timing and duration of HRV segments. The fragmentary spectrum is calculated by the similar basis function algorithm. This numerical tool of the time to frequency and frequency to time Fourier transformations accepts both uniform and non-uniform sampling intervals, and is applicable to signal segments of arbitrary length. Once the fragmentary spectrum is calculated, the inverse transform recovers the original signal and reveals accuracy of spectral estimates. Numerical experiments show that discontinuities at the boundaries of the succession of inter-beat intervals can cause unacceptable distortions of the spectral estimates. We have developed a measure that we call the "RR deltagram" as a form of the HRV data that minimises spectral errors. The analysis of the experimental HRV data from real-life and controlled breathing conditions suggests transient oscillatory components as functionally meaningful elements of highly complex and irregular patterns of HRV. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  3. Heart Rate Variability and Cardiac Vagal Tone in Psychophysiological Research – Recommendations for Experiment Planning, Data Analysis, and Data Reporting

    Science.gov (United States)

    Laborde, Sylvain; Mosley, Emma; Thayer, Julian F.

    2017-01-01

    Psychophysiological research integrating heart rate variability (HRV) has increased during the last two decades, particularly given the fact that HRV is able to index cardiac vagal tone. Cardiac vagal tone, which represents the contribution of the parasympathetic nervous system to cardiac regulation, is acknowledged to be linked with many phenomena relevant for psychophysiological research, including self-regulation at the cognitive, emotional, social, and health levels. The ease of HRV collection and measurement coupled with the fact it is relatively affordable, non-invasive and pain free makes it widely accessible to many researchers. This ease of access should not obscure the difficulty of interpretation of HRV findings that can be easily misconstrued, however, this can be controlled to some extent through correct methodological processes. Standards of measurement were developed two decades ago by a Task Force within HRV research, and recent reviews updated several aspects of the Task Force paper. However, many methodological aspects related to HRV in psychophysiological research have to be considered if one aims to be able to draw sound conclusions, which makes it difficult to interpret findings and to compare results across laboratories. Those methodological issues have mainly been discussed in separate outlets, making difficult to get a grasp on them, and thus this paper aims to address this issue. It will help to provide psychophysiological researchers with recommendations and practical advice concerning experimental designs, data analysis, and data reporting. This will ensure that researchers starting a project with HRV and cardiac vagal tone are well informed regarding methodological considerations in order for their findings to contribute to knowledge advancement in their field. PMID:28265249

  4. Reproducibility for Heart Rate Variability Analysis during 6-Min Walk Test in Patients with Heart Failure and Agreement between Devices.

    Science.gov (United States)

    Braga, Lays Magalhães; Prado, Gustavo Faibischew; Umeda, Iracema Ioco Kikuchi; Kawauchi, Tatiana Satie; Taboada, Adriana Marques Fróes; Azevedo, Raymundo Soares; Pereira Filho, Horacio Gomes; Grupi, César José; Souza, Hayala Cristina Cavenague; Moreira, Dalmo Antônio Ribeiro; Nakagawa, Naomi Kondo

    2016-01-01

    Heart rate variability (HRV) analysis is a useful method to assess abnormal functioning in the autonomic nervous system and to predict cardiac events in patients with heart failure (HF). HRV measurements with heart rate monitors have been validated with an electrocardiograph in healthy subjects but not in patients with HF. We explored the reproducibility of HRV in two consecutive six-minute walk tests (6MW), 60-minute apart, using a heart rate monitor (PolarS810i) and a portable electrocardiograph (called Holter) in 50 HF patients (mean age 59 years, NYHA II, left ventricular ejection fraction ~35%). The reproducibility for each device was analysed using a paired t-test or the Wilcoxon signed-rank test. Additionally, we assessed the agreement between the two devices based on the HRV indices at rest, during the 6MW and during recovery using concordance correlation coefficients (CCC), 95% confidence intervals and Bland-Altman plots. The test-retest for the HRV analyses was reproducible using Holter and PolarS810i at rest but not during recovery. In the second 6MW, patients showed significant increases in rMSSD and walking distance. The PolarS810i measurements had remarkably high concordance correlation [0.86HRV at rest in two consecutive 6MW using Holter and PolarS810i. Additionally, PolarS810i produced good agreements in short-term HRV indices based on Holter simultaneous recordings at rest, during the 6MW and recovery in HF patients.

  5. Heart rate variability | Lutfi | Sudan Journal of Medical Sciences

    African Journals Online (AJOL)

    An important outcome of such analysis is heart rate variability (HRV), which is widely accepted to have prognostic significance in patients with cardiovascular diseases especially after acute myocardial infarction. This is because HRV represents one of the most helpful markers of autonomic balance and hence can predict ...

  6. Geometric Accuracy Investigations of SEVIRI High Resolution Visible (HRV Level 1.5 Imagery

    Directory of Open Access Journals (Sweden)

    Sultan Kocaman Aksakal

    2013-05-01

    Full Text Available GCOS (Global Climate Observing System is a long-term program for monitoring the climate, detecting the changes, and assessing their impacts. Remote sensing techniques are being increasingly used for climate-related measurements. Imagery of the SEVIRI instrument on board of the European geostationary satellites Meteosat-8 and Meteosat-9 are often used for the estimation of essential climate variables. In a joint project between the Swiss GCOS Office and ETH Zurich, geometric accuracy and temporal stability of 1-km resolution HRV channel imagery of SEVIRI have been evaluated over Switzerland. A set of tools and algorithms has been developed for the investigations. Statistical analysis and blunder detection have been integrated in the process for robust evaluation. The relative accuracy is evaluated by tracking large numbers of feature points in consecutive HRV images taken at 15-minute intervals. For the absolute accuracy evaluation, lakes in Switzerland and surroundings are used as reference. 20 lakes digitized from Landsat orthophotos are transformed into HRV images and matched via 2D translation terms at sub-pixel level. The algorithms are tested using HRV images taken on 24 days in 2008 (2 days per month. The results show that 2D shifts that are up to 8 pixels are present both in relative and absolute terms.

  7. Analysis of the respiratory component of heart rate variability in the Cururu toad Rhinella schneideri.

    Science.gov (United States)

    Zena, Lucas A; Leite, Cléo A C; Longhini, Leonardo S; Dias, Daniel P M; da Silva, Glauber S F; Hartzler, Lynn K; Gargaglioni, Luciane H; Bícego, Kênia C

    2017-11-23

    Beat-to-beat variation in heart rate (f H ) has been used as a tool for elucidating the balance between sympathetic and parasympathetic modulation of the heart. A portion of the temporal changes in f H is evidenced by a respiratory influence (cardiorespiratory interaction) on heart rate variability (HRV) with heartbeats increasing and decreasing within a respiratory cycle. Nevertheless, little is known about respiratory effects on HRV in lower vertebrates. By using frequency domain analysis, we provide the first evidence of a ventilatory component in HRV similar to mammalian respiratory sinus arrhythmia in an amphibian, the toad Rhinella schneideri. Increases in the heartbeats arose synchronously with each lung inflation cycle, an intermittent breathing pattern comprised of a series of successive lung inflations. A well-marked peak in the HRV signal matching lung inflation cycle was verified in toads whenever lung inflation cycles exhibit a regular rhythm. The cardiac beat-to-beat variation evoked at the moment of lung inflation accounts for both vagal and sympathetic influences. This cardiorespiratory interaction may arise from interactions between central and peripheral feedback mechanisms governing cardiorespiratory control and may underlie important cardiorespiratory adjustments for gas exchange improvement especially under extreme conditions like low oxygen availability.

  8. DISORDERS OF THE AUTONOMIC NERVOUS SYSTEM IN THE CARDIOLOGY PRACTICE: FOCUS ON THE ANALYSIS OF HEART RATE VARIABILITY

    Directory of Open Access Journals (Sweden)

    E. B. Akhmedova

    2015-09-01

    Full Text Available Heart rate variability (HRV in patients with ischemic heart disease, a life-threatening heart rhythm disorders, as well as diabetes mellitus (DM is considered. A significant association between the autonomic regulation of the cardiovascular system and death from cardiovascular causes is identified. The reactions of the autonomic nervous system (ANS can serve as a precipitating factor of arrhythmias in patients with heart disorders. Analysis of HRV at rest is the main and informative method for determination of the ANS disorders. HRV decreases greatly in patients with acute myocardial infarction, cardiac arrhythmia, and DM, predicting a high risk of death. The leading cause of death in diabetic patients is cardiac autonomic neuropathy, with the development of "silent" ischemia and painless myocardial infarction. Autonomic regulation of the heart rate should be assessed for early diagnosis and prevention of complications in the form of sudden death.

  9. A pilot study on quantification of training load: The use of HRV in training practice.

    Science.gov (United States)

    Saboul, Damien; Balducci, Pascal; Millet, Grégoire; Pialoux, Vincent; Hautier, Christophe

    2016-01-01

    Recent laboratory studies have suggested that heart rate variability (HRV) may be an appropriate criterion for training load (TL) quantification. The aim of this study was to validate a novel HRV index that may be used to assess TL in field conditions. Eleven well-trained long-distance male runners performed four exercises of different duration and intensity. TL was evaluated using Foster and Banister methods. In addition, HRV measurements were performed 5 minutes before exercise and 5 and 30 minutes after exercise. We calculated HRV index (TLHRV) based on the ratio between HRV decrease during exercise and HRV increase during recovery. HRV decrease during exercise was strongly correlated with exercise intensity (R = -0.70; p HRV changes during exercise and recovery phase are affected by both intensity and physiological impact of the exercise. Since the TLHRV formula takes into account the disturbance and the return to homeostatic balance induced by exercise, this new method provides an objective and rational TL index. However, some simplification of the protocol measurement could be envisaged for field use.

  10. Heart rate variability analysis in healthy subjects, patients suffering from congestive heart failure and heart transplanted patients

    Directory of Open Access Journals (Sweden)

    Argentina Leite

    2013-12-01

    Full Text Available This study aimed to find parameters to characterize heart rate variability (HRV and discriminate healthy subjects and patients with heart diseases. The parameters used for discrimination characterize the different components of HRV memory (short and long and are extracted from HRV recordings using parametric as well as non parametric methods. Thus, the parameters are: spectral components at low frequencies (LH and high frequencies (HF which are associated with the short memory of HRV and the long memory parameter (d obtained from autoregressive fractionally integrated moving average (ARFIMA models. In the non parametric context, short memory (α1 and long memory (α2 parameters are obtained from detrended fluctuation analysis (DFA. The sample used in this study contains 24-hour Holter HRV recordings of 30 subjects: 10 healthy individuals, 10 patients suffering from congestive heart failure and 10 heart transplanted patients from the Noltisalis database. It was found that short memory parameters present higher values for the healthy individuals whereas long memory parameters present higher values for the diseased individuals. Moreover, there is evidence that ARFIMA modeling allows the discrimination between the 3 groups under study, being advantageous over DFA.

  11. The influence of physical activity during pregnancy on maternal, fetal or infant heart rate variability: a systematic review.

    Science.gov (United States)

    Dietz, Pavel; Watson, Estelle D; Sattler, Matteo C; Ruf, Wolfgang; Titze, Sylvia; van Poppel, Mireille

    2016-10-26

    Physical activity (PA) during pregnancy has been shown to be associated with several positive effects for mother, fetus, and offspring. Heart rate variability (HRV) is a noninvasive and surrogate marker to determine fetal overall health and the development of fetal autonomic nervous system. In addition, it has been shown to be significantly influenced by maternal behavior. However, the influence of maternal PA on HRV has not yet been systematically reviewed. Therefore, the aim of this systematic review was to assess the influence of regular maternal PA on maternal, fetal or infant HRV. A systematic literature search following a priori formulated criteria of studies that examined the influence of regular maternal PA (assessed for a minimum period of 6 weeks) on maternal, fetal or infant HRV was performed in the databases Pubmed and SPORTDiscus. Quality of each study was assessed using the standardized Quality Assessment Tool for Quantitative Studies (QATQS). Nine articles were included into the present systematic review: two intervention studies, one prospective longitudinal study, and six post-hoc analysis of subsets of the longitudinal study. Of these articles four referred to maternal HRV, five to fetal HRV, and one to infant HRV. The overall global rating for the standardized quality assessment of the articles was moderate to weak. The articles regarding the influence of maternal PA on maternal HRV indicated contrary results. Five of five articles regarding the influence of maternal PA on fetal HRV showed increases of fetal HRV on most parameters depending on maternal PA. The article referring to infant HRV (measured one month postnatal) showed an increased HRV. Based on the current evidence available, our overall conclusion is that the hypothesis that maternal PA influences maternal HRV cannot be supported, but there is a trend that maternal PA might increase fetal and infant HRV (clinical conclusion). Therefore, we recommend that further, high quality studies

  12. Heart rate variability density analysis (Dyx) for identification of appropriate implantable cardioverter defibrillator recipients among elderly patients with acute myocardial infarction and left ventricular systolic dysfunction

    DEFF Research Database (Denmark)

    Jørgensen, Rikke Mørch; Levitan, Jacob; Halevi, Zohar

    2015-01-01

    AIMS: Dyx is a new heart rate variability (HRV) density analysis specifically designed to identify patients at high risk for malignant ventricular arrhythmias. The aim of this study was to test if Dyx can improve risk stratification for malignant ventricular tachyarrhythmias and to test if the pr......AIMS: Dyx is a new heart rate variability (HRV) density analysis specifically designed to identify patients at high risk for malignant ventricular arrhythmias. The aim of this study was to test if Dyx can improve risk stratification for malignant ventricular tachyarrhythmias and to test...

  13. Heart Rate Variability Analysis in an Experimental Model of Hemorrhagic Shock and Resuscitation in Pigs.

    Directory of Open Access Journals (Sweden)

    Edgard Salomão

    Full Text Available The analysis of heart rate variability (HRV has been shown as a promising non-invasive technique for assessing the cardiac autonomic modulation in trauma. The aim of this study was to evaluate HRV during hemorrhagic shock and fluid resuscitation, comparing to traditional hemodynamic and metabolic parameters.Twenty anesthetized and mechanically ventilated pigs were submitted to hemorrhagic shock (60% of estimated blood volume and evaluated for 60 minutes without fluid replacement. Surviving animals were treated with Ringer solution and evaluated for an additional period of 180 minutes. HRV metrics (time and frequency domain as well as hemodynamic and metabolic parameters were evaluated in survivors and non-survivors animals.Seven of the 20 animals died during hemorrhage and initial fluid resuscitation. All animals presented an increase in time-domain HRV measures during haemorrhage and fluid resuscitation restored baseline values. Although not significantly, normalized low-frequency and LF/HF ratio decreased during early stages of haemorrhage, recovering baseline values later during hemorrhagic shock, and increased after fluid resuscitation. Non-surviving animals presented significantly lower mean arterial pressure (43±7 vs 57±9 mmHg, P<0.05 and cardiac index (1.7±0.2 vs 2.6±0.5 L/min/m2, P<0.05, and higher levels of plasma lactate (7.2±2.4 vs 3.7±1.4 mmol/L, P<0.05, base excess (-6.8±3.3 vs -2.3±2.8 mmol/L, P<0.05 and potassium (5.3±0.6 vs 4.2±0.3 mmol/L, P<0.05 at 30 minutes after hemorrhagic shock compared with surviving animals.The HRV increased early during hemorrhage but none of the evaluated HRV metrics was able to discriminate survivors from non-survivors during hemorrhagic shock. Moreover, metabolic and hemodynamic variables were more reliable to reflect hemorrhagic shock severity than HRV metrics.

  14. Heart Rate Variability Analysis in Patients with Allergic Rhinitis

    Directory of Open Access Journals (Sweden)

    Ming-Ying Lan

    2013-01-01

    Full Text Available Background. Very few studies investigate the role of the autonomic nervous system in allergic rhinitis. In this study, we evaluated the autonomic nervous system in allergic rhinitis patients using heart rate variability (HRV analysis. Methods. Eleven patients with allergic rhinitis and 13 healthy controls, aged between 19 and 40 years old, were enrolled in the study. Diagnosis of allergic rhinitis was based on clinical history, symptoms, and positive Phadiatop test. Electrocardiographic recordings on the sitting and supine positions were obtained for HRV analysis. Results. In the supine position, there were no significant statistical differences in very-low-frequency power (VLF, ≤0.04 Hz, low-frequency power (LF, 0.04–0.15 Hz, high-frequency power (HF, 0.15–0.40 Hz, and the ratio of LF to HF (LF/HF between the patient and control groups. The mean RR intervals significantly increased, while LF% and LF/HF significantly decreased in the patient group in the sitting position. Moreover, mean RR intervals, LF, and LF/HF, which were significantly different between the two positions in the control group, did not show a significant change with the posture change in the patient group. Conclusion. These suggest that patients with allergic rhinitis may have poor sympathetic modulation in the sitting position. Autonomic dysfunction may therefore play a role in the pathophysiology of allergic rhinitis.

  15. General anesthesia suppresses normal heart rate variability in humans

    Science.gov (United States)

    Matchett, Gerald; Wood, Philip

    2014-06-01

    The human heart normally exhibits robust beat-to-beat heart rate variability (HRV). The loss of this variability is associated with pathology, including disease states such as congestive heart failure (CHF). The effect of general anesthesia on intrinsic HRV is unknown. In this prospective, observational study we enrolled 100 human subjects having elective major surgical procedures under general anesthesia. We recorded continuous heart rate data via continuous electrocardiogram before, during, and after anesthesia, and we assessed HRV of the R-R intervals. We assessed HRV using several common metrics including Detrended Fluctuation Analysis (DFA), Multifractal Analysis, and Multiscale Entropy Analysis. Each of these analyses was done in each of the four clinical phases for each study subject over the course of 24 h: Before anesthesia, during anesthesia, early recovery, and late recovery. On average, we observed a loss of variability on the aforementioned metrics that appeared to correspond to the state of general anesthesia. Following the conclusion of anesthesia, most study subjects appeared to regain their normal HRV, although this did not occur immediately. The resumption of normal HRV was especially delayed on DFA. Qualitatively, the reduction in HRV under anesthesia appears similar to the reduction in HRV observed in CHF. These observations will need to be validated in future studies, and the broader clinical implications of these observations, if any, are unknown.

  16. Linear and Nonlinear Dynamics of Heart Rate Variability are Correlated with Purpose in Life and Degree of Optimism in Anxiety Disorder Patients.

    Science.gov (United States)

    Oh, Jihoon; Chae, Jeong-Ho

    2018-04-01

    Although heart rate variability (HRV) may be a crucial marker of mental health, how it is related to positive psychological factors (i.e. attitude to life and positive thinking) is largely unknown. Here we investigated the correlation of HRV linear and nonlinear dynamics with psychological scales that measured degree of optimism and happiness in patients with anxiety disorders. Results showed that low- to high-frequency HRV ratio (LF/HF) was increased and the HRV HF parameter was decreased in subjects who were more optimistic and who felt happier in daily living. Nonlinear analysis also showed that HRV dispersion and regulation were significantly correlated with the subjects' optimism and purpose in life. Our findings showed that HRV properties might be related to degree of optimistic perspectives on life and suggests that HRV markers of autonomic nervous system function could reflect positive human mind states.

  17. Low heart rate variability in patients with clinical burnout.

    Science.gov (United States)

    Lennartsson, Anna-Karin; Jonsdottir, Ingibjörg; Sjörs, Anna

    2016-12-01

    Several studies have shown that acute psychosocial stress and chronic psychosocial stress reduce heart rate variability (HRV). It is likely that individuals suffering from burnout have reduced HRV, as a consequence of the long-term stress exposure. This study investigated HRV in 54 patients with clinical burnout (40 women and 14 men) and in 55 individuals reporting low burnout scores (healthy; 24 women and 31 men) and 52 individuals reporting high burnout scores (non-clinical burnout; 33 women and 19 men). The participants underwent a 300s ECG recording in the supine position. Standard deviation of normal R-R intervals (SDNN) and the root mean square of successive normal interval differences (RMSSD) were derived from time domain HRV analysis. Frequency domain HRV measures; total power (TP), low frequency power (LF), high frequency power (HF), and LF/HF ratio were calculated. All HRV measures, except LF/HF ratio, were lower in the clinical burnout patients compared to both the non-clinical burnout group and the healthy group. The difference was larger between the patients and the healthy group than between the patients and the non-clinical burnout group. HRV did not differ significantly between the non-clinical burnout group and the healthy group. Low HRV in burnout patients may constitute one of the links to associated adverse health, since low HRV reflects low parasympathetic activity - and accordingly low anabolic/regenerative activity. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. HRV based Health&Sport markers using video from the face

    OpenAIRE

    Capdevila, Ll.; Moreno, Jordi; Movellan, Javier; Parrado Romero, Eva; Ramos Castro, Juan José

    2012-01-01

    Heart Rate Variability (HRV) is an indicator of health status in the general population and of adaptatio n to stress in athletes. In this paper we compare the performance of two systems to measure HRV: (1) A commercial system based on recording the physiological cardiac signal with (2) A computer vision system that uses a standard video images of the face to estimate RR from changes in skin color of the face. We show that the computer vision system pe...

  19. Poincaré plot analysis of ultra-short-term heart rate variability during recovery from exercise in physically active men.

    Science.gov (United States)

    Gomes, Rayana L; Marques Vanderlei, Luiz C; Garner, David M; Ramos Santana, Milana D; de Abreu, Luiz C; Valenti, Vitor E

    2017-04-26

    Recently there has been increasing interest in the study of ultra-short- term heart rate variability (HRV) in sports performance and exercise physiology. In order to improve standardization of this specific analysis, we evaluated the ultra-short-term HRV analysis through SD1Poincaré index to identify exercise induced responses. We investigated 35 physically active men aged between 18 and 35 years old. Volunteers performed physical exercise on treadmill with intensity of 6.0 km / hour + 1% slope in the first five minutes for physical "warming up." This was followed by 25 minutes with intensity equivalent to 60% of Vmax, with the same slope according to the Conconi threshold. HRV was analyzed in the following periods: the five-minute period before the exercise and the five-minute period immediately after the exercise, the five minutes were divided into five segments of 60 RR intervals. Ultra-short-term RMSSD and SD1 analysis were performed. Ultra-short-term RMSSD and SD1 were significantly (panalysis with the Poincaré plot detected changes in HRV after exercise. Ultra-short-term HRV analysis through Poincaré plot identified heart rate autonomic responses induced by aerobic exercise.

  20. Search for HRV-parameters that detect a sympathetic shift in heart failure patients on beta-blocker treatment

    NARCIS (Netherlands)

    Zhang, Yanru; de Peuter, Olav R.; Kamphuisen, Pieter W.; Karemaker, John M.

    2013-01-01

    Background: A sympathetic shift in heart rate variability (HRV) from high to lower frequencies may be an early signal of deterioration in a monitored patient. Most chronic heart failure (CHF) patients receive (3-blockers. This tends to obscure HRV observation by increasing the fast variations. We

  1. An Objective Screening Method for Major Depressive Disorder Using Logistic Regression Analysis of Heart Rate Variability Data Obtained in a Mental Task Paradigm

    Directory of Open Access Journals (Sweden)

    Guanghao Sun

    2016-11-01

    Full Text Available Background and Objectives: Heart rate variability (HRV has been intensively studied as a promising biological marker of major depressive disorder (MDD. Our previous study confirmed that autonomic activity and reactivity in depression revealed by HRV during rest and mental task (MT conditions can be used as diagnostic measures and in clinical evaluation. In this study, logistic regression analysis (LRA was utilized for the classification and prediction of MDD based on HRV data obtained in an MT paradigm.Methods: Power spectral analysis of HRV on R-R intervals before, during, and after an MT (random number generation was performed in 44 drug-naïve patients with MDD and 47 healthy control subjects at Department of Psychiatry in Shizuoka Saiseikai General Hospital. Logit scores of LRA determined by HRV indices and heart rates discriminated patients with MDD from healthy subjects. The high frequency (HF component of HRV and the ratio of the low frequency (LF component to the HF component (LF/HF correspond to parasympathetic and sympathovagal balance, respectively.Results: The LRA achieved a sensitivity and specificity of 80.0% and 79.0%, respectively, at an optimum cutoff logit score (0.28. Misclassifications occurred only when the logit score was close to the cutoff score. Logit scores also correlated significantly with subjective self-rating depression scale scores (p < 0.05.Conclusion: HRV indices recorded during a mental task may be an objective tool for screening patients with MDD in psychiatric practice. The proposed method appears promising for not only objective and rapid MDD screening, but also evaluation of its severity.

  2. Power Spectral Analysis of Short-Term Heart Rate Variability in Healthy and Arrhythmia Subjects by the Adaptive Continuous Morlet Wavelet Transform

    Directory of Open Access Journals (Sweden)

    Ram Sewak SINGH

    2017-12-01

    Full Text Available Power spectral analysis of short-term heart rate variability (HRV can provide instant valuable information to understand the functioning of autonomic control over the cardiovascular system. In this study, an adaptive continuous Morlet wavelet transform (ACMWT method has been used to describe the time-frequency characteristics of the HRV using band power spectra and the median value of interquartile range. Adaptation of the method was based on the measurement of maximum energy concentration. The ACMWT has been validated on synthetic signals (i.e. stationary, non-stationary as slow varying and fast changing frequency with time modeled as closest to dynamic changes in HRV signals. This method has been also tested in the presence of additive white Gaussian noise (AWGN to show its robustness towards the noise. From the results of testing on synthetic signals, the ACMWT was found to be an enhanced energy concentration estimator for assessment of power spectral of short-term HRV time series compared to adaptive Stockwell transform (AST, adaptive modified Stockwell transform (AMST, standard continuous Morlet wavelet transform (CMWT and Stockwell transform (ST estimators at statistical significance level of 5%. Further, the ACMWT was applied to real HRV data from Fantasia and MIT-BIH databases, grouped as healthy young group (HYG, healthy elderly group (HEG, arrhythmia controlled medication group (ARCMG, and supraventricular tachycardia group (SVTG subjects. The global results demonstrate that spectral indices of low frequency power (LFp and high frequency power (HFp of HRV were decreased in HEG compared to HYG subjects (p<0.0001. While LFp and HFp indices were increased in ARCMG compared to HEG (p<0.00001. The LFp and HFp components of HRV obtained from SVTG were reduced compared to other group subjects (p<0.00001.

  3. Impact of pulmonary arterial hypertension and its therapy on indices of heart rate variability.

    Science.gov (United States)

    Can, Mehmet Mustafa; Kaymaz, Cihangir; Pochi, Nartilla; Aktimur, Tugba

    2013-08-01

    To compare heart rate variability (HRV) indices between pulmonary arterial hypertension (PAH) patients and controls, and to investigate whether therapy improves heart rhythm. Thirty-eight patients and 20 controls underwent Holter monitoring. HRV was analyzed before and after PAH therapy. Various time, and frequency domain indices of HRV analysis including standard deviation of all normal-to-normal intervals, standard deviation of mean values for all normal-to-normal intervals over 5 min, and square root of the mean square differences of successive RR intervals were recorded and analyzed before and after 1 year of PAH therapy. Significant differences with regard to diminished physical capacity, impared cardiac output, increased BNP in PAH cohort; HRV indices were diminished compared to controls and no differences between before and after PAH therapy with respect to analysis of HRV. Patients exhibited depressed HRV and therapy failed to improve HRV indices suggesting urgent unmet need for better therapeutic options. Patients with PAH exhibit severely depressed HRV. Surprisingly, PAH specific therapy for 1 year with phosphodiesterase- 5 inhibitor, prostacyclin analogue, endhotelin receptor antagonist, or their combination failed to improve HRV indices suggesting urgent unmet need for better therapeutic options.

  4. A novel heart rate control model provides insights linking LF-HRV behavior to the open-loop gain.

    Science.gov (United States)

    Dvir, Hila; Bobrovsky, Ben Zion; Gabbay, Uri

    2013-09-20

    Low-frequency heart rate variability (LF-HRV) at rest has already been successfully modeled as self-sustained oscillations in a nonlinear control loop, but these models fail to simulate LF-HRV decreases either during aerobic exercise or in heart failure patients. Following control engineering practices, we assume the existence of a biological excitation (dither) within the heart rate control loop that softens the nonlinearity and studied LF-HRV behavior in a dither-embedded model. We adopted the Ottesen model with some revisions and induced a dither of high-frequency stochastic perturbations. We simulated scenarios of a healthy subject at rest and during aerobic exercise (by decreasing peripheral vascular resistance) and a heart failure patient (by decreasing stroke volume). The simulations resembled physiological LF-HRV behavior, i.e., LF-HRV decreased during aerobic exercise and in the heart failure patient. The simulations exhibited LF-HRV dependency on the open-loop gain, which is related to the product of the feedback gain and the feed forward gain. We are the first to demonstrate that LF-HRV may be dependent on the open-loop gain. Accordingly, reduced open-loop gain results in decreased LF-HRV, and vice versa. Our findings explain a well-known but unexplained observed phenomenon of reduced LF-HRV both in heart failure patients and in healthy subjects performing aerobic exercise. These findings have implications on how changes in LF-HRV can be interpreted physiologically, a necessary step towards the clinical utilization of LF-HRV. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  5. Exploratory multivariate analysis of the effect of fatty fish consumption and medicinal use on heart rate and heart rate variability data

    Directory of Open Access Journals (Sweden)

    Bjorn eGrung

    2015-02-01

    Full Text Available The overall aim of the present study was to explore the relationship between medicinal use and fatty fish consumption on heart rate variability (HRV and heart rate (HR in a group of forensic inpatients on a variety of medications. A total of 49 forensic inpatients, randomly assigned to a fish group (n=27 or a control group (n=22 were included in the present study. Before and by the end of the food intervention period HR and HRV were measured during an experimental test procedure. An additional aim of this paper is to show how multivariate data analysis can highlight differences and similarities between the groups, thus being a valuable addition to traditional statistical hypothesis testing. The results indicate that fish consumption may have a positive effect on both HR and HRV regardless of medication, but that the influence of medication is strong enough to mask the true effect of fish consumption. Without correcting for medication, the fish group and control group become indistinguishable (p = 0.0794, Cohen’s d = 0.60. The effect of medication is demonstrated by establishing a multivariate regression model that estimates HR and HRV in a recovery phase based on HR and HRV data recorded during psychological tests. The model performance is excellent for HR data, but yields poor results for HRV when employed on participants undergoing the more severe medical treatments. This indicates that the HRV behavior of this group is very different from that of the participants on no or lower level of medication. When focusing on the participants on a constant medication regime, a substantial improvement in HRV and HR for the fish group compared to the control group is indicated by a principal component analysis and t tests (p = 0.00029, Cohen’s d = 2.72. In a group of psychiatric inpatients characterized by severe mental health problems consuming different kinds of medication, the fish diet improved HR and HRV, indices of both emotional regulation and

  6. Heart rate variability analysis based on time–frequency representation and entropies in hypertrophic cardiomyopathy patients

    International Nuclear Information System (INIS)

    Clariá, F; Vallverdú, M; Caminal, P; Baranowski, R; Chojnowska, L

    2008-01-01

    In hypertrophic cardiomyopathy (HCM) patients there is an increased risk of premature death, which can occur with little or no warning. Furthermore, classification for sudden cardiac death on patients with HCM is very difficult. The aim of our study was to improve the prognostic value of heart rate variability (HRV) in HCM patients, giving insight into changes of the autonomic nervous system. In this way, the suitability of linear and nonlinear measures was studied to assess the HRV. These measures were based on time–frequency representation (TFR) and on Shannon and Rényi entropies, and compared with traditional HRV measures. Holter recordings of 64 patients with HCM and 55 healthy subjects were analyzed. The HCM patients consisted of two groups: 13 high risk patients, after aborted sudden cardiac death (SCD); 51 low risk patients, without SCD. Five-hour RR signals, corresponding to the sleep period of the subjects, were considered for the analysis as a comparable standard situation. These RR signals were filtered in the three frequency bands: very low frequency band (VLF, 0–0.04 Hz), low frequency band (LF, 0.04–0.15 Hz) and high frequency band (HF, 0.15–0.45 Hz). TFR variables based on instantaneous frequency and energy functions were able to classify HCM patients and healthy subjects (control group). Results revealed that measures obtained from TFR analysis of the HRV better classified the groups of subjects than traditional HRV parameters. However, results showed that nonlinear measures improved group classification. It was observed that entropies calculated in the HF band showed the highest statistically significant levels comparing the HCM group and the control group, p-value < 0.0005. The values of entropy measures calculated in the HCM group presented lower values, indicating a decreasing of complexity, than those calculated from the control group. Moreover, similar behavior was observed comparing high and low risk of premature death, the values of

  7. Evaluation of HRV Biofeedback as a Resilience Building Reserve Component

    Science.gov (United States)

    2017-08-01

    introductory training in either HRV-BART or relaxation breathing alone and be assessed on baseline HRV and mental and physical health questionnaires...receive a 1.5-hour group introductory training in either HRV-BART or relaxation breathing alone and be assessed on baseline HRV and mental and physical...F., Furman, S. A., McCool, M. F., & Porges, S. W. (2012). Statistical strategies to quantify respiratory sinus arrhythmia: Are commonly used metrics

  8. On heart rate variability and autonomic activity in homeostasis and in systemic inflammation.

    Science.gov (United States)

    Scheff, Jeremy D; Griffel, Benjamin; Corbett, Siobhan A; Calvano, Steve E; Androulakis, Ioannis P

    2014-06-01

    Analysis of heart rate variability (HRV) is a promising diagnostic technique due to the noninvasive nature of the measurements involved and established correlations with disease severity, particularly in inflammation-linked disorders. However, the complexities underlying the interpretation of HRV complicate understanding the mechanisms that cause variability. Despite this, such interpretations are often found in literature. In this paper we explored mathematical modeling of the relationship between the autonomic nervous system and the heart, incorporating basic mechanisms such as perturbing mean values of oscillating autonomic activities and saturating signal transduction pathways to explore their impacts on HRV. We focused our analysis on human endotoxemia, a well-established, controlled experimental model of systemic inflammation that provokes changes in HRV representative of acute stress. By contrasting modeling results with published experimental data and analyses, we found that even a simple model linking the autonomic nervous system and the heart confound the interpretation of HRV changes in human endotoxemia. Multiple plausible alternative hypotheses, encoded in a model-based framework, equally reconciled experimental results. In total, our work illustrates how conventional assumptions about the relationships between autonomic activity and frequency-domain HRV metrics break down, even in a simple model. This underscores the need for further experimental work towards unraveling the underlying mechanisms of autonomic dysfunction and HRV changes in systemic inflammation. Understanding the extent of information encoded in HRV signals is critical in appropriately analyzing prior and future studies. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Design and prototyping of a wristband-type wireless photoplethysmographic device for heart rate variability signal analysis.

    Science.gov (United States)

    Ghamari, M; Soltanpur, C; Cabrera, S; Romero, R; Martinek, R; Nazeran, H

    2016-08-01

    Heart Rate Variability (HRV) signal analysis provides a quantitative marker of the Autonomic Nervous System (ANS) function. A wristband-type wireless photoplethysmographic (PPG) device was custom-designed to collect and analyze the arterial pulse in the wrist. The proposed device is comprised of an optical sensor to monitor arterial pulse, a signal conditioning unit to filter and amplify the analog PPG signal, a microcontroller to digitize the analog PPG signal, and a Bluetooth module to transfer the data to a smart device. This paper proposes a novel model to represent the PPG signal as the summation of two Gaussian functions. The paper concludes with a verification procedure for HRV signal analysis during sedentary activities.

  10. Symbolic Analysis of Heart Rate Variability During Exposure to Musical Auditory Stimulation.

    Science.gov (United States)

    Vanderlei, Franciele Marques; de Abreu, Luiz Carlos; Garner, David Matthew; Valenti, Vitor Engrácia

    2016-01-01

    In recent years, the application of nonlinear methods for analysis of heart rate variability (HRV) has increased. However, studies on the influence of music on cardiac autonomic modulation in those circumstances are rare. The research team aimed to evaluate the acute effects on HRV of selected auditory stimulation by 2 musical styles, measuring the results using nonlinear methods of analysis: Shannon entropy, symbolic analysis, and correlation-dimension analysis. Prospective control study in which the volunteers were exposed to music and variables were compared between control (no auditory stimulation) and during exposure to music. All procedures were performed in a sound-proofed room at the Faculty of Science and Technology at São Paulo State University (UNESP), São Paulo, Brazil. Participants were 22 healthy female students, aged between 18 and 30 y. Prior to the actual intervention, the participants remained at rest for 20 min, and then they were exposed to one of the selected types of music, either classical baroque (64-84 dB) or heavy-metal (75-84 dB). Each musical session lasted a total of 5 min and 15 s. At a point occurring up to 1 wk after that day, the participants listened to the second type of music. The 2 types of music were delivered in a random sequence that depended on the group to which the participant was assigned. The study analyzed the following HRV indices through Shannon entropy; symbolic analysis-0V%, 1V%, 2LV%, and 2ULV%; and correlation-dimension analysis. During exposure to auditory stimulation by heavy-metal or classical baroque music, the study established no statistically significant variations regarding the indices for the Shannon entropy; the symbolic analysis-0V%, 1V%, and 2ULV%; and the correlation-dimension analysis. However, during heavy-metal music, the 2LV% index in the symbolic analysis was reduced compared with the controls. Auditory stimulation with the heavy-metal music reduced the parasympathetic modulation of HRV

  11. Validation of Heart Rate Monitor Polar RS800 for Heart Rate Variability Analysis During Exercise.

    Science.gov (United States)

    Hernando, David; Garatachea, Nuria; Almeida, Rute; Casajús, Jose A; Bailón, Raquel

    2018-03-01

    Hernando, D, Garatachea, N, Almeida, R, Casajús, JA, and Bailón, R. Validation of heart rate monitor Polar RS800 for heart rate variability analysis during exercise. J Strength Cond Res 32(3): 716-725, 2018-Heart rate variability (HRV) analysis during exercise is an interesting noninvasive tool to measure the cardiovascular response to the stress of exercise. Wearable heart rate monitors are a comfortable option to measure interbeat (RR) intervals while doing physical activities. It is necessary to evaluate the agreement between HRV parameters derived from the RR series recorded by wearable devices and those derived from an electrocardiogram (ECG) during dynamic exercise of low to high intensity. Twenty-three male volunteers performed an exercise stress test on a cycle ergometer. Subjects wore a Polar RS800 device, whereas ECG was also recorded simultaneously to extract the reference RR intervals. A time-frequency spectral analysis was performed to extract the instantaneous mean heart rate (HRM), and the power of low-frequency (PLF) and high-frequency (PHF) components, the latter centered on the respiratory frequency. Analysis was done in intervals of different exercise intensity based on oxygen consumption. Linear correlation, reliability, and agreement were computed in each interval. The agreement between the RR series obtained from the Polar device and from the ECG is high throughout the whole test although the shorter the RR is, the more differences there are. Both methods are interchangeable when analyzing HRV at rest. At high exercise intensity, HRM and PLF still presented a high correlation (ρ > 0.8) and excellent reliability and agreement indices (above 0.9). However, the PHF measurements from the Polar showed reliability and agreement coefficients around 0.5 or lower when the level of the exercise increases (for levels of O2 above 60%).

  12. Ischemic risk stratification by means of multivariate analysis of the heart rate variability

    International Nuclear Information System (INIS)

    Valencia, José F; Vallverdú, Montserrat; Caminal, Pere; Porta, Alberto; Voss, Andreas; Schroeder, Rico; Vázquez, Rafael; Bayés de Luna, Antonio

    2013-01-01

    In this work, a univariate and multivariate statistical analysis of indexes derived from heart rate variability (HRV) was conducted to stratify patients with ischemic dilated cardiomyopathy (IDC) in cardiac risk groups. Indexes conditional entropy, refined multiscale entropy (RMSE), detrended fluctuation analysis, time and frequency analysis, were applied to the RR interval series (beat-to-beat series), for single and multiscale complexity analysis of the HRV in IDC patients. Also, clinical parameters were considered. Two different end-points after a follow-up of three years were considered: (i) analysis A, with 151 survivor patients as a low risk group and 13 patients that suffered sudden cardiac death as a high risk group; (ii) analysis B, with 192 survivor patients as a low risk group and 30 patients that suffered cardiac mortality as a high risk group. A univariate and multivariate linear discriminant analysis was used as a statistical technique for classifying patients in risk groups. Sensitivity (Sen) and specificity (Spe) were calculated as diagnostic criteria in order to evaluate the performance of the indexes and their linear combinations. Sen and Spe values of 80.0% and 72.9%, respectively, were obtained during daytime by combining one clinical parameter and one index from RMSE, and during nighttime Sen = 80% and Spe = 73.4% were attained by combining one clinical factor and two indexes from RMSE. In particular, relatively long time scales were more relevant for classifying patients into risk groups during nighttime, while during daytime shorter scales performed better. The results suggest that the left atrial size, indexed to body surface and RMSE indexes are those that allow enhanced classification of ischemic patients in their respective risk groups, confirming that a single measurement is not enough to fully characterize ischemic risk patients and the clinical relevance of HRV complexity measures. (paper)

  13. [Heart rate variability and physical exercise. Current status].

    Science.gov (United States)

    Hottenrott, Kuno; Hoos, Olaf; Esperer, Hans Dieter

    2006-09-01

    Heart rate variability (HRV) has long been used in risk stratification for sudden cardiac death and diabetic autonomic neuropathy. In recent years, both time and frequency domain indices of HRV also gained increasing interest in sports and training sciences. In these fields, HRV is currently used for the noninvasive assessment of autonomic changes associated with short-term and long-term endurance exercise training in both leisure sports activity and high-performance training. Furthermore, HRV is being investigated as a diagnostic marker of overreaching and overtraining.A large body of evidence shows that, in healthy subjects and cardiovascular patients of all ages (up to an age of 70 years), regular aerobic training usually results in a significant improvement of overall as well as instantaneous HRV. These changes, which are accompanied by significant reductions in heart rates both at rest and during submaximal exercise, reflect an increase in autonomic efferent activity and a shift in favor of enhanced vagal modulation of the cardiac rhythm. Regular aerobic training of moderate volume and intensity over a minimum period of 3 months seems to be necessary to ensure these effects, which might be associated with a prognostic benefit regarding overall mortality.At present, available data does not allow for final conclusions with respect to the usefulness of traditional HRV indices in assessing an individual's exercise performance and monitoring training load. The discrepant results published so far are due to several factors including insufficient study size and design, and different HRV methods. Large-sized and prospectively designed studies are necessary for clarification. It also remains to be seen, whether the traditional HRV indices prove useful in the diagnosis of overreaching and overtraining. Preliminary results, though promising, need to be confirmed in larger cohorts.A basic problem in HRV analysis is nonstationarity of the heart rate signal, which holds

  14. Effects of moderate and heavy endurance exercise on nocturnal HRV.

    Science.gov (United States)

    Hynynen, E; Vesterinen, V; Rusko, H; Nummela, A

    2010-06-01

    This study examined the effects of endurance exercise on nocturnal autonomic modulation. Nocturnal R-R intervals were collected after a rest day, after a moderate endurance exercise and after a marathon run in ten healthy, physically active men. Heart rate variability (HRV) was analyzed as a continuous four-hour period starting 30 min after going to bed for sleep. In relation to average nocturnal heart rate after rest day, increases to 109+/-6% and 130+/-11% of baseline were found after moderate endurance exercise and marathon, respectively. Standard deviation of R-R intervals decreased to 90+/-9% and 64+/-10%, root-mean-square of differences between adjacent R-R intervals to 87+/-10% and 55+/-16%, and high frequency power to 77+/-19% and 34+/-19% of baseline after moderate endurance exercise and marathon, respectively. Also nocturnal low frequency power decreased to 56+/-26% of baseline after the marathon. Changes in nocturnal heart rate and HRV suggest prolonged dose-response effects on autonomic modulation after exercises, which may give useful information on the extent of exercise-induced nocturnal autonomic modulation and disturbance to the homeostasis.

  15. Analysis of acoustic cardiac signals for heart rate variability and murmur detection using nonnegative matrix factorization-based hierarchical decomposition

    DEFF Research Database (Denmark)

    Shah, Ghafoor; Koch, Peter; Papadias, Constantinos B.

    2014-01-01

    The detection of heart rate variability (HRV) via cardiac auscultation examination can be a useful and inexpensive tool which, however, is challenging in the presence of pathological signals and murmurs. The aim of this research is to analyze acoustic cardiac signals for HRV and murmur detection...

  16. The impact of breathing on HRV measurements: implications for the longitudinal follow-up of athletes.

    Science.gov (United States)

    Saboul, Damien; Pialoux, Vincent; Hautier, Christophe

    2013-01-01

    The purpose of the present work was to compare daily variations of heart rate variability (HRV) parameters between controlled breathing (CB) and spontaneous breathing (SB) sessions during a longitudinal follow-up of athletes. HRV measurements were performed daily on 10 healthy male runners for 21 consecutive days. The signals were recorded during two successive randomised 5-minutes sessions. One session was performed in CB and the other in SB. The results showed significant differences between the two respiration methods in the temporal, nonlinear and frequency domains. However, significant correlations were observed between CB and SB (higher than 0.70 for RMSSD and SD1), demonstrating that during a longitudinal follow-up, these markers provide the same HRV variations regardless of breathing pattern. By contrast, independent day-to-day variations were observed with HF and LF/HF frequency markers, indicating no significant relationship between SB and CB data over time. Therefore, we consider that SB and CB may be used for HRV longitudinal follow-ups only for temporal and nonlinear markers. Indeed, the same daily increases and decreases were observed whatever the breathing method employed. Conversely, frequency markers did not provide the same variations between SB and CB and we propose that these indicators are not reliable enough to be used for day-to-day HRV monitoring.

  17. cHRV Uncovering Daily Stress Dynamics Using Bio-Signal from Consumer Wearables.

    Science.gov (United States)

    Hao, Tian; Chang, Henry; Ball, Marion; Lin, Kun; Zhu, Xinxin

    2017-01-01

    Knowing the dynamics of one's daily stress is essential to effective stress management in the context of smart and connected health. However, there lacks a practical and unobtrusive means to obtain real-time and longitudinal stress information. In this paper, we attempt to derive a convenient HRV-based (heart rate variability) biomarker named cHRV, which can be used to reliably reflect stress dynamics. cHRV's key advantage lies in its low maintenance and high practicality. It can be efficiently calculated only using data from photoplethysmography (PPG) sensors, the mainstream heart rate sensor embedded in most of the consumer wearables like Apple Watch. Benefiting from the proliferation of wearables, cHRV is ideal for day-to-day stress monitoring. To evaluate its feasibility and performance, we have conducted 14 in-lab controlled experiments. The result shows that the proposed cHRV has strong correlation with the stress dynamics (r > 0.95), therefore exhibits great potential for continuous stress assessment.

  18. HRV based health&sport markers using video from the face.

    Science.gov (United States)

    Capdevila, Lluis; Moreno, Jordi; Movellan, Javier; Parrado, Eva; Ramos-Castro, Juan

    2012-01-01

    Heart Rate Variability (HRV) is an indicator of health status in the general population and of adaptation to stress in athletes. In this paper we compare the performance of two systems to measure HRV: (1) A commercial system based on recording the physiological cardiac signal with (2) A computer vision system that uses a standard video images of the face to estimate RR from changes in skin color of the face. We show that the computer vision system performs surprisingly well. It estimates individual RR intervals in a non-invasive manner and with error levels comparable to those achieved by the physiological based system.

  19. A Combined Syntactical and Statistical Approach for R Peak Detection in Real-Time Long-Term Heart Rate Variability Analysis

    Directory of Open Access Journals (Sweden)

    David Pang

    2018-06-01

    Full Text Available Long-term heart rate variability (HRV analysis is useful as a noninvasive technique for autonomic nervous system activity assessment. It provides a method for assessing many physiological and pathological factors that modulate the normal heartbeat. The performance of HRV analysis systems heavily depends on a reliable and accurate detection of the R peak of the QRS complex. Ectopic beats caused by misdetection or arrhythmic events can introduce bias into HRV results, resulting in significant problems in their interpretation. This study presents a novel method for long-term detection of normal R peaks (which represent the normal heartbeat in electrocardiographic signals, intended specifically for HRV analysis. The very low computational complexity of the proposed method, which combines and exploits the advantages of syntactical and statistical approaches, enables real-time applications. The approach was validated using the Massachusetts Institute of Technology–Beth Israel Hospital Normal Sinus Rhythm and the Fantasia database, and has a sensitivity, positive predictivity, detection error rate, and accuracy of 99.998, 99.999, 0.003, and 99.996%, respectively.

  20. Repeatability of heart rate variability in congenital hypothyroidism as analysed by detrended fluctuation analysis

    International Nuclear Information System (INIS)

    Echeverría, J C; Solís, L I; Pérez, J E; Gaitán, M J; Mandujano, M; Sánchez, M C; González-Camarena, R; Rivera, I R

    2009-01-01

    The analysis of heart rate fluctuations, or heart rate variability (HRV), may be applied to explore children's neurodevelopment. However, previous studies have reported poor reliability (repeatability) of HRV measures in children at rest and during light exercise. Whether the reliability can be improved by controlling variables such as physical activity, breathing rate and tidal volume, or by selecting non-conventional techniques for analysing the data remains as an open question. We evaluated the short-term repeatability of RR-interval data from medicated children with congenital hypothyroidism (CH). The α 1 exponents, obtained by detrended fluctuation analysis (DFA), from the data of 21 children collected at two different sessions were compared. Elapsed days between sessions were 59 ± 33, and data were obtained during 10 min, trying to restrict the children's activity while being seated. We found statistical agreement between the means of α 1 exponents for each session (p = 0.94) and no bias with a low-coefficient variation (9.1%); an intraclass correlation coefficient ri = 0.48 ([0.14 0.72], 95% confidence interval) was also estimated. These findings, which were compared with results obtained by conventional time and frequency techniques, indicate the existence of agreement between the α 1 exponents obtained at each session, thereby providing support concerning the repeatability of HRV data as analysed by DFA in children with congenital hypothyroidism. Of particular interest was also the agreement found by using the central frequency of the high-frequency band and the parameter pNN20, both showing better or similar ri than α 1 (0.77 [0.57 0.89] and 0.51 [0.17 0.74], respectively), yet considerably better repeatability than other conventional time and frequency parameters

  1. A Real-Time Analysis Method for Pulse Rate Variability Based on Improved Basic Scale Entropy

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    Yongxin Chou

    2017-01-01

    Full Text Available Base scale entropy analysis (BSEA is a nonlinear method to analyze heart rate variability (HRV signal. However, the time consumption of BSEA is too long, and it is unknown whether the BSEA is suitable for analyzing pulse rate variability (PRV signal. Therefore, we proposed a method named sliding window iterative base scale entropy analysis (SWIBSEA by combining BSEA and sliding window iterative theory. The blood pressure signals of healthy young and old subjects are chosen from the authoritative international database MIT/PhysioNet/Fantasia to generate PRV signals as the experimental data. Then, the BSEA and the SWIBSEA are used to analyze the experimental data; the results show that the SWIBSEA reduces the time consumption and the buffer cache space while it gets the same entropy as BSEA. Meanwhile, the changes of base scale entropy (BSE for healthy young and old subjects are the same as that of HRV signal. Therefore, the SWIBSEA can be used for deriving some information from long-term and short-term PRV signals in real time, which has the potential for dynamic PRV signal analysis in some portable and wearable medical devices.

  2. Value of Serial Heart Rate Variability Measurement for Prediction of Appropriate ICD Discharge in Patients with Heart Failure

    NARCIS (Netherlands)

    ten Sande, Judith N.; Damman, Peter; Tijssen, Jan G. P.; de Groot, Joris R.; Knops, Reinoud E.; Wilde, Arthur A. M.; van Dessel, Pascal F. H. M.

    2014-01-01

    HRV and Appropriate ICD Shock in Heart Failure Introduction Decreased heart rate variability (HRV) is associated with adverse outcomes in patients with heart failure. Our objective was to examine whether decreased HRV predicts appropriate implantable cardioverter defibrillator (ICD) shocks. Methods

  3. Higher resting heart rate variability predicts skill in expressing some emotions.

    Science.gov (United States)

    Tuck, Natalie L; Grant, Rosemary C I; Sollers, John J; Booth, Roger J; Consedine, Nathan S

    2016-12-01

    Vagally mediated heart rate variability (vmHRV) is a measure of cardiac vagal tone, and is widely viewed as a physiological index of the capacity to regulate emotions. However, studies have not directly tested whether vmHRV is associated with the ability to facially express emotions. In extending prior work, the current report tested links between resting vmHRV and the objectively assessed ability to facially express emotions, hypothesizing that higher vmHRV would predict greater expressive skill. Eighty healthy women completed self-reported measures, before attending a laboratory session in which vmHRV and the ability to express six emotions in the face were assessed. A repeated measures analysis of variance revealed a marginal main effect for vmHRV on skill overall; individuals with higher resting vmHRV were only better able to deliberately facially express anger and interest. Findings suggest that differences in resting vmHRV are associated with the objectively assessed ability to facially express some, but not all, emotions, with potential implications for health and well-being. © 2016 Society for Psychophysiological Research.

  4. Frequency analysis of heart rate variability: a useful assessment tool of linearly polarized near-infrared irradiation to stellate ganglion area for burning mouth syndrome.

    Science.gov (United States)

    Momota, Yukihiro; Takano, Hideyuki; Kani, Koichi; Matsumoto, Fumihiro; Motegi, Katsumi; Aota, Keiko; Yamamura, Yoshiko; Omori, Mayuko; Tomioka, Shigemasa; Azuma, Masayuki

    2013-03-01

    Burning mouth syndrome (BMS) is characterized by the following subjective complaints without distinct organic changes: burning sensation in mouth or chronic pain of tongue. BMS is also known as glossodynia; both terms are used equivalently in Japan. Although the real cause of BMS is still unknown, it has been pointed out that BMS is related to some autonomic abnormality, and that stellate ganglion near-infrared irradiation (SGR) corrects the autonomic abnormality. Frequency analysis of heart rate variability (HRV) is expected to be useful for assessing autonomic abnormality. This study investigated whether frequency analysis of HRV could reveal autonomic abnormality associated with BMS, and whether autonomic changes were corrected after SGR. Eight subjects received SGR; the response to SGR was assessed by frequency analysis of HRV. No significant difference of autonomic activity concerning low-frequency (LF) norm, high-frequency (HF) norm, and low-frequency/high-frequency (LF/HF) was found between SGR effective and ineffective groups. Therefore, we proposed new parameters: differential normalized low frequency (D LF norm), differential normalized high frequency (D HF norm), and differential low-frequency/high-frequency (D LF/HF), which were defined as differentials between original parameters just before and after SGR. These parameters as indexes of responsiveness of autonomic nervous system (ANS) revealed autonomic changes in BMS, and BMS seems to be related to autonomic instability rather than autonomic imbalance. Frequency analysis of HRV revealed the autonomic instability associated with BMS and enabled tracing of autonomic changes corrected with SGR. It is suggested that frequency analysis of HRV is very useful in follow up of BMS and for determination of the therapeutic efficacy of SGR. Wiley Periodicals, Inc.

  5. Association of plasma IL-6 and Hsp70 with HRV at different levels of PAHs metabolites.

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    Jian Ye

    Full Text Available Exposure to polycyclic aromatic hydrocarbons (PAHs is associated with reduced heart rate variability (HRV, a strong predictor of cardiovascular diseases, but the mechanism is not well understood.We hypothesized that PAHs might induce systemic inflammation and stress response, contributing to altered cardiac autonomic function.HRV indices were measured using a 3-channel digital Holter monitor in 800 coke oven workers. Plasma levels of interleukin-6 (IL-6 and heat shock protein 70 (Hsp70 were determined using ELISA. Twelve urinary PAHs metabolites (OH-PAHs were measured by gas chromatography-mass spectrometry.We found that significant dose-dependent relationships between four urinary OH-PAHs and IL-6 (all Ptrend<0.05; and an increase in quartiles of IL-6 was significantly associated with a decrease in total power (TP and low frequency (LF (Ptrend = 0.014 and 0.006, respectively. In particular, elevated IL-6 was associated in a dose-dependent manner with decreased TP and LF in the high-PAHs metabolites groups (all Ptrend<0.05, but not in the low-PAHs metabolites groups. No significant association between Hsp70 and HRV in total population was found after multivariate adjustment. However, increased Hsp70 was significantly associated with elevated standard deviation of NN intervals (SDNN, TP and LF in the low-PAHs metabolites groups (all Ptrend<0.05. We also observed that both IL-6 and Hsp70 significantly interacted with multiple PAHs metabolites in relation to HRV.In coke oven workers, increased IL-6 was associated with a dose-response decreased HRV in the high-PAHs metabolites groups, whereas increase of Hsp70 can result in significant dose-related increase in HRV in the low-PAHs metabolites groups.

  6. Heart Rate Variability Analysis in Revascularized Individuals Submitted to an Anaerobic Potency Test

    Directory of Open Access Journals (Sweden)

    Geraldo Mendes Gutian Jr

    2007-10-01

    Full Text Available The objective of this study was to analyze the behavior of autonomic modulation before, during and after the Modified Wingate Test (WanMT, through the analysis of Heart Rate Variability (HRV. Six volunteers between the ages of 40 and 70, post-revascularization procedures (angioplasty and/or surgery, mean duration 10 months, were submitted to supervised training for at least 10 to 14 months. The following protocol, divided into 5 phases, was used: 1 Rest Phase (RP: 180 seconds; 2 Submaximum Phase (SP: 30 seconds; 3 Maximum Phase (MP: 30 seconds; 4 Active Recuperation Phase (ARP; 120 seconds and; 5 Passive Recuperation Phase (PRP: 180 seconds. For the WanMT Test, we selected the load of 3.75% of corporal weight for all volunteers. To analyze the HRV, we used the following parameters: the interval RRr, MNN, SDNN, RMSSD and PNN50. We only observed results for the group according to RMSSD parameters during the rest phase of the test protocol in which the group remained in vagal presence and during all other phases in vagal depression. However, when we analyzed the PNN50, we observed that the group was in medium vagal presence during all of the phases of the test though there was no statistically significant difference (p> 0.05 between the phases. Therefore, we can say that all of the individuals had a similar profile in the autonomic response to the WanMT, confirmed by the parameters studied in the analysis of the HRV in the time domain.

  7. Do physiological and pathological stresses produce different changes in heart rate variability?

    Directory of Open Access Journals (Sweden)

    Andrea eBravi

    2013-07-01

    Full Text Available Although physiological (e.g. exercise and pathological (e.g. infection stress affecting the cardiovascular system have both been documented to be associated with a reduction in overall heart rate variability (HRV, it remains unclear if loss of HRV is ubiquitously similar across different domains of variability analysis or if distinct patterns of altered HRV exist depending on the stressor. Using Continuous Individualized Multiorgan Variability Analysis (CIMVATM software, heart rate (HR and four selected measures of variability were measured over time (windowed analysis from two datasets, a set (n=13 of patients who developed systemic infection (i.e. sepsis after bone marrow transplant, and a matched set of healthy subjects undergoing physical exercise under controlled conditions. HR and the four HRV measures showed similar trends in both sepsis and exercise. The comparison through Wilcoxon sign-rank test of the levels of variability at baseline and during the stress (i.e. exercise or after days of sepsis development showed similar changes, except for LF/HF, ratio of power at low and high frequencies (associated with sympathovagal modulation, which was affected by exercise but did not show any change during sepsis. Furthermore, HRV measures during sepsis showed a lower level of correlation with each other, as compared to HRV during exercise. In conclusion, this exploratory study highlights similar responses during both exercise and infection, with differences in terms of correlation and inter-subject fluctuations, whose physiologic significance merits further investigation.

  8. Comparison of heart rate variability between resting state and external-cuff-inflation-and-deflation state: a pilot study.

    Science.gov (United States)

    Ji, Lizhen; Liu, Chengyu; Li, Peng; Wang, Xinpei; Yan, Chang; Liu, Changchun

    2015-10-01

    Heart rate variability (HRV) has been widely used in clinical research to provide an insight into the autonomic control of the cardiovascular system. Measurement of HRV is generally performed under a relaxed resting state. The effects of other conditions on HRV measurement, such as running, mountaineering, head-up tilt, etc, have also been investigated. This study aimed to explore whether an inflation-and-deflation process applied to a unilateral upper arm cuff would influence the HRV measurement. Fifty healthy young volunteers aged between 21 and 30 were enrolled in this study. Electrocardiogram (ECG) signals were recorded for each subject over a five minute resting state followed by a five minute external-cuff-inflation-and-deflation state (ECID state). A one minute gap was scheduled between the two measurements. Consecutive RR intervals in the ECG were extracted automatically to form the HRV data for each of the two states. Time domain (SDNN, RMSSD and PNN50), frequency domain (LFn, HFn and LF/HF) and nonlinear (VLI, VAI and SampEn) HRV indices were analyzed and compared between the two states. In addition, the effects of mean artery pressure (MAP) and heart rate (HR) on the aforementioned HRV indices were assessed for the two states, respectively, by Pearson correlation analysis. The results showed no significant difference in all aforementioned HRV indices between the resting and the ECID states (all p  >  0.05). The corresponding HRV indices had significant positive correlation (all p    0.05) for either state. Besides, none of the indices showed HR-related change (all p  >  0.05) for either state except the index of VLI in the resting state. To conclude, this pilot study suggested that the applied ECID process hardly influenced those commonly used HRV indices. It would thus be applicable to simultaneously measure both blood pressure and HRV indices in clinical practice.

  9. A Wearable EEG-HEG-HRV Multimodal System With Simultaneous Monitoring of tES for Mental Health Management.

    Science.gov (United States)

    Ha, Unsoo; Lee, Yongsu; Kim, Hyunki; Roh, Taehwan; Bae, Joonsung; Kim, Changhyeon; Yoo, Hoi-Jun

    2015-12-01

    A multimodal mental management system in the shape of the wearable headband and earplugs is proposed to monitor electroencephalography (EEG), hemoencephalography (HEG) and heart rate variability (HRV) for accurate mental health monitoring. It enables simultaneous transcranial electrical stimulation (tES) together with real-time monitoring. The total weight of the proposed system is less than 200 g. The multi-loop low-noise amplifier (MLLNA) achieves over 130 dB CMRR for EEG sensing and the capacitive correlated-double sampling transimpedance amplifier (CCTIA) has low-noise characteristics for HEG and HRV sensing. Measured three-physiology domains such as neural, vascular and autonomic domain signals are combined with canonical correlation analysis (CCA) and temporal kernel canonical correlation analysis (tkCCA) algorithm to find the neural-vascular-autonomic coupling. It supports highly accurate classification with the 19% maximum improvement with multimodal monitoring. For the multi-channel stimulation functionality, after-effects maximization monitoring and sympathetic nerve disorder monitoring, the stimulator is designed as reconfigurable. The 3.37 × 2.25 mm(2) chip has 2-channel EEG sensor front-end, 2-channel NIRS sensor front-end, NIRS current driver to drive dual-wavelength VCSEL and 6-b DAC current source for tES mode. It dissipates 24 mW with 2 mA stimulation current and 5 mA NIRS driver current.

  10. Heart rate variability measured early in patients with evolving acute coronary syndrome and 1-year outcomes of rehospitalization and mortality.

    Science.gov (United States)

    Harris, Patricia R E; Stein, Phyllis K; Fung, Gordon L; Drew, Barbara J

    2014-01-01

    This study sought to examine the prognostic value of heart rate variability (HRV) measurement initiated immediately after emergency department presentation for patients with acute coronary syndrome (ACS). Altered HRV has been associated with adverse outcomes in heart disease, but the value of HRV measured during the earliest phases of ACS related to risk of 1-year rehospitalization and death has not been established. Twenty-four-hour Holter recordings of 279 patients with ACS were initiated within 45 minutes of emergency department arrival; recordings with ≥18 hours of sinus rhythm were selected for HRV analysis (number [N] =193). Time domain, frequency domain, and nonlinear HRV were examined. Survival analysis was performed. During the 1-year follow-up, 94 patients were event-free, 82 were readmitted, and 17 died. HRV was altered in relation to outcomes. Predictors of rehospitalization included increased normalized high frequency power, decreased normalized low frequency power, and decreased low/high frequency ratio. Normalized high frequency >42 ms(2) predicted rehospitalization while controlling for clinical variables (hazard ratio [HR] =2.3; 95% confidence interval [CI] =1.4-3.8, P=0.001). Variables significantly associated with death included natural logs of total power and ultra low frequency power. A model with ultra low frequency power 0.3 ng/mL (HR =4.0; 95% CI =1.3-12.1; P=0.016) revealed that each contributed independently in predicting mortality. Nonlinear HRV variables were significant predictors of both outcomes. HRV measured close to the ACS onset may assist in risk stratification. HRV cut-points may provide additional, incremental prognostic information to established assessment guidelines, and may be worthy of additional study.

  11. Photoplethysmography pulse rate variability as a surrogate measurement of heart rate variability during non-stationary conditions

    International Nuclear Information System (INIS)

    Gil, E; Orini, M; Bailón, R; Laguna, P; Vergara, J M; Mainardi, L

    2010-01-01

    In this paper we assessed the possibility of using the pulse rate variability (PRV) extracted from the photoplethysmography signal as an alternative measurement of the HRV signal in non-stationary conditions. The study is based on analysis of the changes observed during a tilt table test in the heart rate modulation of 17 young subjects. First, the classical indices of HRV analysis were compared to the indices from PRV in intervals where stationarity was assumed. Second, the time-varying spectral properties of both signals were compared by time-frequency (TF) and TF coherence analysis. Third, the effect of replacing PRV with HRV in the assessment of the changes of the autonomic modulation of the heart rate was considered. Time-invariant HRV and PRV indices showed no statistically significant differences (p > 0.05) and high correlation (>0.97). Time-frequency analysis revealed that the TF spectra of both signals were highly correlated (0.99 ± 0.01); the difference between the instantaneous power, in the LF and HF bands, obtained from HRV and PRV was small (<10 −3 s −2 ) and their temporal patterns were highly correlated (0.98 ± 0.04 and 0.95 ± 0.06 in the LF and HF bands, respectively) and TF coherence in the LF and HF bands was high (0.97 ± 0.04 and 0.89 ± 0.08, respectively). Finally, the instantaneous power in the LF band was observed to significantly increase during head-up tilt by both HRV and PRV analysis. These results suggest that although some differences in the time-varying spectral indices extracted from HRV and PRV exist, mainly in the HF band associated with respiration, PRV could be used as a surrogate of HRV during non-stationary conditions, at least during the tilt table test

  12. Temporal Patterns in Sheep Fetal Heart Rate Variability Correlate to Systemic Cytokine Inflammatory Response: A Methodological Exploration of Monitoring Potential Using Complex Signals Bioinformatics.

    Directory of Open Access Journals (Sweden)

    Christophe L Herry

    Full Text Available Fetal inflammation is associated with increased risk for postnatal organ injuries. No means of early detection exist. We hypothesized that systemic fetal inflammation leads to distinct alterations of fetal heart rate variability (fHRV. We tested this hypothesis deploying a novel series of approaches from complex signals bioinformatics. In chronically instrumented near-term fetal sheep, we induced an inflammatory response with lipopolysaccharide (LPS injected intravenously (n = 10 observing it over 54 hours; seven additional fetuses served as controls. Fifty-one fHRV measures were determined continuously every 5 minutes using Continuous Individualized Multi-organ Variability Analysis (CIMVA. CIMVA creates an fHRV measures matrix across five signal-analytical domains, thus describing complementary properties of fHRV. We implemented, validated and tested methodology to obtain a subset of CIMVA fHRV measures that matched best the temporal profile of the inflammatory cytokine IL-6. In the LPS group, IL-6 peaked at 3 hours. For the LPS, but not control group, a sharp increase in standardized difference in variability with respect to baseline levels was observed between 3 h and 6 h abating to baseline levels, thus tracking closely the IL-6 inflammatory profile. We derived fHRV inflammatory index (FII consisting of 15 fHRV measures reflecting the fetal inflammatory response with prediction accuracy of 90%. Hierarchical clustering validated the selection of 14 out of 15 fHRV measures comprising FII. We developed methodology to identify a distinctive subset of fHRV measures that tracks inflammation over time. The broader potential of this bioinformatics approach is discussed to detect physiological responses encoded in HRV measures.

  13. Interferon lambda 1-3 expression in infants hospitalized for RSV or HRV associated bronchiolitis.

    Science.gov (United States)

    Selvaggi, Carla; Pierangeli, Alessandra; Fabiani, Marco; Spano, Lucia; Nicolai, Ambra; Papoff, Paola; Moretti, Corrado; Midulla, Fabio; Antonelli, Guido; Scagnolari, Carolina

    2014-05-01

    The airway expression of type III interferons (IFNs) was evaluated in infants hospitalized for respiratory syncytial virus (RSV) or rhinovirus (HRV) bronchiolitis. As an additional objective we sought to determine whether a different expression of IFN lambda 1-3 was associated with different harboring viruses, the clinical course of bronchiolitis or with the levels of well established IFN stimulated genes (ISGs), such as mixovirus resistance A (MxA) and ISG56. The analysis was undertaken in 118 infants with RSV or HRV bronchiolitis. Nasopharyngeal washes were collected for virological studies and molecular analysis of type III IFN responses. RSV elicited higher levels of IFN lambda subtypes when compared with HRV. A similar expression of type III IFN was found in RSVA or RSVB infected infants and in those infected with HRVA or HRVC viruses. Results also indicate that IFN lambda 1 and IFN lambda 2-3 levels were correlated with each other and with MxA and ISG56-mRNAs. In addition, a positive correlation exists between the IFN lambda1 levels and the clinical score index during RSV infection. In particular, higher IFN lambda 1 levels are associated to an increase of respiratory rate. These findings show that differences in the IFN lambda 1-3 levels in infants with RSV or HRV infections are present and that the expression of IFN lambda 1 correlates with the severity of RSV bronchiolitis. Copyright © 2014 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

  14. An exploratory clinical study to determine the utility of heart rate variability analysis in the assessment of dosha imbalance

    Directory of Open Access Journals (Sweden)

    P. Ram Manohar

    2018-04-01

    Full Text Available The present study is a comparison of the data of spectral analysis of heart rate variability with clinical evaluation of pathological state of doshas. The calculated cardiointervalography values are combined into three integral indexes, which according to the authors' opinion reflect the influence on heart rhythm of vata, pitta and kapha, the regulation systems of the body known as doshas in Ayurveda. Seven gross dosha imbalances were assessed to test the agreement between the two methods in this study. Heart Rate Variability (HRV spectral data was collected from 42 participants to make the comparison with the clinical assessment of dosha imbalance. Clinical method of dosha assessment and method of calculating integral indexes by cardiointervalography data showed substantial agreement by Kappa coefficient statistic (k = 0.78 in assessment of gross dosha imbalance. The results of the data generated from this pilot study warrant further studies to rigorously validate the algorithms of HRV analysis in understanding dosha imbalance in Ayurvedic clinical practice and research settings. Keywords: Heart rate variability, Ayurveda, Spectral analysis

  15. A Pilot Study on Measuring the Readers’ Emotions Using HRV Biofeedback at University Malaysia Pahang

    Directory of Open Access Journals (Sweden)

    Iftikhar Yousaf

    2016-11-01

    Full Text Available Positive associations have been found between reading and emotions. Various techniques, including traditional as well as modern, have been used to measure emotions in the previous studies. However, emotional measurement of the readers of a literary piece through HRV Biofeedback has never been investigated. A study was undertaken to assess whether Heart Rate Variability (HRV biofeedback regarding  measurement of emotions in the readers of English Literature is likely to be effective or not for the first time at University Malaysia Pahang. In this study two scripts of the plays “Dr. Faustus” and “Waiting for Godot” were used. The Scripts were prepared from the Original Texts of these two plays, which might convey the overall message of the plays to the readers and resultantly produce the desired effect on the readers’ emotions. The total words of these two scripts were around 1050 each, allowing the students to complete one script in 7-8 minutes. Six subjects were selected randomly. While they were sitting calm and quiet at the desk, photoplethysmograph sensor was attached to their one of the earlobes which was connected to the emWave Desktop-PC software to record their Baseline HRV. The subjects, one at a time, read the Script 1 “Waiting for Godot” silently. After completion of the reading of Script 1, the emWave software was stopped and the HRV of the subject was recorded and saved automatically in the computer. The same process was repeated with Script 2 “Dr. Faustus”. In this way, emWave software recorded three HRV data for every subject. Results show obvious changes and significant correlations in the HRV of the participants while reading both the scripts. VLF increased for Script 1 while it decreased for Script 2. On the other hand, HF increased for Script 1 and further increased for Script 2.  LF decreased for Script 1 and increased for Script 2. These results point out the tendency that the stress level of the

  16. Phytoscreening with SPME: Variability Analysis.

    Science.gov (United States)

    Limmer, Matt A; Burken, Joel G

    2015-01-01

    Phytoscreening has been demonstrated at a variety of sites over the past 15 years as a low-impact, sustainable tool in delineation of shallow groundwater contaminated with chlorinated solvents. Collection of tree cores is rapid and straightforward, but low concentrations in tree tissues requires sensitive analytics. Solid-phase microextraction (SPME) is amenable to the complex matrix while allowing for solvent-less extraction. Accurate quantification requires the absence of competitive sorption, examined here both in laboratory experiments and through comprehensive examination of field data. Analysis of approximately 2,000 trees at numerous field sites also allowed testing of the tree genus and diameter effects on measured tree contaminant concentrations. Collectively, while these variables were found to significantly affect site-adjusted perchloroethylene (PCE) concentrations, the explanatory power of these effects was small (adjusted R(2) = 0.031). 90th quantile chemical concentrations in trees were significantly reduced by increasing Henry's constant and increasing hydrophobicity. Analysis of replicate tree core data showed no correlation between replicate relative standard deviation (RSD) and wood type or tree diameter, with an overall median RSD of 30%. Collectively, these findings indicate SPME is an appropriate technique for sampling and analyzing chlorinated solvents in wood and that phytoscreening is robust against changes in tree type and diameter.

  17. Simultaneously measured pupillary light reflex and heart rate variability in healthy children

    International Nuclear Information System (INIS)

    Daluwatte, C; Yao, G; Miles, J H

    2012-01-01

    We investigated the potential inter-relationship between two measures of autonomic nervous system: pupillary light reflex (PLR) and heart rate variability (HRV), in healthy children of 8–16 years old. PLR was measured at both dark- and light-adapted conditions with various stimulation intensities. Simultaneously measured HRV was obtained in five different PLR testing phases: before PLR test, light-adapted PLR test, dark adaptation, dark-adapted PLR test and after PLR test. The frequency domain HRV parameters measured during the PLR test were significantly different from those measured during rest. Both the regression analysis and factor analysis indicated that PLR and HRV parameters were not correlated, which suggests that they may provide complementary assessment of different aspects of the overall autonomic nervous system. (paper)

  18. Simultaneously measured pupillary light reflex and heart rate variability in healthy children

    Energy Technology Data Exchange (ETDEWEB)

    Daluwatte, C; Yao, G [Department of Biological Engineering, University of Missouri, Columbia, MO 65211 (United States); Miles, J H, E-mail: YaoG@missouri.edu [Child Health and Thompson Center for Autism and Neurodevelopmental Disorders, University of Missouri, Columbia, MO 65211 (United States)

    2012-06-15

    We investigated the potential inter-relationship between two measures of autonomic nervous system: pupillary light reflex (PLR) and heart rate variability (HRV), in healthy children of 8–16 years old. PLR was measured at both dark- and light-adapted conditions with various stimulation intensities. Simultaneously measured HRV was obtained in five different PLR testing phases: before PLR test, light-adapted PLR test, dark adaptation, dark-adapted PLR test and after PLR test. The frequency domain HRV parameters measured during the PLR test were significantly different from those measured during rest. Both the regression analysis and factor analysis indicated that PLR and HRV parameters were not correlated, which suggests that they may provide complementary assessment of different aspects of the overall autonomic nervous system. (paper)

  19. Heart-Rate Variability-More than Heart Beats?

    Science.gov (United States)

    Ernst, Gernot

    2017-01-01

    Heart-rate variability (HRV) is frequently introduced as mirroring imbalances within the autonomous nerve system. Many investigations are based on the paradigm that increased sympathetic tone is associated with decreased parasympathetic tone and vice versa . But HRV is probably more than an indicator for probable disturbances in the autonomous system. Some perturbations trigger not reciprocal, but parallel changes of vagal and sympathetic nerve activity. HRV has also been considered as a surrogate parameter of the complex interaction between brain and cardiovascular system. Systems biology is an inter-disciplinary field of study focusing on complex interactions within biological systems like the cardiovascular system, with the help of computational models and time series analysis, beyond others. Time series are considered surrogates of the particular system, reflecting robustness or fragility. Increased variability is usually seen as associated with a good health condition, whereas lowered variability might signify pathological changes. This might explain why lower HRV parameters were related to decreased life expectancy in several studies. Newer integrating theories have been proposed. According to them, HRV reflects as much the state of the heart as the state of the brain. The polyvagal theory suggests that the physiological state dictates the range of behavior and psychological experience. Stressful events perpetuate the rhythms of autonomic states, and subsequently, behaviors. Reduced variability will according to this theory not only be a surrogate but represent a fundamental homeostasis mechanism in a pathological state. The neurovisceral integration model proposes that cardiac vagal tone, described in HRV beyond others as HF-index, can mirror the functional balance of the neural networks implicated in emotion-cognition interactions. Both recent models represent a more holistic approach to understanding the significance of HRV.

  20. On time-frequence analysis of heart rate variability

    NARCIS (Netherlands)

    H.G. van Steenis (Hugo)

    2002-01-01

    textabstractThe aim of this research is to develop a time-frequency method suitable to study HRV in greater detail. The following approach was used: • two known time-frequency representations were applied to HRV to understand its advantages and disadvantages in describing HRV in frequency and in

  1. Clusters of Insomnia Disorder: An Exploratory Cluster Analysis of Objective Sleep Parameters Reveals Differences in Neurocognitive Functioning, Quantitative EEG, and Heart Rate Variability.

    Science.gov (United States)

    Miller, Christopher B; Bartlett, Delwyn J; Mullins, Anna E; Dodds, Kirsty L; Gordon, Christopher J; Kyle, Simon D; Kim, Jong Won; D'Rozario, Angela L; Lee, Rico S C; Comas, Maria; Marshall, Nathaniel S; Yee, Brendon J; Espie, Colin A; Grunstein, Ronald R

    2016-11-01

    To empirically derive and evaluate potential clusters of Insomnia Disorder through cluster analysis from polysomnography (PSG). We hypothesized that clusters would differ on neurocognitive performance, sleep-onset measures of quantitative ( q )-EEG and heart rate variability (HRV). Research volunteers with Insomnia Disorder (DSM-5) completed a neurocognitive assessment and overnight PSG measures of total sleep time (TST), wake time after sleep onset (WASO), and sleep onset latency (SOL) were used to determine clusters. From 96 volunteers with Insomnia Disorder, cluster analysis derived at least two clusters from objective sleep parameters: Insomnia with normal objective sleep duration (I-NSD: n = 53) and Insomnia with short sleep duration (I-SSD: n = 43). At sleep onset, differences in HRV between I-NSD and I-SSD clusters suggest attenuated parasympathetic activity in I-SSD (P insomnia clusters derived from cluster analysis differ in sleep onset HRV. Preliminary data suggest evidence for three clusters in insomnia with differences for sustained attention and sleep-onset q -EEG. Insomnia 100 sleep study: Australia New Zealand Clinical Trials Registry (ANZCTR) identification number 12612000049875. URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=347742. © 2016 Associated Professional Sleep Societies, LLC.

  2. The Effect of Sex on Heart Rate Variability at High Altitude.

    Science.gov (United States)

    Boos, Christopher John; Vincent, Emma; Mellor, Adrian; O'Hara, John; Newman, Caroline; Cruttenden, Richard; Scott, Phylip; Cooke, Mark; Matu, Jamie; Woods, David Richard

    2017-12-01

    There is evidence suggesting that high altitude (HA) exposure leads to a fall in heart rate variability (HRV) that is linked to the development of acute mountain sickness (AMS). The effects of sex on changes in HRV at HA and its relationship to AMS are unknown. HRV (5-min single-lead ECG) was measured in 63 healthy adults (41 men and 22 women) 18-56 yr of age at sea level (SL) and during a HA trek at 3619, 4600, and 5140 m, respectively. The main effects of altitude (SL, 3619 m, 4600 m, and 5140 m) and sex (men vs women) and their potential interaction were assessed using a factorial repeated-measures ANOVA. Logistic regression analyses were performed to assess the ability of HRV to predict AMS. Men and women were of similar age (31.2 ± 9.3 vs 31.7 ± 7.5 yr), ethnicity, and body and mass index. There was main effect for altitude on heart rate, SD of normal-to-normal (NN) intervals (SDNN), root mean square of successive differences (RMSSD), number of pairs of successive NN differing by >50 ms (NN50), NN50/total number of NN, very low-frequency power, low-frequency (LF) power, high-frequency (HF) power, and total power (TP). The most consistent effect on post hoc analysis was reduction in these HRV measures between 3619 and 5140 m at HA. Heart rate was significantly lower and SDNN, RMSSD, LF power, HF power, and TP were higher in men compared with women at HA. There was no interaction between sex and altitude for any of the HRV indices measured. HRV was not predictive of AMS development. Increasing HA leads to a reduction in HRV. Significant differences between men and women emerge at HA. HRV was not predictive of AMS.

  3. Concurrent sympathetic activation and vagal withdrawal in hyperthyroidism: Evidence from detrended fluctuation analysis of heart rate variability

    Science.gov (United States)

    Chen, Jin-Long; Shiau, Yuo-Hsien; Tseng, Yin-Jiun; Chiu, Hung-Wen; Hsiao, Tzu-Chien; Wessel, Niels; Kurths, Jürgen; Chu, Woei-Chyn

    2010-05-01

    Despite many previous studies on the association between hyperthyroidism and the hyperadrenergic state, controversies still exist. Detrended fluctuation analysis (DFA) is a well recognized method in the nonlinear analysis of heart rate variability (HRV), and it has physiological significance related to the autonomic nervous system. In particular, an increased short-term scaling exponent α1 calculated from DFA is associated with both increased sympathetic activity and decreased vagal activity. No study has investigated the DFA of HRV in hyperthyroidism. This study was designed to assess the sympathovagal balance in hyperthyroidism. We performed the DFA along with the linear analysis of HRV in 36 hyperthyroid Graves’ disease patients (32 females and 4 males; age 30 ± 1 years, means ± SE) and 36 normal controls matched by sex, age and body mass index. Compared with the normal controls, the hyperthyroid patients revealed a significant increase ( Phyperthyroid 1.28±0.04 versus control 0.91±0.02), long-term scaling exponent α2 (1.05±0.02 versus 0.90±0.01), overall scaling exponent α (1.11±0.02 versus 0.89±0.01), low frequency power in normalized units (LF%) and the ratio of low frequency power to high frequency power (LF/HF); and a significant decrease ( Phyperthyroidism is characterized by concurrent sympathetic activation and vagal withdrawal. This sympathovagal imbalance state in hyperthyroidism helps to explain the higher prevalence of atrial fibrillation and exercise intolerance among hyperthyroid patients.

  4. Somatic, Endurance Performance and Heart Rate Variability Profiles of Professional Soccer Players Grouped According to Age

    Directory of Open Access Journals (Sweden)

    Botek Michal

    2016-12-01

    Full Text Available This cross-sectional study compared somatic, endurance performance determinants and heart rate variability (HRV profiles of professional soccer players divided into different age groups: GI (17–19.9 years; n = 23, GII (20–24.9 years; n = 45, GIII (25–29.9 years; n = 30, and GIV (30–39 years; n = 26. Players underwent somatic and HRV assessment and maximal exercise testing. HRV was analyzed by spectral analysis of HRV, and high (HF and low (LF frequency power was transformed by a natural logarithm (Ln. Players in GIV (83 ± 7 kg were heavier (p 25 years showed negligible differences in Pmax unlike the age group differences demonstrated in VO2max. A shift towards relative sympathetic dominance, particularly due to reduced vagal activity, was apparent after approximately 8 years of competing at the professional level.

  5. Heart Rate Variability during Social Interactions in Children with and without Psychopathology: A Meta-Analysis

    Science.gov (United States)

    Shahrestani, Sara; Stewart, Elizabeth M.; Quintana, Daniel S.; Hickie, Ian B.; Guastella, Adam J.

    2014-01-01

    Background: The inability to regulate autonomic activity during social interactions is believed to contribute to social and emotional dysregulation in children. Research has employed heart rate variability (HRV) during both socially engaging and socially disengaging dyadic tasks between children and adults to assess this. Methods: We conducted a…

  6. The prognostic value of heart rate variability in the elderly, changing the perspective: from sympathovagal balance to chaos theory.

    Science.gov (United States)

    Nicolini, Paola; Ciulla, Michele M; De Asmundis, Carlo; Magrini, Fabio; Brugada, Pedro

    2012-05-01

    Heart rate variability (HRV) is the temporal beat-to-beat variation in successive RR intervals on an electrocardiographic (ECG) recording and it reflects the regulation of the heart rate (HR) by the autonomic nervous system (ANS). HRV analysis is a noninvasive tool for the assessment of autonomic function that gained momentum in the late 1980s when its clinical relevance as a predictor of mortality was established by a milestone study by Kleiger et al. in patients with postacute myocardial infarction. In the last few decades, the increasing availability of commercial ECG devices offering HRV analysis has made HRV a favorite marker for risk stratification in the setting of cardiovascular disease. The rapid aging of the world population and the growing popularity of HRV have also fueled interest for the prognostic value of HRV in the elderly, outside a specific cardiological context. However, the discussion of HRV measures in the elderly is still very much centered on the rather reductionistic model of sympathovagal balance, with the orthosympathetic and parasympathetic limbs of the ANS exercising opposing effects on the heart via autonomic tone. The expanding application of nonlinear dynamics to medicine has brought to the forefront the notion of system complexity, embedded in the mathematical concepts of chaos theory and fractals, and provides an opportunity to suggest a broader interpretation for the prognostic significance of HRV, especially in the elderly. Although the use of novel indices of HRV may be hampered by practical issues, a more holistic approach to HRV may still be safeguarded if traditional time- and frequency-domain measures are viewed in terms of autonomic modulation. This review focuses on HRV in geriatric populations. It considers studies on the prognostic value of HRV in elderly subjects, discussing the potential confounding effect of erratic rhythm, and concentrates on the conceptual distinction between autonomic tone and autonomic modulation

  7. Time-variant coherence between heart rate variability and EEG activity in epileptic patients: an advanced coupling analysis between physiological networks

    International Nuclear Information System (INIS)

    Piper, D; Schiecke, K; Pester, B; Witte, H; Benninger, F; Feucht, M

    2014-01-01

    Time-variant coherence analysis between the heart rate variability (HRV) and the channel-related envelopes of adaptively selected EEG components was used as an indicator for the occurrence of (correlative) couplings between the central autonomic network (CAN) and the epileptic network before, during and after epileptic seizures. Two groups of patients were investigated, a group with left and a group with right hemispheric temporal lobe epilepsy. The individual EEG components were extracted by a signal-adaptive approach, the multivariate empirical mode decomposition, and the envelopes of each resulting intrinsic mode function (IMF) were computed by using Hilbert transform. Two IMFs, whose envelopes were strongly correlated with the HRV’s low-frequency oscillation (HRV-LF; ≈0.1 Hz) before and after the seizure were identified. The frequency ranges of these IMFs correspond to the EEG delta-band. The time-variant coherence was statistically quantified and tensor decomposition of the time-frequency coherence maps was applied to explore the topography-time-frequency characteristics of the coherence analysis. Results allow the hypothesis that couplings between the CAN, which controls the cardiovascular-cardiorespiratory system, and the ‘epileptic neural network’ exist. Additionally, our results confirm the hypothesis of a right hemispheric lateralization of sympathetic cardiac control of the HRV-LF. (paper)

  8. Operant Variability: A Conceptual Analysis

    Science.gov (United States)

    Barba, Lourenco de Souza

    2012-01-01

    Some researchers claim that variability is an operant dimension of behavior. The present paper reviews the concept of operant behavior and emphasizes that differentiation is the behavioral process that demonstrates an operant relation. Differentiation is conceived as change in the overlap between two probability distributions: the distribution of…

  9. Effects of cigarette smoke on Holter ECG recordings in patients with arterial hypertension. Part 1: Time domain parameters of heart rate variability.

    Science.gov (United States)

    Gać, Paweł; Sobieszczańska, Małgorzata

    2014-01-01

    This report was intended to evaluate the effect of cigarette smoke on heart rate variability (HRV) in patients with arterial hypertension (AH). 223 individuals were qalified to the studies. The following groups of patients not suffering from other disease which may affect HRV were delineated: 1 - patients with AH (n=145); 2 - patients without AH (n=48). In group 1 the following patient groups were studied: A - active smokers (n=42), B - non-smokers exposed to cigarette smoke (n=30), C - non-smokers not exposed to tobacco smoke (n=34), D - former smokers (n=26). A time domain HRV analysis was carried out. Group 1 versus group 2 manifested significantly lower mean values of most parameters in the HRV time domain analysis. Subgroups A, B and D versus subgroup C also exhibited significantly lower mean values of most parameters in the HRV time domain analysis. Active cigarette smoking and passive exposure to tobacco smoke represented independent risk factors for a decreased HRV. Active and passive exposure to cigarette smoke decreases HRV in hypertensive patients. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Effect of atrioventricular conduction on heart rate variability

    KAUST Repository

    Ahmad, Talha Jamal; Ali, Hussnain; Majeed, S. M Imran; Khan, Shoab A.

    2011-01-01

    This paper discusses the effect of atrioventricular conduction time (AVCT) on the short-term Heart Rate Variability (HRV) by computing HRV parameters using intervals between the onsets of successive P waves (PP time series) for three groups: normal

  11. Automatic seizure detection based on the combination of newborn multi-channel EEG and HRV information

    Science.gov (United States)

    Mesbah, Mostefa; Balakrishnan, Malarvili; Colditz, Paul B.; Boashash, Boualem

    2012-12-01

    This article proposes a new method for newborn seizure detection that uses information extracted from both multi-channel electroencephalogram (EEG) and a single channel electrocardiogram (ECG). The aim of the study is to assess whether additional information extracted from ECG can improve the performance of seizure detectors based solely on EEG. Two different approaches were used to combine this extracted information. The first approach, known as feature fusion, involves combining features extracted from EEG and heart rate variability (HRV) into a single feature vector prior to feeding it to a classifier. The second approach, called classifier or decision fusion, is achieved by combining the independent decisions of the EEG and the HRV-based classifiers. Tested on recordings obtained from eight newborns with identified EEG seizures, the proposed neonatal seizure detection algorithms achieved 95.20% sensitivity and 88.60% specificity for the feature fusion case and 95.20% sensitivity and 94.30% specificity for the classifier fusion case. These results are considerably better than those involving classifiers using EEG only (80.90%, 86.50%) or HRV only (85.70%, 84.60%).

  12. Combination of Empirical Mode Decomposition Components of HRV Signals for Discriminating Emotional States

    Directory of Open Access Journals (Sweden)

    Ateke Goshvarpour

    2016-06-01

    Full Text Available Introduction Automatic human emotion recognition is one of the most interesting topics in the field of affective computing. However, development of a reliable approach with a reasonable recognition rate is a challenging task. The main objective of the present study was to propose a robust method for discrimination of emotional responses thorough examination of heart rate variability (HRV. In the present study, considering the non-stationary and non-linear characteristics of HRV, empirical mode decomposition technique was utilized as a feature extraction approach. Materials and Methods In order to induce the emotional states, images indicating four emotional states, i.e., happiness, peacefulness, sadness, and fearfulness were presented. Simultaneously, HRV was recorded in 47 college students. The signals were decomposed into some intrinsic mode functions (IMFs. For each IMF and different IMF combinations, 17 standard and non-linear parameters were extracted. Wilcoxon test was conducted to assess the difference between IMF parameters in different emotional states. Afterwards, a probabilistic neural network was used to classify the features into emotional classes. Results Based on the findings, maximum classification rates were achieved when all IMFs were fed into the classifier. Under such circumstances, the proposed algorithm could discriminate the affective states with sensitivity, specificity, and correct classification rate of 99.01%, 100%, and 99.09%, respectively. In contrast, the lowest discrimination rates were attained by IMF1 frequency and its combinations. Conclusion The high performance of the present approach indicated that the proposed method is applicable for automatic emotion recognition.

  13. Comparison of the Polar S810i monitor and the ECG for the analysis of heart rate variability in the time and frequency domains

    Directory of Open Access Journals (Sweden)

    L.C.M. Vanderlei

    2008-10-01

    Full Text Available The aim of the present study was to compare heart rate variability (HRV at rest and during exercise using a temporal series obtained with the Polar S810i monitor and a signal from a LYNX® signal conditioner (BIO EMG 1000 model with a channel configured for the acquisition of ECG signals. Fifteen healthy subjects aged 20.9 ± 1.4 years were analyzed. The subjects remained at rest for 20 min and performed exercise for another 20 min with the workload selected to achieve 60% of submaximal heart rate. RR series were obtained for each individual with a Polar S810i instrument and with an ECG analyzed with a biological signal conditioner. The HRV indices (rMSSD, pNN50, LFnu, HFnu, and LF/HF were calculated after signal processing and analysis. The unpaired Student t-test and intraclass correlation coefficient were used for data analysis. No statistically significant differences were observed when comparing the values analyzed by means of the two devices for HRV at rest and during exercise. The intraclass correlation coefficient demonstrated satisfactory correlation between the values obtained by the devices at rest (pNN50 = 0.994; rMSSD = 0.995; LFnu = 0.978; HFnu = 0.978; LF/HF = 0.982 and during exercise (pNN50 = 0.869; rMSSD = 0.929; LFnu = 0.973; HFnu = 0.973; LF/HF = 0.942. The calculation of HRV values by means of temporal series obtained from the Polar S810i instrument appears to be as reliable as those obtained by processing the ECG signal captured with a signal conditioner.

  14. Autonomic dysfunction in mild cognitive impairment: evidence from power spectral analysis of heart rate variability in a cross-sectional case-control study.

    Directory of Open Access Journals (Sweden)

    Paola Nicolini

    Full Text Available Mild cognitive impairment (MCI is set to become a major health problem with the exponential ageing of the world's population. The association between MCI and autonomic dysfunction, supported by indirect evidence and rich with clinical implications in terms of progression to dementia and increased risk of mortality and falls, has never been specifically demonstrated.To conduct a comprehensive assessment of autonomic function in subjects with MCI by means of power spectral analysis (PSA of heart rate variability (HRV at rest and during provocative manoeuvres.This cross-sectional study involved 80 older outpatients (aged ≥ 65 consecutively referred to a geriatric unit and diagnosed with MCI or normal cognition (controls based on neuropsychological testing. PSA was performed on 5-minute electrocardiographic recordings under three conditions--supine rest with free breathing (baseline, supine rest with paced breathing at 12 breaths/minute (parasympathetic stimulation, and active standing (orthosympathetic stimulation--with particular focus on the changes from baseline to stimulation of indices of sympathovagal balance: normalized low frequency (LFn and high frequency (HFn powers and the LF/HF ratio. Blood pressure (BP was measured at baseline and during standing. Given its exploratory nature in a clinical population the study included subjects on medications with a potential to affect HRV.There were no significant differences in HRV indices between the two groups at baseline. MCI subjects exhibited smaller physiological changes in all three HRV indices during active standing, consistently with a dysfunction of the orthosympathetic system. Systolic BP after 10 minutes of standing was lower in MCI subjects, suggesting dysautonomia-related orthostatic BP dysregulation.Our study is novel in providing evidence of autonomic dysfunction in MCI. This is associated with orthostatic BP dysregulation and the ongoing follow-up of the study population will

  15. Interchangeability of electrocardiography and blood pressure measurement for determining heart rate and heart rate variability in free-moving domestic pigs in various behavioral contexts

    Directory of Open Access Journals (Sweden)

    Annika eKrause

    2015-11-01

    Full Text Available This study assessed the interchangeability between heart rate (HR and heart rate variability (HRV measures derived from a series of interbeat intervals (IBIs recorded via electrocardiogram (ECG and intra-arterial blood pressure (BP in various behavioral contexts. Five minutes of simultaneously recorded IBIs from ECG and BP signals in 11 female domestic pigs during resting, feeding and active behavior were analyzed. Comparisons were made for measures of HR, SDNN (the standard deviation of IBIs and RMSSD (the root mean of the squared distances of subsequent IBIs derived from ECG and BP signals for each behavior category using statistical procedures with different explanatory power (linear regression, intraclass correlation coefficient (ICC, Bland and Altman plots and analysis of variance (ANOVA. Linear regression showed a strong relationship for HR during all behaviors and for HRV during resting. Excellent ICCs (lower 95% CI > 0.75 and narrow limits of agreement (LoA in all behavior categories were found for HR. ICCs for HRV reached the critical lower 95% CI value of 0.75 only during resting. Using Bland and Altman plots, HRV agreement was unacceptable for all of the behavior categories. ANOVA showed significant differences between the methods in terms of HRV. BP systematically overestimated HRV compared with ECG. Our findings reveal that HR data recorded via BP agree well those recorded using ECG independently of the activity of the subject, whereas ECG and BP cannot be used interchangeably in the context of HRV in free-moving domestic pigs.

  16. Structural Covariance of the Prefrontal-Amygdala Pathways Associated with Heart Rate Variability.

    Science.gov (United States)

    Wei, Luqing; Chen, Hong; Wu, Guo-Rong

    2018-01-01

    The neurovisceral integration model has shown a key role of the amygdala in neural circuits underlying heart rate variability (HRV) modulation, and suggested that reciprocal connections from amygdala to brain regions centered on the central autonomic network (CAN) are associated with HRV. To provide neuroanatomical evidence for these theoretical perspectives, the current study used covariance analysis of MRI-based gray matter volume (GMV) to map structural covariance network of the amygdala, and then determined whether the interregional structural correlations related to individual differences in HRV. The results showed that covariance patterns of the amygdala encompassed large portions of cortical (e.g., prefrontal, cingulate, and insula) and subcortical (e.g., striatum, hippocampus, and midbrain) regions, lending evidence from structural covariance analysis to the notion that the amygdala was a pivotal node in neural pathways for HRV modulation. Importantly, participants with higher resting HRV showed increased covariance of amygdala to dorsal medial prefrontal cortex and anterior cingulate cortex (dmPFC/dACC) extending into adjacent medial motor regions [i.e., pre-supplementary motor area (pre-SMA)/SMA], demonstrating structural covariance of the prefrontal-amygdala pathways implicated in HRV, and also implying that resting HRV may reflect the function of neural circuits underlying cognitive regulation of emotion as well as facilitation of adaptive behaviors to emotion. Our results, thus, provide anatomical substrates for the neurovisceral integration model that resting HRV may index an integrative neural network which effectively organizes emotional, cognitive, physiological and behavioral responses in the service of goal-directed behavior and adaptability.

  17. Nonlinear Heart Rate Variability features for real-life stress detection. Case study: students under stress due to university examination.

    Science.gov (United States)

    Melillo, Paolo; Bracale, Marcello; Pecchia, Leandro

    2011-11-07

    This study investigates the variations of Heart Rate Variability (HRV) due to a real-life stressor and proposes a classifier based on nonlinear features of HRV for automatic stress detection. 42 students volunteered to participate to the study about HRV and stress. For each student, two recordings were performed: one during an on-going university examination, assumed as a real-life stressor, and one after holidays. Nonlinear analysis of HRV was performed by using Poincaré Plot, Approximate Entropy, Correlation dimension, Detrended Fluctuation Analysis, Recurrence Plot. For statistical comparison, we adopted the Wilcoxon Signed Rank test and for development of a classifier we adopted the Linear Discriminant Analysis (LDA). Almost all HRV features measuring heart rate complexity were significantly decreased in the stress session. LDA generated a simple classifier based on the two Poincaré Plot parameters and Approximate Entropy, which enables stress detection with a total classification accuracy, a sensitivity and a specificity rate of 90%, 86%, and 95% respectively. The results of the current study suggest that nonlinear HRV analysis using short term ECG recording could be effective in automatically detecting real-life stress condition, such as a university examination.

  18. Endurance performance and nocturnal HRV indices.

    Science.gov (United States)

    Nummela, A; Hynynen, E; Kaikkonen, P; Rusko, H

    2010-03-01

    The effects of endurance training on endurance performance characteristics and cardiac autonomic modulation during night sleep were investigated. Twenty-four sedentary subjects trained over four weeks two hours per week at an average running intensity of 76+/-4% of their heart rate reserve. The R to R ECG-intervals were recorded and heart rate variability indices including high frequency power (HFP) were calculated for the nights following the training days every week. The subjects were divided into responders and non-responders according to the improvements in the maximal velocity of the incremental treadmill test (v(max)). The responders improved their v(max) by 10.9+/-46 % (p < 0.001) while no changes were observed in the non-responders (1.6+/-3.0%), although there were no differences in any training load variables between the groups. In the responders nocturnal HFP was significantly higher during the fourth training week compared to the first training week (p=0.036). Furthermore, a significant correlation was observed between the change in v(max) and the change in nocturnal HFP (r=0.482, p=0.042). It was concluded that after similar training, an increase in cardiac vagal modulation was related to improved v(max) in the sedentary subjects. Georg Thieme Verlag KG Stuttgart.New York.

  19. Sensory trigeminal ULF-TENS stimulation reduces HRV response to experimentally induced arithmetic stress: A randomized clinical trial.

    Science.gov (United States)

    Monaco, Annalisa; Cattaneo, Ruggero; Ortu, Eleonora; Constantinescu, Marian Vladimir; Pietropaoli, Davide

    2017-05-01

    Ultra Low Frequency Transcutaneous Electric Nervous Stimulation (ULF-TENS) is extensively used for pain relief and for the diagnosis and treatment of temporomandibular disorders (TMD). In addition to its local effects, ULF-TENS acts on the autonomic nervous system (ANS), with particular reference to the periaqueductal gray (PAG), promoting the release of endogenous opioids and modulating descending pain systems. It has been suggested that the PAG participates in the coupling between the emotional stimulus and the appropriate behavioral autonomic response. This function is successfully investigated by HRV. Therefore, our goal is to investigate the effects of trigeminal ULF-TENS stimulation on autonomic behavior in terms of HRV and respiratory parameters during an experimentally-induced arithmetic stress test in healthy subjects. Thirty healthy women between 25 and 35years of age were enrolled and randomly assigned to either the control (TENS stimulation off) or test group (TENS stimulation on). Heart (HR, LF, HF, LF/HF ratio, DET, RMSSD, PNN50, RR) and respiratory (BR) rate were evaluated under basal, T1 (TENS off/on), and stress (mathematical task) conditions. Results showed that HRV parameters and BR significantly changed during the arithmetic stress paradigm (pTENS and control group could be discriminated only by non-linear HRV data, namely RR and DET (p=0.038 and p=0.027, respectively). During the arithmetic task, LF/HF ratio was the most sensitive parameter to discriminate between groups (p=0.019). Our data suggest that trigeminal sensory ULF-TENS reduces the autonomic response in terms of HRV and BR during acute mental stress in healthy subjects. Future directions of our work aim at applying the HRV and BR analysis, with and without TENS stimulation, to individuals with dysfunctional ANS among those with TMD. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Linear and non-linear interdependence of EEG and HRV frequency bands in human sleep.

    Science.gov (United States)

    Chaparro-Vargas, Ramiro; Dissanayaka, P Chamila; Patti, Chanakya Reddy; Schilling, Claudia; Schredl, Michael; Cvetkovic, Dean

    2014-01-01

    The characterisation of functional interdependencies of the autonomic nervous system (ANS) stands an evergrowing interest to unveil electroencephalographic (EEG) and Heart Rate Variability (HRV) interactions. This paper presents a biosignal processing approach as a supportive computational resource in the estimation of sleep dynamics. The application of linear, non-linear methods and statistical tests upon 10 overnight polysomnographic (PSG) recordings, allowed the computation of wavelet coherence and phase locking values, in order to identify discerning features amongst the clinical healthy subjects. Our findings showed that neuronal oscillations θ, α and σ interact with cardiac power bands at mid-to-high rank of coherence and phase locking, particularly during NREM sleep stages.

  1. Harmonic and complex analysis in several variables

    CERN Document Server

    Krantz, Steven G

    2017-01-01

    Authored by a ranking authority in harmonic analysis of several complex variables, this book embodies a state-of-the-art entrée at the intersection of two important fields of research: complex analysis and harmonic analysis. Written with the graduate student in mind, it is assumed that the reader has familiarity with the basics of complex analysis of one and several complex variables as well as with real and functional analysis. The monograph is largely self-contained and develops the harmonic analysis of several complex variables from the first principles. The text includes copious examples, explanations, an exhaustive bibliography for further reading, and figures that illustrate the geometric nature of the subject. Each chapter ends with an exercise set. Additionally, each chapter begins with a prologue, introducing the reader to the subject matter that follows; capsules presented in each section give perspective and a spirited launch to the segment; preludes help put ideas into context. Mathematicians and...

  2. Comparative Genetic Analyses of Human Rhinovirus C (HRV-C) Complete Genome from Malaysia

    Science.gov (United States)

    Khaw, Yam Sim; Chan, Yoke Fun; Jafar, Faizatul Lela; Othman, Norlijah; Chee, Hui Yee

    2016-01-01

    Human rhinovirus-C (HRV-C) has been implicated in more severe illnesses than HRV-A and HRV-B, however, the limited number of HRV-C complete genomes (complete 5′ and 3′ non-coding region and open reading frame sequences) has hindered the in-depth genetic study of this virus. This study aimed to sequence seven complete HRV-C genomes from Malaysia and compare their genetic characteristics with the 18 published HRV-Cs. Seven Malaysian HRV-C complete genomes were obtained with newly redesigned primers. The seven genomes were classified as HRV-C6, C12, C22, C23, C26, C42, and pat16 based on the VP4/VP2 and VP1 pairwise distance threshold classification. Five of the seven Malaysian isolates, namely, 3430-MY-10/C22, 8713-MY-10/C23, 8097-MY-11/C26, 1570-MY-10/C42, and 7383-MY-10/pat16 are the first newly sequenced complete HRV-C genomes. All seven Malaysian isolates genomes displayed nucleotide similarity of 63–81% among themselves and 63–96% with other HRV-Cs. Malaysian HRV-Cs had similar putative immunogenic sites, putative receptor utilization and potential antiviral sites as other HRV-Cs. The genomic features of Malaysian isolates were similar to those of other HRV-Cs. Negative selections were frequently detected in HRV-Cs complete coding sequences indicating that these sequences were under functional constraint. The present study showed that HRV-Cs from Malaysia have diverse genetic sequences but share conserved genomic features with other HRV-Cs. This genetic information could provide further aid in the understanding of HRV-C infection. PMID:27199901

  3. Assessment of Heart Rate Variability during an Endurance Mountain Trail Race by Multi-Scale Entropy Analysis

    Directory of Open Access Journals (Sweden)

    Montserrat Vallverdú

    2017-12-01

    Full Text Available The aim of the study was to analyze heart rate variability (HRV response to high-intensity exercise during a 35-km mountain trail race and to ascertain whether fitness level could influence autonomic nervous system (ANS modulation. Time-domain, frequency-domain, and multi-scale entropy (MSE indexes were calculated for eleven mountain-trail runners who completed the race. Many changes were observed, mostly related to exercise load and fatigue. These changes were characterized by increased mean values and standard deviations of the normal-to-normal intervals associated with sympathetic activity, and by decreased differences between successive intervals related to parasympathetic activity. Normalized low frequency (LF power suggested that ANS modulation varied greatly during the race and between individuals. Normalized high frequency (HF power, associated with parasympathetic activity, varied considerably over the race, and tended to decrease at the final stages, whereas changes in the LF/HF ratio corresponded to intervals with varying exercise load. MSE indexes, related to system complexity, indicated the existence of many interactions between the heart and its neurological control mechanism. The time-domain, frequency-domain, and MSE indexes were also able to discriminate faster from slower runners, mainly in the more difficult and in the final stages of the race. These findings suggest the use of HRV analysis to study cardiac function mechanisms in endurance sports.

  4. Depressed mood, positive affect, and heart rate variability in patients with suspected coronary artery disease.

    Science.gov (United States)

    Bhattacharyya, Mimi R; Whitehead, Daisy L; Rakhit, Roby; Steptoe, Andrew

    2008-11-01

    To test associations between heart rate variability (HRV), depressed mood, and positive affect in patients with suspected coronary artery disease (CAD). Depression is associated with impaired HRV post acute cardiac events, but evidence in patients with stable coronary artery disease (CAD) is inconsistent. Seventy-six patients (52 men, 24 women; mean age = 61.1 years) being investigated for suspected CAD on the basis of symptomatology and positive noninvasive tests, completed 24-hour electrocardiograms. The Beck Depression Inventory (BDI) was administered, and positive and depressed affect was measured over the study period with the Day Reconstruction Method (DRM). A total of 46 (60.5%) patients were later found to have definite CAD. HRV was analyzed, using spectral analysis. Typical diurnal profiles of HRV were observed, with greater normalized high frequency (HF) and lower normalized low frequency (LF) power in the night compared with the day. BDI depression scores were not consistently associated with HRV. But positive affect was associated with greater normalized HF power (p = .039) and reduced normalized LF power (p = .007) independently of age, gender, medication with beta blockers, CAD status, body mass index, smoking, and habitual physical activity level. In patients with definite CAD, depressed affect assessed using the DRM was associated with reduced normalized HF power and heightened normalized LF power (p = .007) independently of covariates. Relationships between depression and HRV in patients with CAD may depend on affective experience over the monitoring period. Enhanced parasympathetic cardiac control may be a process through which positive affect protects against cardiovascular disease.

  5. The "Chaos Theory" and nonlinear dynamics in heart rate variability analysis: does it work in short-time series in patients with coronary heart disease?

    Science.gov (United States)

    Krstacic, Goran; Krstacic, Antonija; Smalcelj, Anton; Milicic, Davor; Jembrek-Gostovic, Mirjana

    2007-04-01

    Dynamic analysis techniques may quantify abnormalities in heart rate variability (HRV) based on nonlinear and fractal analysis (chaos theory). The article emphasizes clinical and prognostic significance of dynamic changes in short-time series applied on patients with coronary heart disease (CHD) during the exercise electrocardiograph (ECG) test. The subjects were included in the series after complete cardiovascular diagnostic data. Series of R-R and ST-T intervals were obtained from exercise ECG data after sampling digitally. The range rescaled analysis method determined the fractal dimension of the intervals. To quantify fractal long-range correlation's properties of heart rate variability, the detrended fluctuation analysis technique was used. Approximate entropy (ApEn) was applied to quantify the regularity and complexity of time series, as well as unpredictability of fluctuations in time series. It was found that the short-term fractal scaling exponent (alpha(1)) is significantly lower in patients with CHD (0.93 +/- 0.07 vs 1.09 +/- 0.04; P chaos theory during the exercise ECG test point out the multifractal time series in CHD patients who loss normal fractal characteristics and regularity in HRV. Nonlinear analysis technique may complement traditional ECG analysis.

  6. Heart rate variability in workers chronically exposed to lead.

    Science.gov (United States)

    Gajek, Jacek; Zyśko, Dorota; Chlebda, Ewa

    2004-07-01

    Lead is a strong neurotoxin. The effects of lead on the activity of the autonomic nervous system, assessed by the use of heart rate variability (HRV) analysis, have not yet been established. To assess the effects of occupational chronic lead exposure on the autonomic nervous system activity. The study group consisted of 22 copper foundry workers (mean age 41.8+/-8.7 years) who had elevated parameters of lead overload and were admitted to the hospital for chelate therapy. The control group consisted of 13 age-matched healthy males. Lead concentration was measured with the use of atomic absorption spectrophotometry, and concentration of free protoporphyrins in erythrocytes (FEP) using a fluorometric method. Each patient underwent 24-hour ambulatory ECG monitoring, and standard short-term as well as long-term HRV parameters were obtained. There were no significant differences between patients and controls in HRV parameters. In the control group, HRV parameters correlated with age. In patients, a significant negative correlation between lead concentration and some short-term HRV parameters calculated during the night was found: SDNN (r=-0.48, p<0.05), TP (r=-0.48, p<0.01) and LF (r=-0.48, p<0.01). In patients, a negative correlation between lead concentration and HFnight/HFday index was found (r=-0.47 p<0.01), whereas in controls this correlation was positive (r=0.66 p<0.05). Overall HRV indices are similar in subjects exposed to lead and in healthy controls. A decrease in the physiological elevation of HF values during the night, together with an increase in lead blood concentration and lack of relationship between age and HRV parameters in workers chronically exposed to lead may suggest disturbances of the autonomic system. In subjects not exposed to lead a decrease in heart rate with an increase in FEP concentration was observed.

  7. Clusters of Insomnia Disorder: An Exploratory Cluster Analysis of Objective Sleep Parameters Reveals Differences in Neurocognitive Functioning, Quantitative EEG, and Heart Rate Variability

    Science.gov (United States)

    Miller, Christopher B.; Bartlett, Delwyn J.; Mullins, Anna E.; Dodds, Kirsty L.; Gordon, Christopher J.; Kyle, Simon D.; Kim, Jong Won; D'Rozario, Angela L.; Lee, Rico S.C.; Comas, Maria; Marshall, Nathaniel S.; Yee, Brendon J.; Espie, Colin A.; Grunstein, Ronald R.

    2016-01-01

    Study Objectives: To empirically derive and evaluate potential clusters of Insomnia Disorder through cluster analysis from polysomnography (PSG). We hypothesized that clusters would differ on neurocognitive performance, sleep-onset measures of quantitative (q)-EEG and heart rate variability (HRV). Methods: Research volunteers with Insomnia Disorder (DSM-5) completed a neurocognitive assessment and overnight PSG measures of total sleep time (TST), wake time after sleep onset (WASO), and sleep onset latency (SOL) were used to determine clusters. Results: From 96 volunteers with Insomnia Disorder, cluster analysis derived at least two clusters from objective sleep parameters: Insomnia with normal objective sleep duration (I-NSD: n = 53) and Insomnia with short sleep duration (I-SSD: n = 43). At sleep onset, differences in HRV between I-NSD and I-SSD clusters suggest attenuated parasympathetic activity in I-SSD (P insomnia clusters derived from cluster analysis differ in sleep onset HRV. Preliminary data suggest evidence for three clusters in insomnia with differences for sustained attention and sleep-onset q-EEG. Clinical Trial Registration: Insomnia 100 sleep study: Australia New Zealand Clinical Trials Registry (ANZCTR) identification number 12612000049875. URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=347742. Citation: Miller CB, Bartlett DJ, Mullins AE, Dodds KL, Gordon CJ, Kyle SD, Kim JW, D'Rozario AL, Lee RS, Comas M, Marshall NS, Yee BJ, Espie CA, Grunstein RR. Clusters of Insomnia Disorder: an exploratory cluster analysis of objective sleep parameters reveals differences in neurocognitive functioning, quantitative EEG, and heart rate variability. SLEEP 2016;39(11):1993–2004. PMID:27568796

  8. Effects of breathing patterns and light exercise on linear and nonlinear heart rate variability.

    Science.gov (United States)

    Weippert, Matthias; Behrens, Kristin; Rieger, Annika; Kumar, Mohit; Behrens, Martin

    2015-08-01

    Despite their use in cardiac risk stratification, the physiological meaning of nonlinear heart rate variability (HRV) measures is not well understood. The aim of this study was to elucidate effects of breathing frequency, tidal volume, and light exercise on nonlinear HRV and to determine associations with traditional HRV indices. R-R intervals, blood pressure, minute ventilation, breathing frequency, and respiratory gas concentrations were measured in 24 healthy male volunteers during 7 conditions: voluntary breathing at rest, and metronome guided breathing (0.1, 0.2 and 0.4 Hz) during rest, and cycling, respectively. The effect of physical load was significant for heart rate (HR; p < 0.001) and traditional HRV indices SDNN, RMSSD, lnLFP, and lnHFP (p < 0.01 for all). It approached significance for sample entropy (SampEn) and correlation dimension (D2) (p < 0.1 for both), while HRV detrended fluctuation analysis (DFA) measures DFAα1 and DFAα2 were not affected by load condition. Breathing did not affect HR but affected all traditional HRV measures. D2 was not affected by breathing; DFAα1 was moderately affected by breathing; and DFAα2, approximate entropy (ApEn), and SampEn were strongly affected by breathing. DFAα1 was strongly increased, whereas DFAα2, ApEn, and SampEn were decreased by slow breathing. No interaction effect of load and breathing pattern was evident. Correlations to traditional HRV indices were modest (r from -0.14 to -0.67, p < 0.05 to <0.01). In conclusion, while light exercise does not significantly affect short-time HRV nonlinear indices, respiratory activity has to be considered as a potential contributor at rest and during light dynamic exercise.

  9. Relative influence of age, resting heart rate and sedentary life style in short-term analysis of heart rate variability

    OpenAIRE

    E.R. Migliaro; P. Contreras; S. Bech; A. Etxagibel; M. Castro; R. Ricca; K. Vicente

    2001-01-01

    In order to assess the relative influence of age, resting heart rate (HR) and sedentary life style, heart rate variability (HRV) was studied in two different groups. The young group (YG) consisted of 9 sedentary subjects aged 15 to 20 years (YG-S) and of 9 nonsedentary volunteers (YG-NS) also aged 15 to 20. The elderly sedentary group (ESG) consisted of 16 sedentary subjects aged 39 to 82 years. HRV was assessed using a short-term procedure (5 min). R-R variability was calculated in the time-...

  10. Eating Habits and Food Additive Intakes Are Associated with Emotional States Based on EEG and HRV in Healthy Korean Children and Adolescents.

    Science.gov (United States)

    Kim, Jin Young; Kang, Hye Lim; Kim, Dae-Keun; Kang, Seung Wan; Park, Yoo Kyoung

    2017-07-01

    Recent study suggests that psychological issues and eating habits are closely related. In this study, we aimed to find the association between eating habits and intakes of artificial sweeteners with emotional states of schoolchildren using quantitatively analyzing objective biosignals. The study was conducted at the National Standard Reference Data Center for Korean EEG as a cross-sectional study. Three hundred eighteen healthy children who have not been diagnosed with neurologic or psychiatric disorders were evaluated (168 girls and 150 boys; mean age of 11.8 ± 3.6 years). Analysis indicators were a dietary intake checklist for children's nutrition-related behavior score (NBS), consisting of 19 items; food frequency questionnaires (FFQs), consisting of 76 items; the Child Depression Inventory (CDI); State-Trait Anxiety Inventory-State (STAI-S); State-Trait Anxiety Inventory-Trait (STAI-T); electroencephalograph (EEG); and heart rate variability (HRV). Higher scores on the CDI, STAI-S, and STAI-T indicate negative emotions, and these scores were significantly decreased from the first to the fourth quartiles. The HRV results showed that the standard deviation of all normal-to-normal (SDNN) intervals was significantly higher in the first quartile than in the fourth quartile (p healthy children and adolescents.

  11. Prediction and early detection of delirium in the intensive care unit by using heart rate variability and machine learning.

    Science.gov (United States)

    Oh, Jooyoung; Cho, Dongrae; Park, Jaesub; Na, Se Hee; Kim, Jongin; Heo, Jaeseok; Shin, Cheung Soo; Kim, Jae-Jin; Park, Jin Young; Lee, Boreom

    2018-03-27

    Delirium is an important syndrome found in patients in the intensive care unit (ICU), however, it is usually under-recognized during treatment. This study was performed to investigate whether delirious patients can be successfully distinguished from non-delirious patients by using heart rate variability (HRV) and machine learning. Electrocardiography data of 140 patients was acquired during daily ICU care, and HRV data were analyzed. Delirium, including its type, severity, and etiologies, was evaluated daily by trained psychiatrists. HRV data and various machine learning algorithms including linear support vector machine (SVM), SVM with radial basis function (RBF) kernels, linear extreme learning machine (ELM), ELM with RBF kernels, linear discriminant analysis, and quadratic discriminant analysis were utilized to distinguish delirium patients from non-delirium patients. HRV data of 4797 ECGs were included, and 39 patients had delirium at least once during their ICU stay. The maximum classification accuracy was acquired using SVM with RBF kernels. Our prediction method based on HRV with machine learning was comparable to previous delirium prediction models using massive amounts of clinical information. Our results show that autonomic alterations could be a significant feature of patients with delirium in the ICU, suggesting the potential for the automatic prediction and early detection of delirium based on HRV with machine learning.

  12. [Spectral analysis of Heart Rate Variability in psychiatric patients: autonomic nervous system evaluation in psychotic, anxiety and depressive disorders].

    Science.gov (United States)

    Lo Turco, Giovanni; Grimaldi Di Terresena, Liria

    2012-01-01

    The aim of this study was to test the primary hypothesis of altered Heart Rate Variability (HRV) and heart rate in a sample of patients with mental disorders and the secondary hypothesis of normalization of HRV values as a result of clinical improvement. The study was conducted on a sample of 90 patients with psychotic, anxiety and mood disorders. Each patient was subjected to detection of HRV and heart rate via a photoplethysmographic sensor and evaluated with rating scales based on the specific disorder. The parameters detected in the sample were compared with a control group of healthy subjects. There were no significant differences of cardiac autonomic modulation between the group of patients in whom is possible exclude the drug influence and the control group; significantly lower values of HRV parameters in the group of patients with drug influence, and especially in subgroup of psychotic patients, compared to controls, are, instead, detected. The study also shows a significant increase in heart rate as a common feature in mental disorders, regardless of treatment. Clinical improvement appears to promote the normalization of the variability in patients with high DS of tachogram. The study suggests a potential increased risk of cardiovascular mortality in patients, as evidenced by the increased values of heart rate, regardless of drug treatment. This risk is even more pronounced in psychotic patients in drug treatment because of the simultaneous significant reduction of HRV parameters.

  13. High Altitude Affects Nocturnal Non-linear Heart Rate Variability: PATCH-HA Study

    Directory of Open Access Journals (Sweden)

    Christopher J. Boos

    2018-04-01

    Full Text Available Background: High altitude (HA exposure can lead to changes in resting heart rate variability (HRV, which may be linked to acute mountain sickness (AMS development. Compared with traditional HRV measures, non-linear HRV appears to offer incremental and prognostic data, yet its utility and relationship to AMS have been barely examined at HA. This study sought to examine this relationship at terrestrial HA.Methods: Sixteen healthy British military servicemen were studied at baseline (800 m, first night and over eight consecutive nights, at a sleeping altitude of up to 3600 m. A disposable cardiac patch monitor was used, to record the nocturnal cardiac inter-beat interval data, over 1 h (0200–0300 h, for offline HRV assessment. Non-linear HRV measures included Sample entropy (SampEn, the short (α1, 4–12 beats and long-term (α2, 13–64 beats detrend fluctuation analysis slope and the correlation dimension (D2. The maximal rating of perceived exertion (RPE, during daily exercise, was assessed using the Borg 6–20 RPE scale.Results: All subjects completed the HA exposure. The average age of included subjects was 31.4 ± 8.1 years. HA led to a significant fall in SpO2 and increase in heart rate, LLS and RPE. There were no significant changes in the ECG-derived respiratory rate or in any of the time domain measures of HRV during sleep. The only notable changes in frequency domain measures of HRV were an increase in LF and fall in HFnu power at the highest altitude. Conversely, SampEn, SD1/SD2 and D2 all fell, whereas α1 and α2 increased (p < 0.05. RPE inversely correlated with SD1/SD2 (r = -0.31; p = 0.002, SampEn (r = -0.22; p = 0.03, HFnu (r = -0.27; p = 0.007 and positively correlated with LF (r = 0.24; p = 0.02, LF/HF (r = 0.24; p = 0.02, α1 (r = 0.32; p = 0.002 and α2 (r = 0.21; p = 0.04. AMS occurred in 7/16 subjects (43.8% and was very mild in 85.7% of cases. HRV failed to predict AMS.Conclusion: Non-linear HRV is more sensitive to the

  14. Sex and family history of cardiovascular disease influence heart rate variability during stress among healthy adults.

    Science.gov (United States)

    Emery, Charles F; Stoney, Catherine M; Thayer, Julian F; Williams, DeWayne; Bodine, Andrew

    2018-07-01

    Studies of sex differences in heart rate variability (HRV) typically have not accounted for the influence of family history (FH) of cardiovascular disease (CVD). This study evaluated sex differences in HRV response to speech stress among men and women (age range 30-49 years) with and without a documented FH of CVD. Participants were 77 adults (mean age = 39.8 ± 6.2 years; range: 30-49 years; 52% female) with positive FH (FH+, n = 32) and negative FH (FH-, n = 45) of CVD, verified with relatives of participants. Cardiac activity for all participants was recorded via electrocardiogram during a standardized speech stress task with three phases: 5-minute rest, 5-minute speech, and 5-minute recovery. Outcomes included time domain and frequency domain indicators of HRV and heart rate (HR) at rest and during stress. Data were analyzed with repeated measures analysis of variance, with sex and FH as between subject variables and time/phase as a within subject variable. Women exhibited higher HR than did men and greater HR reactivity in response to the speech stress. However, women also exhibited greater HRV in both the time and frequency domains. FH+ women generally exhibited elevated HRV, despite the elevated risk of CVD associated with FH+. Although women participants exhibited higher HR at rest and during stress, women (both FH+ and FH-) also exhibited elevated HRV reactivity, reflecting greater autonomic control. Thus, enhanced autonomic function observed in prior studies of HRV among women is also evident among FH+ women during a standardized stress task. Copyright © 2018 Elsevier Inc. All rights reserved.

  15. Physical Exercise Improves Heart Rate Variability in Patients with Type 2 Diabetes: A Systematic Review.

    Science.gov (United States)

    Villafaina, Santos; Collado-Mateo, Daniel; Fuentes, Juan Pedro; Merellano-Navarro, Eugenio; Gusi, Narcis

    2017-09-23

    The aim of the present systematic review is to provide an up-to-date analysis of the research on the effects of exercise programs on heart rate variability (HRV) in individuals with type 2 diabetes mellitus (T2DM). An electronic search of the literature (PubMed, PEDro and Web of Science) was performed. "HRV", "heart rate variability", "exercise", "physical" and "diabetes" were the terms used for article retrieval. Lastly, 15 articles were selected. PRISMA methodology was employed and data were extracted according to the PICOS approach. Although HRV is not routinely measured in the management of T2DM, it is an important measure due to its relation with mortality and diabetic neuropathy. Physical exercise has become a therapy for T2DM, because it improves physical fitness and functional capacity, enhances metabolic control and insulin sensitivity, reduces inflammatory markers and neuropathy symptoms and can increase the regenerative capacity of cutaneous axons, slowing or preventing neuropathy progression. However, it is not clear to what extent physical exercise can improve HRV in this population. Participation in the 15 selected studies was similar in men and women (48.01% men and 51.99% women). All the intervention programs included aerobic training, and it was complemented by strength training in four studies. Duration of physical exercise sessions ranged between 30 and 75 min, the frequency being between 2 and 7 days/week. Statistically significant improvements in groups with diabetes, relative to baseline, were observed in nine studies. More than 3 days per week of aerobic training, complemented by strength training, during at least 3 months seems to improve HRV in T2DM. Weekly frequency might be the most important factor to improve HRV. These aspects could help to design better programs based in scientific evidence, incorporating HRV as an important variable associated with diabetic neuropathy and mortality.

  16. [Evaluation of autonomic nervous system function with heart rate variability analysis in patients with hyperthyroidism and during euthyroidism after pharmacologic and surgical treatment].

    Science.gov (United States)

    Barczyński, M; Tabor, S; Thor, P

    1997-01-01

    The aim of the present study was both to estimate autonomic nervous system (ANS) function in patients with hyperthyroidism by the heart rate variability (HRV) analysis and to evaluate the impact of pharmacological and surgical treatment on the ANS function. Analysis of the HRV underwent 10 female patients in course of thyreotoxicosis and after reaching full clinical and biochemical euthyroidism, after pharmacological therapy and in month after surgical treatment. The 10 minutes records at rest, in horizontal position were evaluated. The HRV parameters like mean of the heart rate, mean of RR intervals, standard deviation of all normal RR intervals (SDNN), range of the heart rate variability, low frequency (LF), high frequency (HF) components of the heart rate power spectral density and LF/HF ratio were assessed. The results were compared to those obtained from 10 age-, sex-, and body mass index-matched control subjects. The statistical significance (p hyperthyroidism in comparison to the control group (151.6/346.8 ms; 2.4/0.74; 24.4/57.2 ms2). In course of pharmacological euthyroidism there were statistically significant (p hyperthyroidism (270/151.6 ms; 0.995/2.4; 39/24.4 ms2). In euthyroidism after surgical treatment all the above parameters kept the similar levels as in pharmacological euthyroidism (no statistical significance for p hyperthyroid patients there is advantage of sympathetic part of ANS over parasympathetic one which is due to sharp reduction of parasympathetic system activity. Pharmacological therapy with thyreostatics normalises balance of ANS to the level of the control group and after surgical treatment the balance keeps the same. Moreover, in the estimation of ANS as important as LF/HF ratio is the mean range of RR intervals.

  17. High resolution heart rate variability analysis in patients with angina pectoris during coronary artery bypass graft surgery

    Science.gov (United States)

    Mironov, V. A.; Mironova, T. F.; Kuvatov, V. A.; Nokhrina, O. Yu.; Kuvatova, E. V.

    2017-12-01

    The purpose of the study is approbation of the capabilities of high-resolution rhythmocardiography (RCG) for the determination of the actual cardiovascular status of operated patients with angina pectoris during coronary artery bypass graft surgery (CABGS) for myocardial revascularization. The research was done by means of a KAP-RK-02-Mikor hardware-software complex with a monitor record and the time- and frequency-domain analyses of heart rate variability (HRV). Monitor records were made at each stage of CABGS in 123 patients. As a result, HRV manifested itself as a fairly adequate and promising method for the determination of the cardiovascular status during CABGS. In addition, the data of the HRV study during CABGS testify to the capability of RCG to determine the high risk of life-threatening cardioarrhythmias before and during operation, to different changes in sinoatrial heart node (SN) dysregulation, and contain the HRV symptoms of a high death risk before, during and after shunting. The loss of the peripheral autonomic sympathetic and parasympathetic control in SN in the form of the autonomic cardioneuropathy syndrome is a predictor of the complications related to CABGS. The obtained data on RCG monitoring of HRV recording are suggestive of wide prospects of the high-resolution RCG method to be used in cardiac surgery as a whole. The actual multivariant dysregulations of SN pacemaker activity testify to its adequacy to the pathophysiology of each period of the cardiac operation, according to the initial ischemic damages and localization of cardiosurgical manipulations during CABGS.

  18. Exposure to Fine Particulate Matter Leads to Rapid Heart Rate Variability Changes

    Directory of Open Access Journals (Sweden)

    Michael Riediker

    2018-01-01

    Full Text Available Introduction: Heart Rate Variability (HRV reflects the adaptability of the heart to internal and external stimuli. Reduced HRV is a predictor of post-infarction mortality. We previously found in road maintenance workers HRV-increases several hours after exposure to fine particulate matter (PM2.5. This seemed to conflict with studies where PM-exposure acutely reduced HRV. We therefore assessed whether time from exposure to HRV-assessment could explain the differences observed.Methods: On five non-consecutive days, workers carried nephelometers providing 1-min-interval PM2.5-exposure. Five-min HRV-intervals of SDNN (Standard Deviation of Normal to Normal beat intervals and pNN50 (Percentage of the interval differences exceeding 50 ms were extracted from 24-h electrocardiograms (ECGs. Following 60 min PM2.5-exposure, changes in HRV-parameters were assessed during 120-min visually and by regression analysis with control for time at work, at home, and during the night using autoregressive integrating moving average (ARIMA models to account for autocorrelation of the time-series. Additional controls included changing the time windows and including body mass index (BMI and age in the models.Result: Pattern analysis of 12,669 data points showed high modulation of mean, standard deviation (SD, and time trend of HRV (SDNN and pNN50 at low, and much reduced modulation at high PM2.5-exposures. The time trend following exposure was highly symmetrical, resembling a funnel plot. Regression analysis showed significant associations of decreasing SDNN and pNN50 (average, SD, and absolute value of time trend with increasing PM2.5-exposure, which remained significant when controlling for activity phases. Changing time windows did not change the pattern of response. Including BMI and age did not change the results.Conclusions: The reduced modulation of HRV following PM2.5-exposure is striking. It suggests strong interference with homeostatic controls. Such an

  19. Music close to one's heart: heart rate variability with music, diagnostic with e-bra and smartphone

    Science.gov (United States)

    Hegde, Shantala; Kumar, Prashanth S.; Rai, Pratyush; Mathur, Gyanesh N.; Varadan, Vijay K.

    2012-04-01

    Music is a powerful elicitor of emotions. Emotions evoked by music, through autonomic correlates have been shown to cause significant modulation of parameters like heart rate and blood pressure. Consequently, Heart Rate Variability (HRV) analysis can be a powerful tool to explore evidence based therapeutic functions of music and conduct empirical studies on effect of musical emotion on heart function. However, there are limitations with current studies. HRV analysis has produced variable results to different emotions evoked via music, owing to variability in the methodology and the nature of music chosen. Therefore, a pragmatic understanding of HRV correlates of musical emotion in individuals listening to specifically chosen music whilst carrying out day to day routine activities is needed. In the present study, we aim to study HRV as a single case study, using an e-bra with nano-sensors to record heart rate in real time. The e-bra developed previously, has several salient features that make it conducive for this study- fully integrated garment, dry electrodes for easy use and unrestricted mobility. The study considers two experimental conditions:- First, HRV will be recorded when there is no music in the background and second, when music chosen by the researcher and by the subject is playing in the background.

  20. Classification of acute stress using linear and non-linear heart rate variability analysis derived from sternal ECG

    DEFF Research Database (Denmark)

    Tanev, George; Saadi, Dorthe Bodholt; Hoppe, Karsten

    2014-01-01

    Chronic stress detection is an important factor in predicting and reducing the risk of cardiovascular disease. This work is a pilot study with a focus on developing a method for detecting short-term psychophysiological changes through heart rate variability (HRV) features. The purpose of this pilot...... study is to establish and to gain insight on a set of features that could be used to detect psychophysiological changes that occur during chronic stress. This study elicited four different types of arousal by images, sounds, mental tasks and rest, and classified them using linear and non-linear HRV...

  1. Short-term versus long-term heart rate variability in ischemic cardiomyopathy risk stratification

    Directory of Open Access Journals (Sweden)

    Andreas eVoss

    2013-12-01

    Full Text Available In industrialized countries with aging populations, heart failure affects 0.3%-2% of the general population. The investigation of 24h-ECG recordings revealed the potential of nonlinear indices of heart rate variability (HRV for enhanced risk stratification in patients with ischemic heart failure (IHF. However, long-term analyses are time-consuming, expensive and delay the initial diagnosis. The objective of this study was to investigate whether 30min short-term HRV analysis is sufficient for comparable risk stratification in IHF in comparison to 24h-HRV analysis. From 256 IHF patients (221 at low risk (IHFLR and 35 at high risk (IHFHR a 24h beat-to-beat time series b the first 30min segment c the 30min most stationary day segment and d the 30min most stationary night segment were investigated. We calculated linear (time and frequency domain and nonlinear HRV analysis indices. Optimal parameter sets for risk stratification in IHF were determined for 24 hours and for each 30min segment by applying discriminant analysis on significant clinical and non-clinical indices. Long- and short-term HRV indices from frequency domain and particularly from nonlinear dynamics revealed high univariate significances (p

  2. Robust cluster analysis and variable selection

    CERN Document Server

    Ritter, Gunter

    2014-01-01

    Clustering remains a vibrant area of research in statistics. Although there are many books on this topic, there are relatively few that are well founded in the theoretical aspects. In Robust Cluster Analysis and Variable Selection, Gunter Ritter presents an overview of the theory and applications of probabilistic clustering and variable selection, synthesizing the key research results of the last 50 years. The author focuses on the robust clustering methods he found to be the most useful on simulated data and real-time applications. The book provides clear guidance for the varying needs of bot

  3. EEG, HRV and Psychological Correlates while Playing Bejeweled II: A Randomized Controlled Study.

    Science.gov (United States)

    Russoniello, Carmen V; O'Brien, Kevin; Parks, Jennifer M

    2009-01-01

    Stress related medical disorders such as cardiovascular disease, diabetes, depression, and anxiety are serious medical issues that can cause disability and death. Interventions to prevent their development and exacerbation are needed. Casual video games (CVGs) are fun, easy to play, spontaneous and tremendously popular. People report that they play these games because they decrease their stress and improve their mood. This study tested this theory by comparing people playing Bejeweled II a popular CVG with control subjects measured under similar conditions. Electroencephalographic (EEG) changes after playing Bejeweled II were consistent with increased mood and corroborated with similar findings on psychological reports. Moreover, heart rate variability (HRV) changes consistent with autonomic nervous system relaxation or decreased physical stress were also recorded. It is concluded, therefore, that playing a CVG like Bejeweled II can increase mood and decrease stress. These finding have broad implications and include the potential development of prescriptive interventions using Bejeweled II to prevent and treat stress related medical disorders. Finally, these findings demonstrate a method using EEG, HRV and psychological correlates to understand the psychophysiological or cybernetic interconnection between participant and video game.

  4. Spectral analysis of cardiac rate variability Análisis espectral de la variabilidad de la frecuencia cardíaca

    Directory of Open Access Journals (Sweden)

    Diego Luis Alvarez Montoya

    1999-02-01

    Full Text Available In the last years relationship between autonomic nervous system (ANS function and cardiovascular mortality has been recognized. This has motivated research to find quantitative markers of autonomic balance. Heart rate variability (HRV is one of the most promising methods. HRV is defined as the variations occurred in the time interval between consecutive heartbeats and it is thought to depend on the ANS modulation. Tacogram (recording of cardiac frequency in time is used to evaluate HRV. The study of HRV started 30 years ago and has gained importance in the last 10 years. There are several methods to evaluate HRV. The most accepted today are frequency domain methods (spectral analysis. Spectral analysis consists in the decomposition in order to obtain the spectral components. There are high frequency components (HF, related to vagal tone, low frequency (LF components, related to the modulation of both sympathetic and vagal modulation, and very low frequency components which have not been related to any physiological variable. Time domain methods, are basically statistic and evaluate variability using means and standard deviations. These methods seem to have less advantages than spectral methods. HRV is correlated with physiological adaptations to changes in internal and external environment and to the presence of diseases. This article presents the main techniques in the time and frequency domains and their relationship with physiological changes and specific diseases. En los últimos años, se ha reconocido la relación existente entre el funcionamiento del sistema nervioso autónomo (SNA y la mortalidad cardiovascular. Esto ha motivado la búsqueda de marcadores cuantitativos del balance autonómico. La Variabilidad de la Frecuencia Cardíaca (VFC representa uno de los más promisorios. La VFC se define como la variación que ocurre en el intervalo de tiempo entre latidos consecutivos y se ha propuesto que su comportamiento depende de la

  5. Scalable conditional induction variables (CIV) analysis

    DEFF Research Database (Denmark)

    Oancea, Cosmin Eugen; Rauchwerger, Lawrence

    2015-01-01

    parallelizing compiler and evaluated its impact on five Fortran benchmarks. We have found that that there are many important loops using CIV subscripts and that our analysis can lead to their scalable parallelization. This in turn has led to the parallelization of the benchmark programs they appear in.......Subscripts using induction variables that cannot be expressed as a formula in terms of the enclosing-loop indices appear in the low-level implementation of common programming abstractions such as filter, or stack operations and pose significant challenges to automatic parallelization. Because...... the complexity of such induction variables is often due to their conditional evaluation across the iteration space of loops we name them Conditional Induction Variables (CIV). This paper presents a flow-sensitive technique that summarizes both such CIV-based and affine subscripts to program level, using the same...

  6. Multiscale Entropy Analysis of Heart Rate Variability for Assessing the Severity of Sleep Disordered Breathing

    Directory of Open Access Journals (Sweden)

    Wen-Yao Pan

    2015-01-01

    Full Text Available Obstructive sleep apnea (OSA is an independent cardiovascular risk factor to which autonomic nervous dysfunction has been reported to be an important contributor. Ninety subjects recruited from the sleep center of a single medical center were divided into four groups: normal snoring subjects without OSA (apnea hypopnea index, AHI < 5, n = 11, mild OSA (5 ≤ AHI < 15, n = 10, moderate OSA (15 ≤ AHI < 30, n = 24, and severe OSA (AHI ≥ 30, n = 45. Demographic (i.e., age, gender, anthropometric (i.e., body mass index, neck circumference, and polysomnographic (PSG data were recorded and compared among the different groups. For each subject, R-R intervals (RRI from 10 segments of 10-minute electrocardiogram recordings during non-rapid eye movement sleep at stage N2 were acquired and analyzed for heart rate variability (HRV and sample entropy using multiscale entropy index (MEI that was divided into small scale (MEISS, scale 1–5 and large scale (MEILS, scale 6–10. Our results not only demonstrated that MEISS could successfully distinguish normal snoring subjects and those with mild OSA from those with moderate and severe disease, but also revealed good correlation between MEISS and AHI with Spearman correlation analysis (r = −0.684, p < 0.001. Therefore, using the two parameters of EEG and ECG, MEISS may serve as a simple preliminary screening tool for assessing the severity of OSA before proceeding to PSG analysis.

  7. Fractal scaling behavior of heart rate variability in response to meditation techniques

    International Nuclear Information System (INIS)

    Alvarez-Ramirez, J.; Rodríguez, E.; Echeverría, J.C.

    2017-01-01

    Highlights: • The scaling properties of heart rate variability in premeditation and meditation states were studied. • Mindfulness meditation induces a decrement of the HRV long-range scaling correlations. • Mindfulness meditation can be regarded as a type of induced deep sleep-like dynamics. - Abstract: The rescaled range (R/S) analysis was used for analyzing the fractal scaling properties of heart rate variability (HRV) of subjects undergoing premeditation and meditation states. Eight novice subjects and four advanced practitioners were considered. The corresponding pre-meditation and meditation HRV data were obtained from the Physionet database. The results showed that mindfulness meditation induces a decrement of the HRV long-range scaling correlations as quantified with the time-variant Hurst exponent. The Hurst exponent for advanced meditation practitioners decreases up to values of 0.5, reflecting uncorrelated (e.g., white noise-like) HRV dynamics. Some parallelisms between mindfulness meditation and deep sleep (Stage 4) are discussed, suggesting that the former can be regarded as a type of induced deep sleep-like dynamics.

  8. Can Wearable Devices Accurately Measure Heart Rate Variability? A Systematic Review.

    Science.gov (United States)

    Georgiou, Konstantinos; Larentzakis, Andreas V; Khamis, Nehal N; Alsuhaibani, Ghadah I; Alaska, Yasser A; Giallafos, Elias J

    2018-03-01

    A growing number of wearable devices claim to provide accurate, cheap and easily applicable heart rate variability (HRV) indices. This is mainly accomplished by using wearable photoplethysmography (PPG) and/or electrocardiography (ECG), through simple and non-invasive techniques, as a substitute of the gold standard RR interval estimation through electrocardiogram. Although the agreement between pulse rate variability (PRV) and HRV has been evaluated in the literature, the reported results are still inconclusive especially when using wearable devices. The purpose of this systematic review is to investigate if wearable devices provide a reliable and precise measurement of classic HRV parameters in rest as well as during exercise. A search strategy was implemented to retrieve relevant articles from MEDLINE and SCOPUS databases, as well as, through internet search. The 308 articles retrieved were reviewed for further evaluation according to the predetermined inclusion/exclusion criteria. Eighteen studies were included. Sixteen of them integrated ECG - HRV technology and two of them PPG - PRV technology. All of them examined wearable devices accuracy in RV detection during rest, while only eight of them during exercise. The correlation between classic ECG derived HRV and the wearable RV ranged from very good to excellent during rest, yet it declined progressively as exercise level increased. Wearable devices may provide a promising alternative solution for measuring RV. However, more robust studies in non-stationary conditions are needed using appropriate methodology in terms of number of subjects involved, acquisition and analysis techniques implied.

  9. Visibility graph analysis of very short-term heart rate variability during sleep

    Science.gov (United States)

    Hou, F. Z.; Li, F. W.; Wang, J.; Yan, F. R.

    2016-09-01

    Based on a visibility-graph algorithm, complex networks were constructed from very short-term heart rate variability (HRV) during different sleep stages. Network measurements progressively changed from rapid eye movement (REM) sleep to light sleep and then deep sleep, exhibiting promising ability for sleep assessment. Abnormal activation of the cardiovascular controls with enhanced 'small-world' couplings and altered fractal organization during REM sleep indicates that REM could be a potential risk factor for adverse cardiovascular event, especially in males, older individuals, and people who are overweight. Additionally, an apparent influence of gender, aging, and obesity on sleep was demonstrated in healthy adults, which may be helpful for establishing expected sleep-HRV patterns in different populations.

  10. Heart rate variability measured early in patients with evolving acute coronary syndrome and 1-year outcomes of rehospitalization and mortality

    Directory of Open Access Journals (Sweden)

    Harris PR

    2014-08-01

    Full Text Available Patricia R E Harris,1 Phyllis K Stein,2 Gordon L Fung,3 Barbara J Drew4 1Electrocardiographic Monitoring Research Laboratory, School of Nursing, Department of Physiological Nursing, University of California, San Francisco, CA, USA; 2Heart Rate Variability Laboratory, School of Medicine, Division of Cardiology, Washington University, St Louis, MO, USA; 3Cardiology Services, Mount Zion, Department of Medicine, Division of Cardiology, University of California, San Francisco, CA, USA; 4School of Nursing, Department of Physiological Nursing, Division of Cardiology, University of California, San Francisco, CA, USA Objective: This study sought to examine the prognostic value of heart rate variability (HRV measurement initiated immediately after emergency department presentation for patients with acute coronary syndrome (ACS. Background: Altered HRV has been associated with adverse outcomes in heart disease, but the value of HRV measured during the earliest phases of ACS related to risk of 1-year rehospitalization and death has not been established. Methods: Twenty-four-hour Holter recordings of 279 patients with ACS were initiated within 45 minutes of emergency department arrival; recordings with ≥18 hours of sinus rhythm were selected for HRV analysis (number [N] =193. Time domain, frequency domain, and nonlinear HRV were examined. Survival analysis was performed. Results: During the 1-year follow-up, 94 patients were event-free, 82 were readmitted, and 17 died. HRV was altered in relation to outcomes. Predictors of rehospitalization included increased normalized high frequency power, decreased normalized low frequency power, and decreased low/high frequency ratio. Normalized high frequency >42 ms2 predicted rehospitalization while controlling for clinical variables (hazard ratio [HR] =2.3; 95% confidence interval [CI] =1.4–3.8, P=0.001. Variables significantly associated with death included natural logs of total power and ultra low frequency

  11. Autonomic dysfunction in HIV patients on antiretroviral therapy: studies of heart rate variability

    DEFF Research Database (Denmark)

    Lebech, Anne-Mette; Kristoffersen, Ulrik Sloth; Mehlsen, Jesper

    2007-01-01

    of healthy volunteers (n = 12) were included. All were non-smokers, non-diabetic and had never received medication for dyslipidaemia or hypertension. Following a 10 min resting period a 5 min ECG recording was performed. Heart rate variability (HRV) analysis was performed in accordance with current...

  12. Heart rate variability in workers of various professions in contrasting seasons of the year

    Directory of Open Access Journals (Sweden)

    Alexander Markov

    2016-10-01

    Full Text Available Objectives: It is known that professional occupation affects the heart rate variability (HRV. However, most studies have not taken into account seasonal features of the HRV. The aim of this study has been to evaluate the HRV differences in winter and in summer in the case of the Ministry of the Russian Federation for Civil Defense, Emergencies and Elimination of Consequences of Natural Disasters (EMERCOM workers and scientific workers from the Komi Science Center of the Ural Branch of the Russian Academy of Sciences. Material and Methods: The short-term HRV was examined for 13 EMERCOM workers and 13 scientific workers. The data was collected in winter (December and summer (July for the same groups of workers. The time domain and frequency domain HRV analyses were performed. The EMERCOM workers had more contact with the external environment than the scientific workers. Results: The two-way analysis of variance with repeated observations on a single factor has shown that “Season” and interaction of two factors “Season” and “Profession” significantly influenced the HRV among volunteers. The “Profession” factor did not influence the HRV parameters (except for the heart rate in winter, p = 0.042. Seasonal changes in the HRV parameters were not significant in the case of scientific workers. In contrast, the EMERCOM workers showed significantly decreased parameters of parasympathetic activity (the root-mean-square of successive differences in RR intervals, percentage of consecutive RR intervals differing by > 50 ms and the relative value high frequency power, p = 0.001, p = 0.014 and p = 0.009, respectively and increased parameters of sympathetic activity (the stress index and ratio of low-frequency power to high-frequency power, p = 0.012 and p = 0.006, respectively in winter as compared to summer. Conclusions: The results of our study indicate that, unlike the scientific workers, the EMERCOM workers showed significant changes in the

  13. Methodological Framework for Estimating the Correlation Dimension in HRV Signals

    Directory of Open Access Journals (Sweden)

    Juan Bolea

    2014-01-01

    Full Text Available This paper presents a methodological framework for robust estimation of the correlation dimension in HRV signals. It includes (i a fast algorithm for on-line computation of correlation sums; (ii log-log curves fitting to a sigmoidal function for robust maximum slope estimation discarding the estimation according to fitting requirements; (iii three different approaches for linear region slope estimation based on latter point; and (iv exponential fitting for robust estimation of saturation level of slope series with increasing embedded dimension to finally obtain the correlation dimension estimate. Each approach for slope estimation leads to a correlation dimension estimate, called D^2, D^2⊥, and D^2max. D^2 and D^2max estimate the theoretical value of correlation dimension for the Lorenz attractor with relative error of 4%, and D^2⊥ with 1%. The three approaches are applied to HRV signals of pregnant women before spinal anesthesia for cesarean delivery in order to identify patients at risk for hypotension. D^2 keeps the 81% of accuracy previously described in the literature while D^2⊥ and D^2max approaches reach 91% of accuracy in the same database.

  14. Nonlinear Methods to Assess Changes in Heart Rate Variability in Type 2 Diabetic Patients

    Energy Technology Data Exchange (ETDEWEB)

    Bhaskar, Roy, E-mail: imbhaskarall@gmail.com [Indian Institute of Technology (India); University of Connecticut, Farmington, CT (United States); Ghatak, Sobhendu [Indian Institute of Technology (India)

    2013-10-15

    Heart rate variability (HRV) is an important indicator of autonomic modulation of cardiovascular function. Diabetes can alter cardiac autonomic modulation by damaging afferent inputs, thereby increasing the risk of cardiovascular disease. We applied nonlinear analytical methods to identify parameters associated with HRV that are indicative of changes in autonomic modulation of heart function in diabetic patients. We analyzed differences in HRV patterns between diabetic and age-matched healthy control subjects using nonlinear methods. Lagged Poincaré plot, autocorrelation, and detrended fluctuation analysis were applied to analyze HRV in electrocardiography (ECG) recordings. Lagged Poincare plot analysis revealed significant changes in some parameters, suggestive of decreased parasympathetic modulation. The detrended fluctuation exponent derived from long-term fitting was higher than the short-term one in the diabetic population, which was also consistent with decreased parasympathetic input. The autocorrelation function of the deviation of inter-beat intervals exhibited a highly correlated pattern in the diabetic group compared with the control group. The HRV pattern significantly differs between diabetic patients and healthy subjects. All three statistical methods employed in the study may prove useful to detect the onset and extent of autonomic neuropathy in diabetic patients.

  15. Nonlinear Methods to Assess Changes in Heart Rate Variability in Type 2 Diabetic Patients

    International Nuclear Information System (INIS)

    Bhaskar, Roy; Ghatak, Sobhendu

    2013-01-01

    Heart rate variability (HRV) is an important indicator of autonomic modulation of cardiovascular function. Diabetes can alter cardiac autonomic modulation by damaging afferent inputs, thereby increasing the risk of cardiovascular disease. We applied nonlinear analytical methods to identify parameters associated with HRV that are indicative of changes in autonomic modulation of heart function in diabetic patients. We analyzed differences in HRV patterns between diabetic and age-matched healthy control subjects using nonlinear methods. Lagged Poincaré plot, autocorrelation, and detrended fluctuation analysis were applied to analyze HRV in electrocardiography (ECG) recordings. Lagged Poincare plot analysis revealed significant changes in some parameters, suggestive of decreased parasympathetic modulation. The detrended fluctuation exponent derived from long-term fitting was higher than the short-term one in the diabetic population, which was also consistent with decreased parasympathetic input. The autocorrelation function of the deviation of inter-beat intervals exhibited a highly correlated pattern in the diabetic group compared with the control group. The HRV pattern significantly differs between diabetic patients and healthy subjects. All three statistical methods employed in the study may prove useful to detect the onset and extent of autonomic neuropathy in diabetic patients

  16. Scalable conditional induction variables (CIV) analysis

    KAUST Repository

    Oancea, Cosmin E.

    2015-02-01

    Subscripts using induction variables that cannot be expressed as a formula in terms of the enclosing-loop indices appear in the low-level implementation of common programming abstractions such as Alter, or stack operations and pose significant challenges to automatic parallelization. Because the complexity of such induction variables is often due to their conditional evaluation across the iteration space of loops we name them Conditional Induction Variables (CIV). This paper presents a flow-sensitive technique that summarizes both such CIV-based and affine subscripts to program level, using the same representation. Our technique requires no modifications of our dependence tests, which is agnostic to the original shape of the subscripts, and is more powerful than previously reported dependence tests that rely on the pairwise disambiguation of read-write references. We have implemented the CIV analysis in our parallelizing compiler and evaluated its impact on five Fortran benchmarks. We have found that that there are many important loops using CIV subscripts and that our analysis can lead to their scalable parallelization. This in turn has led to the parallelization of the benchmark programs they appear in.

  17. Heart rate variability to assess ventilatory thresholds in professional basketball players

    OpenAIRE

    Domingo Jesús Ramos-Campo; Jacobo A. Rubio-Arias; Vicente Ávila-Gandía; Cristian Marín-Pagán; Antonio Luque; Pedro E. Alcaraz

    2017-01-01

    Purpose: The aim of this study was to determine if heart rate variability (HRV) during incremental test could be used to estimate ventilatory threshold (VT) in professional basketball players, with sufficient precision to be used in their training. Furthermore, the second aim was to analyse the association between HRV and 3 methods of VT determination by gas analysis. Methods: Twenty-four professional basketball players (age: 23.4 ± 4.9 years; height: 195.4 ± 9.8 cm; body mass: 92.2 ± 11.9...

  18. Feasibility, Reliability and Predictive Value Of In-Ambulance Heart Rate Variability Registration

    NARCIS (Netherlands)

    Yperzeele, Laetitia; van Hooff, Robbert-Jan; De Smedt, Ann; Nagels, Guy; Hubloue, Ives; De Keyser, Jacques; Brouns, Raf

    2016-01-01

    Background Heart rate variability (HRV) is a parameter of autonomic nervous system function. A decrease of HRV has been associated with disease severity, risk of complications and prognosis in several conditions. Objective We aim to investigate the feasibility and the reliability of in-ambulance HRV

  19. Advances in heart rate variability signal analysis: joint position statement by the e-Cardiology ESC Working Group and the European Heart Rhythm Association co-endorsed by the Asia Pacific Heart Rhythm Society.

    Science.gov (United States)

    Sassi, Roberto; Cerutti, Sergio; Lombardi, Federico; Malik, Marek; Huikuri, Heikki V; Peng, Chung-Kang; Schmidt, Georg; Yamamoto, Yoshiharu

    2015-09-01

    Following the publication of the Task Force document on heart rate variability (HRV) in 1996, a number of articles have been published to describe new HRV methodologies and their application in different physiological and clinical studies. This document presents a critical review of the new methods. A particular attention has been paid to methodologies that have not been reported in the 1996 standardization document but have been more recently tested in sufficiently sized populations. The following methods were considered: Long-range correlation and fractal analysis; Short-term complexity; Entropy and regularity; and Nonlinear dynamical systems and chaotic behaviour. For each of these methods, technical aspects, clinical achievements, and suggestions for clinical application were reviewed. While the novel approaches have contributed in the technical understanding of the signal character of HRV, their success in developing new clinical tools, such as those for the identification of high-risk patients, has been rather limited. Available results obtained in selected populations of patients by specialized laboratories are nevertheless of interest but new prospective studies are needed. The investigation of new parameters, descriptive of the complex regulation mechanisms of heart rate, has to be encouraged because not all information in the HRV signal is captured by traditional methods. The new technologies thus could provide after proper validation, additional physiological, and clinical meaning. Multidisciplinary dialogue and specialized courses in the combination of clinical cardiology and complex signal processing methods seem warranted for further advances in studies of cardiac oscillations and in the understanding normal and abnormal cardiac control processes. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

  20. Linear and nonlinear analysis of heart rate variability in healthy subjects and after acute myocardial infarction in patients

    Directory of Open Access Journals (Sweden)

    V.C. Kunz

    2012-05-01

    Full Text Available The objectives of this study were to evaluate and compare the use of linear and nonlinear methods for analysis of heart rate variability (HRV in healthy subjects and in patients after acute myocardial infarction (AMI. Heart rate (HR was recorded for 15 min in the supine position in 10 patients with AMI taking β-blockers (aged 57 ± 9 years and in 11 healthy subjects (aged 53 ± 4 years. HRV was analyzed in the time domain (RMSSD and RMSM, the frequency domain using low- and high-frequency bands in normalized units (nu; LFnu and HFnu and the LF/HF ratio and approximate entropy (ApEn were determined. There was a correlation (P < 0.05 of RMSSD, RMSM, LFnu, HFnu, and the LF/HF ratio index with the ApEn of the AMI group on the 2nd (r = 0.87, 0.65, 0.72, 0.72, and 0.64 and 7th day (r = 0.88, 0.70, 0.69, 0.69, and 0.87 and of the healthy group (r = 0.63, 0.71, 0.63, 0.63, and 0.74, respectively. The median HRV indexes of the AMI group on the 2nd and 7th day differed from the healthy group (P < 0.05: RMSSD = 10.37, 19.95, 24.81; RMSM = 23.47, 31.96, 43.79; LFnu = 0.79, 0.79, 0.62; HFnu = 0.20, 0.20, 0.37; LF/HF ratio = 3.87, 3.94, 1.65; ApEn = 1.01, 1.24, 1.31, respectively. There was agreement between the methods, suggesting that these have the same power to evaluate autonomic modulation of HR in both AMI patients and healthy subjects. AMI contributed to a reduction in cardiac signal irregularity, higher sympathetic modulation and lower vagal modulation.

  1. Heart rate variability: a tool to explore the sleeping brain?

    Directory of Open Access Journals (Sweden)

    Florian eChouchou

    2014-12-01

    Full Text Available Sleep is divided into two main sleep stages: 1 non-rapid eye movement sleep (non-REMS, characterized among others by reduced global brain activity; and 2 rapid eye movement sleep (REMS, characterized by global brain activity similar to that of wakefulness. Results of heart rate variability (HRV analysis, which is widely used to explore autonomic modulation, have revealed higher parasympathetic tone during normal non-REMS and a shift toward sympathetic predominance during normal REMS. Moreover, HRV analysis combined with brain imaging has identified close connectivity between autonomic cardiac modulation and activity in brain areas such as the amygdala and insular cortex during REMS, but no connectivity between brain and cardiac activity during non-REMS. There is also some evidence for an association between HRV and dream intensity and emotionality. Following some technical considerations, this review addresses how brain activity during sleep contributes to changes in autonomic cardiac activity, organized into three parts: 1 the knowledge on autonomic cardiac control, 2 differences in brain and autonomic activity between non-REMS and REMS, and 3 the potential of HRV analysis to explore the sleeping brain, and the implications for psychiatric disorders.

  2. Automatic sleep staging using empirical mode decomposition, discrete wavelet transform, time-domain, and nonlinear dynamics features of heart rate variability signals.

    Science.gov (United States)

    Ebrahimi, Farideh; Setarehdan, Seyed-Kamaledin; Ayala-Moyeda, Jose; Nazeran, Homer

    2013-10-01

    The conventional method for sleep staging is to analyze polysomnograms (PSGs) recorded in a sleep lab. The electroencephalogram (EEG) is one of the most important signals in PSGs but recording and analysis of this signal presents a number of technical challenges, especially at home. Instead, electrocardiograms (ECGs) are much easier to record and may offer an attractive alternative for home sleep monitoring. The heart rate variability (HRV) signal proves suitable for automatic sleep staging. Thirty PSGs from the Sleep Heart Health Study (SHHS) database were used. Three feature sets were extracted from 5- and 0.5-min HRV segments: time-domain features, nonlinear-dynamics features and time-frequency features. The latter was achieved by using empirical mode decomposition (EMD) and discrete wavelet transform (DWT) methods. Normalized energies in important frequency bands of HRV signals were computed using time-frequency methods. ANOVA and t-test were used for statistical evaluations. Automatic sleep staging was based on HRV signal features. The ANOVA followed by a post hoc Bonferroni was used for individual feature assessment. Most features were beneficial for sleep staging. A t-test was used to compare the means of extracted features in 5- and 0.5-min HRV segments. The results showed that the extracted features means were statistically similar for a small number of features. A separability measure showed that time-frequency features, especially EMD features, had larger separation than others. There was not a sizable difference in separability of linear features between 5- and 0.5-min HRV segments but separability of nonlinear features, especially EMD features, decreased in 0.5-min HRV segments. HRV signal features were classified by linear discriminant (LD) and quadratic discriminant (QD) methods. Classification results based on features from 5-min segments surpassed those obtained from 0.5-min segments. The best result was obtained from features using 5-min HRV

  3. Cardiac Autonomic Responses during Exercise and Post-exercise Recovery Using Heart Rate Variability and Systolic Time Intervals—A Review

    Science.gov (United States)

    Michael, Scott; Graham, Kenneth S.; Davis, Glen M.

    2017-01-01

    Cardiac parasympathetic activity may be non-invasively investigated using heart rate variability (HRV), although HRV is not widely accepted to reflect sympathetic activity. Instead, cardiac sympathetic activity may be investigated using systolic time intervals (STI), such as the pre-ejection period. Although these autonomic indices are typically measured during rest, the “reactivity hypothesis” suggests that investigating responses to a stressor (e.g., exercise) may be a valuable monitoring approach in clinical and high-performance settings. However, when interpreting these indices it is important to consider how the exercise dose itself (i.e., intensity, duration, and modality) may influence the response. Therefore, the purpose of this investigation was to review the literature regarding how the exercise dosage influences these autonomic indices during exercise and acute post-exercise recovery. There are substantial methodological variations throughout the literature regarding HRV responses to exercise, in terms of exercise protocols and HRV analysis techniques. Exercise intensity is the primary factor influencing HRV, with a greater intensity eliciting a lower HRV during exercise up to moderate-high intensity, with minimal change observed as intensity is increased further. Post-exercise, a greater preceding intensity is associated with a slower HRV recovery, although the dose-response remains unclear. A longer exercise duration has been reported to elicit a lower HRV only during low-moderate intensity and when accompanied by cardiovascular drift, while a small number of studies have reported conflicting results regarding whether a longer duration delays HRV recovery. “Modality” has been defined multiple ways, with limited evidence suggesting exercise of a greater muscle mass and/or energy expenditure may delay HRV recovery. STI responses during exercise and recovery have seldom been reported, although limited data suggests that intensity is a key

  4. Exposure to Discrimination and Heart Rate Variability Reactivity to Acute Stress among Women with Diabetes.

    Science.gov (United States)

    Wagner, Julie; Lampert, Rachel; Tennen, Howard; Feinn, Richard

    2015-08-01

    Exposure to racial discrimination has been linked to physiological reactivity. This study investigated self-reported exposure to racial discrimination and parasympathetic [high-frequency heart rate variability (HF-HRV)] and sympathetic (norepinephrine and cortisol) activity at baseline and then again after acute laboratory stress. Lifetime exposure to racial discrimination was measured with the Schedule of Racist Events scale. Thirty-two women (16 Black and 16 White) with type 2 diabetes performed a public speaking stressor. Beat-to-beat intervals were recorded on electrocardiograph recorders, and HF-HRV was calculated using spectral analysis and natural log transformed. Norepinephrine and cortisol were measured in blood. Higher discrimination predicted lower stressor HF-HRV, even after controlling for baseline HF-HRV. When race, age, A1c and baseline systolic blood pressure were also controlled, racial discrimination remained a significant independent predictor of stressor HF-HRV. There was no association between lifetime discrimination and sympathetic markers. In conclusion, preliminary data suggest that among women with type 2 diabetes mellitus (T2DM), exposure to racial discrimination is adversely associated with parasympathetic, but not sympathetic, reactivity. Copyright © 2013 John Wiley & Sons, Ltd.

  5. Precompetitive assessment of heart rate variability in elite female athletes during play offs.

    Science.gov (United States)

    D'Ascenzi, Flavio; Alvino, Federico; Natali, Benedetta M; Cameli, Matteo; Palmitesta, Paola; Boschetti, Giampaolo; Bonifazi, Marco; Mondillo, Sergio

    2014-05-01

    Heart rate variability (HRV) has been rarely applied in elite athletes prior to competition. The aim of this study was to examine the changes in HRV in elite female volleyball players before a stressful match during play offs and to evaluate the impact on sport-specific performance. A short-term resting HRV analysis was applied right after the night sleep in ten female athletes 1 and 2 days prior to the match and the day of the competition. Approaching the decisive match, RR interval, resting heart rate (HR), pNN50, rMSDD and SD1 did not significantly vary. SD2 significantly increased in comparison with first-day measurement (Psports exhibit a slight change in HRV prior to a decisive competition, without a pronounced variation of the autonomic nervous system activity. A day-to-day HRV measurement could be a useful tool to evaluate the impact of a competition on the autonomic nervous system in athletes, also considering the relationship between sympathetic activity and athletic performance. © 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  6. Heart Rate Variability of Athletes Across Concussion Recovery Milestones: A Preliminary Study.

    Science.gov (United States)

    Senthinathan, Arrani; Mainwaring, Lynda M; Hutchison, Michael

    2017-05-01

    To assess heart rate variability (HRV) in athletes with concussion across three phases of recovery. A prospective matched control group design included the collection of HRV and symptoms measured by the Rivermead Post-Concussion Questionnaire. These measures were taken at 3 phases of recovery [(1) symptomatic; (2). asymptomatic; and (3) one-week after return-to-play (RTP)]. The same protocol was completed by noninjured athletes. Interuniversity sports teams at a single institution. 11 athletes, across 7 sports, diagnosed with concussion, and 11 matched-athlete controls volunteered for the study. Physician diagnosed concussion and a sitting to standing protocol for HRV monitoring. The frequency, time, and nonlinear domains of HRV were assessed along with the absolute difference between sitting and standing for each. A 2 x 3 (group x phase) repeated-measures analysis of variance revealed significant interactions for sitting High Frequency (HF) norm, sitting Low Frequency (LF) norm, the difference between sitting and standing HF norm, and difference between sitting and standing LF norm. Acutely, athletes with concussion displayed increased LF norm and decreased HF norm while sitting and a decreased change in their HF and LF norm measures between sitting and standing. A significant group effect for sample entropy when standing was detected, with the concussed group displaying decreased values compared with the matched controls. Athletes with concussion displayed autonomic dysfunction in some measures of HRV that persisted beyond RTP and were related to a previous history of concussion.

  7. Effects of fluid overload on heart rate variability in chronic kidney disease patients on hemodialysis.

    Science.gov (United States)

    Ferrario, Manuela; Moissl, Ulrich; Garzotto, Francesco; Cruz, Dinna N; Clementi, Anna; Brendolan, Alessandra; Tetta, Ciro; Gatti, Emanuele; Signorini, Maria G; Cerutti, Sergio; Ronco, Claudio

    2014-02-04

    While fluid overload (FO) and alterations in the autonomic nervous system (ANS) such as hypersympathetic activity, are known risk factors for cardiovascular morbidity and mortality in patients on chronic hemodialysis (HD), their relationship has not been thoroughly studied. In this observational study involving 69 patients on chronic HD, FO was assessed by whole body bioimpedance measurements before the midweek HD session and ANS activity reflected by Heart Rate Variability (HRV) was measured using 24-hour Holter electrocardiogram recordings starting before the same HD treatment. In total, 13 different HRV indices were analyzed, comprising a mixture of time domain, frequency domain and complexity parameters. A correlation analysis was performed between the HRV indices and hydration status indices. Successively, patients were retrospectively assigned to a high FO (H, FO > 2.5 L) or low FO (L, FO ≤ 2.5 L) group and these were further compared also after stratification by diabetes mellitus. Finally, a small number of patients without diabetes with significant and persistent FO were followed up for 3 months post-study to investigate how normalization of fluid status affects HRV. SDANN, VLF, LZC and HF% parameters significantly correlate with FO (correlation coefficients were respectively r = -0.40, r = -0.37, r = -0.28 and r = 0.26, p-value hydration status (correlation coefficients were respectively r = -0.31 and r = -0.33, p-value hydration status is accompanied by improved HRV.

  8. The level of intelligence and heart rate variability in men after myocardial infarction.

    Science.gov (United States)

    Pecyna, M B

    2006-09-01

    Heart rate variability (HRV) reflects periodic changes taking place in heart rhythm, which are controlled by the autonomic nervous system (ANS) and external factors. The aim of the present study was to assess the relationship between HRV and the level of intelligence using the Raven Advanced Matrices Test in 95 men (mean age 41.6 +/-3.7 SD yr) who experienced myocardial infarction during two years preceding the psychophysiological examination. HRV was analyzed from the EEG signal recordings in the time and spectral domains. It was found that post-myocardial infarct men of the higher than average intelligence had significantly increased HRV; the finding was reflected in the analysis of both time and frequency domains. Although both sympathetic and parasympathetic components showed an increase in the frequency domain, the former did disproportionately more, achieving substantial predominance. The results indicate that active mental processes and attitude, linked to a higher intelligence level, might be a beneficial prognostic marker, as is higher HRV, for the overall post-infarction cardiac mortality and for return of such subjects back to normal life. The corollary is that the assessment of IQ in post-infarction patients seems a simple screening method that may help presage the health and social course the patient takes.

  9. Depression and reduced heart rate variability after cardiac surgery: the mediating role of emotion regulation.

    Science.gov (United States)

    Patron, Elisabetta; Messerotti Benvenuti, Simone; Favretto, Giuseppe; Gasparotto, Renata; Palomba, Daniela

    2014-02-01

    Heart rate variability (HRV), as an index of autonomic nervous system (ANS) functioning, is reduced by depression after cardiac surgery, but the underlying mechanisms of this relationship are poorly understood. Poor emotion regulation as a core symptom of depression has also been associated with altered ANS functioning. The present study aimed to examine whether emotion dysregulation could be a mediator of the depression-reduced HRV relationship observed after cardiac surgery. Self-reported emotion regulation and four-minute HRV were measured in 25 depressed and 43 nondepressed patients after cardiac surgery. Mediation analysis was conducted to evaluate emotion regulation as a mediator of the depression-reduced HRV relationship. Compared to nondepressed patients, those with depression showed lower standard deviation of normal-to-normal (NN) intervals (pbehavior partially mediated the effect of depression on LF n.u. and HF n.u. Results confirmed previous findings showing that depression is associated with reduced HRV, especially a reduced vagal tone and a sympathovagal imbalance, after cardiac surgery. This study also provides preliminary evidence that increased trait levels of suppression of emotion-expressive behavior may mediate the depression-related sympathovagal imbalance after cardiac surgery. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Quantifying Effects of Pharmacological Blockers of Cardiac Autonomous Control Using Variability Parameters.

    Science.gov (United States)

    Miyabara, Renata; Berg, Karsten; Kraemer, Jan F; Baltatu, Ovidiu C; Wessel, Niels; Campos, Luciana A

    2017-01-01

    Objective: The aim of this study was to identify the most sensitive heart rate and blood pressure variability (HRV and BPV) parameters from a given set of well-known methods for the quantification of cardiovascular autonomic function after several autonomic blockades. Methods: Cardiovascular sympathetic and parasympathetic functions were studied in freely moving rats following peripheral muscarinic (methylatropine), β1-adrenergic (metoprolol), muscarinic + β1-adrenergic, α1-adrenergic (prazosin), and ganglionic (hexamethonium) blockades. Time domain, frequency domain and symbolic dynamics measures for each of HRV and BPV were classified through paired Wilcoxon test for all autonomic drugs separately. In order to select those variables that have a high relevance to, and stable influence on our target measurements (HRV, BPV) we used Fisher's Method to combine the p -value of multiple tests. Results: This analysis led to the following best set of cardiovascular variability parameters: The mean normal beat-to-beat-interval/value (HRV/BPV: meanNN), the coefficient of variation (cvNN = standard deviation over meanNN) and the root mean square differences of successive (RMSSD) of the time domain analysis. In frequency domain analysis the very-low-frequency (VLF) component was selected. From symbolic dynamics Shannon entropy of the word distribution (FWSHANNON) as well as POLVAR3, the non-linear parameter to detect intermittently decreased variability, showed the best ability to discriminate between the different autonomic blockades. Conclusion: Throughout a complex comparative analysis of HRV and BPV measures altered by a set of autonomic drugs, we identified the most sensitive set of informative cardiovascular variability indexes able to pick up the modifications imposed by the autonomic challenges. These indexes may help to increase our understanding of cardiovascular sympathetic and parasympathetic functions in translational studies of experimental diseases.

  11. Heart rate variability in patients with mitral stenosis: A study of 20 cases from King Abdulaziz Univ. Hospital

    International Nuclear Information System (INIS)

    Al-Hazimi, A.; Al-Ama, N.; Marouf, M.

    2002-01-01

    Left atrial enlargement in mitral stenosis predisposes to atrial fibrillation (AF). Analysis of heart rate variability (HRV) prior to the onset of an arrhythmia may show alterations in autonomic balance that are known to predispose to the development of AF. The aim of this study was to determine whether HRV in patients with rheumatic mitral stenosis (MS) is abnormal in comparison to normal controls, and to find the relationship between the left atrial size and HRV in patients with MS in sinus rhythm in AF. A series of 24-hour ambulatory Holter electrocardiogram recordings were obtained for 10 consecutive, newly diagnosed untreated subjects with pure mitral stenosis in sinus rhythm, 10 with mitral stenosis complicated by atrial fibrillation and 10 age-matched normal controls. Digitized records were processed using time domain and power spectral analysis. In patients with mitral stenosis in sinus rhythm, we observed significant decrease of the standard deviation of RR intervals (SDRR), as well as of the root mean square of successive RR interval differences (RMSSD) and Edinburgh index (sNN50), while in patients with AF, the RMSSD and sNN50 were much larger than those in normal. The areas under all spectral bands were markedly increased in patients with AF compared with normal. HRV measures were independent of atrial size in both groups. Decreased HRV in mitral stenosis patients with sinus rhythm suggests increased sympathetic activity in patients prone to atrial fibrillation, while marked increased of HRV in patients with AF may indicate that parasympathetic activity modulates the intrinsic behavior of the atrioventricular node during atrial fibrillation. The evaluation of HRV may be a useful tool for the identification of patients predisposed to AF. (author)

  12. Intratesticular and subcutaneous lidocaine alters the intraoperative haemodynamic responses and heart rate variability in male cats undergoing castration

    NARCIS (Netherlands)

    Moldal, E.R.; Eriksen, T.; Kirpensteijn, J.; Nødtvedt, A.; Kristensen, A.T.; Sparta, F.M.; Haga, H.A.

    2013-01-01

    Abstract OBJECTIVE: To evaluate the usefulness of intratesticular and subcutaneous lidocaine in alleviating the intraoperative nociceptive response to castration, measured by pulse rate (PR) and mean arterial pressure (MAP), and to test the applicability of heart rate variability (HRV) analysis in

  13. Creating historical range of variation (HRV) time series using landscape modeling: Overview and issues [Chapter 8

    Science.gov (United States)

    Robert E. Keane

    2012-01-01

    Simulation modeling can be a powerful tool for generating information about historical range of variation (HRV) in landscape conditions. In this chapter, I will discuss several aspects of the use of simulation modeling to generate landscape HRV data, including (1) the advantages and disadvantages of using simulation, (2) a brief review of possible landscape models. and...

  14. Resting state connectivity of the medial prefrontal cortex covaries with individual differences in high-frequency heart rate variability.

    Science.gov (United States)

    Jennings, J Richard; Sheu, Lei K; Kuan, Dora C-H; Manuck, Stephen B; Gianaros, Peter J

    2016-04-01

    Resting high-frequency heart rate variability (HF-HRV) relates to cardiac vagal control and predicts individual differences in health and longevity, but its functional neural correlates are not well defined. The medial prefrontal cortex (mPFC) encompasses visceral control regions that are components of intrinsic networks of the brain, particularly the default mode network (DMN) and the salience network (SN). Might individual differences in resting HF-HRV covary with resting state neural activity in the DMN and SN, particularly within the mPFC? This question was addressed using fMRI data from an eyes-open, 5-min rest period during which echoplanar brain imaging yielded BOLD time series. Independent component analysis yielded functional connectivity estimates defining the DMN and SN. HF-HRV was measured in a rest period outside of the scanner. Midlife (52% female) adults were assessed in two studies (Study 1, N = 107; Study 2, N = 112). Neither overall DMN nor SN connectivity strength was related to HF-HRV. However, HF-HRV related to connectivity of one region within mPFC shared by the DMN and SN, namely, the perigenual anterior cingulate cortex, an area with connectivity to other regions involved in autonomic control. In sum, HF-HRV does not seem directly related to global resting state activity of intrinsic brain networks, but rather to more localized connectivity. A mPFC region was of particular interest as connectivity related to HF-HRV was shared by the DMN and SN. These findings may indicate a functional basis for the coordination of autonomic cardiac control with engagement and disengagement from the environment. © 2015 Society for Psychophysiological Research.

  15. Does heart rate variability reflect the systemic inflammatory response in a fetal sheep model of lipopolysaccharide-induced sepsis?

    International Nuclear Information System (INIS)

    Durosier, Lucien D; Cao, Mingju; Frasch, Martin G; Herry, Christophe L; Seely, Andrew J E; Cortes, Marina; Burns, Patrick; Desrochers, André; Fecteau, Gilles

    2015-01-01

    Fetal inflammatory response occurs during chorioamnionitis, a frequent and often subclinical inflammation associated with increased risk for brain injury and life-lasting neurologic deficits. No means of early detection exist. We hypothesized that systemic fetal inflammation without septic shock will be reflected in alterations of fetal heart rate (FHR) variability (fHRV) distinguishing baseline versus inflammatory response states.In chronically instrumented near-term fetal sheep (n = 24), we induced an inflammatory response with lipopolysaccharide (LPS) injected intravenously (n = 14). Ten additional fetuses served as controls. We measured fetal plasma inflammatory cytokine IL-6 at baseline, 1, 3, 6, 24 and 48 h. 44 fHRV measures were determined continuously every 5 min using continuous individualized multi-organ variability analysis (CIMVA). CIMVA creates an fHRV measures matrix across five signal-analytical domains, thus describing complementary properties of fHRV. Using principal component analysis (PCA), a widely used technique for dimensionality reduction, we derived and quantitatively compared the CIMVA fHRV PCA signatures of inflammatory response in LPS and control groups.In the LPS group, IL-6 peaked at 3 h. In parallel, PCA-derived fHRV composite measures revealed a significant difference between LPS and control group at different time points. For the LPS group, a sharp increase compared to baseline levels was observed between 3 h and 6 h, and then abating to baseline levels, thus tracking closely the IL-6 inflammatory profile. This pattern was not observed in the control group. We also show that a preselection of fHRV measures prior to the PCA can potentially increase the difference between LPS and control groups, as early as 1 h post LPS injection.We propose a fHRV composite measure that correlates well with levels of inflammation and tracks well its temporal profile. Our results highlight the potential role of HRV to study and monitor the

  16. Association of physical capacity with heart rate variability based on a short-duration measurement of resting pulse rate in older adults with obesity.

    Directory of Open Access Journals (Sweden)

    Chun-De Liao

    Full Text Available Obesity can limit physical capacity and lower physical activity levels in elderly people. Low physical activity levels may be mediated by autonomic dysfunction with decreased heart rate variability (HRV. However, the relationship between autonomic dysfunction and low physical capability remains unclear. This cross-sectional study investigated the association of low physical capability with HRV in older adults with obesity.We recruited 231 old man and 210 old women with a mean (range age of 65.5 (51-78 and 62.9 (52-76 years, respectively. Physical capability was measured using mobility tasks, including functional reach, single-leg stance (SLS, gait speed (GS, timed up and go, and timed chair rise (TCR, and the scores on these tasks were merged and transformed into a global physical capability score (GPCS. HRV was measured using a 7-min resting pulse-based technique, and the time- and frequency-domain indices of HRV were obtained including standard deviation of normal-to-normal intervals (SDNN, root mean square of successive differences at rest (rMSSD, and high-frequency (HF power. All HRV indices were natural log (ln transformed for analysis. Participants were divided into high, moderate, and low physical-capability groups according to their physical performance. Multivariate analysis of covariance was performed to test differences in HRV indices among physical-capability groups with participants' characteristics serving as covariates. A stepwise regression model was established to identify the determinants of HRV indices. We used hierarchical regression analysis to identify the association of the GPCS with HRV indices.In both men and women, the low physical-capability group exhibited significantly increased heart rate (P <0.05 and decreased HRV in terms of a decreased ln[SDNN] (P <0.001, ln[rMSSD] (P <0.05 and ln[HF] (P <0.05, compared with the high physical-capability group. GS positively predicted ln[SDNN], whereas SLS, GS, and TCR were

  17. Scalable conditional induction variables (CIV) analysis

    KAUST Repository

    Oancea, Cosmin E.; Rauchwerger, Lawrence

    2015-01-01

    challenges to automatic parallelization. Because the complexity of such induction variables is often due to their conditional evaluation across the iteration space of loops we name them Conditional Induction Variables (CIV). This paper presents a flow

  18. Multiwavelength Variability Analysis of 3C 279

    Energy Technology Data Exchange (ETDEWEB)

    Patiño-Álvarez, Víctor M. [Max-Planck-Institut für Radioastronomie, Bonn (Germany); Fernandes, Sunil [Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX (United States); Chavushyan, Vahram [Instituto Nacional de Astrofísica Óptica y Electrónica, Puebla (Mexico); López-Rodríguez, Erique [SOFIA Science Center, NASA Ames Center, Mountain View, CA (United States); León-Tavares, Jonathan [Centre for Remote Sensing and Earth Observation Processes (TAP), Flemish Institute for Technological Research (VITO), Mol (Belgium); Schlegel, Eric M. [Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX (United States); Carrasco, Luis; Valdés, José R.; Carramiñana, Alberto, E-mail: patinoavm@mpifr-bonn.mpg.de [Instituto Nacional de Astrofísica Óptica y Electrónica, Puebla (Mexico)

    2017-11-23

    We present a multifrequency analysis of the variability in the flat-spectrum radio quasar 3C 279 from 2008 to 2014. Our multiwavelength datasets range from 1 mm to gamma-rays, with additional optical polarimetry. Cross-correlation analysis shows a significant correlation between the UV continuum emission, the optical and NIR bands, at a delay consistent with zero, implying co-spatial emission regions. We also find a correlation between the UV continuum and the 1 mm data, which implies that the dominant process in producing the UV continuum is synchrotron emission. Based on the behavior of the gamma-ray light curve with respect to other bands, we identified three different activity periods. During period A we find a significant correlation at zero delay between the UV continuum and the gamma-rays, implying co-spatial emission regions which points toward synchrotron self-Compton as dominant gamma-ray emission mechanism. During period C we find a delay between the UV continuum and the gamma-rays, as well as a correlation at zero delay between X-rays and gamma-rays, both results implying that external inverse Compton is the dominant gamma-ray emission mechanism. During period B there are multiple flares in the bands from 1 mm to UV, however, none of these show a counterpart in the gamma-rays band. We propose that this is caused by an increase in the gamma-ray opacity due to electron-positron pair production.

  19. The role of human rhinovirus (HRV) species on asthma exacerbation severity in children and adolescents.

    Science.gov (United States)

    Lambert, Katrina A; Prendergast, Luke A; Dharmage, Shyamali C; Tang, Mimi; O'Sullivan, Molly; Tran, Thomas; Druce, Julian; Bardin, Philip; Abramson, Michael J; Erbas, Bircan

    2017-10-11

    It is recognized that human rhinovirus (HRV) infection is an important factor in asthma exacerbations requiring hospitalization in children. However, previous studies have disagreed on the differential impact of various HRV species. We sought to assess the impact of HRV species on the severity of asthma exacerbations in children and adolescents. We also examined whether the effect of HRV species on severity was modified by age and gender. Virus strain was determined for 113 children with HRV detectable at the time of admission for asthma exacerbation. Patient characteristics were collected on admission and exacerbation severity was scored using several validated scales. HRV species by itself was not associated with moderate/severe vs. mild exacerbations. Boys with HRV-C infections were more likely (OR: 3.7, 95% CI: 1.2-13.4) to have a moderate/severe exacerbation than girls with HRV-C (p = 0.04 for interaction term). Higher odds were observed in younger boys (3 years old: OR: 9.1, 95% CI: 1.8-47.1 vs 5 years old: OR: 3.3, 95% CI: 0.9-11.8 vs 7 years old: OR: 1.2, 95% CI: 0.2-6.6). In contrast, children with HRV-C infection and sensitized to pollen during the pollen season were less likely to have moderate/severe exacerbations (p = 0.01 for the interaction term). Acute asthma exacerbations are more likely to be moderate/severe in boys under 5 years of age who had HRV-C infection on admission. The opposite was found in children with sensitization to pollen during pollen season.

  20. QT Interval Adaption to RR Interval Changes and Correlation Analysis between Heart Rate Variability and QT Interval Variability%QT间期对RR间期变化的响应及HRV与QTV的关联性分析

    Institute of Scientific and Technical Information of China (English)

    朱逸; 杨啸林; 彭屹

    2013-01-01

    体表心电图作为无创和连续的监测手段,在心脏安全评测方面具有重要而不可替代的位置.心电图中的间期时间序列包含着重要信息,其中以反映心动周期的RR间期序列,以及以QT间期为代表的反映心室复极化时程的间期序列,在临床上最为基础,相关的研究具有更为重要的意义.文中从应用基础研究的角度,就QT间期对于RR间期变化的响应,以及心率变异性(HRV)和QT间期变异性(QTV)关联性分析,分别介绍了其分析方法和研究进展,并且展望了可能的应用前景.%As a noninvasive and continuous monitoring method, surface electrocardiogram is significant in evaluating cardiac safety. The time interval series extracted from surface electrocardiogran contain important information. The RR and QT interval series, representing the cardiac cycle and the duration of ventricular repolarization, are with more research value. From the perspective of applied basic research, the methods and progress, concerning the QT interval adaption to RR interval changes and correlation analysis between heart rale variability (HRV) and QT interval variability (QTV) , were introduced here. And their potential applications were discussed as well.

  1. Heart rate turbulence and variability in patients with ventricular arrhythmias

    Directory of Open Access Journals (Sweden)

    Diego Tarricone

    2009-08-01

    Full Text Available Background: To evaluate the changes in autonomic neural control mechanisms before malignant ventricular arrhythmias, we measured heart rate variability (HRV and heart rate turbulence (HRT in patients with ventricular tachycardia or fibrillation (Group I; n=6, non sustained ventricular tachycardia (Group II; n=32, frequent premature ventricular beats (Group III; n=26 and with ICD implantation (Group IV; n=11. Methods: Time domain parameters of HRV and turbulence onset (TO and slope (TS were calculated on 24 hour Holter recordings. Normal values were: SDNN > 70 msec for HRV, TO <0% and TS >2.5 msec/RR-I for HRT. Results: Whereas SDNN was within normal range and similar in all study groups, HRT parameters were significantly different in patients who experienced VT/VF during Holter recording. Abnormal TO and/or TS were present in 100% of Group I patients and only in about 50% of Group II and IV. On the contrary, normal HRT parameters were present in 40-70% of Group II, III and IV patients and none of Group I. Conclusions: These data suggest that HRT analysis is more suitable than HRV to detect those transient alterations in autonomic control mechanisms that are likely to play a major trigger role in the genesis of malignant cardiac arrhythmias. (Heart International 2007; 3: 51-7

  2. Reproducibility of heart rate variability, blood pressure variability and baroreceptor sensitivity during rest and head-up tilt

    DEFF Research Database (Denmark)

    Højgaard, Michael V; Agner, Erik; Kanters, Jørgen K

    2005-01-01

    OBJECTIVE: Previous studies have indicated moderate-to-poor reproducibility of heart rate variability (HRV) but the reproducibility of blood pressure variability (BPV) and spectral measures of baroreceptor sensitivity (BRS) are not well established. METHODS: We measured normal-to-normal heart beat...... pressures were extracted for the assessment of day-to-day and short-term reproducibility. Power spectrum analysis (Fourier) and transfer function analysis was performed. Reproducibility was assessed using the coefficient of variation (CV). The reproducibility of the mean RR interval, mean systolic......, diastolic and mean blood pressure was good (CVspectral parameters of HRV (CV range 18-36%) and BPV (16-44%) and moderate reproducibility of BRS (14-20%). CONCLUSION: Spectral estimates of BRS had only moderate reproducibility although...

  3. Multiscale time irreversibility of heart rate and blood pressure variability during orthostasis

    International Nuclear Information System (INIS)

    Chladekova, L; Czippelova, B; Turianikova, Z; Tonhajzerova, I; Calkovska, A; Javorka, M; Baumert, M

    2012-01-01

    Time irreversibility is a characteristic feature of non-equilibrium, complex systems such as the cardiovascular control mediated by the autonomic nervous system (ANS). Time irreversibility analysis of heart rate variability (HRV) and blood pressure variability (BPV) represents a new approach to assess cardiovascular regulatory mechanisms. The aim of this paper was to assess the changes in HRV and BPV irreversibility during the active orthostatic test (a balance of ANS shifted towards sympathetic predominance) in 28 healthy young subjects. We used three different time irreversibility indices—Porta’s, Guzik's and Ehler's indices (P%, G% and E, respectively) derived from data segments containing 1000 beat-to-beat intervals on four timescales. We observed an increase in the HRV and a decrease in the BPV irreversibility during standing compared to the supine position. The postural change in irreversibility was confirmed by surrogate data analysis. The differences were more evident in G% and E than P% and for higher scale factors. Statistical analysis showed a close relationship between G% and E. Contrary to this, the association between P% and G% and P% and E was not proven. We conclude that time irreversibility of beat-to-beat HRV and BPV is significantly altered during orthostasis, implicating involvement of the autonomous nervous system in its generation. (paper)

  4. Heart rate variability: a tool to explore the sleeping brain?

    OpenAIRE

    Chouchou, Florian; Desseilles, Martin

    2014-01-01

    Sleep is divided into two main sleep stages: (1) non-rapid eye movement sleep (non-REMS), characterized among others by reduced global brain activity; and (2) rapid eye movement sleep (REMS), characterized by global brain activity similar to that of wakefulness. Results of heart rate variability (HRV) analysis, which is widely used to explore autonomic modulation, have revealed higher parasympathetic tone during normal non-REMS and a shift toward sympathetic predominance during normal REMS. M...

  5. Multiwavelength Variability Analysis of 3C 279

    Directory of Open Access Journals (Sweden)

    Víctor M. Patiño-Álvarez

    2017-11-01

    Full Text Available We present a multifrequency analysis of the variability in the flat-spectrum radio quasar 3C 279 from 2008 to 2014. Our multiwavelength datasets range from 1 mm to gamma-rays, with additional optical polarimetry. Cross-correlation analysis shows a significant correlation between the UV continuum emission, the optical and NIR bands, at a delay consistent with zero, implying co-spatial emission regions. We also find a correlation between the UV continuum and the 1 mm data, which implies that the dominant process in producing the UV continuum is synchrotron emission. Based on the behavior of the gamma-ray light curve with respect to other bands, we identified three different activity periods. During period A we find a significant correlation at zero delay between the UV continuum and the gamma-rays, implying co-spatial emission regions which points toward synchrotron self-Compton as dominant gamma-ray emission mechanism. During period C we find a delay between the UV continuum and the gamma-rays, as well as a correlation at zero delay between X-rays and gamma-rays, both results implying that external inverse Compton is the dominant gamma-ray emission mechanism. During period B there are multiple flares in the bands from 1 mm to UV, however, none of these show a counterpart in the gamma-rays band. We propose that this is caused by an increase in the gamma-ray opacity due to electron-positron pair production.

  6. Lack of Association of Estrogen Receptor Alpha Gene Polymorphisms with Cardiorespiratory and Metabolic Variables in Young Women

    Directory of Open Access Journals (Sweden)

    Mario Hirata

    2012-10-01

    Full Text Available This study examined the association of estrogen receptor alpha gene (ESR1 polymorphisms with cardiorespiratory and metabolic parameters in young women. In total, 354 healthy women were selected for cardiopulmonary exercise testing and short-term heart rate (HR variability (HRV evaluation. The HRV analysis was determined by the temporal indices rMSSD (square root of the mean squared differences of successive R–R intervals (RRi divided by the number of RRi minus one, SDNN (root mean square of differences from mean RRi, divided by the number of RRi and power spectrum components by low frequency (LF, high frequency (HF and LF/HF ratio. Blood samples were obtained for serum lipids, estradiol and DNA extraction. ESR1 rs2234693 and rs9340799 polymorphisms were analyzed by PCR and fragment restriction analysis. HR and oxygen uptake (VO2 values did not differ between the ESR1 polymorphisms with respect to autonomic modulation. We not find a relationship between ESR1 T–A, T–G, C–A and C–G haplotypes and cardiorespiratory and metabolic variables. Multiple linear regression analysis demonstrated that VO2, total cholesterol and triglycerides influence HRV (p < 0.05. The results suggest that ESR1 variants have no effect on cardiorespiratory and metabolic variables, while HRV indices are influenced by aerobic capacity and lipids in healthy women.

  7. Analyses of heart rate variability in young soccer players: the effects of sport activity.

    Science.gov (United States)

    Bricout, Véronique-Aurélie; Dechenaud, Simon; Favre-Juvin, Anne

    2010-04-19

    The use of heart rate variability (HRV) in the management of sport training is a practice which tends to spread, especially in order to prevent the occurrence of states of fatigue. To estimate the HRV parameters obtained using a heart rate recording, according to different loads of sporting activities, and to make the possible link with the appearance of fatigue. Eight young football players, aged 14.6 years+/-2 months, playing at league level in Rhône-Alpes, training for 10 to 20 h per week, were followed over a period of 5 months, allowing to obtain 54 recordings of HRV in three different conditions: (i) after rest (ii) after a day with training and (iii) after a day with a competitive match. Under the effect of a competitive match, the HRV temporal indicators (heart rate, RR interval, and pNN50) were significantly altered compared to the rest day. The analysis of the sympathovagal balance rose significantly as a result of the competitive constraint (0.72+/-0.17 vs. 0.90+/-0.20; pHRV is an objective and non-invasive monitoring of management of the training of young sportsmen. HRV analysis allowed to highlight any neurovegetative adjustments according to the physical loads. Thus, under the effect of an increase of physical and psychological constraints that a football match represents, the LF/HF ratio rises significantly; reflecting increased sympathetic stimulation, which beyond certain limits could be relevant to prevent the emergence of a state of fatigue. 2009 Elsevier B.V. All rights reserved.

  8. Heart rate variability - a historical perspective.

    Science.gov (United States)

    Billman, George E

    2011-01-01

    Heart rate variability (HRV), the beat-to-beat variation in either heart rate or the duration of the R-R interval - the heart period, has become a popular clinical and investigational tool. The temporal fluctuations in heart rate exhibit a marked synchrony with respiration (increasing during inspiration and decreasing during expiration - the so called respiratory sinus arrhythmia, RSA) and are widely believed to reflect changes in cardiac autonomic regulation. Although the exact contributions of the parasympathetic and the sympathetic divisions of the autonomic nervous system to this variability are controversial and remain the subject of active investigation and debate, a number of time and frequency domain techniques have been developed to provide insight into cardiac autonomic regulation in both health and disease. It is the purpose of this essay to provide an historical overview of the evolution in the concept of HRV. Briefly, pulse rate was first measured by ancient Greek physicians and scientists. However, it was not until the invention of the "Physician's Pulse Watch" (a watch with a second hand that could be stopped) in 1707 that changes in pulse rate could be accurately assessed. The Rev. Stephen Hales (1733) was the first to note that pulse varied with respiration and in 1847 Carl Ludwig was the first to record RSA. With the measurement of the ECG (1895) and advent of digital signal processing techniques in the 1960s, investigation of HRV and its relationship to health and disease has exploded. This essay will conclude with a brief description of time domain, frequency domain, and non-linear dynamic analysis techniques (and their limitations) that are commonly used to measure HRV.

  9. [Sports medical aspects in cardiac risk stratification--heart rate variability and exercise capacity].

    Science.gov (United States)

    Banzer, W; Lucki, K; Bürklein, M; Rosenhagen, A; Vogt, L

    2006-12-01

    The present study investigates the association of the predicted CHD-risk (PROCAM) with the individual endurance capacity and heart rate variability (HRV) in a population-based sample of sedentary elderly. After stratification, in 57 men (48.1+/-9.5 yrs.) with an overall PROCAM-risk or =10% (50.8+/-5.6 points) cycle ergometries and short-term HRV analysis of time (RRMEAN, SDNN, RMSSD) and frequency domain parameters (LF, HF, TP, LF/HF) were conducted. Additionally the autonomic stress index (SI) was calculated. Nonparametric tests were used for statistical correlation analysis (Spearman rho) and group comparisons (Mann-Whitney). For endurance capacity [W/kg] (r=-0.469, pHRV analysis in risk stratification and outline the interrelation of a decreased exercise capacity and autonomic function with a raised individual 10-year cardiac risk. As an independent parameter of the vegetative regulatory state the stress index may contribute to an increased practical relevance of short-time HRV analysis.

  10. Heart Rate Variability Is Associated with Exercise Capacity in Patients with Cardiac Syndrome X.

    Directory of Open Access Journals (Sweden)

    Dai-Yin Lu

    Full Text Available Heart rate variability (HRV reflects the healthiness of autonomic nervous system, which is associated with exercise capacity. We therefore investigated whether HRV could predict the exercise capacity in the adults with cardiac syndrome X (CSX. A total of 238 subjects (57±12 years, 67.8% men, who were diagnosed as CSX by the positive exercise stress test and nearly normal coronary angiogram were enrolled. Power spectrum from the 24-hour recording of heart rate was analyzed in frequency domain using total power (TP and spectral components of the very low frequency (VLF, low frequency (LF and high frequency (HF ranges. Among the study population, 129 subjects with impaired exercise capacity during the treadmill test had significantly lower HRV indices than those with preserved exercise capacity (≥90% of the age predicted maximal heart rate. After accounting for age, sex, and baseline SBP and heart rate, VLF (odds ratio per 1SD and 95% CI: 2.02, 1.19-3.42, LF (1.67, 1.10-2.55, and TP (1.82, 1.17-2.83 remained significantly associated with preserved exercise capacity. In addition, increased HRV indices were also associated with increased exercise duration, rate-pressure product, and heart rate recovery, independent of age, body mass index, and baseline SBP and heart rate. In subgroup analysis, HRV indices demonstrated similar predictive values related to exercise capacity across various subpopulations, especially in the young. In patients with CSX, HRV was independently associated with exercise capacity, especially in young subjects. The healthiness of autonomic nervous system may have a role in modulating the exercise capacity in patients with CSX.

  11. A pilot randomized study of a gratitude journaling intervention on HRV and inflammatory biomarkers in Stage B heart failure patients

    Science.gov (United States)

    Redwine, Laura; Henry, Brook L.; Pung, Meredith A.; Wilson, Kathleen; Chinh, Kelly; Knight, Brian; Jain, Shamini; Rutledge, Thomas; Greenberg, Barry; Maisel, Alan; Mills, Paul J

    2016-01-01

    Objective Stage B, asymptomatic heart failure (HF) presents a therapeutic window for attenuating disease progression and development of HF symptoms, and improving quality of life. Gratitude, the practice of appreciating positive life features, is highly related to quality of life, leading to development of promising clinical interventions. However, few gratitude studies have investigated objective measures of physical health; most relied on self-report measures. We conducted a pilot study in Stage B HF patients to examine whether gratitude journaling improved biomarkers related to HF prognosis. Methods Patients (N = 70; mean age = 66.2 years, SD = 7.6) were randomized to an 8-week gratitude journaling intervention or treatment as usual (TAU). Baseline (T1) assessments included 6-item Gratitude Questionnaire (GQ-6), resting heart rate variability (HRV), and an inflammatory biomarker index. At T2 (mid-intervention) GQ6 was measured. At T3 (post-intervention), T1 measures were repeated but also included a gratitude journaling task. Results The gratitude intervention was associated with improved trait gratitude scores (F = 6.0, p = .017, η2 = .10), reduced inflammatory biomarker index score over time (F = 9.7, p = .004, η2 = .21) and increased parasympathetic HRV responses during the gratitude journaling task (F = 4.2, p = .036, η2 = .15), compared with TAU. However, there were no resting pre- to post-intervention group differences in HRV (p's > .10). Conclusions Gratitude journaling may improve biomarkers related to HF morbidity, such as reduced inflammation; large-scale studies with active control conditions are needed to confirm these findings. PMID:27187845

  12. Heart rate variability in type 2 diabetes mellitus.

    Science.gov (United States)

    Stuckey, Melanie I; Petrella, Robert J

    2013-01-01

    Heart rate variability (HRV) is a noninvasive measure of cardiac autonomic modulation. Time and frequency domain measures have primarily been examined in patients with type 2 diabetes mellitus (T2D). Not only do frequency domain HRV parameters tend to be reduced in T2D, but healthy individuals with low HRV are also more likely to develop T2D. Furthermore, patients with T2D with low HRV have an increased prevalence of complications and risk of mortality compared with those with normal autonomic function. These findings provide support for the use of HRV as a risk indicator in T2D. Exercise is considered an important component to T2D prevention and treatment strategies. To date, few studies have examined the changes in HRV with exercise in T2D. One study showed changes in resting HRV, two studies showed changes in HRV during or following acute stressors, and one study showed no changes in HRV but improvements in baroreflex sensitivity. The most pronounced changes in HRV were realized following the exercise intervention with the greatest frequency of supervised exercise sessions and with the greatest intensity and duration of exercise bouts. These findings suggest that exercise following current American College of Sports Medicine/American Diabetes Association guidelines may be important in the prevention and treatment of T2D to improve autonomic function and reduce the risk of complications and mortality.

  13. Blood pressure and heart rate variability analysis of orthostatic challenge in normal human pregnancies.

    Science.gov (United States)

    Heiskanen, Nonna; Saarelainen, Heli; Valtonen, Pirjo; Lyyra-Laitinen, Tiina; Laitinen, Tomi; Vanninen, Esko; Heinonen, Seppo

    2008-11-01

    The aim of the present study was to evaluate pregnancy-related changes in autonomic regulatory functions in healthy subjects. We studied cardiovascular autonomic responses to head-up tilt (HUT) in 28 pregnant women during the third trimester of pregnancy and 3 months after parturition. The maternal ECG and non-invasive beat-to-beat blood pressure were recorded in the horizontal position (left-lateral position) and during HUT in the upright position. Stroke volume was assessed from blood pressure signal by using the arterial pulse contour method. Heart rate variability (HRV) was analysed in frequency domain, and baroreflex sensitivity by the cross-spectral and the sequence methods. In the horizontal position, all frequency components of HRV were lower during pregnancy than 3 months after parturition (P pregnancy had no influence on normalized low frequency and high frequency powers. During pregnancy haemodynamics was well balanced with only minor changes in response to postural change while haemodynamic responses to HUT were more remarkable after parturition. In pregnant women HRV and especially its very low frequency component increased in response to HUT, whereas at 3 months after parturition the direction of these changes was opposite. Parasympathetic deactivation towards term is likely to contribute to increased heart rate and cardiac output at rest, whereas restored sympathetic modulation with modest responses may contribute stable peripheral resistance and sufficient placental blood supply under stimulated conditions. It is important to understand cardiovascular autonomic nervous system and haemodynamic control in normal pregnancy before being able to judge whether they are dysregulated in complicated pregnancies.

  14. Using variable combination population analysis for variable selection in multivariate calibration.

    Science.gov (United States)

    Yun, Yong-Huan; Wang, Wei-Ting; Deng, Bai-Chuan; Lai, Guang-Bi; Liu, Xin-bo; Ren, Da-Bing; Liang, Yi-Zeng; Fan, Wei; Xu, Qing-Song

    2015-03-03

    Variable (wavelength or feature) selection techniques have become a critical step for the analysis of datasets with high number of variables and relatively few samples. In this study, a novel variable selection strategy, variable combination population analysis (VCPA), was proposed. This strategy consists of two crucial procedures. First, the exponentially decreasing function (EDF), which is the simple and effective principle of 'survival of the fittest' from Darwin's natural evolution theory, is employed to determine the number of variables to keep and continuously shrink the variable space. Second, in each EDF run, binary matrix sampling (BMS) strategy that gives each variable the same chance to be selected and generates different variable combinations, is used to produce a population of subsets to construct a population of sub-models. Then, model population analysis (MPA) is employed to find the variable subsets with the lower root mean squares error of cross validation (RMSECV). The frequency of each variable appearing in the best 10% sub-models is computed. The higher the frequency is, the more important the variable is. The performance of the proposed procedure was investigated using three real NIR datasets. The results indicate that VCPA is a good variable selection strategy when compared with four high performing variable selection methods: genetic algorithm-partial least squares (GA-PLS), Monte Carlo uninformative variable elimination by PLS (MC-UVE-PLS), competitive adaptive reweighted sampling (CARS) and iteratively retains informative variables (IRIV). The MATLAB source code of VCPA is available for academic research on the website: http://www.mathworks.com/matlabcentral/fileexchange/authors/498750. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Association of Depressive Symptoms and Heart Rate Variability in Vietnam War-Era Twins: A Longitudinal Twin Difference Study.

    Science.gov (United States)

    Huang, Minxuan; Shah, Amit; Su, Shaoyong; Goldberg, Jack; Lampert, Rachel J; Levantsevych, Oleksiy M; Shallenberger, Lucy; Pimple, Pratik; Bremner, J Douglas; Vaccarino, Viola

    2018-05-16

    Depressive symptoms are associated with lower heart rate variability (HRV), an index of autonomic dysregulation, but the direction of the association remains unclear. To investigate the temporal association between depression and HRV. A longitudinal, cross-lagged twin difference study, with baseline assessments from March 2002 to March 2006 (visit 1) and a 7-year follow-up (visit 2) at an academic research center with participants recruited from a national twin registry. Twins (n = 166) from the Vietnam Era Twin Registry, who served in the US military during the Vietnam War, and were discordant for depression at baseline were recruited. At both visits, depressive symptoms were measured using the Beck Depression Inventory-II (BDI-II), and HRV was measured through 24-hour electrocardiogram monitoring. To assess the direction of the association, within-pair differences in multivariable mixed-effects regression models were examined, and standardized β coefficients for both pathways were calculated. The associations were evaluated separately in monozygotic and dizygotic twins. In the final analytic sample (N = 146), all participants were men, 138 (95%) were white, and the mean (SD) age was 54 (3) years at baseline. Results showed consistent associations between visit 1 HRV and visit 2 BDI score across all HRV domains and models (β coefficients ranging from -0.14 to -0.29), which were not explained by antidepressants or other participant characteristics. The magnitude of the association was similar in the opposite pathway linking visit 1 BDI score to visit 2 HRV, with β coefficients ranging from 0.05 to -0.30, but it was largely explained by antidepressant use. In stratified analysis by zygosity, significant associations were observed in monozygotic and dizygotic twins for the path linking visit 1 HRV to visit 2 BDI score, although the associations were slightly stronger in dizygotic twins. The association between depression and autonomic dysregulation

  16. Complexity and time asymmetry of heart rate variability are altered in acute mental stress.

    Science.gov (United States)

    Visnovcova, Z; Mestanik, M; Javorka, M; Mokra, D; Gala, M; Jurko, A; Calkovska, A; Tonhajzerova, I

    2014-07-01

    We aimed to study the complexity and time asymmetry of short-term heart rate variability (HRV) as an index of complex neurocardiac control in response to stress using symbolic dynamics and time irreversibility methods. ECG was recorded at rest and during and after two stressors (Stroop, arithmetic test) in 70 healthy students. Symbolic dynamics parameters (NUPI, NCI, 0V%, 1V%, 2LV%, 2UV%), and time irreversibility indices (P%, G%, E) were evaluated. Additionally, HRV magnitude was quantified by linear parameters: spectral powers in low (LF) and high frequency (HF) bands. Our results showed a reduction of HRV complexity in stress (lower NUPI with both stressors, lower NCI with Stroop). Pattern classification analysis revealed significantly higher 0V% and lower 2LV% with both stressors, indicating a shift in sympathovagal balance, and significantly higher 1V% and lower 2UV% with Stroop. An unexpected result was found in time irreversibility: significantly lower G% and E with both stressors, P% index significantly declined only with arithmetic test. Linear HRV analysis confirmed vagal withdrawal (lower HF) with both stressors; LF significantly increased with Stroop and decreased with arithmetic test. Correlation analysis revealed no significant associations between symbolic dynamics and time irreversibility. Concluding, symbolic dynamics and time irreversibility could provide independent information related to alterations of neurocardiac control integrity in stress-related disease.

  17. Complexity and time asymmetry of heart rate variability are altered in acute mental stress

    International Nuclear Information System (INIS)

    Visnovcova, Z; Mestanik, M; Javorka, M; Mokra, D; Calkovska, A; Tonhajzerova, I; Gala, M; Jurko, A

    2014-01-01

    We aimed to study the complexity and time asymmetry of short-term heart rate variability (HRV) as an index of complex neurocardiac control in response to stress using symbolic dynamics and time irreversibility methods. ECG was recorded at rest and during and after two stressors (Stroop, arithmetic test) in 70 healthy students. Symbolic dynamics parameters (NUPI, NCI, 0V%, 1V%, 2LV%, 2UV%), and time irreversibility indices (P%, G%, E) were evaluated. Additionally, HRV magnitude was quantified by linear parameters: spectral powers in low (LF) and high frequency (HF) bands. Our results showed a reduction of HRV complexity in stress (lower NUPI with both stressors, lower NCI with Stroop). Pattern classification analysis revealed significantly higher 0V% and lower 2LV% with both stressors, indicating a shift in sympathovagal balance, and significantly higher 1V% and lower 2UV% with Stroop. An unexpected result was found in time irreversibility: significantly lower G% and E with both stressors, P% index significantly declined only with arithmetic test. Linear HRV analysis confirmed vagal withdrawal (lower HF) with both stressors; LF significantly increased with Stroop and decreased with arithmetic test. Correlation analysis revealed no significant associations between symbolic dynamics and time irreversibility. Concluding, symbolic dynamics and time irreversibility could provide independent information related to alterations of neurocardiac control integrity in stress-related disease. (paper)

  18. The role of heart rate variability in sports physiology.

    Science.gov (United States)

    Dong, Jin-Guo

    2016-05-01

    Heart rate variability (HRV) is a relevant marker reflecting cardiac modulation by sympathetic and vagal components of the autonomic nervous system (ANS). Although the clinical application of HRV is mainly associated with the prediction of sudden cardiac death and assessing cardiovascular and metabolic illness progression, recent observations have suggested its applicability to physical exercise training. HRV is becoming one of the most useful tools for tracking the time course of training adaptation/maladaptation of athletes and in setting the optimal training loads leading to improved performances. However, little is known regarding the role of HRV and the internal effects of physical exercise on an athlete, which may be useful in designing fitness programs ensuring sufficient training load that may correspond with the specific ability of the athlete. In this review, we offer a comprehensive assessment of investigations concerning the interrelation between HRV and ANS, and examine how the application of HRV to physical exercise may play a role in sports physiology.

  19. Metaiodobenzylguanidine and heart rate variability in heart failure

    International Nuclear Information System (INIS)

    Kurata, Chinori; Shouda, Sakae; Mikami, Tadashi; Uehara, Akihiko; Ishikawa, Keiko; Tawarahara, Kei; Nakano, Tomoyasu; Matoh, Fumitaka; Takeuchi, Kazuhiko

    1998-01-01

    It is assumed that the low-frequency power (LF) of heart rate variability (HRV) increases with progress of congestive heart failure (CHF), therefore positively correlating with cardiac 123 I-metaiodobenzylguanidine (MIBG) washout. It is demonstrated here that HRV, including normalized LF, correlated inversely with MIBG washout and positively with the ratio of heart-to-mediastinum MIBG activity in controls and CHF patients, whereas these correlations were not observed within CHF patients. Thus MIBG washout may increase and HRV including normalized LF may decrease with CHF, although the HRV and MIBG measures may not similarly change in proportion to the severity of the cardiac autonomic dysfunction in CHF. (author)

  20. Metaiodobenzylguanidine and heart rate variability in heart failure

    Energy Technology Data Exchange (ETDEWEB)

    Kurata, Chinori; Shouda, Sakae; Mikami, Tadashi; Uehara, Akihiko; Ishikawa, Keiko [Hamamatsu Univ., Shizuoka (Japan). School of Medicine; Tawarahara, Kei; Nakano, Tomoyasu; Matoh, Fumitaka; Takeuchi, Kazuhiko

    1998-10-01

    It is assumed that the low-frequency power (LF) of heart rate variability (HRV) increases with progress of congestive heart failure (CHF), therefore positively correlating with cardiac {sup 123}I-metaiodobenzylguanidine (MIBG) washout. It is demonstrated here that HRV, including normalized LF, correlated inversely with MIBG washout and positively with the ratio of heart-to-mediastinum MIBG activity in controls and CHF patients, whereas these correlations were not observed within CHF patients. Thus MIBG washout may increase and HRV including normalized LF may decrease with CHF, although the HRV and MIBG measures may not similarly change in proportion to the severity of the cardiac autonomic dysfunction in CHF. (author)

  1. Reproducibility of heart rate variability parameters measured in healthy subjects at rest and after a postural change maneuver

    Directory of Open Access Journals (Sweden)

    E.M. Dantas

    2010-10-01

    Full Text Available Heart rate variability (HRV provides important information about cardiac autonomic modulation. Since it is a noninvasive and inexpensive method, HRV has been used to evaluate several parameters of cardiovascular health. However, the internal reproducibility of this method has been challenged in some studies. Our aim was to determine the intra-individual reproducibility of HRV parameters in short-term recordings obtained in supine and orthostatic positions. Electrocardiographic (ECG recordings were obtained from 30 healthy subjects (20-49 years, 14 men using a digital apparatus (sampling ratio = 250 Hz. ECG was recorded for 10 min in the supine position and for 10 min in the orthostatic position. The procedure was repeated 2-3 h later. Time and frequency domain analyses were performed. Frequency domain included low (LF, 0.04-0.15 Hz and high frequency (HF, 0.15-0.4 Hz bands. Power spectral analysis was performed by the autoregressive method and model order was set at 16. Intra-subject agreement was assessed by linear regression analysis, test of difference in variances and limits of agreement. Most HRV measures (pNN50, RMSSD, LF, HF, and LF/HF ratio were reproducible independent of body position. Better correlation indexes (r > 0.6 were obtained in the orthostatic position. Bland-Altman plots revealed that most values were inside the agreement limits, indicating concordance between measures. Only SDNN and NNv in the supine position were not reproducible. Our results showed reproducibility of HRV parameters when recorded in the same individual with a short time between two exams. The increased sympathetic activity occurring in the orthostatic position probably facilitates reproducibility of the HRV indexes.

  2. The Effect of Valsartan on Heart Rate Variability and Heart Rate Recovery in Patients with Mild to Moderate Mitral Stenosis

    Directory of Open Access Journals (Sweden)

    Ali Metin Esen

    2010-04-01

    Full Text Available Summary: Atrial fibrillation (AF is known to be one of the most important complications of mitral stenosis (MS. It has been reported that autonomic nervous system (ANS had an effect on AF development, heart rate variability (HRV and heart rate recovery (HRR were under the control of ANS, and their disorders were present in MS. We studied the effect of Valsartan on HRV and HRT, and thus its effect on ANS. Methods: Eleven patients (39±8 years, 10 females with mild to moderate MS were included in the study. Sixteen volunteers (38±8 years, 14 females matched for age and sex were selected for control group. All subjects underwent transthoracic echocardiography (TTE, symptom-limited treadmill test and 24 hour Holter monitorization.The patients were administered 160 mg of Valsartan daily for 14 weeks. TTE, treadmill test and Holter monitorization were repeated at the end of treatment period. In Holter monitorization, the time and frequency domain analysis of HRV and in exercise test, HRR at first and third minutes (HRR1 and HRR3 were examined. Results: Before Valsartan treatment, no significant difference was found in HRR and HRV parameters between the two groups. Systolic and diastolic blood pressure, and also HRR1values were significantly decreased after treatment of Valsartan (117±6 vs. 107±4 mmHg p<0.002, 76±6 vs. 69±9 mmHg p<0.044, 44±14 vs. 33±12 p< 0.014, respectively, while the exercise time was significantly increased (786±114 vs. 846±95 sn p< 0.044. In Holter analysis neither time nor frequency domain of HRV parameters showed a meaningful change. Conclusion: In moderate MS, treatment with Valsartan improved the effort capacity, while autonomic function parameters have been defined on the base of HRV and HRR were not significantly different.

  3. Altered Heart Rate Variability During Gaming in Internet Gaming Disorder.

    Science.gov (United States)

    Lee, Deokjong; Hong, Sung Jun; Jung, Young-Chul; Park, Jinsick; Kim, In Young; Namkoong, Kee

    2018-04-01

    Internet gaming disorder (IGD) is characterized by addiction to online gaming and reduced executive control, particularly when individuals are exposed to gaming-related cues. Executive control can be measured as vagally mediated heart rate variability (HRV), which corresponds to variability in the time interval between heart beats. In this study, we investigated whether individuals with IGD have altered HRV while playing online games. We hypothesized that while gaming, individuals with IGD would exhibit phasic suppression of vagally mediated HRV, which would reflect executive control dysfunction during game play. To test this, we measured the changes of HRV when young males with IGD were engaged in real-time online gaming. The changes of HRV were associated with the severity of IGD assessed by self-reports and prefrontal gray matter volume (GMV) calculated by voxel-based morphometry. We included 23 IGD subjects and 18 controls in our analyses. Changes in HRV were not statistically different between IGD subjects and controls. Within the IGD group, however, subjects showed significant decreases in high-frequency (HF) HRV during gaming. Furthermore, the degree of decrease correlated with IGD severity and prefrontal GMV. Importantly, this phasic suppression of HF-HRV in response to gaming did not occur in control subjects. In conclusion, young males with IGD showed an altered HRV response while playing an online game, reflecting their difficulties in executive control over gaming. The dynamics between executive control and reward seeking may be out of balance during game play in IGD.

  4. Gaussian Mixture Model of Heart Rate Variability

    Science.gov (United States)

    Costa, Tommaso; Boccignone, Giuseppe; Ferraro, Mario

    2012-01-01

    Heart rate variability (HRV) is an important measure of sympathetic and parasympathetic functions of the autonomic nervous system and a key indicator of cardiovascular condition. This paper proposes a novel method to investigate HRV, namely by modelling it as a linear combination of Gaussians. Results show that three Gaussians are enough to describe the stationary statistics of heart variability and to provide a straightforward interpretation of the HRV power spectrum. Comparisons have been made also with synthetic data generated from different physiologically based models showing the plausibility of the Gaussian mixture parameters. PMID:22666386

  5. Heart rate variability enhances the prognostic value of established parameters in patients with congestive heart failure.

    Science.gov (United States)

    Krüger, C; Lahm, T; Zugck, C; Kell, R; Schellberg, D; Schweizer, M W F; Kübler, W; Haass, M

    2002-12-01

    This prospective study evaluated whether heart rate variability (HRV) assessed from Holter ECG has prognostic value in addition to established parameters in patients with congestive heart failure (CHF). The study included 222 patients with CHF due to dilated or ischemic cardiomyopathy (left ventricular ejection fraction LVEF 21+/-1%; mean+/-SEM). During a mean follow-up of 15+/-1 months, 38 (17%) patients died and 45 (20%) were hospitalized due to worsening of CHF. The HRV parameter SDNN (standard deviation of all intervals between normal beats) was significantly lower in non-surviving or hospitalized than in event-free patients (118+/-6 vs 142+/-5 ms), as were LVEF (18+/-1 vs 23+/-1%), and peak oxygen uptake during exercise (peak VO(2)) (12.8+/-0.5 vs 15.6+/-0.5 ml/min/kg). While each of these parameters was a risk predictor in univariate analysis, multivariate analysis revealed that HRV provides both independent and additional prognostic information with respect to the risk 'cardiac mortality or deterioration of CHF'. It is concluded that the determination of HRV enhances the prognostic power given by the most widely used parameters LVEF and peak VO(2) in the prediction of mortality or deterioration of CHF and thus enables to improve risk stratification.

  6. A novel Heart Rate Variability analysis using Lagged Poincaré plot: A study on hedonic visual elicitation.

    Science.gov (United States)

    Nardelli, M; Greco, A; Valenza, G; Lanata, A; Bailon, R; Scilingo, E P

    2017-07-01

    This paper reports on a novel method for the analysis of Heart Rate Variability (HRV) through Lagged Poincaré Plot (LPP) theory. Specifically a hybrid method, LPP symb , including LPP quantifiers and related symbolic dynamics was proposed. LPP has been applied to investigate the autonomic response to pleasant and unpleasant pictures extracted from the International Affective Picture System (IAPS). IAPS pictures are standardized in terms of level of arousal, i.e. the intensity of the evoked emotion, and valence, i.e. the level of pleasantness/unpleasantness, according to the Circumplex model of Affects (CMA). Twenty-two healthy subjects were enrolled in the experiment, which comprised four sessions with increasing arousal level. Within each session valence increased from positive to negative. An ad-hoc pattern recognition algorithm using a Leave-One-Subject-Out (LOSO) procedure based on a Quadratic Discriminant Classifier (QDC) was implemented. Our pattern recognition system was able to classify pleasant and unpleasant sessions with an accuracy of 71.59%. Therefore, we can suggest the use of the LPP symb for emotion recognition.

  7. The effects of exposure to environmental factors on Heart Rate Variability: An ecological perspective

    International Nuclear Information System (INIS)

    Schnell, Izhak; Potchter, Oded; Epstein, Yoram; Yaakov, Yaron; Hermesh, Hagai; Brenner, Shmuel; Tirosh, Emanuel

    2013-01-01

    The impact of human exposure to environmental factors on Heart Rate Variability (HRV) was examined in the urban space of Tel-Aviv-Jaffa. Four environmental factors were investigated: thermal and social loads; CO concentrations and noise. Levels of HRV are explained mainly by subjective social stresses, noise and CO. The most interesting result is the fact that while subjective social stress and noise increase HRV, low levels of CO are reducing HRV to some extent moderating the impact of subjective social stress and noise. Beyond the poisoning effect of CO and the fact that extremely low levels of HRV associated with high dozes of CO increase risk for life, low levels of CO may have a narcotic effect, as it is measured by HRV. The effects of thermal loads on HRV are negligible probably due to the use of behavioral means in order to neutralize heat and cold effects. -- Highlights: ► The impact of human exposure to environmental factors on Heart Rate Variability (HRV) was examined. ► Previous studies measured human exposure to pollution by fixed monitoring stations. ► This study measured actual personal exposure by mini sensors. ► High level of subjective social load and noise increase HRV. ► Low levels of CO may have a narcotic effect, as it is measured by HRV. -- The research focuses on the effects of environmental factors; noise, subjective social stress, thermal load and CO on Heart Rate Variability

  8. Continuous variable polarization entanglement, experiment and analysis

    International Nuclear Information System (INIS)

    Bowen, Warwick P; Treps, Nicolas; Schnabel, Roman; Ralph, Timothy C; Lam, Ping Koy

    2003-01-01

    We generate and characterize continuous variable polarization entanglement between two optical beams. We first produce quadrature entanglement, and by performing local operations we transform it into a polarization basis. We extend two entanglement criteria, the inseparability criteria proposed by Duan et al (2000 Phys. Rev. Lett. 84 2722) and the Einstein-Podolsky-Rosen (EPR) paradox criteria proposed by Reid and Drummond (1988 Phys. Rev. Lett. 60 2731), to Stokes operators; and use them to characterize the entanglement. Our results for the EPR paradox criteria are visualized in terms of uncertainty balls on the Poincare sphere. We demonstrate theoretically that using two quadrature entangled pairs it is possible to entangle three orthogonal Stokes operators between a pair of beams, although with a bound √3 times more stringent than for the quadrature entanglement

  9. Continuous variable polarization entanglement, experiment and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bowen, Warwick P [Department of Physics, Faculty of Science, Australian National University, ACT 0200 (Australia); Treps, Nicolas [Department of Physics, Faculty of Science, Australian National University, ACT 0200 (Australia); Schnabel, Roman [Department of Physics, Faculty of Science, Australian National University, ACT 0200 (Australia); Ralph, Timothy C [Department of Physics, Centre for Quantum Computer Technology, University of Queensland, St Lucia, QLD 4072 (Australia); Lam, Ping Koy [Department of Physics, Faculty of Science, Australian National University, ACT 0200 (Australia)

    2003-08-01

    We generate and characterize continuous variable polarization entanglement between two optical beams. We first produce quadrature entanglement, and by performing local operations we transform it into a polarization basis. We extend two entanglement criteria, the inseparability criteria proposed by Duan et al (2000 Phys. Rev. Lett. 84 2722) and the Einstein-Podolsky-Rosen (EPR) paradox criteria proposed by Reid and Drummond (1988 Phys. Rev. Lett. 60 2731), to Stokes operators; and use them to characterize the entanglement. Our results for the EPR paradox criteria are visualized in terms of uncertainty balls on the Poincare sphere. We demonstrate theoretically that using two quadrature entangled pairs it is possible to entangle three orthogonal Stokes operators between a pair of beams, although with a bound {radical}3 times more stringent than for the quadrature entanglement.

  10. Coffee Consumption and Heart Rate Variability: The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) Cohort Study.

    Science.gov (United States)

    de Oliveira, Rackel Aguiar Mendes; Araújo, Larissa Fortunato; de Figueiredo, Roberta Carvalho; Goulart, Alessandra C; Schmidt, Maria Ines; Barreto, Sandhi Maria; Ribeiro, Antonio Luiz Pinho

    2017-07-13

    Studies have shown that acute coffee ingestion can affect cardiovascular autonomic activity, although the chronic effects on heart rate variability (HRV) remain controversial. A cross-sectional study with baseline data (2008-2010) from ELSA-Brasil cohort of 15,105 (aged 35-74), based in six Brazilian states. Coffee consumption in the previous 12 months was measured using the semi-quantitative food frequency questionnaire, and HRV was obtained through electrocardiographic tracings during 10 min at rest. Independent association between the frequency of coffee consumption "never or almost never", "≤1 cup/day", "2-3 cups/day", "≥3 cups/day", and HRV was estimated using generalized linear regression, adjusting for socio-demographic characteristics, health-related behavior, markers of abnormal metabolism, and the presence of coronary artery disease. Further, we applied Bonferroni correction in the full models. The mean age was 52 years (standard deviation (SD) = 9.1), and 52% was female; 9.5% never/almost never consumed coffee. In univariate analysis, coffee consumers had reduced values of HRV indexes, but after full adjustments and correction for multiple comparisons, these associations disappeared. A trend of reduction in HRV vagal indexes was observed in those that consumed ≥3 cups of coffee/day. Most of the effects attributed to the chronic use of coffee on the HRV indexes is related to the higher prevalence of unhealthy habits in coffee users, such as smoking and alcohol use. Adjustment for confounding factors weaken this association, making it non-significant. The effect of higher daily doses of coffee on the autonomic system should be evaluated in further studies.

  11. Coffee Consumption and Heart Rate Variability: The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil Cohort Study

    Directory of Open Access Journals (Sweden)

    Rackel Aguiar Mendes de Oliveira

    2017-07-01

    Full Text Available Studies have shown that acute coffee ingestion can affect cardiovascular autonomic activity, although the chronic effects on heart rate variability (HRV remain controversial. Method: A cross-sectional study with baseline data (2008–2010 from ELSA-Brasil cohort of 15,105 (aged 35–74, based in six Brazilian states. Coffee consumption in the previous 12 months was measured using the semi-quantitative food frequency questionnaire, and HRV was obtained through electrocardiographic tracings during 10 min at rest. Independent association between the frequency of coffee consumption “never or almost never”, “≤1 cup/day”, “2–3 cups/day”, “≥3 cups/day”, and HRV was estimated using generalized linear regression, adjusting for socio-demographic characteristics, health-related behavior, markers of abnormal metabolism, and the presence of coronary artery disease. Further, we applied Bonferroni correction in the full models. Results: The mean age was 52 years (standard deviation (SD = 9.1, and 52% was female; 9.5% never/almost never consumed coffee. In univariate analysis, coffee consumers had reduced values of HRV indexes, but after full adjustments and correction for multiple comparisons, these associations disappeared. A trend of reduction in HRV vagal indexes was observed in those that consumed ≥3 cups of coffee/day. Conclusion: Most of the effects attributed to the chronic use of coffee on the HRV indexes is related to the higher prevalence of unhealthy habits in coffee users, such as smoking and alcohol use. Adjustment for confounding factors weaken this association, making it non-significant. The effect of higher daily doses of coffee on the autonomic system should be evaluated in further studies.

  12. Clinical and non-clinical depression and anxiety in young people: A scoping review on heart rate variability.

    Science.gov (United States)

    Paniccia, Melissa; Paniccia, David; Thomas, Scott; Taha, Tim; Reed, Nick

    2017-12-01

    Heart rate variability (HRV), a measure of cardiac autonomic nervous system functioning, has emerged as a physiological indicator for emotional regulation and psychological well-being. HRV is understudied in the context of depression and anxiety in young people (10-24years old). Main objectives: (1) describe the nature and breadth of reviewed studies; and (2) synthesize main findings in the context of clinical and non-clinical populations of young people with depression and/or anxiety. The Arksey and O'Malley methodology was utilized for this scoping review. CINHAL, EMBASE, Medline, PsychInfo, Scopus, Web of Science, as well as grey literature, were searched. Two reviewers screened titles, abstracts and full papers for inclusion. A total of 20 citations were included in the final review (19 citations peer-reviewed journal articles, 1 journal abstract). Numerical and thematic analysis was used to summarize study findings. In clinical populations of either depression or anxiety, HRV was lower compared to controls. In non-clinical populations of either depression or anxiety, HRV was found to be lower in those who reported more depression or anxiety symptoms. The quality of the reviewed articles was not assessed which limits the ability to generate conclusions regarding study findings. Changes in HRV were found across the spectrum of clinical and non-clinical populations of young people with depression or anxiety. Neurophysiological research on depression and anxiety in young people can act as a first step to understanding how physiological flexibility (i.e. HRV) is related to psychological flexibility (i.e. adaptive or maladaptive responses to life events). Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Fourier analysis in several complex variables

    CERN Document Server

    Ehrenpreis, Leon

    2006-01-01

    Suitable for advanced undergraduates and graduate students, this text develops comparison theorems to establish the fundamentals of Fourier analysis and to illustrate their applications to partial differential equations.The three-part treatment begins by establishing the quotient structure theorem or fundamental principle of Fourier analysis. Topics include the geometric structure of ideals and modules, quantitative estimates, and examples in which the theory can be applied. The second part focuses on applications to partial differential equations and covers the solution of homogeneous and inh

  14. Decreased heart rate variability in surgeons during night shifts

    DEFF Research Database (Denmark)

    Amirian, Ilda; Toftegård Andersen, Lærke; Rosenberg, Jacob

    2014-01-01

    BACKGROUND: Heart rate variability (HRV) has been used as a measure of stress and mental strain in surgeons. Low HRV has been associated with death and increased risk of cardiac events in the general population. The aim of this study was to clarify the effect of a 17-hour night shift on surgeons'...

  15. Effects of Liraglutide on Heart Rate and Heart Rate Variability

    DEFF Research Database (Denmark)

    Kumarathurai, Preman; Anholm, Christian; Larsen, Bjørn Strøier

    2017-01-01

    OBJECTIVE: Reduced heart rate variability (HRV) and increased heart rate (HR) have been associated with cardiovascular mortality. Glucagon-like peptide 1 receptor agonists (GLP-1 RAs) increase HR, and studies have suggested that they may reduce HRV. We examined the effect of the GLP-1 RA...

  16. Heart Rate Variability and Drawing Impairment in Hypoxemic COPD

    Science.gov (United States)

    Incalzi, Raffaele Antonelli; Corsonello, Andrea; Trojano, Luigi; Pedone, Claudio; Acanfora, Domenico; Spada, Aldo; D'Addio, Gianni; Maestri, Roberto; Rengo, Franco; Rengo, Giuseppe

    2009-01-01

    We studied 54 patients with hypoxemic chronic obstructive pulmonary disease (COPD). The Mini Mental State Examination and the Mental Deterioration Battery were used for neuropsychological assessment. Heart rate variability (HRV) was assessed based on 24-h Holter ECG recording. Mann-Whitney test was used to compare HRV parameters of patients…

  17. Heart rate variability among caregivers of chronically bedridden patients

    Directory of Open Access Journals (Sweden)

    Amrith Pakkala

    2013-01-01

    Full Text Available Background: Caregivers of chronically bedridden patients are likely to suffer from mental and physical exhaustion leading to stress. This is important in view of the prevailing socioeconomic as well as the healthcare system available in a developing country like India. Therefore, the present study is designed to measure heart rate variability (HRV among this special group of population who give care to long-term bedridden patients. Materials and Methods: Fifteen female subjects were enrolled from among attendants of patients admitted with an immediate history of a cerebrovascular accident with locomotor deficits, who required constant care. They were free from any type of physical and mental health issues, nonsmokers and nonaddicts. Each care giver was subjected to HRV analysis on three occasions: The first record was performed in the 1 st week of their arrival in the hospital as caregivers. The second observation was recorded after 3 months of caregiving. The final HRV analysis was done after 6 months of care giving. Two types of parameters were analyzed: Time domain and frequency domain. Statistical analysis was done using paired t-test. Results: Both the HRV parameters: Time and frequency domain, showed decreased values during the 3 rd and 6 th month recording as compared to the 1 st week recording. The decrease is much more during the 6 th month recording as compared to the 3 rd month recording. Statistically significant decrease is observed in mean RR interval, heart rate, very low frequency (VLF, and LF only when the 1 st week recording is compared with the 3 rd month recording, but when the 1 st week recording was compared with the 6 th month recording significant decrease was found in mean RR interval and heart rate. Conclusion: Subjects involved in taking care of chronically ill bedridden patients are likely to undergo a lot of physical and mental stress, thus affecting their autonomic status. HRV analysis using short term

  18. Smartphone-Enabled Heart Rate Variability and Acute Mountain Sickness.

    Science.gov (United States)

    Mellor, Adrian; Bakker-Dyos, Josh; OʼHara, John; Woods, David Richard; Holdsworth, David A; Boos, Christopher J

    2018-01-01

    The autonomic system and sympathetic activation appears integral in the pathogenesis of acute mountain sickness (AMS) at high altitude (HA), yet a link between heart rate variability (HRV) and AMS has not been convincingly shown. In this study we investigated the utility of the smartphone-derived HRV score to predict and diagnose AMS at HA. Twenty-one healthy adults were investigated at baseline at 1400 m and over 10 days during a trek to 5140 m. HRV was recorded using the ithlete HRV device. Acute mountain sickness occurred in 11 subjects (52.4%) at >2650 m. HRV inversely correlated with AMS Scores (r = -0.26; 95% CI, -0.38 to -0.13: P HRV significantly fell at 3700, 4100, and 5140 m versus low altitude. HRV scores were lower in those with both mild (69.7 ± 14.0) and severe AMS (67.1 ± 13.1) versus those without AMS (77.5 ± 13.1; effect size n = 0.043: P = 0.007). The HRV score was weakly predictive of severe AMS (AUC 0.74; 95% CI, 0.58-0.89: P = 0.006). The change (delta) in the HRV Score (compared with baseline at 1400 m) was a moderate diagnostic marker of severe AMS (AUC 0.80; 95% CI, 0.70-0.90; P = 0.0004). A fall in the HRV score of >5 had a sensitivity of 83% and specificity of 60% to identify severe AMS (likelihood ratio 1.9). Baseline HRV at 1400 m was not predictive of either AMS at higher altitudes. The ithlete HRV score can be used to help in the identification of severe AMS; however, a baseline score is not predictive of future AMS development at HA.

  19. Origin of heart rate variability and turbulence: an appraisal of autonomic modulation of cardiovascular function.

    Directory of Open Access Journals (Sweden)

    Federico eLombardi

    2011-12-01

    Full Text Available Assessment of autonomic modulation of sinus node by non-invasive techniques has provided relevant clinical information in patients with several cardiac and non-cardiac diseases and has facilitated the appraisal of neural regulatory mechanisms in normal and diseased subjects. The finding that even during resting conditions the heart period changes on a beat to beat basis and that after a premature ventricular beat there are small variations in RR interval whose measurements may be utilised to evaluate the autonomic modulation of sinus node, has provided unprecedented clinical and pathophysiological information. Heart rate variability (HRV and Heart Rate Turbulence (HRT have been extensively utilised in the clinical setting. To explain the negative predictive value of a reduced HRV it was determined that overall HRV was largely dependent on vagal mechanisms and that a reduction in HRV could reflect an increased sympathetic and a reduced vagal modulation of sinus node; i.e. an autonomic alteration favouring cardiac electrical instability. This initial interpretation was challenged by several findings indicating a greater complexity of the relationship between neural input and sinus node responsiveness as well as the possible interference with non-neural mechanisms.Under controlled conditions, however, the computation of low and high frequency components and of their ratio seems capable of providing adequate information on sympatho-vagal balance in normal subjects as well as in most patients with a preserved left ventricular function, thus providing a unique tool to investigate neural control mechanisms. Analysis on non-linear dynamics of HRV has also been utilised to describe the fractal like characteristic of the variability signal and proven effective to identify patients at risk for sudden cardiac death. A reduction on HRT parameters reflecting reduced baroreflex sensitivity as a likely result of a reduced vagal and of an increased sympathetic

  20. Training adaptation and heart rate variability in elite endurance athletes: opening the door to effective monitoring.

    Science.gov (United States)

    Plews, Daniel J; Laursen, Paul B; Stanley, Jamie; Kilding, Andrew E; Buchheit, Martin

    2013-09-01

    The measurement of heart rate variability (HRV) is often considered a convenient non-invasive assessment tool for monitoring individual adaptation to training. Decreases and increases in vagal-derived indices of HRV have been suggested to indicate negative and positive adaptations, respectively, to endurance training regimens. However, much of the research in this area has involved recreational and well-trained athletes, with the small number of studies conducted in elite athletes revealing equivocal outcomes. For example, in elite athletes, studies have revealed both increases and decreases in HRV to be associated with negative adaptation. Additionally, signs of positive adaptation, such as increases in cardiorespiratory fitness, have been observed with atypical concomitant decreases in HRV. As such, practical ways by which HRV can be used to monitor training status in elites are yet to be established. This article addresses the current literature that has assessed changes in HRV in response to training loads and the likely positive and negative adaptations shown. We reveal limitations with respect to how the measurement of HRV has been interpreted to assess positive and negative adaptation to endurance training regimens and subsequent physical performance. We offer solutions to some of the methodological issues associated with using HRV as a day-to-day monitoring tool. These include the use of appropriate averaging techniques, and the use of specific HRV indices to overcome the issue of HRV saturation in elite athletes (i.e., reductions in HRV despite decreases in resting heart rate). Finally, we provide examples in Olympic and World Champion athletes showing how these indices can be practically applied to assess training status and readiness to perform in the period leading up to a pinnacle event. The paper reveals how longitudinal HRV monitoring in elites is required to understand their unique individual HRV fingerprint. For the first time, we demonstrate how

  1. Depression, anxiety, and heart rate variability: A case-control study in Taiwan

    Directory of Open Access Journals (Sweden)

    Li-Fen Chen

    2014-01-01

    Full Text Available Objective: Decreased heart rate variability (HRV has been reported in persons with major depressive disorder (MDD, but the results obtained are inconsistent. Little is known about the impact of comorbid anxiety disorders on HRV in MDD patients. Both issues necessitate further investigation. Materials and Methods: Forty-nine unmedicated, physically healthy, MDD patients without comorbidity, 21 MDD patients with comorbid generalized anxiety disorder (GAD, 24 MDD patients with comorbid panic disorder (PD, and 81 matched controls were recruited. The Hamilton Depression Rating Scale and the Hamilton Anxiety Rating Scale are employed to assess the severity of depression and anxiety, respectively. The cardiac autonomic function was evaluated by measuring the HRV parameters. The frequency-domain indices of HRV were obtained. Results: MDD patients without comorbidity had lower high-frequency (HF-HRV (which reflected vagal control of HRV than controls. Any comorbid anxiety disorder (GAD or PD was associated with significantly faster heart rates, relative to the controls, and caused greater reductions in HF-HRV among MDD patients. MDD participants with comorbid GAD displayed the greatest reductions in HF-HRV, relative to controls. Correlation analyses revealed that the severity of both depression and anxiety were significantly associated with the mean R wave to R wave (R-R intervals, variance, low-frequency (LF-HRV, and HF-HRV. Conclusion: The present results show decreased HRV in MDD patients, suggesting that reduction in HRV is a psychophysiological marker of MDD. MDD patients with comorbid GAD had the greatest reductions in HRV. Further investigation of the links between MDD and comorbid GAD, HRV, and cardiovascular disease is warranted.

  2. Heart Rate Variability as an Indicator of Chronic Stress Caused by Lameness in Dairy Cows.

    Directory of Open Access Journals (Sweden)

    Levente Kovács

    Full Text Available Most experimental studies on animal stress physiology have focused on acute stress, while chronic stress, which is also encountered in intensive dairy cattle farming--e.g. in case of lameness--, has received little attention. We investigated heart rate (HR and heart rate variability (HRV as indicators of the autonomic nervous system activity and fecal glucocorticoid concentrations as the indicator of the hypothalamic-pituitary-adrenal axis activity in lame (with locomotion scores 4 and 5; n = 51 and non-lame (with locomotion scores 1 and 2; n = 52 Holstein-Friesian cows. Data recorded during the periods of undisturbed lying--representing baseline cardiac activity--were involved in the analysis. Besides linear analysis methods of the cardiac inter-beat interval (time-domain geometric, frequency domain and Poincaré analyses non-linear HRV parameters were also evaluated. With the exception of standard deviation 1 (SD1, all HRV indices were affected by lameness. Heart rate was lower in lame cows than in non-lame ones. Vagal tone parameters were higher in lame cows than in non-lame animals, while indices of the sympathovagal balance reflected on a decreased sympathetic activity in lame cows. All geometric and non-linear HRV measures were lower in lame cows compared to non-lame ones suggesting that chronic stress influenced linear and non-linear characteristics of cardiac function. Lameness had no effect on fecal glucocorticoid concentrations. Our results demonstrate that HRV analysis is a reliable method in the assessment of chronic stress, however, it requires further studies to fully understand the elevated parasympathetic and decreased sympathetic tone in lame animals.

  3. Conserved variable analysis of the marine boundary layer and air

    Indian Academy of Sciences (India)

    The present study is based on the observed features of the MBL (Marine Boundary Layer) during the Bay of Bengal and Monsoon Experiment (BOBMEX) - Pilot phase. Conserved Variable Analysis (CVA) of the conserved variables such as potential temperature, virtual potential temperature, equivalent potential temperature ...

  4. Heart rate variability in major depressive disorder and after antidepressant treatment with agomelatine and paroxetine: Findings from the Taiwan Study of Depression and Anxiety (TAISDA).

    Science.gov (United States)

    Yeh, Ta-Chuan; Kao, Lien-Cheng; Tzeng, Nian-Sheng; Kuo, Terry B J; Huang, San-Yuan; Chang, Chuan-Chia; Chang, Hsin-An

    2016-01-04

    Evidence from previous studies suggests that heart rate variability (HRV) is reduced in major depressive disorder (MDD). However, whether this reduction is attributable to the disorder per se or to medication, since antidepressants may also affect HRV, is still debated. There is a dearth of information regarding the effects of agomelatine, a novel antidepressant, on HRV. Here, we investigated whether HRV is reduced in MDD and compared the effects of agomelatine and paroxetine on HRV. We recruited 618 physically healthy unmedicated patients with MDD and 506 healthy volunteers aged 20-65 years. Frequency-domain measures of resting HRV were obtained at the time of enrollment for all participants. For patients with MDD, these measures were obtained again after 6 weeks of either agomelatine or paroxetine monotherapy. Compared with healthy subjects, unmedicated patients with MDD exhibited significantly lower variance (total HRV), low frequency (LF), and high frequency (HF) HRV, and a higher LF/HF ratio. Depression severity independently contributed to decreased HRV and vagal tone. Fifty-six patients completed the open-label trial (n=29 for agomelatine, n=27 for paroxetine). Between-group analyses showed a significant group-by-time interaction for LF-HRV and HF-HRV, driven by increases in LF-HRV and HF-HRV only after agomelatine treatment. Within the paroxetine-treated group, there were no significant changes in mean R-R intervals or any HRV indices. We therefore concluded that MDD is associated with reduced HRV, which is inversely related to depression severity. Compared with paroxetine, agomelatine has a more vagotonic effect, suggesting greater cardiovascular safety. Clinicians should consider HRV effects while selecting antidepressants especially for depressed patients who already have decreased cardiac vagal tone. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Analysis of Dynamic Characteristics of Portal Frame with Variable Section

    OpenAIRE

    Hao Jianing

    2016-01-01

    Combined with a portal frame design, by the use of finite element software ANSYS, the finite element model of single specimens of portal rigid frame and the overall portal rigid frame building are established. portal rigid frame’s beam and column is variable cross section. Through the modal analysis, comparative analysis of the frequency and vibration type of the radiolabeling specimens and finite element model of the whole, for the further development of variable cross-section portal rigid f...

  6. Major depressive disorder and generalized anxiety disorder show different autonomic dysregulations revealed by heart-rate variability analysis in first-onset drug-naïve patients without comorbidity.

    Science.gov (United States)

    Shinba, Toshikazu

    2017-02-01

    The aim of the present study was to examine whether depression and anxiety disorder manifest different autonomic dysregulations using heart-rate variability (HRV) and heart rate (HR) measurements. HRV and HR were recorded both at rest and during task execution (random-number generation) in first-onset drug-naïve patients with major depressive disorder (MDD, n = 14) and generalized anxiety disorder (GAD, n = 11) as well as in healthy controls (n = 41). The patients showed no comorbidity of depression and anxiety disorder. GAD patients did not exhibit panic or phobic symptoms at the time of measurement. Following power spectrum analysis of HR trend, the high- (HF) and low-frequency (LF) components, the sum (LF + HF), and the LF/HF ratio were compared among the groups. In the MDD patients, as previously reported, HF was low and the LF/HF ratio was high during the initial-rest condition, and HF was less reactive to the task. In contrast, GAD patients showed significantly high HF, although autonomic reactivity was not impaired. The results indicate that baseline autonomic activity and its reactivity to behavioral changes are different between MDD and GAD in the early stage of illness. High parasympathetic tone in GAD may reflect responses of the parasympathetic system to anxiety. MDD is accompanied by an autonomic shift toward sympathetic activation and a reduced reactivity to task. © 2016 The Authors. Psychiatry and Clinical Neurosciences © 2016 Japanese Society of Psychiatry and Neurology.

  7. Soluble urokinase plasminogen activator receptor, C-reactive protein and triglyceride are associated with heart rate variability in non-diabetic Danes

    DEFF Research Database (Denmark)

    Intzilakis, Theodoros; Hartmann, Gro; Mouridsen, Mette R

    2013-01-01

    and is a predictor of poor outcome. As HRV and its determinants in non-diabetic individuals have not been studied properly, the aim of this observational study was to evaluate possible associations between HRV vs. impaired fasting glucose, insulin resistance, lipidaemia and markers of inflammation and immune......Heart rate variability (HRV) is associated with an increased risk of cardiovascular morbidity and mortality. HRV is in part a function of the activity of the autonomic nervous system and has been associated with low-grade inflammation. In patients with type 2 diabetes, HRV is decreased...

  8. Poincaré plot indexes of heart rate variability detect dynamic autonomic modulation during general anesthesia induction.

    Science.gov (United States)

    Hsu, Che-Hao; Tsai, Ming-Ya; Huang, Go-Shine; Lin, Tso-Chou; Chen, Kuen-Pao; Ho, Shung-Tai; Shyu, Liang-Yu; Li, Chi-Yuan

    2012-03-01

    Beat-to-beat heart rate variability (HRV) is caused by the fluctuating balance of sympathetic and parasympathetic tone. The Poincaré plot has been used to evaluate HRV. In this study, we validate that this new method may qualitatively and quantitatively assess the sympathovagal fluctuation in patients during induction of anesthesia with sevoflurane. Twenty-eight young patients were allocated for the study. The patients received a tilt test and on the next day they sustained anesthesia induced with inhaled anesthetics. Electrocardiography signals from the patients were relayed to an analogue-digital converter. The Poincaré plot is quantified by measuring SD1, SD2, and SD1/SD2. Power spectral analyses were performed and LF, HF and HF/LF were calculated. The LF power and the SD2 of the Poincaré plot increased while subjects were tilt-up from the supine position. Additionally, a significant correlation were found between LF and SD2, HF and SD1 (p plot respectively. However, the LF, SD2 and LF/HF increased; the HF, SD1 and SD1/SD2 ratio decreased after intubation stimulation. Poincaré plot and power spectral analysis of HRV during tilt test and sevoflurane induction significantly correlate. Poincaré plot analysis is easier and more sensitive at evaluating the sympathovagal balance and observing the beat-to-beat HRV. Copyright © 2012. Published by Elsevier B.V.

  9. Sensitivity to mental effort and test-retest reliability of heart rate variability measures in healthy seniors.

    Science.gov (United States)

    Mukherjee, Shalini; Yadav, Rajeev; Yung, Iris; Zajdel, Daniel P; Oken, Barry S

    2011-10-01

    To determine (1) whether heart rate variability (HRV) was a sensitive and reliable measure in mental effort tasks carried out by healthy seniors and (2) whether non-linear approaches to HRV analysis, in addition to traditional time and frequency domain approaches were useful to study such effects. Forty healthy seniors performed two visual working memory tasks requiring different levels of mental effort, while ECG was recorded. They underwent the same tasks and recordings 2 weeks later. Traditional and 13 non-linear indices of HRV including Poincaré, entropy and detrended fluctuation analysis (DFA) were determined. Time domain, especially mean R-R interval (RRI), frequency domain and, among non-linear parameters - Poincaré and DFA were the most reliable indices. Mean RRI, time domain and Poincaré were also the most sensitive to different mental effort task loads and had the largest effect size. Overall, linear measures were the most sensitive and reliable indices to mental effort. In non-linear measures, Poincaré was the most reliable and sensitive, suggesting possible usefulness as an independent marker in cognitive function tasks in healthy seniors. A large number of HRV parameters was both reliable as well as sensitive indices of mental effort, although the simple linear methods were the most sensitive. Copyright © 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  10. Review and classification of variability analysis techniques with clinical applications.

    Science.gov (United States)

    Bravi, Andrea; Longtin, André; Seely, Andrew J E

    2011-10-10

    Analysis of patterns of variation of time-series, termed variability analysis, represents a rapidly evolving discipline with increasing applications in different fields of science. In medicine and in particular critical care, efforts have focussed on evaluating the clinical utility of variability. However, the growth and complexity of techniques applicable to this field have made interpretation and understanding of variability more challenging. Our objective is to provide an updated review of variability analysis techniques suitable for clinical applications. We review more than 70 variability techniques, providing for each technique a brief description of the underlying theory and assumptions, together with a summary of clinical applications. We propose a revised classification for the domains of variability techniques, which include statistical, geometric, energetic, informational, and invariant. We discuss the process of calculation, often necessitating a mathematical transform of the time-series. Our aims are to summarize a broad literature, promote a shared vocabulary that would improve the exchange of ideas, and the analyses of the results between different studies. We conclude with challenges for the evolving science of variability analysis.

  11. Review and classification of variability analysis techniques with clinical applications

    Science.gov (United States)

    2011-01-01

    Analysis of patterns of variation of time-series, termed variability analysis, represents a rapidly evolving discipline with increasing applications in different fields of science. In medicine and in particular critical care, efforts have focussed on evaluating the clinical utility of variability. However, the growth and complexity of techniques applicable to this field have made interpretation and understanding of variability more challenging. Our objective is to provide an updated review of variability analysis techniques suitable for clinical applications. We review more than 70 variability techniques, providing for each technique a brief description of the underlying theory and assumptions, together with a summary of clinical applications. We propose a revised classification for the domains of variability techniques, which include statistical, geometric, energetic, informational, and invariant. We discuss the process of calculation, often necessitating a mathematical transform of the time-series. Our aims are to summarize a broad literature, promote a shared vocabulary that would improve the exchange of ideas, and the analyses of the results between different studies. We conclude with challenges for the evolving science of variability analysis. PMID:21985357

  12. Sympathomodulatory effects of Saam acupuncture on heart rate variability in night-shift-working nurses.

    Science.gov (United States)

    Hwang, Deok-Sang; Kim, Hyee Kwon; Seo, Jung Chul; Shin, Im Hee; Kim, Dal Ho; Kim, Yong-Suk

    2011-01-01

    We assessed the effects of Saam (traditional Korean) acupuncture on the autonomic nervous system in night-shift nurses using power-spectral heart-rate variability (HRV) analysis. This study had a 2 × 4 cross-over design with a series of six (n = 1) controlled trials. Six night-shift nurses were randomly divided into two groups, and each nurse received four acupuncture treatments on the third day of night-shift work. One group started with Saam acupuncture (gallbladder jeonggyeok), while the other started with sham acupuncture. Saam acupuncture and sham acupuncture were applied in turn. HRV was measured before and after treatment. For statistical analysis, the results of the two groups were combined, and a Bayesian model was used to compare the changes in HRV values before and after treatment, between Saam and sham acupuncture. As the ratio of low- to high-frequency power (LF/HF) for HRV increased on the third day of night-shift work in the pilot study, HRV measurements were made on the third day. Compared with sham acupuncture, Saam acupuncture reduced sympathetic activity; the overall median treatment effect estimate in LF normalised units decreased by -17.4 (confidence interval (CI): -26.67, -8.725) and that for LF/HF decreased by -1.691 (CI: -3.222, -0.3789). The overall median treatment effect estimate in HF normalised units increased by 17.41 (CI: 6.393, 27.13) with Saam acupuncture, suggesting an increase in parasympathetic activity. Saam acupuncture may attenuate the imbalance between sympathetic and parasympathetic activities induced by night-shift work in nurses. Copyright © 2010 Elsevier Ltd. All rights reserved.

  13. Potential side effects of unhealthy lifestyle choices and health risks on basal and reactive heart rate variability in college drinkers.

    Science.gov (United States)

    Udo, Tomoko; Mun, Eun-Young; Buckman, Jennifer F; Vaschillo, Evgeny G; Vaschillo, Bronya; Bates, Marsha E

    2013-09-01

    Emerging adults often begin making independent lifestyle choices during college, yet the association of these choices with fundamental indicators of health and adaptability is unclear. The present study examined the relationship between health risks and neurocardiac function in college drinkers. Heart rate variability (HRV) was assessed at baseline and in reaction to a paced breathing challenge in 212 college drinkers (53.8% women). Basal HRV served as a general indicator of health. Reactive HRV (during paced breathing) was used as a marker of an individual's adaptability to challenge. The relationship of HRV to alcohol use, cigarette use, exercise, sleep, and body mass index (BMI) was assessed. Greater alcohol use and less exercise were associated with lower basal HRV. BMI was unrelated to basal HRV but was negatively associated with reactive HRV during the breathing challenge. High levels of alcohol use and lack of exercise are negative correlates of cardiovascular and general health, even in apparently healthy college drinkers. The negative relationship between BMI and reactive HRV suggests that overweight individuals have reduced ability to psychophysiologically adapt to challenges; understanding the temporal course of this relationship is needed. This study highlights the importance of examining HRV at baseline and in response to a challenge to capture the active neurocardiac processes that contribute to health and adaptive responding. The suppressive effects of health risks on HRV are modifiable; thus, HRV may be useful in evaluating the health benefits of lifestyle change and in promoting change behaviors in college drinkers.

  14. Real analysis series, functions of several variables, and applications

    CERN Document Server

    Laczkovich, Miklós

    2017-01-01

    This book develops the theory of multivariable analysis, building on the single variable foundations established in the companion volume, Real Analysis: Foundations and Functions of One Variable. Together, these volumes form the first English edition of the popular Hungarian original, Valós Analízis I & II, based on courses taught by the authors at Eötvös Loránd University, Hungary, for more than 30 years. Numerous exercises are included throughout, offering ample opportunities to master topics by progressing from routine to difficult problems. Hints or solutions to many of the more challenging exercises make this book ideal for independent study, or further reading. Intended as a sequel to a course in single variable analysis, this book builds upon and expands these ideas into higher dimensions. The modular organization makes this text adaptable for either a semester or year-long introductory course. Topics include: differentiation and integration of functions of several variables; infinite numerica...

  15. Heart rate variability during pre-competition and competition periods in volleyball players

    OpenAIRE

    Podstawski Robert; Boraczyński Michał; Nowosielska-Swadźba Danuta; Zwolińska Danuta

    2014-01-01

    Study aim: Regular exercise training is thought to modify cardiac autonomic control. One of the body’s responses to training stimuli is heart rate variability (HRV). The use of HRV in the management of sport training is a common practice. The objective of the present study was to assess the impact of the physical activity level on HRV of 1st league national volleyball players prior to and during the competition period.

  16. Heart rate variability during pre-competition and competition periods in volleyball players

    Directory of Open Access Journals (Sweden)

    Podstawski Robert

    2014-01-01

    Full Text Available Study aim: Regular exercise training is thought to modify cardiac autonomic control. One of the body’s responses to training stimuli is heart rate variability (HRV. The use of HRV in the management of sport training is a common practice. The objective of the present study was to assess the impact of the physical activity level on HRV of 1st league national volleyball players prior to and during the competition period.

  17. Emotion regulation and trader expertise: heart rate variability on the trading floor

    OpenAIRE

    Fenton-O'Creevy, Mark; Lins, Jeffrey; Vohra, Shalini; Richards, Daniel; Davies, Gareth; Schaaff, Kristina

    2012-01-01

    We describe a psychophysiological study of the emotion regulation of investment bank traders. Building on work on the role of emotions in financial decision-making, we examine the relationship between market conditions, trader experience and emotion regulation whilst trading, as indexed by high frequency heart rate variability (HF HRV). We find a significant inverse relationship between HF HRV and market volatility and a positive relationship between HF HRV and trader experience. We argue tha...

  18. The very low-frequency band of heart rate variability represents the slow recovery component after a mental stress task.

    Directory of Open Access Journals (Sweden)

    Harunobu Usui

    Full Text Available The very low-frequency (VLF band of heart rate variability (HRV has different characteristics compared with other HRV components. Here we investigated differences in HRV changes after a mental stress task. After the task, the high-frequency (HF band and ratio of high- to low-frequency bands (LF/HF immediately returned to baseline. We evaluated the characteristics of VLF band changes after a mental stress task. We hypothesized that the VLF band decreases during the Stroop color word task and there would be a delayed recovery for 2 h after the task (i.e., the VLF change would exhibit a "slow recovery". Nineteen healthy, young subjects were instructed to rest for 10 min, followed by a Stroop color word task for 20 min. After the task, the subjects were instructed to rest for 120 min. For all subjects, R-R interval data were collected; analysis was performed for VLF, HF, and LF/HF ratio. HRV during the rest time and each 15-min interval of the recovery time were compared. An analysis of the covariance was performed to adjust for the HF band and LF/HF ratio as confounding variables of the VLF component. HF and VLF bands significantly decreased and the LF/HF ratio significantly increased during the task compared with those during rest time. During recovery, the VLF band was significantly decreased compared with the rest time. After the task, the HF band and LF/HF ratio immediately returned to baseline and were not significantly different from the resting values. After adjusting for HF and LF/HF ratio, the VLF band had significantly decreased compared with that during rest. The VLF band is the "slow recovery" component and the HF band and LF/HF ratio are the "quick recovery" components of HRV. This VLF characteristic may clarify the unexplained association of the VLF band in cardiovascular disease prevention.

  19. The very low-frequency band of heart rate variability represents the slow recovery component after a mental stress task.

    Science.gov (United States)

    Usui, Harunobu; Nishida, Yusuke

    2017-01-01

    The very low-frequency (VLF) band of heart rate variability (HRV) has different characteristics compared with other HRV components. Here we investigated differences in HRV changes after a mental stress task. After the task, the high-frequency (HF) band and ratio of high- to low-frequency bands (LF/HF) immediately returned to baseline. We evaluated the characteristics of VLF band changes after a mental stress task. We hypothesized that the VLF band decreases during the Stroop color word task and there would be a delayed recovery for 2 h after the task (i.e., the VLF change would exhibit a "slow recovery"). Nineteen healthy, young subjects were instructed to rest for 10 min, followed by a Stroop color word task for 20 min. After the task, the subjects were instructed to rest for 120 min. For all subjects, R-R interval data were collected; analysis was performed for VLF, HF, and LF/HF ratio. HRV during the rest time and each 15-min interval of the recovery time were compared. An analysis of the covariance was performed to adjust for the HF band and LF/HF ratio as confounding variables of the VLF component. HF and VLF bands significantly decreased and the LF/HF ratio significantly increased during the task compared with those during rest time. During recovery, the VLF band was significantly decreased compared with the rest time. After the task, the HF band and LF/HF ratio immediately returned to baseline and were not significantly different from the resting values. After adjusting for HF and LF/HF ratio, the VLF band had significantly decreased compared with that during rest. The VLF band is the "slow recovery" component and the HF band and LF/HF ratio are the "quick recovery" components of HRV. This VLF characteristic may clarify the unexplained association of the VLF band in cardiovascular disease prevention.

  20. Heart Rate Variability in Men with Erectile dysfunction

    Directory of Open Access Journals (Sweden)

    Ji Yong Lee

    2011-06-01

    Full Text Available Purpose The objective of this study is to investigate alteration of autonomic nervous system (ANS activity in patients suffering from erectile dysfunction (ED by comparing parameters of heart rate variability (HRV between men with ED and healthy subjects. Methods A retrospective review was performed on 40 ED patients (mean age, 46.0±8.49 years without any disease and 180 healthy control people (mean age, 44.4±7.83 years without ED in our institution from June 2008 to July 2010. And electrocardiographic signals were obtained to measure HRV parameters for both patients and controls in a resting state. Results For the time domain analysis, square root of the mean differences between successive RR intervals (RMSSD representing parasympathetic activity was lower in patients than controls although P-value was not statistically significant (P=0.060. For the frequency domain analysis, high frequency (HF representing parasympathetic activity was lower in patients than controls (P=0.232 and low frequency (LF representing mainly sympathetic activity was higher in patients than controls (P=0.416. Lastly, LF/HF ratio reflecting sympathetic/parasympathetic activity ratio was statistically higher in patients than controls (P=0.027. Conclusions Patients with ED exhibited different HRV parameters compared with normal controls. This suggests that the patients with ED may have some kind of imbalance in the ANS and it may be possible that general imbalance of the ANS is one of the causes of ED. Thus, HRV analysis may give valuable diagnostic information and serve as a rapid screening tool to evaluate altered ANS activity in patients with ED.

  1. Effect of heart rate correction on pre- and post-exercise heart rate variability to predict risk of mortality – an experimental study on the FINCAVAS cohort

    Directory of Open Access Journals (Sweden)

    Paruthi ePradhapan

    2014-06-01

    Full Text Available The non-linear inverse relationship between RR-intervals and heart rate (HR contributes significantly to the heart rate variability (HRV parameters and their performance in mortality prediction. To determine the level of influence HR exerts over HRV parameters’ prognostic power, we studied the predictive performance for different HR levels by applying eight correction procedures, multiplying or dividing HRV parameters by the mean RR-interval (RRavg to the power 0.5-16. Data collected from 1288 patients in The Finnish Cardiovascular Study (FINCAVAS, who satisfied the inclusion criteria, was used for the analyses. HRV parameters (RMSSD, VLF Power and LF Power were calculated from 2-minute segment in the rest phase before exercise and 2-minute recovery period immediately after peak exercise. Area under the receiver operating characteristic curve (AUC was used to determine the predictive performance for each parameter with and without HR corrections in rest and recovery phases. The division of HRV parameters by segment’s RRavg to the power 2 (HRVDIV-2 showed the highest predictive performance under the rest phase (RMSSD: 0.67/0.66; VLF Power: 0.70/0.62; LF Power: 0.79/0.65; cardiac mortality/non-cardiac mortality with minimum correlation to HR (r = -0.15 to 0.15. In the recovery phase, Kaplan-Meier (KM survival analysis revealed good risk stratification capacity at HRVDIV-2 in both groups (cardiac and non-cardiac mortality. Although higher powers of correction (HRVDIV-4 and HRVDIV-8 improved predictive performance during recovery, they induced an increased positive correlation to HR. Thus, we inferred that predictive capacity of HRV during rest and recovery is augmented when its dependence on HR is weakened by applying appropriate correction procedures.

  2. Investigation of the relationship between anxiety and heart rate variability in fibromyalgia: A new quantitative approach to evaluate anxiety level in fibromyalgia syndrome.

    Science.gov (United States)

    Bilgin, Suleyman; Arslan, Evren; Elmas, Onur; Yildiz, Sedat; Colak, Omer H; Bilgin, Gurkan; Koyuncuoglu, Hasan Rifat; Akkus, Selami; Comlekci, Selcuk; Koklukaya, Etem

    2015-12-01

    Fibromyalgia syndrome (FMS) is identified by widespread musculoskeletal pain, sleep disturbance, nonrestorative sleep, fatigue, morning stiffness and anxiety. Anxiety is very common in Fibromyalgia and generally leads to a misdiagnosis. Self-rated Beck Anxiety Inventory (BAI) and doctor-rated Hamilton Anxiety Inventory (HAM-A) are frequently used by specialists to determine anxiety that accompanies fibromyalgia. However, these semi-quantitative anxiety tests are still subjective as the tests are scored using doctor-rated or self-rated scales. In this study, we investigated the relationship between heart rate variability (HRV) frequency subbands and anxiety tests. The study was conducted with 56 FMS patients and 34 healthy controls. BAI and HAM-A test scores were determined for each participant. ECG signals were then recruited and 71 HRV subbands were obtained from these ECG signals using Wavelet Packet Transform (WPT). The subbands and anxiety tests scores were analyzed and compared using multilayer perceptron neural networks (MLPNN). The results show that a HRV high frequency (HF) subband in the range of 0.15235Hz to 0.40235Hz, is correlated with BAI scores and another HRV HF subband, frequency range of 0.15235Hz to 0.28907Hz is correlated with HAM-A scores. The overall accuracy is 91.11% for HAM-A and 90% for BAI with MLPNN analysis. Doctor-rated or self-rated anxiety tests should be supported with quantitative and more objective methods. Our results show that the HRV parameters will be able to support the anxiety tests in the clinical evaluation of fibromyalgia. In other words, HRV parameters can potentially be used as an auxiliary diagnostic method in conjunction with anxiety tests. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Analysis of Dynamic Characteristics of Portal Frame with Variable Section

    Directory of Open Access Journals (Sweden)

    Hao Jianing

    2016-01-01

    Full Text Available Combined with a portal frame design, by the use of finite element software ANSYS, the finite element model of single specimens of portal rigid frame and the overall portal rigid frame building are established. portal rigid frame’s beam and column is variable cross section. Through the modal analysis, comparative analysis of the frequency and vibration type of the radiolabeling specimens and finite element model of the whole, for the further development of variable cross-section portal rigid frame of earthquake and wind vibration analysis lay the foundation.

  4. Longitudinal association of short-term, metronome-paced heart rate variability and echocardiographically assessed cardiac structure at a 4-year follow-up: results from the prospective, population-based CARLA cohort.

    Science.gov (United States)

    Medenwald, Daniel; Swenne, Cees A; Frantz, Stefan; Nuding, Sebastian; Kors, Jan A; Pietzner, Diana; Tiller, Daniel; Greiser, Karin H; Kluttig, Alexander; Haerting, Johannes

    2017-12-01

    To assess the value of cardiac structure/function in predicting heart rate variability (HRV) and the possibly predictive value of HRV on cardiac parameters. Baseline and 4-year follow-up data from the population-based CARLA cohort were used (790 men, 646 women, aged 45-83 years at baseline and 50-87 years at follow-up). Echocardiographic and HRV recordings were performed at baseline and at follow-up. Linear regression models with a quadratic term were used. Crude and covariate adjusted estimates were calculated. Missing values were imputed by means of multiple imputation. Heart rate variability measures taken into account consisted of linear time and frequency domain [standard deviation of normal-to-normal intervals (SDNN), high-frequency power (HF), low-frequency power (LF), LF/HF ratio] and non-linear measures [detrended fluctuation analysis (DFA1), SD1, SD2, SD1/SD2 ratio]. Echocardiographic parameters considered were ventricular mass index, diastolic interventricular septum thickness, left ventricular diastolic dimension, left atrial dimension systolic (LADS), and ejection fraction (Teichholz). A negative quadratic relation between baseline LADS and change in SDNN and HF was observed. The maximum HF and SDNN change (an increase of roughly 0.02%) was predicted at LADS of 3.72 and 3.57 cm, respectively, while the majority of subjects experienced a decrease in HRV. There was no association between further echocardiographic parameters and change in HRV, and there was no evidence of a predictive value of HRV in the prediction of changes in cardiac structure. In the general population, LADS predicts 4-year alteration in SDNN and HF non-linearly. Because of the novelty of the result, analyses should be replicated in other populations. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions please email: journals.permissions@oup.com.

  5. A meta analysis of the variability in firm performance attributable to human resource variables

    Directory of Open Access Journals (Sweden)

    Lloyd Kapondoro

    2015-01-01

    Full Text Available The contribution of Human Resource Management (HRM practices to organisation-wide performance is a critical aspect of the Human Resource (HR value proposition. The purpose of the study was to describe the strength of HRM practices and systems in influencing overall organisational performance. While research has concluded that there is a significant positive relationship between HRM practices or systems and an organisation’s market performance, the strength of this relationship has relatively not received much analysis in order to explain the degree to which HRM practices explain variance in firm performance. The study undertook a meta-analysis of published researches in international journals. The study established that HRM variables accounted for an average of 31% of the variability in firm performance. Cohen’s f2 calculated for this study as a meta effect size calculation yielded an average of 0.681, implying that HRM variables account for 68% of variability in firm performance. A one sample Kolmogorov-Smirnov test showed that the distribution of R2 is not normal. A major managerial implication of this study is that effective HRM practices have a significant business case. The study provides, quantitatively, the average variability in firm success that HRM accounts for.

  6. Variability Bugs in Highly Configurable Systems: A Qualitative Analysis

    DEFF Research Database (Denmark)

    Abal, Iago; Melo, Jean; Stanciulescu, Stefan

    2018-01-01

    Variability-sensitive verification pursues effective analysis of the exponentially many variants in number of features of a program family. Several variability-aware techniques have been proposed, but researchers still lack examples of concrete bugs induced by variability, occurring in real large......-scale systems. A collection of real world bugs is needed to evaluate tool implementations of variability-sensitive analyses by testing them on real bugs. We present a qualitative study of 98 diverse variability bugs collected from bug-fixing commits in the Apache, BusyBox, Linux kernel and Marlin repositories....... We analyze each of the bugs, and record the results in a database. For each bug, we create a self-contained simplified C99 version and a simplified patch, in order to help researchers who are not experts on these subject studies to understand them, so that they can use it for evaluation...

  7. Power calculator for instrumental variable analysis in pharmacoepidemiology.

    Science.gov (United States)

    Walker, Venexia M; Davies, Neil M; Windmeijer, Frank; Burgess, Stephen; Martin, Richard M

    2017-10-01

    Instrumental variable analysis, for example with physicians' prescribing preferences as an instrument for medications issued in primary care, is an increasingly popular method in the field of pharmacoepidemiology. Existing power calculators for studies using instrumental variable analysis, such as Mendelian randomization power calculators, do not allow for the structure of research questions in this field. This is because the analysis in pharmacoepidemiology will typically have stronger instruments and detect larger causal effects than in other fields. Consequently, there is a need for dedicated power calculators for pharmacoepidemiological research. The formula for calculating the power of a study using instrumental variable analysis in the context of pharmacoepidemiology is derived before being validated by a simulation study. The formula is applicable for studies using a single binary instrument to analyse the causal effect of a binary exposure on a continuous outcome. An online calculator, as well as packages in both R and Stata, are provided for the implementation of the formula by others. The statistical power of instrumental variable analysis in pharmacoepidemiological studies to detect a clinically meaningful treatment effect is an important consideration. Research questions in this field have distinct structures that must be accounted for when calculating power. The formula presented differs from existing instrumental variable power formulae due to its parametrization, which is designed specifically for ease of use by pharmacoepidemiologists. © The Author 2017. Published by Oxford University Press on behalf of the International Epidemiological Association

  8. [Relations between biomedical variables: mathematical analysis or linear algebra?].

    Science.gov (United States)

    Hucher, M; Berlie, J; Brunet, M

    1977-01-01

    The authors, after a short reminder of one pattern's structure, stress on the possible double approach of relations uniting the variables of this pattern: use of fonctions, what is within the mathematical analysis sphere, use of linear algebra profiting by matricial calculation's development and automatiosation. They precise the respective interests on these methods, their bounds and the imperatives for utilization, according to the kind of variables, of data, and the objective for work, understanding phenomenons or helping towards decision.

  9. Heart Rate Variability (HRV) biofeedback: A new training approach for operator’s performance enhancement

    OpenAIRE

    Auditya Purwandini Sutarto; Muhammad Nubli Abdul Wahab; Nora Mat Zin

    2010-01-01

    The widespread implementation of advanced and complex systems requires predominantly operators’ cognitive functions and less importance of human manual control. On the other hand, most operators perform their cognitive functions below their peak cognitive capacity level due to fatigue, stress, and boredom. Thus, there is a need to improve their cognitive functions during work. The goal of this paper is to present a psychophysiology training approach derived from cardiovascular response ...

  10. HEART RATE VARIABILITY PARAMETERS IN PATIENTS WITH ARTERIAL HYPERTENSION IN DEPENDENCE ON THE TYPE OF DAILY BLOOD PRESSURE PROFILE

    Directory of Open Access Journals (Sweden)

    S. G. B. K. Gorantla

    2017-06-01

    Full Text Available Violation of functioning of the autonomic nervous system is an important factor in the formation and progression of arterial hypertension (AH. Abnormal nocturnal blood pressure (BP reduction is regarded as an independent prognostic factor for cardiovascular complications in patients with AH. One of the possible factors that determine the violation of BP circadian rhythm can be imbalance of different parts of autonomic nervous system. The aim of our study was to study heart rate variability (HRV in patients with AH, dependently of BP profile. 72 patients with AH were examined. Average age was 57 ± 11 years. All patients underwent ambulatory BP (ABPM and ECG monitoring. To define the daily profile the nocturnal BP dip was quantified and for HRV evaluation the frequency analysis method was used. HRV changes in patients with AH present with reduced total power and with a violation in the ratio of the powers of very low, low and high frequencies, enhanced sympathycotension and influence of humoral factors. Violations of systolic BP (SBP daily profile was mainly characterized by an increase in the power of low frequency waves, which indicates an intensification of sympathetic and decreased parasympathetic influences. Violations of diastolic BP (DBP daily profile were mainly characterized by a relative increase in the power of very low frequency waves. The obtained results showed that in the management of patients with AH it is important not only to control the circadian SBP and DBP profiles, but the evaluation of HRV also.

  11. A Novel Feature Level Fusion for Heart Rate Variability Classification Using Correntropy and Cauchy-Schwarz Divergence.

    Science.gov (United States)

    Goshvarpour, Ateke; Goshvarpour, Atefeh

    2018-04-30

    Heart rate variability (HRV) analysis has become a widely used tool for monitoring pathological and psychological states in medical applications. In a typical classification problem, information fusion is a process whereby the effective combination of the data can achieve a more accurate system. The purpose of this article was to provide an accurate algorithm for classifying HRV signals in various psychological states. Therefore, a novel feature level fusion approach was proposed. First, using the theory of information, two similarity indicators of the signal were extracted, including correntropy and Cauchy-Schwarz divergence. Applying probabilistic neural network (PNN) and k-nearest neighbor (kNN), the performance of each index in the classification of meditators and non-meditators HRV signals was appraised. Then, three fusion rules, including division, product, and weighted sum rules were used to combine the information of both similarity measures. For the first time, we propose an algorithm to define the weights of each feature based on the statistical p-values. The performance of HRV classification using combined features was compared with the non-combined features. Totally, the accuracy of 100% was obtained for discriminating all states. The results showed the strong ability and proficiency of division and weighted sum rules in the improvement of the classifier accuracies.

  12. [Quantitative analysis of drug expenditures variability in dermatology units].

    Science.gov (United States)

    Moreno-Ramírez, David; Ferrándiz, Lara; Ramírez-Soto, Gabriel; Muñoyerro, M Dolores

    2013-01-01

    Variability in adjusted drug expenditures among clinical departments raises the possibility of difficult access to certain therapies at the time that avoidable expenditures may also exist. Nevertheless, drug expenditures are not usually applied to clinical practice variability analysis. To identify and quantify variability in drug expenditures in comparable dermatology department of the Servicio Andaluz de Salud. Comparative economic analysis regarding the drug expenditures adjusted to population and health care production in 18 dermatology departments of the Servicio Andaluz de Salud. The 2012 cost and production data (homogeneous production units -HPU-)were provided by Inforcoan, the cost accounting information system of the Servicio Andaluz de Salud. The observed drug expenditure ratio ranged from 0.97?/inh to 8.90?/inh and from 208.45?/HPU to 1,471.95?/ HPU. The Pearson correlation between drug expenditure and population was 0.25 and 0.35 for the correlation between expenditure and homogeneous production (p=0.32 and p=0,15, respectively), both Pearson coefficients confirming the lack of correlation and arelevant degree of variability in drug expenditures. The quantitative analysis of variability performed through Pearson correlation has confirmed the existence of drug expenditure variability among comparable dermatology departments. Copyright © 2013 SEFH. Published by AULA MEDICA. All rights reserved.

  13. Relationship between dysfunctional breathing patterns and ability to achieve target heart rate variability with features of "coherence" during biofeedback.

    Science.gov (United States)

    Courtney, Rosalba; Cohen, Marc; van Dixhoorn, Jan

    2011-01-01

    Heart rate variability (HRV) biofeedback is a self-regulation strategy used to improve conditions including asthma, stress, hypertension, and chronic obstructive pulmonary disease. Respiratory muscle function affects hemodynamic influences on respiratory sinus arrhythmia (RSA), and HRV and HRV-biofeedback protocols often include slow abdominal breathing to achieve physiologically optimal patterns of HRV with power spectral distribution concentrated around the 0.1-Hz frequency and large amplitude. It is likely that optimal balanced breathing patterns and ability to entrain heart rhythms to breathing reflect physiological efficiency and resilience and that individuals with dysfunctional breathing patterns may have difficulty voluntarily modulating HRV and RSA. The relationship between breathing movement patterns and HRV, however, has not been investigated. This study examines how individuals' habitual breathing patterns correspond with their ability to optimize HRV and RSA. Breathing pattern was assessed using the Manual Assessment of Respiratory Motion (MARM) and the Hi Lo manual palpation techniques in 83 people with possible dysfunctional breathing before they attempted HRV biofeedback. Mean respiratory rate was also assessed. Subsequently, participants applied a brief 5-minute biofeedback protocol, involving breathing and positive emotional focus, to achieve HRV patterns proposed to reflect physiological "coherence" and entrainment of heart rhythm oscillations to other oscillating body systems. Thoracic-dominant breathing was associated with decreased coherence of HRV (r = -.463, P = .0001). Individuals with paradoxical breathing had the lowest HRV coherence (t(8) = 10.7, P = .001), and the negative relationship between coherence of HRV and extent of thoracic breathing was strongest in this group (r = -.768, P = .03). Dysfunctional breathing patterns are associated with decreased ability to achieve HRV patterns that reflect cardiorespiratory efficiency and

  14. [Heart rate variability study based on a novel RdR RR Intervals Scatter Plot].

    Science.gov (United States)

    Lu, Hongwei; Lu, Xiuyun; Wang, Chunfang; Hua, Youyuan; Tian, Jiajia; Liu, Shihai

    2014-08-01

    On the basis of Poincare scatter plot and first order difference scatter plot, a novel heart rate variability (HRV) analysis method based on scatter plots of RR intervals and first order difference of RR intervals (namely, RdR) was proposed. The abscissa of the RdR scatter plot, the x-axis, is RR intervals and the ordinate, y-axis, is the difference between successive RR intervals. The RdR scatter plot includes the information of RR intervals and the difference between successive RR intervals, which captures more HRV information. By RdR scatter plot analysis of some records of MIT-BIH arrhythmias database, we found that the scatter plot of uncoupled premature ventricular contraction (PVC), coupled ventricular bigeminy and ventricular trigeminy PVC had specific graphic characteristics. The RdR scatter plot method has higher detecting performance than the Poincare scatter plot method, and simpler and more intuitive than the first order difference method.

  15. Heart rate variability to monitor performance in elite athletes: Criticalities and avoidable pitfalls.

    Science.gov (United States)

    Lucini, Daniela; Marchetti, Ilaria; Spataro, Antonio; Malacarne, Mara; Benzi, Manuela; Tamorri, Stefano; Sala, Roberto; Pagani, Massimo

    2017-08-01

    Spectral analysis of Heart Rate Variability (HRV) is a simple, non-invasive technique that is widely used in sport to assess sympatho-vagal regulation of the heart. Its employment is increasing partly due to the rising usage of wearable devices. However data acquisition using these devices may be suboptimal because they cannot discriminate between sinus and non-sinus beats and do not record any data regarding respiratory frequency. This information is mandatory for a correct clinical interpretation. This study involved 974 elite athletes, all of them underwent a complete autonomic assessment, by way of Autoregressive HRV analysis. In 91 subjects (9% of the total population) we observed criticalities of either cardiac rhythm or respiration. Through perusal of one-lead ECG analysis we observed that 77 subjects had atrial or ventricular ectopy, i.e. conditions which impair stationarity and sinus rhythm. Running anyway autonomic nervous system analysis in this population, we observed that RR variance and raw values of LF and HF regions are significantly higher in arrhythmic subjects. In addition 14 subjects had slow (about 6 breath/min, 0.1Hz) respiration. This condition clouds the separation between LF from HF spectral regions of RR interval variability, respectively markers of the prevalent sympathetic and vagal modulation of SA node and of their synergistic interaction. Caution must be payed when assessing HRV with non-ECG wearable devices. Recording ECG signal and ensuring that respiratory rate is higher than 10 breath/min are both prerequisites for a more reliable analysis of HRV particularly in athletes. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Comprehensive multilevel in vivo and in vitro analysis of heart rate fluctuations in mice by ECG telemetry and electrophysiology.

    Science.gov (United States)

    Fenske, Stefanie; Pröbstle, Rasmus; Auer, Franziska; Hassan, Sami; Marks, Vanessa; Pauza, Danius H; Biel, Martin; Wahl-Schott, Christian

    2016-01-01

    The normal heartbeat slightly fluctuates around a mean value; this phenomenon is called physiological heart rate variability (HRV). It is well known that altered HRV is a risk factor for sudden cardiac death. The availability of genetic mouse models makes it possible to experimentally dissect the mechanism of pathological changes in HRV and its relation to sudden cardiac death. Here we provide a protocol that allows for a comprehensive multilevel analysis of heart rate (HR) fluctuations. The protocol comprises a set of techniques that include in vivo telemetry and in vitro electrophysiology of intact sinoatrial network preparations or isolated single sinoatrial node (SAN) cells. In vitro preparations can be completed within a few hours, with data acquisition within 1 d. In vivo telemetric ECG requires 1 h for surgery and several weeks for data acquisition and analysis. This protocol is of interest to researchers investigating cardiovascular physiology and the pathophysiology of sudden cardiac death.

  17. Distinguishing molecular features and clinical characteristics of a putative new rhinovirus species, human rhinovirus C (HRV C.

    Directory of Open Access Journals (Sweden)

    Peter McErlean

    Full Text Available BACKGROUND: Human rhinoviruses (HRVs are the most frequently detected pathogens in acute respiratory tract infections (ARTIs and yet little is known about the prevalence, recurrence, structure and clinical impact of individual members. During 2007, the complete coding sequences of six previously unknown and highly divergent HRV strains were reported. To catalogue the molecular and clinical features distinguishing the divergent HRV strains, we undertook, for the first time, in silico analyses of all available polyprotein sequences and performed retrospective reviews of the medical records of cases in which variants of the prototype strain, HRV-QPM, had been detected. METHODOLOGY/PRINCIPLE FINDINGS: Genomic analyses revealed that the six divergent strains, residing within a clade we previously called HRV A2, had the shortest polyprotein of all picornaviruses investigated. Structure-based amino acid alignments identified conserved motifs shared among members of the genus Rhinovirus as well as substantive deletions and insertions unique to the divergent strains. Deletions mostly affected regions encoding proteins traditionally involved in antigenicity and serving as HRV and HEV receptor footprints. Because the HRV A2 strains cannot yet be cultured, we created homology models of predicted HRV-QPM structural proteins. In silico comparisons confirmed that HRV-QPM was most closely related to the major group HRVs. HRV-QPM was most frequently detected in infants with expiratory wheezing or persistent cough who had been admitted to hospital and required supplemental oxygen. It was the only virus detected in 65% of positive individuals. These observations contributed to an objective clinical impact ranging from mild to severe. CONCLUSIONS: The divergent strains did not meet classification requirements for any existing species of the genus Rhinovirus or Enterovirus. HRV A2 strains should be partitioned into at least one new species, putatively called Human

  18. Sensitivity, Specificity and Predictive Value of Heart Rate Variability Indices in Type 1 Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    Anne Kastelianne França da Silva

    Full Text Available Abstract Background: Heart rate variability (HRV indices may detect autonomic changes with good diagnostic accuracy. Type diabetes mellitus (DM individuals may have changes in autonomic modulation; however, studies of this nature in this population are still scarce. Objective: To compare HRV indices between and assess their prognostic value by measurements of sensitivity, specificity and predictive values in young individuals with type 1 DM and healthy volunteers. Methods: In this cross-sectional study, physical and clinical assessment was performed in 39 young patients with type 1 DM and 43 young healthy controls. For HRV analysis, beat-to-beat heart rate variability was measured in dorsal decubitus, using a Polar S810i heart rate monitor, for 30 minutes. The following indices were calculated: SDNN, RMSSD, PNN50, TINN, RRTri, LF ms2, HF ms2, LF un, HF un, LF/HF, SD1, SD2, SD1/SD2, and ApEn. Results: Type 1 DM subjects showed a decrease in sympathetic and parasympathetic activities, and overall variability of autonomic nervous system. The RMSSD, SDNN, PNN50, LF ms2, HF ms2, RRTri, SD1 and SD2 indices showed greater diagnostic accuracy in discriminating diabetic from healthy individuals. Conclusion: Type 1 DM individuals have changes in autonomic modulation. The SDNN, RMSSD, PNN50, RRtri, LF ms2, HF ms2, SD1 and SD2 indices may be alternative tools to discriminate individuals with type 1 DM.

  19. Effective Analysis of C Programs by Rewriting Variability

    DEFF Research Database (Denmark)

    Iosif-Lazar, Alexandru Florin; Melo, Jean; Dimovski, Aleksandar

    2017-01-01

    and effective analysis and verification of real-world C program families. Importance. We report some interesting variability-related bugs that we discovered using various state-of-the-art single-program C verification tools, such as Frama-C, Clang, LLBMC.......Context. Variability-intensive programs (program families) appear in many application areas and for many reasons today. Different family members, called variants, are derived by switching statically configurable options (features) on and off, while reuse of the common code is maximized. Inquiry....... Verification of program families is challenging since the number of variants is exponential in the number of features. Existing single-program analysis and verification tools cannot be applied directly to program families, and designing and implementing the corresponding variability-aware versions is tedious...

  20. Effects of Moxa (Folium Artemisiae argyi Smoke Exposure on Heart Rate and Heart Rate Variability in Healthy Young Adults: A Randomized, Controlled Human Study

    Directory of Open Access Journals (Sweden)

    Yingxue Cui

    2013-01-01

    Full Text Available Objective. To determine the effects of the moxa smoke on human heart rate (HR and heart rate variability (HRV. Methods. Fifty-five healthy young adults were randomly divided into experimental (n=28 and control (n=27 groups. Experimental subjects were exposed to moxa smoke (2.5 ± 0.5 mg/m3 twice for 25 minutes in one week. ECG monitoring was performed before, during, and after exposure. Control subjects were exposed to normal indoor air in a similar environment and similarly monitored. Followup was performed the following week. Short-term (5 min HRV parameters were analyzed with HRV analysis software. SPSS software was used for statistical analysis. Results. During and after the first exposure, comparison of percentage changes or changes in all parameters between groups showed no significant differences. During the second exposure, percentage decrease in HR, percentage increases in lnTP, lnHF, lnLF, and RMSSD, and increase in PNN50 were significantly greater in the experimental group than in control. Conclusion. No significant adverse HRV effects were associated with this clinically routine 25-minute exposure to moxa smoke, and the data suggests that short-term exposure to moxa smoke might have positive regulating effects on human autonomic function. Further studies are warranted to confirm these findings.

  1. Heart rate variability interventions for concussion and rehabilitation.

    Science.gov (United States)

    Conder, Robert L; Conder, Alanna A

    2014-01-01

    The study of heart rate variability (HRV) has emerged as an essential component of cardiovascular health, as well as a physiological mechanism by which one can increase the interactive communication between the cardiac and the neurocognitive systems (i.e., the body and the brain). It is well-established that lack of HRV implies cardiopathology, morbidity, reduced quality-of-life, and precipitous mortality. On the positive, optimal HRV has been associated with good cardiovascular health, autonomic nervous system (ANS) control, emotional regulation, and enhanced neurocognitive processing. In addition to health benefits, optimal HRV has been shown to improve neurocognitive performance by enhancing focus, visual acuity and readiness, and by promoting emotional regulation needed for peak performance. In concussed athletes and soldiers, concussions not only alter brain connectivity, but also alter cardiac functioning and impair cardiovascular performance upon exertion. Altered sympathetic and parasympathetic balance in the ANS has been postulated as a critical factor in refractory post concussive syndrome (PCS). This article will review both the pathological aspects of reduced HRV on athletic performance, as well as the cardiovascular and cerebrovascular components of concussion and PCS. Additionally, this article will review interventions with HRV biofeedback (HRV BFB) training as a promising and underutilized treatment for sports and military-related concussion. Finally, this article will review research and promising case studies pertaining to use of HRV BFB for enhancement of cognition and performance, with applicability to concussion rehabilitation.

  2. Heart rate variability alters cardiac repolarization and electromechanical dynamics.

    Science.gov (United States)

    Phadumdeo, Vrishti M; Weinberg, Seth H

    2018-04-07

    Heart rate continuously varies due to autonomic regulation, stochasticity in pacemaking, and circadian rhythm, collectively termed heart rate variability (HRV), during normal physiological conditions. Low HRV is clinically associated with an elevated risk of cardiac arrhythmias. Alternans, a beat-to-beat alternation in action potential duration (APD) and/or intracellular calcium (Ca) transient, is a well-known risk factor associated with cardiac arrhythmias that is typically studied under conditions of a constant pacing rate, i.e., the absence of HRV. In this study, we investigate the effects of HRV on the interplay between APD, Ca, and electromechanical properties, employing a nonlinear discrete-time map model that governs APD and intracellular Ca cycling with a stochastic pacing period. We find that HRV can decrease variation in APD and peak Ca at fast pacing rates for which alternans is present. Further, increased HRV typically disrupts the alternating pattern for both APD and peak Ca and weakens the correlation between APD and peak Ca, thus decoupling Ca-mediated instabilities from repolarization alternation. We find that the efficacy of these effects is regulated by the sarcoplasmic reticulum Ca uptake rate. Overall, these results demonstrate that HRV disrupts arrhythmogenic alternans and suggests that HRV may be a significant factor in preventing life-threatening arrhythmias. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. GIS and correlation analysis of geo-environmental variables ...

    African Journals Online (AJOL)

    GIS and correlation analysis of geo-environmental variables influencing malaria prevalence in the Saboba district of Northern Ghana. ... The study also applied spline interpolation technique to map malaria prevalence in the district using standardised malaria incidence. The result indicates that distance to marshy areas is ...

  4. Variability, correlation and path coefficient analysis of seedling traits ...

    African Journals Online (AJOL)

    Indirect selection is a useful means for improving yield in cotton crop. The objective of the present study was to determine the genetic variability, broad sense heritability, genetic advance and correlation among the six seedling traits and their direct and indirect effects on cotton yield by using path coefficient analysis.

  5. Omitted Variable Sensitivity Analysis with the Annotated Love Plot

    Science.gov (United States)

    Hansen, Ben B.; Fredrickson, Mark M.

    2014-01-01

    The goal of this research is to make sensitivity analysis accessible not only to empirical researchers but also to the various stakeholders for whom educational evaluations are conducted. To do this it derives anchors for the omitted variable (OV)-program participation association intrinsically, using the Love plot to present a wide range of…

  6. Nonlinear canonical correlation analysis with k sets of variables

    NARCIS (Netherlands)

    van der Burg, Eeke; de Leeuw, Jan

    1987-01-01

    The multivariate technique OVERALS is introduced as a non-linear generalization of canonical correlation analysis (CCA). First, two sets CCA is introduced. Two sets CCA is a technique that computes linear combinations of sets of variables that correlate in an optimal way. Two sets CCA is then

  7. Variable precision rough set for multiple decision attribute analysis

    Institute of Scientific and Technical Information of China (English)

    Lai; Kin; Keung

    2008-01-01

    A variable precision rough set (VPRS) model is used to solve the multi-attribute decision analysis (MADA) problem with multiple conflicting decision attributes and multiple condition attributes. By introducing confidence measures and a β-reduct, the VPRS model can rationally solve the conflicting decision analysis problem with multiple decision attributes and multiple condition attributes. For illustration, a medical diagnosis example is utilized to show the feasibility of the VPRS model in solving the MADA...

  8. Reduced heart rate variability in chronic severe traumatic brain injury: Association with impaired emotional and social functioning, and potential for treatment using biofeedback.

    Science.gov (United States)

    Francis, Heather M; Fisher, Alana; Rushby, Jacqueline A; McDonald, Skye

    2016-01-01

    Heart rate variability (HRV) may provide an index of capacity for social functioning and may be remediated by HRV biofeedback. Given reductions in HRV are found following traumatic brain injury (TBI), the present study aimed to determine whether lower HRV in TBI is associated with social function, and whether HRV biofeedback might be a useful remediation technique in this population. Resting state HRV and measures of social and emotional processing were collected in 30 individuals with severe TBI (3-34 years post-injury) and 30 controls. This was followed by a single session of HRV biofeedback. HRV was positively associated with social cognition and empathy, and negatively associated with alexithymia for the TBI group. Both TBI and control groups showed significantly increased HRV on both time-domain (i.e., SDNN, rMSSD) and frequency-domain measures (LF, HF, LF:HF ratio) during biofeedback compared to baseline. These results suggest that decreased HRV is linked to social and emotional function following severe TBI, and may be a novel target for therapy using HRV biofeedback techniques.

  9. Heart Rate Variability is a Moderating Factor in the Workload-Injury Relationship of Competitive CrossFit™ Athletes

    OpenAIRE

    Williams, Sean; Booton, Thomas; Watson, Matthew; Rowland, Daniel; Altini, Marco

    2017-01-01

    Heart rate variability (HRV) is a popular tool for monitoring training adaptation and readiness in athletes, but it also has the potential to indicate early signs of somatic tissue overload prior to the onset of pain or fully developed injury. Therefore, the aim of this study was to investigate the interaction between HRV, workloads, and risk of overuse problems in competitive CrossFit™ athletes. Daily resting HRV and workloads (duration × session-RPE) were recorded in six competitive CrossFi...

  10. A Statistical Analysis of Cointegration for I(2) Variables

    DEFF Research Database (Denmark)

    Johansen, Søren

    1995-01-01

    be conducted using the ¿ sup2/sup distribution. It is shown to what extent inference on the cointegration ranks can be conducted using the tables already prepared for the analysis of cointegration of I(1) variables. New tables are needed for the test statistics to control the size of the tests. This paper...... contains a multivariate test for the existence of I(2) variables. This test is illustrated using a data set consisting of U.K. and foreign prices and interest rates as well as the exchange rate....

  11. Frequency spectrum analysis of finger photoplethysmographic waveform variability during haemodialysis.

    Science.gov (United States)

    Javed, Faizan; Middleton, Paul M; Malouf, Philip; Chan, Gregory S H; Savkin, Andrey V; Lovell, Nigel H; Steel, Elizabeth; Mackie, James

    2010-09-01

    This study investigates the peripheral circulatory and autonomic response to volume withdrawal in haemodialysis based on spectral analysis of photoplethysmographic waveform variability (PPGV). Frequency spectrum analysis was performed on the baseline and pulse amplitude variabilities of the finger infrared photoplethysmographic (PPG) waveform and on heart rate variability extracted from the ECG signal collected from 18 kidney failure patients undergoing haemodialysis. Spectral powers were calculated from the low frequency (LF, 0.04-0.145 Hz) and high frequency (HF, 0.145-0.45 Hz) bands. In eight stable fluid overloaded patients (fluid removal of >2 L) not on alpha blockers, progressive reduction in relative blood volume during haemodialysis resulted in significant increase in LF and HF powers of PPG baseline and amplitude variability (P analysis of finger PPGV may provide valuable information on the autonomic vascular response to blood volume reduction in haemodialysis, and can be potentially utilized as a non-invasive tool for assessing peripheral circulatory control during routine dialysis procedure.

  12. Capturing heterogeneity in gene expression studies by surrogate variable analysis.

    Directory of Open Access Journals (Sweden)

    Jeffrey T Leek

    2007-09-01

    Full Text Available It has unambiguously been shown that genetic, environmental, demographic, and technical factors may have substantial effects on gene expression levels. In addition to the measured variable(s of interest, there will tend to be sources of signal due to factors that are unknown, unmeasured, or too complicated to capture through simple models. We show that failing to incorporate these sources of heterogeneity into an analysis can have widespread and detrimental effects on the study. Not only can this reduce power or induce unwanted dependence across genes, but it can also introduce sources of spurious signal to many genes. This phenomenon is true even for well-designed, randomized studies. We introduce "surrogate variable analysis" (SVA to overcome the problems caused by heterogeneity in expression studies. SVA can be applied in conjunction with standard analysis techniques to accurately capture the relationship between expression and any modeled variables of interest. We apply SVA to disease class, time course, and genetics of gene expression studies. We show that SVA increases the biological accuracy and reproducibility of analyses in genome-wide expression studies.

  13. Heart rate variability and swimming.

    Science.gov (United States)

    Koenig, Julian; Jarczok, Marc N; Wasner, Mieke; Hillecke, Thomas K; Thayer, Julian F

    2014-10-01

    Professionals in the domain of swimming have a strong interest in implementing research methods in evaluating and improving training methods to maximize athletic performance and competitive outcome. Heart rate variability (HRV) has gained attention in research on sport and exercise to assess autonomic nervous system activity underlying physical activity and sports performance. Studies on swimming and HRV are rare. This review aims to summarize the current evidence on the application of HRV in swimming research and draws implications for future research. A systematic search of databases (PubMed via MEDLINE, PSYNDEX and Embase) according to the PRISMA statement was employed. Studies were screened for eligibility on inclusion criteria: (a) empirical investigation (HRV) in humans (non-clinical); (b) related to swimming; (c) peer-reviewed journal; and (d) English language. The search revealed 194 studies (duplicates removed), of which the abstract was screened for eligibility. Fourteen studies meeting the inclusion criteria were included in the review. Included studies broadly fell into three classes: (1) control group designs to investigate between-subject differences (i.e. swimmers vs. non-swimmers, swimmers vs. other athletes); (2) repeated measures designs on within-subject differences of interventional studies measuring HRV to address different modalities of training or recovery; and (3) other studies, on the agreement of HRV with other measures. The feasibility and possibilities of HRV within this particular field of application are well documented within the existing literature. Future studies, focusing on translational approaches that transfer current evidence in general practice (i.e. training of athletes) are needed.

  14. Inter-individual Differences in Heart Rate Variability Are Associated with Inter-individual Differences in Empathy and Alexithymia

    Directory of Open Access Journals (Sweden)

    Alexander Lischke

    2018-02-01

    Full Text Available In the present study, we investigated whether inter-individual differences in vagally mediated heart rate variability (vmHRV would be associated with inter-individual differences in empathy and alexithymia. To this end, we determined resting state HF-HRV in 90 individuals that also completed questionnaires assessing inter-individual differences in empathy and alexithymia. Our categorical and dimensional analyses revealed that inter-individual differences in HF-HRV were differently associated with inter-individual differences in empathy and alexithymia. We found that individuals with high HF-HRV reported more empathy and less alexithymia than individuals with low HF-HRV. Moreover, we even found that an increase in HF-HRV was associated with an increase in empathy and a decrease in alexithymia across all participants. Taken together, these findings indicate that individuals with high HF-HRV are more empathetic and less alexithymic than individuals with low HF-HRV. These differences in empathy and alexithymia may explain why individuals with high HF-HRV are more successful in sharing and understanding the mental and emotional states of others than individuals with low HF-HRV.

  15. Metabolic Syndrome and Short-Term Heart Rate Variability in Adults with Intellectual Disabilities

    Science.gov (United States)

    Chang, Yaw-Wen; Lin, Jin-Ding; Chen, Wei-Liang; Yen, Chia-Feng; Loh, Ching-Hui; Fang, Wen-Hui; Wu, Li-Wei

    2012-01-01

    Metabolic syndrome (MetS) increases the risk of cardiovascular events. Heart rate variability (HRV) represents autonomic functioning, and reduced HRV significantly increases cardiovascular mortality. The aims of the present paper are to assess the prevalence of MetS in adults with intellectual disabilities (ID), the difference in short-term HRV…

  16. Validity of (Ultra-)Short Recordings for Heart Rate Variability Measurements

    NARCIS (Netherlands)

    Muñoz Venegas, Loretto; van Roon, Arie; Riese, Harriette; Thio, Chris; Oostenbroek, Emma; Westrik, Iris; de Geus, Eco J. C.; Gansevoort, Ron; Lefrandt, Joop; Nolte, Ilja M.; Snieder, Harold

    2015-01-01

    Objectives In order to investigate the applicability of routine 10s electrocardiogram (ECG) recordings for time-domain heart rate variability (HRV) calculation we explored to what extent these (ultra-)short recordings capture the "actual" HRV. Methods The standard deviation of normal-to-normal

  17. State-related differences in heart rate variability in bipolar disorder

    DEFF Research Database (Denmark)

    Faurholt-Jepsen, Maria; Brage, Søren; Kessing, Lars Vedel

    2017-01-01

    Heart rate variability (HRV) is a validated measure of sympato-vagal balance in the autonomic nervous system. HRV appears decreased in patients with bipolar disorder (BD) compared with healthy individuals, but the extent of state-related alterations has been sparingly investigated. The present...... bipolar disorder and could...

  18. Genetic loci associated with heart rate variability and their effects on cardiac disease risk

    NARCIS (Netherlands)

    Nolte, Ilja M; Munoz, M Loretto; Tragante, Vinicius; Amare, Azmeraw T; Jansen, Rick; Vaez, Ahmad; von der Heyde, Benedikt; Avery, Christy L; Bis, Joshua C; Dierckx, Bram; van Dongen, Jenny; Gogarten, Stephanie M; Goyette, Philippe; Hernesniemi, Jussi; Huikari, Ville; Hwang, Shih-Jen; Jaju, Deepali; Kerr, Kathleen F; Kluttig, Alexander; Krijthe, Bouwe P; Kumar, Jitender; van der Laan, Sander W; Lyytikäinen, Leo-Pekka; Maihofer, Adam X; Minassian, Arpi; van der Most, Peter J; Müller-Nurasyid, Martina; Nivard, Michel; Salvi, Erika; Stewart, James D; Thayer, Julian F; Verweij, Niek; Wong, Andrew; Zabaneh, Delilah; Zafarmand, Mohammad H; Abdellaoui, Abdel; Albarwani, Sulayma; Albert, Christine; Alonso, Alvaro; Ashar, Foram; Auvinen, Juha; Axelsson, Tomas; Baker, Dewleen G; de Bakker, Paul I W; Barcella, Matteo; Bayoumi, Riad; Bieringa, Rob J; Boomsma, Dorret; Boucher, Gabrielle; Britton, Annie R; Christophersen, Ingrid; Dietrich, Andrea; Ehret, George B; Ellinor, Patrick T; Eskola, Markku; Felix, Janine F; Floras, John S; Franco, Oscar H; Friberg, Peter; Gademan, Maaike G J; Geyer, Mark A; Giedraitis, Vilmantas; Hartman, Catharina A; Hemerich, Daiane; Hofman, Albert; Hottenga, Jouke-Jan; Huikuri, Heikki; Hutri-Kähönen, Nina; Jouven, Xavier; Junttila, Juhani; Juonala, Markus; Kiviniemi, Antti M; Kors, Jan A.; Kumari, Meena; Kuznetsova, Tatiana; Laurie, Cathy C; Lefrandt, Joop D.; Li, Yong; Li, Yun; Liao, Duanping; Limacher, Marian C; Lin, Henry J; Lindgren, Cecilia M; Lubitz, Steven A; Mahajan, Anubha; McKnight, Barbara; Zu Schwabedissen, Henriette Meyer; Milaneschi, Yuri; Mononen, Nina; Morris, Andrew P; Nalls, Mike A; Navis, Gerjan; Neijts, Melanie; Nikus, Kjell; North, Kari E; O'Connor, Daniel T; Ormel, Johan; Perz, Siegfried; Peters, Annette; Psaty, Bruce M; Raitakari, Olli T; Risbrough, Victoria B; Sinner, Moritz F; Siscovick, David; Smit, Johannes H; Smith, Nicholas L; Soliman, Elsayed Z; Sotoodehnia, Nona; Staessen, Jan A; Stein, Phyllis K; Stilp, Adrienne M; Stolarz-Skrzypek, Katarzyna; Strauch, Konstantin; Sundström, Johan; Swenne, Cees A.; Syvänen, Ann-Christine; Tardif, Jean-Claude; Taylor, Kent D; Teumer, Alexander; Thornton, Timothy A; Tinker, Lesley E; Uitterlinden, André G; van Setten, Jessica; Voss, Andreas; Waldenberger, Melanie; Wilhelmsen, Kirk C; Willemsen, Gonneke; Wong, Quenna; Zhang, Zhu-Ming; Zonderman, Alan B; Cusi, Daniele; Evans, Michele K; Greiser, Halina K; van der Harst, Pim; Hassan, Mohammad; Ingelsson, Erik; Järvelin, Marjo-Riitta; Kääb, Stefan; Kähönen, Mika; Kivimaki, Mika; Kooperberg, Charles; Kuh, Diana; Lehtimäki, Terho; Lind, Lars; Nievergelt, Caroline M; O'Donnell, Chris J; Oldehinkel, Albertine J; Penninx, Brenda; Reiner, Alexander P; Riese, Harriëtte; Van Roon, Arie M.; Rioux, John D; Rotter, Jerome I; Sofer, Tamar; Stricker, Bruno H; Tiemeier, Henning; Vrijkotte, Tanja G M; Asselbergs, Folkert W; Brundel, Bianca J J M; Heckbert, Susan R; Whitsel, Eric A; den Hoed, Marcel; Snieder, Harold; de Geus, Eco J C

    2017-01-01

    Reduced cardiac vagal control reflected in low heart rate variability (HRV) is associated with greater risks for cardiac morbidity and mortality. In two-stage meta-analyses of genome-wide association studies for three HRV traits in up to 53,174 individuals of European ancestry, we detect 17

  19. EFFECT OF BRONCHODILATORS ON HEART RATE VARIABILITY IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE

    Directory of Open Access Journals (Sweden)

    H. H. Shugushev

    2015-12-01

    Full Text Available Aim. To study effect of long-acting theophylline (Theotard, KRKA and combination of salmeterol and fluticasone (Seretide, GlaxoSmithKline on heart rhythm variability (HRV and number of arrhythmic episodes in patients with chronic obstructive pulmonary disease (COPD.Material and methods. 144 patients with COPD and 35 patients of control group were examined. The analysis of HRV and Holter monitoring were made f on 2th and 14th days.Results. Treatment with both drugs led to increase in power of low- and high frequencies and their ratio (LF/HF, decrease in rate of supraventricular and ventricular arrhythmias. Theophylline therapy raised in a number of single and pair supraventricular extrasystoles. Treatment with combination of salmeterol and fluticasone did not change a number of extrasystoles.Conclusion. Combination of salmeterol and fluticasone is more preferable as a broncholytic therapy for patients with COPD and heart rhythm disorders.

  20. Dynamics of spectral components of heart rate variability during changes in autonomic balance

    DEFF Research Database (Denmark)

    Højgaard, M V; Holstein-Rathlou, N H; Agner, E

    1998-01-01

    Frequency domain analysis of heart rate variability (HRV) has been proposed as a semiquantitative method for assessing activities in the autonomic nervous system. We examined whether absolute powers, normalized powers, and the low frequency-to-high frequency ratio (LF/HF) derived from the HRV power...... spectrum could detect shifts in autonomic balance in a setting with low sympathetic nervous tone. Healthy subjects were examined for 3 h in the supine position during 1) control conditions (n = 12), 2) acute beta-blockade (n = 11), and 3) chronic beta-blockade (n = 10). Heart rate fell during the first 40...... min of the control session (72 +/- 2 to 64 +/- 2 beats/min; P powers of all spectral areas rose during the first 60 min in all three settings, more so with beta-blockade (P

  1. [Heart rate variability as a method of assessing the autonomic nervous system in polycystic ovary syndrome].

    Science.gov (United States)

    de Sá, Joceline Cássia Ferezini; Costa, Eduardo Caldas; da Silva, Ester; Azevedo, George Dantas

    2013-09-01

    Polycystic ovary syndrome (PCOS) is an endocrine disorder associated with several cardiometabolic risk factors, such as central obesity, insulin resistance, type 2 diabetes, metabolic syndrome, and hypertension. These factors are associated with adrenergic overactivity, which is an important prognostic factor for the development of cardiovascular disorders. Given the common cardiometabolic disturbances occurring in PCOS women, over the last years studies have investigated the cardiac autonomic control of these patients, mainly based on heart rate variability (HRV). Thus, in this review, we will discuss the recent findings of the studies that investigated the HRV of women with PCOS, as well as noninvasive methods of analysis of autonomic control starting from basic indexes related to this methodology.

  2. Multivariate analysis between air pollutants and meteorological variables in Seoul

    International Nuclear Information System (INIS)

    Kim, J.; Lim, J.

    2005-01-01

    Multivariate analysis was conducted to analyze the relationship between air pollutants and meteorological variables measured in Seoul from January 1 to December 31, 1999. The first principal component showed the contrast effect between O 3 and the other pollutants. The second principal component showed the contrast effect between CO, SO 2 , NO 2 , and O 3 , PM 10 , TSP. Based on the cluster analysis, three clusters represented different air pollution levels, seasonal characteristics of air pollutants, and meteorological conditions. Discriminant analysis with air environment index (AEI) was carried out to develop an air pollution index function. (orig.)

  3. EFFECT OF FUROSEMIDE AND TORASEMIDE ON HEART RATE VARIABILITY AND VENTRICULAR RHYTHM DISORDERS IN PATIENTS WITH CHRONIC HEART FAILURE COMPLICATING ISCHEMIC HEART DISEASE: COMPARATIVE NONRANDOMIZED STUDY

    Directory of Open Access Journals (Sweden)

    H. H. Shugushev

    2010-01-01

    Full Text Available Aim. To study effect of diuretic therapy with furosemide and torasemide on heart rate variability (HRV and frequency of ventriclar rhythm disorders in patients with chronic heart failure (CHF complicating ischemic heart disease (IHD.Material and methods. Patients (n=107 with CHF III-IV functional class (NYHA complicating IHD were examined. The first group of patients received furosemide, 20-60 mg QD (n=52, the second group received torasemide, 5-20 mg QD (n=55. Analysis of heart rhythm disorders and the basic HRV indicators was performed by ECG 10-minute recordings initially and after 10 days of therapy.Results. Decrease in time and spectral HRV parameters and increase in daily number of ventricular extrasystoles was found in furosemide treated patients. Improvement of HRV parameters and reduction of daily number of ventricular rhythm disorders was found torasemide treated patients.Conclusion. Torasemide therapy improves an autonomic regulation of heart rhythm and leads to the reduction of ventricular heart rhythm disorders in patients with CHF complicating IHD.

  4. Identification of anaerobic threshold by analysis of heart rate variability during discontinuous dynamic and resistance exercise protocols in healthy older men.

    Science.gov (United States)

    Simões, Rodrigo Polaquini; Castello-Simões, Viviane; Mendes, Renata Gonçalves; Archiza, Bruno; Dos Santos, Daniel Augusto; Bonjorno, José Carlos; de Oliveira, Claudio Ricardo; Catai, Aparecida Maria; Arena, Ross; Borghi-Silva, Audrey

    2014-03-01

    The purposes of this study were to determine anaerobic threshold (AT) during discontinuous dynamic and resistive exercise protocols by analysing of heart rate variability (HRV) and blood lactate (BL) in healthy elderly subjects and compare the cardiovascular, metabolic and autonomic variables obtained from these two forms of exercise. Fourteen elderly (70 ± 4 years) apparently healthy males underwent the following tests: (i) incremental ramp test on cycle ergometer, (ii) one repetition maximum (1RM) leg press at 45°, (iii) a discontinuous exercise test on a cycle ergometer (DET-C) protocol and (iv) a resistance exercise leg press (DET-L) protocol. Heart rate, blood pressure and BL were obtained during each increment of exercise intensity. No significant differences (P>0·05) were found between methods of AT determination (BL and HRV) nor the relative intensity corresponding to AT (30% of maximum intensity) between the types of exercise (DET-C and DET-L). Furthermore, no significant differences (P>0·05) were found between the DET-C and DET-L in relation to HRV, however, the DET-L provided higher values of systolic blood pressure and BL (Presistive exercise protocols were similar when compared at the same relative intensity. However, DET-L resulted in higher values of blood pressure and BL at workloads beyond AT. © 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  5. Causality and cointegration analysis between macroeconomic variables and the Bovespa.

    Directory of Open Access Journals (Sweden)

    Fabiano Mello da Silva

    Full Text Available The aim of this study is to analyze the causality relationship among a set of macroeconomic variables, represented by the exchange rate, interest rate, inflation (CPI, industrial production index as a proxy for gross domestic product in relation to the index of the São Paulo Stock Exchange (Bovespa. The period of analysis corresponded to the months from January 1995 to December 2010, making a total of 192 observations for each variable. Johansen tests, through the statistics of the trace and of the maximum eigenvalue, indicated the existence of at least one cointegration vector. In the analysis of Granger (1988 causality tests via error correction, it was found that a short-term causality existed between the CPI and the Bovespa. Regarding the Granger (1988 long-term causality, the results indicated a long-term behaviour among the macroeconomic variables with the BOVESPA. The results of the long-term normalized vector for the Bovespa variable showed that most signals of the cointegration equation parameters are in accordance with what is suggested by the economic theory. In other words, there was a positive behaviour of the GDP and a negative behaviour of the inflation and of the exchange rate (expected to be a positive relationship in relation to the Bovespa, with the exception of the Selic rate, which was not significant with that index. The variance of the Bovespa was explained by itself in over 90% at the twelfth month, followed by the country risk, with less than 5%.

  6. Causality and cointegration analysis between macroeconomic variables and the Bovespa.

    Science.gov (United States)

    da Silva, Fabiano Mello; Coronel, Daniel Arruda; Vieira, Kelmara Mendes

    2014-01-01

    The aim of this study is to analyze the causality relationship among a set of macroeconomic variables, represented by the exchange rate, interest rate, inflation (CPI), industrial production index as a proxy for gross domestic product in relation to the index of the São Paulo Stock Exchange (Bovespa). The period of analysis corresponded to the months from January 1995 to December 2010, making a total of 192 observations for each variable. Johansen tests, through the statistics of the trace and of the maximum eigenvalue, indicated the existence of at least one cointegration vector. In the analysis of Granger (1988) causality tests via error correction, it was found that a short-term causality existed between the CPI and the Bovespa. Regarding the Granger (1988) long-term causality, the results indicated a long-term behaviour among the macroeconomic variables with the BOVESPA. The results of the long-term normalized vector for the Bovespa variable showed that most signals of the cointegration equation parameters are in accordance with what is suggested by the economic theory. In other words, there was a positive behaviour of the GDP and a negative behaviour of the inflation and of the exchange rate (expected to be a positive relationship) in relation to the Bovespa, with the exception of the Selic rate, which was not significant with that index. The variance of the Bovespa was explained by itself in over 90% at the twelfth month, followed by the country risk, with less than 5%.

  7. Heart rate variability is associated with psychosocial stress in distinct social domains.

    Science.gov (United States)

    Lischke, Alexander; Jacksteit, Robert; Mau-Moeller, Anett; Pahnke, Rike; Hamm, Alfons O; Weippert, Matthias

    2018-03-01

    Psychosocial stress is associated with substantial morbidity and mortality. Accordingly, there is a growing interest in biomarkers that indicate whether individuals show adaptive (i.e., stress-buffering and health-promoting) or maladaptive (i.e., stress-escalating and health-impairing) stress reactions in social contexts. As heart rate variability (HRV) has been suggested to be a biomarker of adaptive behavior during social encounters, it may be possible that inter-individual differences in HRV are associated with inter-individual differences regarding stress in distinct social domains. To test this hypothesis, resting state HRV and psychosocial stress was assessed in 83 healthy community-dwelling individuals (age: 18-35years). HRV was derived from heart rate recordings during spontaneous and instructed breathing to assess the robustness of possible associations between inter-individual differences in HRV and inter-individual differences in psychosocial stress. Psychosocial stress was determined with a self-report questionnaire assessing stress in distinct social domains. A series of categorical and dimensional analyses revealed an association between inter-individual differences in HRV and inter-individual differences in psychosocial stress: Individuals with high HRV reported less stress in social life, but not in family life, work life or everyday life, than individuals with low HRV. On basis of these findings, it may be assumed that individuals with high HRV experience less psychosocial stress than individuals with low HRV. Although such an assumption needs to be corroborated by further findings, it seems to be consistent with previous findings showing that individuals with high HRV suffer less from stress and stress-related disorders than individuals with low HRV. Copyright © 2018 Elsevier Inc. All rights reserved.

  8. Heart rate variability biofeedback reduces food cravings in high food cravers.

    Science.gov (United States)

    Meule, Adrian; Freund, Rebecca; Skirde, Ann Kathrin; Vögele, Claus; Kübler, Andrea

    2012-12-01

    Heart rate variability (HRV) biofeedback has been reported to increase HRV while decreasing symptoms in patients with mental disorders. In addition, associations between low HRV and lowered self-regulation were found in non-clinical samples, e.g., in individuals with strong chocolate cravings or unsuccessful dieting. The current study aimed at decreasing food cravings with HRV-biofeedback in individuals frequently experiencing such cravings. Participants (N = 56) with strong or low food cravings associated with a lack of control over eating were selected from the local community. Half of the participants with strong cravings (craving-biofeedback; n = 14) performed 12 sessions of HRV-biofeedback while the other half (craving-control; n = 14) and a group with low cravings (non-craving-control; n = 28) received no intervention. Subjective food cravings related to a lack of control over eating decreased from pre- to post-measurement in the craving-biofeedback group, but remained constant in the control groups. Moreover, only the craving-biofeedback group showed a decrease in eating and weight concerns. Although HRV-biofeedback was successful in reducing food cravings, this change was not accompanied by an increase in HRV. Instead, HRV decreased in the craving-control group. This study provides preliminary evidence that HRV-biofeedback could be beneficial for attenuating dysfunctional eating behavior although specific mechanisms remain to be elucidated.

  9. The Use of Categorical Variables in Data Envelopment Analysis

    OpenAIRE

    Rajiv D. Banker; Richard C. Morey

    1986-01-01

    Data Envelopment Analysis has now been extensively applied in a range of empirical settings to identify relative inefficiencies, and provide targets for improvements. It accomplishes this by developing peer groups for each unit being operated. The use of categorical variables is an important extension which can improve the peer group construction process and incorporate "on-off" characteristics, e.g., presence of drive-in window or not in a banking network. It relaxes the stringent need for f...

  10. Stability analysis for cellular neural networks with variable delays

    International Nuclear Information System (INIS)

    Zhang Qiang; Wei Xiaopeng; Xu Jin

    2006-01-01

    Some sufficient conditions for the global exponential stability of cellular neural networks with variable delay are obtained by means of a method based on delay differential inequality. The method, which does not make use of Lyapunov functionals, is simple and effective for the stability analysis of neural networks with delay. Some previously established results in the literature are shown to be special cases of the presented result

  11. Heart rate variability and implication for sport concussion.

    Science.gov (United States)

    Bishop, Scott A; Dech, Ryan T; Guzik, Przemyslaw; Neary, J Patrick

    2017-11-16

    Finding sensitive and specific markers for sports-related concussion is both challenging and clinically important. Such biomarkers might be helpful in the management of patients with concussion (i.e. diagnosis, monitoring and risk prediction). Among many parameters, blood flow-pressure metrics and heart rate variability (HRV) have been used to gauge concussion outcomes. Reports on the relation between HRV and both acute and prolonged concussion recovery are conflicting. While some authors report on differences in the low-frequency (LF) component of HRV during postural manipulations and postexercise conditions, others observe no significant differences in various HRV measures. Despite the early success of using the HRV LF for concussion recovery, the interpretation of the LF is debated. Recent research suggests the LF power is a net effect of several intrinsic modulatory factors from both sympathetic and parasympathetic branches of the autonomic nervous system, vagally mediated baroreflex and even some respiratory influences at lower respiratory rate. There are only a few well-controlled concussion studies that specifically examine the contribution of the autonomic nervous system branches with HRV for concussion management. This study reviews the most recent HRV- concussion literature and the underlying HRV physiology. It also highlights cerebral blood flow studies related to concussion and the importance of multimodal assessment of various biological signals. It is hoped that a better understanding of the physiology behind HRV might generate cost-effective, repeatable and reliable protocols, all of which will improve the interpretation of HRV throughout concussion recovery. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  12. Diminution of Heart Rate Variability in Bipolar Depression

    Directory of Open Access Journals (Sweden)

    Brandon Hage

    2017-12-01

    Full Text Available Autonomic nervous system (ANS dysregulation in depression is associated with symptoms associated with the ANS. The beat-to-beat pattern of heart rate defined as heart rate variability (HRV provides a noninvasive portal to ANS function and has been proposed to represent a means of quantifying resting vagal tone. We quantified HRV in bipolar depressed (BDD patients as a measure of ANS dysregulation seeking to establish HRV as a potential diagnostic and prognostic biomarker for treatment outcome. Forty-seven BDD patients were enrolled. They were randomized to receive either escitalopram–celecoxib or escitalopram-placebo over 8 weeks in a double-blind study design. Thirty-five patients completed the HRV studies. Thirty-six healthy subjects served as controls. HRV was assessed at pretreatment and end of study and compared with that of controls. HRV was quantified and corrected for artifacts using an algorithm that incorporates time and frequency domains to address non-stationarity of the beat-to-beat heart rate pattern. Baseline high frequency-HRV (i.e., respiratory sinus arrhythmia was lower in BDD patients than controls, although the difference did not reach significance. Baseline low-frequency HRV was significantly lower in BDD patients (ln4.20 than controls (ln = 5.50 (p < 0.01. Baseline heart period was significantly shorter (i.e., faster heart rate in BDD patients than controls. No significant change in HRV parameters were detected over the course of the study with either treatment. These findings suggest that components of HRV may be diminished in BDD patients.

  13. Effect of atrioventricular conduction on heart rate variability

    KAUST Repository

    Ahmad, Talha Jamal

    2011-08-01

    This paper discusses the effect of atrioventricular conduction time (AVCT) on the short-term Heart Rate Variability (HRV) by computing HRV parameters using intervals between the onsets of successive P waves (PP time series) for three groups: normal, arrhythmia and sudden cardiac death (SCD) patients. A very precise wavelet transform based ECG delineator was developed to detect PP, PR and RR time series. Mean PR variation in arrhythmia and SCD group was found to be significantly high as compared to the normal group. It was observed that when PR variations in arrhythmia and SCD cases crossed a certain threshold, RR variability no longer provided a very accurate estimate of HRV. In such cases, PP variability was able to provide a better assessment of HRV. © 2011 IEEE.

  14. A state-and-transition simulation modeling approach for estimating the historical range of variability

    Directory of Open Access Journals (Sweden)

    Kori Blankenship

    2015-04-01

    Full Text Available Reference ecological conditions offer important context for land managers as they assess the condition of their landscapes and provide benchmarks for desired future conditions. State-and-transition simulation models (STSMs are commonly used to estimate reference conditions that can be used to evaluate current ecosystem conditions and to guide land management decisions and activities. The LANDFIRE program created more than 1,000 STSMs and used them to assess departure from a mean reference value for ecosystems in the United States. While the mean provides a useful benchmark, land managers and researchers are often interested in the range of variability around the mean. This range, frequently referred to as the historical range of variability (HRV, offers model users improved understanding of ecosystem function, more information with which to evaluate ecosystem change and potentially greater flexibility in management options. We developed a method for using LANDFIRE STSMs to estimate the HRV around the mean reference condition for each model state in ecosystems by varying the fire probabilities. The approach is flexible and can be adapted for use in a variety of ecosystems. HRV analysis can be combined with other information to help guide complex land management decisions.

  15. An analysis of prediction skill of monthly mean climate variability

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Arun; Chen, Mingyue; Wang, Wanqiu [Climate Prediction Center, National Centers for Environmental Prediction (CPC/NCEP), Camp Springs, MD (United States)

    2011-09-15

    In this paper, lead-time and spatial dependence in skill for prediction of monthly mean climate variability is analyzed. The analysis is based on a set of extensive hindcasts from the Climate Forecast System at the National Centers for Environmental Prediction. The skill characteristics of initialized predictions is also compared with the AMIP simulations forced with the observed sea surface temperature (SST) to quantify the role of initial versus boundary conditions in the prediction of monthly means. The analysis is for prediction of monthly mean SST, precipitation, and 200-hPa height. The results show a rapid decay in skill with lead time for the atmospheric variables in the extratropical latitudes. Further, after a lead-time of approximately 30-40 days, the skill of monthly mean prediction is essentially a boundary forced problem, with SST anomalies in the tropical central/eastern Pacific playing a dominant role. Because of the larger contribution from the atmospheric internal variability to monthly time-averages (compared to seasonal averages), skill for monthly mean prediction associated with boundary forcing is also lower. The analysis indicates that the prospects of skillful prediction of monthly means may remain a challenging problem, and may be limited by inherent limits in predictability. (orig.)

  16. Heart rate variability biofeedback improves cardiorespiratory resting function during sleep.

    Science.gov (United States)

    Sakakibara, Masahito; Hayano, Junichiro; Oikawa, Leo O; Katsamanis, Maria; Lehrer, Paul

    2013-12-01

    The present study was designed to examine the effect of heart rate variability (HRV) biofeedback on the cardiorespiratory resting function during sleep in daily life. Forty-five healthy young adults were randomly assigned to one of three groups: HRV biofeedback, Autogenic Training(AT), and no-treatment control. Participants in the HRV biofeedback were instructed to use a handheld HRV biofeedback device before their habitual bedtime, those in the AT were asked to listen to an audiotaped instruction before bedtime,and those in the control were asked to engage in their habitual activity before bedtime. Pulse wave signal during sleep at their own residences was measured continuously with a wrist watch-type transdermal photoelectric sensor for three time points. Baseline data were collected on the first night of measurements, followed by two successive nights for HRV biofeedback, AT, or control. Cardiorespiratory resting function was assessed quantitatively as the amplitude of high frequency(HF) component of pulse rate variability, a surrogate measure of respiratory sinus arrhythmia. HF component increased during sleep in the HRV biofeedback group,although it remained unchanged in the AT and control groups. These results suggest that HRV biofeedback before sleep may improve cardiorespiratory resting function during sleep.

  17. Wavelet and receiver operating characteristic analysis of heart rate variability

    Science.gov (United States)

    McCaffery, G.; Griffith, T. M.; Naka, K.; Frennaux, M. P.; Matthai, C. C.

    2002-02-01

    Multiresolution wavelet analysis has been used to study the heart rate variability in two classes of patients with different pathological conditions. The scale dependent measure of Thurner et al. was found to be statistically significant in discriminating patients suffering from hypercardiomyopathy from a control set of normal subjects. We have performed Receiver Operating Characteristc (ROC) analysis and found the ROC area to be a useful measure by which to label the significance of the discrimination, as well as to describe the severity of heart dysfunction.

  18. Heart rate variability in the standing position reflects training adaptation in professional soccer players.

    Science.gov (United States)

    Ravé, Guillaume; Fortrat, Jacques-Olivier

    2016-08-01

    To show that heart rate variability (HRV) in the standing position better reflects the way in which athletes adapt to training in so-called intermittent sports than the indicator of resting parasympathetic tone usually employed in endurance sports. Twenty professional soccer players (intermittent sport) took part in a 5-week training session divided into three successive periods: "Warm-up", "Intensive training" and "Tapering". At the beginning and end of each of the three periods, a stand test was carried out and the heart rate was recorded, beat by beat (Polar Team 2). We analysed HRV to determine the indicator mostly used to demonstrate training adaptation in endurance sports (lnRMSSD supine, natural logarithm of root mean square of the successive differences) as well as indicators obtained by means of spectral analysis in both supine and standing position. A decrease in heart rate was observed in the supine position at rest during training (-5.2 ± 1.3 bpm) while lnRMSSD and spectral analysis indicators remained unchanged. The "Warm-up" caused an increase in spectral analysis total power in standing position which was further highlighted by "Tapering" (3.39 ± 0.09, 3.61 ± 0.08 and 3.65 ± 0.09 log ms(2), respectively). However, the autonomic changes are probably more complex than a change in autonomic activity or balance since spectral analysis autonomic indicators remained unchanged. HRV in the standing position could monitor training adaptation in intermittent sports contrary to the indicator usually employed in endurance sports. However, the significance of the HRV change in the standing position during training remains unclear.

  19. Seasonal Variations in Heart Rate Variability as an Indicator of Stress in Free-Ranging Pregnant Przewalski's Horses (E. ferus przewalskii within the Hortobágy National Park in Hungary

    Directory of Open Access Journals (Sweden)

    Friederike Pohlin

    2017-09-01

    Full Text Available Background: Ecosystems with seasonal fluctuations in climate and food availability present physiological challenges to resident mammals and may cause “stress.” The two predominant physiological responses to stressors are (1 the activation of the hypothalamic-pituitary-adrenal axis and (2 the modulation of the autonomic nervous system. To date, the primary indicator for “stress” in wildlife- and zoo animal research are glucocorticoid levels. By measuring the autonomic regulation of cardiac activity, particularly the vagal tone, heart rate variability (HRV is presently emerging as a suitable indicator of “stress” in farm- and domestic animal research.Objective: The aim of this study was to use HRV, a novel method in wildlife research, to assess seasonal patterns of “stress” in a group of free-ranging Przewalski's horses (Equus ferus przewalskii.Methods: Six pregnant Przewalski's horses from one harem within the Hortobágy National Park in Hungary were subjected to the study. We used a dedicated telemetry system consisting of a subcutaneously implanted transmitter and a receiver and storage unit in a collar to record HRV, heart rate (HR, subcutaneous body temperature, and activity throughout a one-year study period—climate data was also collected. We defined “stress” as a decrease in parasympathetic nervous system tone and calculated RMSSD (root mean square of successive differences as a measure of HRV. Linear mixed effects models with random intercept per individual were used for statistical analysis.Results: HRV and HR varied considerably throughout the year. Similar to temperate ruminants and hibernating mammals, Przewalski's horses experienced lower HR and HRV during winter, when resources are limited indicating decreased metabolic rates coupled with “stress.” In spring, we observed a drop of HRV along with a peak in HR indicating an increase of allostatic load that is most likely associated with increased energy

  20. Expanded flux variability analysis on metabolic network of Escherichia coli

    Institute of Scientific and Technical Information of China (English)

    CHEN Tong; XIE ZhengWei; OUYANG Qi

    2009-01-01

    Flux balance analysis,based on the mass conservation law in a cellular organism,has been extensively employed to study the interplay between structures and functions of cellular metabolic networks.Consequently,the phenotypes of the metabolism can be well elucidated.In this paper,we introduce the Expanded Flux Variability Analysis (EFVA) to characterize the intrinsic nature of metabolic reactions,such as flexibility,modularity and essentiality,by exploring the trend of the range,the maximum and the minimum flux of reactions.We took the metabolic network of Escherichia coli as an example and analyzed the variability of reaction fluxes under different growth rate constraints.The average variability of all reactions decreases dramatically when the growth rate increases.Consider the noise effect on the metabolic system,we thus argue that the microorganism may practically grow under a suboptimal state.Besides,under the EFVA framework,the reactions are easily to be grouped into catabolic and anabolic groups.And the anabolic groups can be further assigned to specific biomass constitute.We also discovered the growth rate dependent essentiality of reactions.

  1. Drowsiness detection using heart rate variability.

    Science.gov (United States)

    Vicente, José; Laguna, Pablo; Bartra, Ariadna; Bailón, Raquel

    2016-06-01

    It is estimated that 10-30 % of road fatalities are related to drowsy driving. Driver's drowsiness detection based on biological and vehicle signals is being studied in preventive car safety. Autonomous nervous system activity, which can be measured noninvasively from the heart rate variability (HRV) signal obtained from surface electrocardiogram, presents alterations during stress, extreme fatigue and drowsiness episodes. We hypothesized that these alterations manifest on HRV and thus could be used to detect driver's drowsiness. We analyzed three driving databases in which drivers presented different sleep-deprivation levels, and in which each driving minute was annotated as drowsy or awake. We developed two different drowsiness detectors based on HRV. While the drowsiness episodes detector assessed each minute of driving as "awake" or "drowsy" with seven HRV derived features (positive predictive value 0.96, sensitivity 0.59, specificity 0.98 on 3475 min of driving), the sleep-deprivation detector discerned if a driver was suitable for driving or not, at driving onset, as function of his sleep-deprivation state. Sleep-deprivation state was estimated from the first three minutes of driving using only one HRV feature (positive predictive value 0.80, sensitivity 0.62, specificity 0.88 on 30 drivers). Incorporating drowsiness assessment based on HRV signal may add significant improvements to existing car safety systems.

  2. Quantitative analysis of spatial variability of geotechnical parameters

    Science.gov (United States)

    Fang, Xing

    2018-04-01

    Geotechnical parameters are the basic parameters of geotechnical engineering design, while the geotechnical parameters have strong regional characteristics. At the same time, the spatial variability of geotechnical parameters has been recognized. It is gradually introduced into the reliability analysis of geotechnical engineering. Based on the statistical theory of geostatistical spatial information, the spatial variability of geotechnical parameters is quantitatively analyzed. At the same time, the evaluation of geotechnical parameters and the correlation coefficient between geotechnical parameters are calculated. A residential district of Tianjin Survey Institute was selected as the research object. There are 68 boreholes in this area and 9 layers of mechanical stratification. The parameters are water content, natural gravity, void ratio, liquid limit, plasticity index, liquidity index, compressibility coefficient, compressive modulus, internal friction angle, cohesion and SP index. According to the principle of statistical correlation, the correlation coefficient of geotechnical parameters is calculated. According to the correlation coefficient, the law of geotechnical parameters is obtained.

  3. Heart rate variability changes in business process outsourcing employees working in shifts.

    Science.gov (United States)

    Kunikullaya, Kirthana U; Kirthi, Suresh K; Venkatesh, D; Goturu, Jaisri

    2010-10-31

    Irregular and poor quality sleep is common in business process outsourcing (BPO) employees due to continuous shift working. The influence of this on the cardiac autonomic activity was investigated by the spectral analysis of heart rate variability (HRV). 36 night shift BPO employees (working from 22:00 to 06:00h) and 36 age and sex matched day shift BPO employees (working from 08:00 to 16:00h) were recruited for the study. Five minute electrocardiogram (ECG) was recorded in all the subjects. Heart rate variability was analyzed by fast Fourier transformation using RMS Vagus HRV software. The results were analyzed using Mann Whitney U test, Student t-test, Wilcoxon signed rank test and were expressed as mean ± SD. Sleepiness was significantly higher among night shift workers as measured by Epworth Sleepiness Scale (p<0.001). Night shift BPO employees were found to have a trend towards lower values of vagal parameters - HF power (ms(2)), and higher values of sympathovagal parameters like LF Power (ms(2)) and the LF/HF power (%) suggesting decreased vagal activity and sympathetic over activity, when compared to day shift employees. However, HRV parameters did not vary significantly between the day shift employees and night shift workers baseline values, and also within the night shift group. Night shift working increased the heart rate and shifted the sympathovagal balance towards sympathetic dominance and decreased vagal parameters of HRV. This is an indicator of unfavorable change in the myocardial system, and thus shows increased risk of cardiovascular disease among the night shift employees.

  4. Evaluation of Heart Rate Variability by means of Laser Doppler Vibrometry measurements

    International Nuclear Information System (INIS)

    Cosoli, G; Casacanditella, L; Tomasini, EP; Scalise, L

    2015-01-01

    Heart Rate Variability (HRV) analysis aims to study the physiological variability of the Heart Rate (HR), which is related to the health conditions of the subject. HRV is assessed measuring heart periods (HP) on a time window of >5 minutes (1)-(2). HPs are determined from signals of different nature: electrocardiogram (ECG), photoplethysmogram (PPG), phonocardiogram (PCG) or vibrocardiogram (VCG) (3)-(4)-(5). The fundamental aspect is the identification of a feature in each heartbeat that allows to accurately compute cardiac periods (such as R peaks in ECG), in order to make possible the measurement of all the typical HRV evaluations on those intervals. VCG is a non-contact technique (4), very favourable in medicine, which detects the vibrations on the skin surface (e.g. on the carotid artery) resulting from vascular blood motion consequent to electrical signal (ECG).In this paper, we propose the use of VCG for the measurement of a signal related to HRV and the use of a novel algorithm based on signal geometry (7) to detect signal peaks, in order to accurately determine cardiac periods and the Poincare plot (9)-(10). The results reported are comparable to the ones reached with the gold standard (ECG) and in literature (3)-(5). We report mean values of HP of 832±54 ms and 832±55 ms by means of ECG and VCG, respectively. Moreover, this algorithm allow us to identify particular features of ECG and VCG signals, so that in the future we will be able to evaluate specific correlations between the two. (paper)

  5. Radiograph and passive data analysis using mixed variable optimization

    Science.gov (United States)

    Temple, Brian A.; Armstrong, Jerawan C.; Buescher, Kevin L.; Favorite, Jeffrey A.

    2015-06-02

    Disclosed herein are representative embodiments of methods, apparatus, and systems for performing radiography analysis. For example, certain embodiments perform radiographic analysis using mixed variable computation techniques. One exemplary system comprises a radiation source, a two-dimensional detector for detecting radiation transmitted through a object between the radiation source and detector, and a computer. In this embodiment, the computer is configured to input the radiographic image data from the two-dimensional detector and to determine one or more materials that form the object by using an iterative analysis technique that selects the one or more materials from hierarchically arranged solution spaces of discrete material possibilities and selects the layer interfaces from the optimization of the continuous interface data.

  6. Improved Gender Recognition during Stepping Activity for Rehab Application Using the Combinatorial Fusion Approach of EMG and HRV

    Directory of Open Access Journals (Sweden)

    Nor Aziyatul Izni Mohd Rosli

    2017-03-01

    Full Text Available Gender recognition is trivial for a physiotherapist, but it is considered a challenge for computers. The electromyography (EMG and heart rate variability (HRV were utilized in this work for gender recognition during exercise using a stepper. The relevant features were extracted and selected. The selected features were then fused to automatically predict gender recognition. However, the feature selection for gender classification became a challenge to ensure better accuracy. Thus, in this paper, a feature selection approach based on both the performance and the diversity between the two features from the rank-score characteristic (RSC function in a combinatorial fusion approach (CFA (Hsu et al. was employed. Then, the features from the selected feature sets were fused using a CFA. The results were then compared with other fusion techniques such as naive bayes (NB, decision tree (J48, k-nearest neighbor (KNN and support vector machine (SVM. Besides, the results were also compared with previous researches in gender recognition. The experimental results showed that the CFA was efficient and effective for feature selection. The fusion method was also able to improve the accuracy of the gender recognition rate. The CFA provides much better gender classification results which is 94.51% compared to Barani’s work (90.34%, Nazarloo’s work (92.50%, and other classifiers.

  7. Non-linear indices of heart rate variability during endodontic treatment.

    Science.gov (United States)

    Santana, Milana Drumond Ramos; Pita Neto, Ivo Cavalcante; Martiniano, Eli Carlos; Monteiro, Larissa Raylane Lucas; Ramos, José Lucas Souza; Garner, David M; Valenti, Vitor Engácia; Abreu, Luiz Carlos de

    2016-01-01

    Dental treatment promotes psychosomatic change that can influence the procedure and compromise the general well-being of the patient. In this context, it highlights the importance of evaluating the function of the autonomic nervous system in individuals undergoing endodontic treatment. Thus, this manuscript aimed to analyse cardiac autonomic modulation, through non-linear indices of heart rate variability (HRV) during endodontic treatment. Analysis of 50 subjects of either sex aged between 18 and 40 years diagnosed with irreversible pulp necrosis of lower molars undergoing endodontic treatment was undertaken. We carried out fractal and symbolic analysis of HRV, which was recorded in the first session of the endodontic treatment at four intervals: T1: 0-10 min before the onset of the treatment session; T2: 0-10 min after the application of anaesthesia; T3: throughout the period of treatment; and T4: 0-30 min after the end of the treatment session. There was reduction of α1 in T2 compared to T1 and T4 (p endodontic treatment, and after applying local anaesthetic the parasympathetic component of HRV increases. These data indicate that endodontic treatment acutely overcharges the heart, supporting the stress involved in this situation.

  8. Analysis and Prediction of Micromilling Stability with Variable Tool Geometry

    Directory of Open Access Journals (Sweden)

    Ziyang Cao

    2014-11-01

    Full Text Available Micromilling can fabricate miniaturized components using micro-end mill at high rotational speeds. The analysis of machining stability in micromilling plays an important role in characterizing the cutting process, estimating the tool life, and optimizing the process. A numerical analysis and experimental method are presented to investigate the chatter stability in micro-end milling process with variable milling tool geometry. The schematic model of micromilling process is constructed and the calculation formula to predict cutting force and displacements is derived. This is followed by a detailed numerical analysis on micromilling forces between helical ball and square end mills through time domain and frequency domain method and the results are compared. Furthermore, a detailed time domain simulation for micro end milling with straight teeth and helical teeth end mill is conducted based on the machine-tool system frequency response function obtained through modal experiment. The forces and displacements are predicted and the simulation result between variable cutter geometry is deeply compared. The simulation results have important significance for the actual milling process.

  9. Electromagnetic fields from mobile phone base station - variability analysis.

    Science.gov (United States)

    Bienkowski, Pawel; Zubrzak, Bartlomiej

    2015-09-01

    The article describes the character of electromagnetic field (EMF) in mobile phone base station (BS) surroundings and its variability in time with an emphasis on the measurement difficulties related to its pulse and multi-frequency nature. Work also presents long-term monitoring measurements performed recently in different locations in Poland - small city with dispersed building development and in major polish city - dense urban area. Authors tried to determine the trends in changing of EMF spectrum analyzing daily changes of measured EMF levels in those locations. Research was performed using selective electromagnetic meters and also EMF meter with spectrum analysis.

  10. Heart rate variability and hear left ventricle hypertrophy in clean-up workers after Chernobyl accident with essential hypertension

    International Nuclear Information System (INIS)

    Khomazyuk, Yi.M.; Sidorenko, G.V.

    2004-01-01

    Correlation of heart rate variability (HRV) and hear left ventricle hypertrophy (LVH) in clean-up workers of Chernobyl accident with essential hypertension was estimated. Lowering of total HRV, parasympathetic and sympathetic activity associated with increased range of LVH was discovered

  11. An analysis of the variable radial velocity of alpha cygni

    International Nuclear Information System (INIS)

    Lucy, L.B.

    1976-01-01

    On the basis of 447 radial velocities obtained at the Lick Observatory by Paddock in the years 1927--1935, an attempt is made to discover the nature of the semiregular variability of α Cygni (A2 Ia). Harmonic analysis of the 144 velocities obtained in 1931 suggests that this variability is due to the simultaneous excitation of many discrete pulsation modes. The amplitudes and periods of these modes are then determined by least-squares fitting to all the data, and a final solution is obtained that comprises 16 terms with periods from 6.9 to 100.8 days. All terms are found to have highly significant amplitudes, and most terms also pass a test of the stability of their amplitudes and phases. Reasons are given for believing that most terms represent nonradial oscillations, and this leads to the suggestion that the resulting surface motions are to be identified with macroturbulence. An argument is also given for believing that the pulsational instability persists down to periods at which atmospheric oscillations become progressive, and this leads to the suggestion that such waves are observed as microturbulence and give rise to the observed mass loss. The importance of further monitoring of the variability of supergiants is stressed

  12. PATH ANALYSIS WITH LOGISTIC REGRESSION MODELS : EFFECT ANALYSIS OF FULLY RECURSIVE CAUSAL SYSTEMS OF CATEGORICAL VARIABLES

    OpenAIRE

    Nobuoki, Eshima; Minoru, Tabata; Geng, Zhi; Department of Medical Information Analysis, Faculty of Medicine, Oita Medical University; Department of Applied Mathematics, Faculty of Engineering, Kobe University; Department of Probability and Statistics, Peking University

    2001-01-01

    This paper discusses path analysis of categorical variables with logistic regression models. The total, direct and indirect effects in fully recursive causal systems are considered by using model parameters. These effects can be explained in terms of log odds ratios, uncertainty differences, and an inner product of explanatory variables and a response variable. A study on food choice of alligators as a numerical exampleis reanalysed to illustrate the present approach.

  13. Heart Rate Variability and Wavelet-based Studies on ECG Signals from Smokers and Non-smokers

    Science.gov (United States)

    Pal, K.; Goel, R.; Champaty, B.; Samantray, S.; Tibarewala, D. N.

    2013-12-01

    The current study deals with the heart rate variability (HRV) and wavelet-based ECG signal analysis of smokers and non-smokers. The results of HRV indicated dominance towards the sympathetic nervous system activity in smokers. The heart rate was found to be higher in case of smokers as compared to non-smokers ( p smokers from the non-smokers. The results indicated that when RMSSD, SD1 and RR-mean features were used concurrently a classification efficiency of > 90 % was achieved. The wavelet decomposition of the ECG signal was done using the Daubechies (db 6) wavelet family. No difference was observed between the smokers and non-smokers which apparently suggested that smoking does not affect the conduction pathway of heart.

  14. Pozorování aktivity autonomního nervového systému prostřednictvím spektrální analýzy variability srdeční frekvence u hráčů ledního hokeje Autonomic nervous system observation through to use of spectral analysis of heart rate variability in ice hockey players

    Directory of Open Access Journals (Sweden)

    Iva Řehová

    2007-01-01

    Full Text Available Cílem studie bylo poodhalit vliv pravidelného sportovního tréninku na aktivitu autonomního nervového systému (ANS, která byla hodnocena pomocí spektrální analýzy variability srdeční frekvence (SA HRV. K vyhodnocení výsledků SA HRV byly použity komplexní indexy (celkové skóre – TS, aktivita vagu – VA, sympatovagová balance – SVB a věkově standardizovaná hodnota celkového spektrálního výkonu (PT (Stejskal et al., 2002. Výzkumný soubor tvořili čtyři hráči ledního hokeje. Na základě získaných výsledků jsme došli k závěru, že kvalita sportovního tréninku ovlivňuje aktivitu ANS. Změny aktivity ANS, a tím velikosti adaptability sportovce, mohou významně ovlivnit sportovní výkon. Optimalizace adaptačních procesů prostřednictvím kontroly tréninkového zatížení na základě měření SA HRV může přinést nové aspekty řízení sportovního tréninku. The aim of our study was to investigate the infl uence of regular sport training on the activity of the autonomic nervous system (ANS and to disclose patterns of interrelations between them. The activity of the ANS was evaluated by means of the spectral analysis of heart rate variability (SA HRV. We used complex indices (total score – TS, vagal activity – VA, sympathovagal balance – SVB and age standardized values of total spectral power (PT for SA HRV results evaluation (Stejskal et al., 2002. The study group consisted of four ice hockey players, of whom all were 17 years old. The SA HRV was monitored by using VarCor PF7 hardware and VarCorMulti computer software, which enables four individuals to be measured at the same time. The examination of heart rate variability took place once a week in the morning. Information about the previous day’s training load, the duration and quality of sleep, and their self-reported health status (SRH was also obtained by completing a questionnaire before the SA HRV examination. Overall sports

  15. Emotional stress and heart rate variability measures associated with cardiovascular risk in relocated Katrina survivors.

    Science.gov (United States)

    Tucker, Phebe; Pfefferbaum, Betty; Jeon-Slaughter, Haekyung; Khan, Qaiser; Garton, Theresa

    2012-01-01

    To explore the effects of hurricane exposure and forced relocation on the mind and body, we compared psychiatric diagnoses and symptoms with heart rate variability (HRV) for 34 relocated Katrina survivors and 34 demographically matched controls. All participants were healthy and free of psychiatric and cardiovascular medications. We measured symptoms of posttraumatic stress disorder (PTSD) (Clinician-Administered PTSD Scale 1) and depression (Beck Depression Inventory), Axis I psychiatric diagnoses (Structured Clinical Interview for DSM-IV), psychosocial disability (Sheehan Disability Scale), and power spectral analysis HRV reactivity to trauma reminders. Katrina-related PTSD occurred in 38% of survivors and 12% of controls. Survivors reported higher levels of PTSD and depression symptoms, within diagnostic ranges, and greater psychosocial disability than controls. Survivors had higher resting heart rate (80.82 [standard deviation = 13.60] versus 74.85 [10.67], p = .05), lower parasympathetic (high-frequency [HF] normalized unit) baseline HRV activity (40.14 [23.81] versus 50.67 [19.93], p = .04) and less reactivity with trauma cues (-2.63 [20.70] versus -11.96 [15.84], p = .04), and higher baseline sympathovagal activity (low frequency/HF ratio) (2.84 [3.08] versus 1.35 [1.08], p = .04) than controls. Survivors with depression (n = 12) and with depression and PTSD combined (n = 7), but not those with PTSD (n = 13), had flattened parasympathetic responsiveness to trauma cues. HRV indices correlated with depressive (low frequency/HF, p = .01; HF normalized unit, p = .046) but not PTSD symptoms (p values > .05). Results showed this multilayer trauma's impact on emotional health and HRV-based measures of autonomic nervous system dysregulation. Specifically, dysregulation of depressed survivors' HRV in response to trauma reminders supports more autonomic involvement in traumatic loss/depression than in PTSD. Diagnostic criteria for PTSD include physiologic reactivity

  16. Heart and soul: heart rate variability and major depression.

    Science.gov (United States)

    Kidwell, Meyrick; Ellenbroek, Bart A

    2018-04-01

    There is a bidirectional relationship between affective disorders and cardiovascular abnormalities, often described as a downward spiral, whereas major depressive disorders (MDD, and anxiety disorders) significantly increase the risk of developing cardiovascular diseases (CVD); CVD are also associated with increased risk of developing MDD (and anxiety disorders). Moreover, the prognosis and progression of CVD is significantly worsened in the presence of MDD. Heart rate variability (HRV) has often been suggested as a potential mediator in this comorbidity. In this review, we discuss HRV alterations in MDD. However, we mainly focus on the direct relationship between HRV alterations and psychiatric symptoms, rather than its relationship with CVD, as this has been reviewed elsewhere. After a general introduction to HRV and how it can be measured, we review how HRV is altered in MDD. We subsequently describe how antidepressant drugs affect HRV, showing that some classes (such as tricyclics) generally worsen HRV, whereas others (most notably selective serotonin reuptake inhibitors) have a more positive influence. We also review the effects of several other treatments, with a special focus on vagal nerve stimulation, finishing with some further considerations and recommendation for further research, both in humans and animals.

  17. Exercise training improves heart rate variability after methamphetamine dependency.

    Science.gov (United States)

    Dolezal, Brett Andrew; Chudzynski, Joy; Dickerson, Daniel; Mooney, Larissa; Rawson, Richard A; Garfinkel, Alan; Cooper, Christopher B

    2014-06-01

    Heart rate variability (HRV) reflects a healthy autonomic nervous system and is increased with physical training. Methamphetamine dependence (MD) causes autonomic dysfunction and diminished HRV. We compared recently abstinent methamphetamine-dependent participants with age-matched, drug-free controls (DF) and also investigated whether HRV can be improved with exercise training in the methamphetamine-dependent participants. In 50 participants (MD = 28; DF = 22), resting heart rate (HR; R-R intervals) was recorded over 5 min while seated using a monitor affixed to a chest strap. Previously reported time domain (SDNN, RMSSD, pNN50) and frequency domain (LFnu, HFnu, LF/HF) parameters of HRV were calculated with customized software. MD were randomized to thrice-weekly exercise training (ME = 14) or equal attention without training (MC = 14) over 8 wk. Groups were compared using paired and unpaired t-tests. Statistical significance was set at P ≤ 0.05. Participant characteristics were matched between groups (mean ± SD): age = 33 ± 6 yr; body mass = 82.7 ± 12 kg, body mass index = 26.8 ± 4.1 kg·min. Compared with DF, the MD group had significantly higher resting HR (P HRV indices were similar between ME and MC groups. However, after training, the ME group significantly (all P HRV, based on several conventional indices, was diminished in recently abstinent, methamphetamine-dependent individuals. Moreover, physical training yielded a marked increase in HRV, representing increased vagal modulation or improved autonomic balance.

  18. Analysis of the Variables that Affect Bookstore Customer Satisfaction

    Directory of Open Access Journals (Sweden)

    Elis Ratna Wulan

    2016-02-01

    Full Text Available Competition, which becomes more widespread, complex, and intense, drives companies to must be able to see the various opportunities that exist and to identify strategies for creating customer satisfaction. As an example of a company must be able to produce products with good quality, reasonable price, facilities, and companies are able to create a positive image in the eyes of consumers. This strategy is quite important in facing the competitive level of competition with rival firms. This research is aimed to analysis simultaneously or partially positive effect of the facilities, prices and corporate image on customer satisfaction, as well as analyzing the most dominant variable in effecting bookstore customer satisfaction. Data used in this research are primary data from Tmbookstore customer in Cianjur city, West Java Indonesia, which were collected from respondents using valid and reliable questionnaire. A total of 100 respondents were selected from Tmbookstore visitors by accidental sampling. Data were analyzed using multiple regression analysis. Results of the research indicate that product, price, location, and simultaneously affect to bookstore consumer satisfaction. Partially, only two of the three variables that affect bookstore consumer satisfaction namely price and company image. Image of the company is the most a dominant impact on bookstore customer satisfaction.

  19. Sensitivity analysis and power for instrumental variable studies.

    Science.gov (United States)

    Wang, Xuran; Jiang, Yang; Zhang, Nancy R; Small, Dylan S

    2018-03-31

    In observational studies to estimate treatment effects, unmeasured confounding is often a concern. The instrumental variable (IV) method can control for unmeasured confounding when there is a valid IV. To be a valid IV, a variable needs to be independent of unmeasured confounders and only affect the outcome through affecting the treatment. When applying the IV method, there is often concern that a putative IV is invalid to some degree. We present an approach to sensitivity analysis for the IV method which examines the sensitivity of inferences to violations of IV validity. Specifically, we consider sensitivity when the magnitude of association between the putative IV and the unmeasured confounders and the direct effect of the IV on the outcome are limited in magnitude by a sensitivity parameter. Our approach is based on extending the Anderson-Rubin test and is valid regardless of the strength of the instrument. A power formula for this sensitivity analysis is presented. We illustrate its usage via examples about Mendelian randomization studies and its implications via a comparison of using rare versus common genetic variants as instruments. © 2018, The International Biometric Society.

  20. Analysis of the Variables that Affect Bookstore Customer Satisfaction

    Directory of Open Access Journals (Sweden)

    Elis Ratna Wulan

    2015-06-01

    Full Text Available Competition, which becomes more widespread, complex, and intense, drives companies to must be able to see the various opportunities that exist and to identify strategies for creating customer satisfaction. As an example of a company must be able to produce products with good quality, reasonable price, facilities, and companies are able to create a positive image in the eyes of consumers. This strategy is quite important in facing the competitive level of competition with rival firms. This research is aimed to analysis simultaneously or partially positive effect of the facilities, prices and corporate image on customer satisfaction, as well as analyzing the most dominant variable in effecting bookstore customer satisfaction.  Data used in this research are primary data from Tmbookstore customer in Cianjur city, West Java Indonesia, which were collected from respondents using valid and reliable questionnaire. A total of 100 respondents were selected from Tmbookstore visitors by accidental sampling. Data were analyzed using multiple regression analysis. Results of the research indicate that product, price, location, and simultaneously affect to bookstore consumer satisfaction. Partially, only two of the three variables that affect bookstore consumer satisfaction namely price and company image. Image of the company is the most a dominant impact on bookstore customer satisfaction.

  1. Real analysis foundations and functions of one variable

    CERN Document Server

    Laczkovich, Miklós

    2015-01-01

    Based on courses given at Eötvös Loránd University (Hungary) over the past 30 years, this introductory textbook develops the central concepts of the analysis of functions of one variable - systematically, with many examples and illustrations, and in a manner that builds upon, and sharpens, the students' mathematical intuition. The modular organization of the book makes it adaptable for either semester or year-long introductory courses, while the wealth of material allows for it to be used at various levels of student sophistication in all programs where analysis is a part of the curriculum, including teachers' education. In the spirit of learning-by-doing, Real Analysis includes more than 500 engaging exercises for the student keen on mastering the basics of analysis. There are frequent hints and occasional complete solutions provided for the more challenging exercises making it an ideal choice for independent study. The book includes a solid grounding in the basics of logic and proofs, sets, and real numb...

  2. Heart rate and heart rate variability modification in chronic insomnia patients.

    Science.gov (United States)

    Farina, Benedetto; Dittoni, Serena; Colicchio, Salvatore; Testani, Elisa; Losurdo, Anna; Gnoni, Valentina; Di Blasi, Chiara; Brunetti, Riccardo; Contardi, Anna; Mazza, Salvatore; Della Marca, Giacomo

    2014-01-01

    Chronic insomnia is highly prevalent in the general population, provoking personal distress and increased risk for psychiatric and medical disorders. Autonomic hyper-arousal could be a pathogenic mechanism of chronic primary insomnia. The aim of this study was to investigate autonomic activity in patients with chronic primary insomnia by means of heart rate variability (HRV) analysis. Eighty-five consecutive patients affected by chronic primary insomnia were enrolled (38 men and 47 women; mean age: 53.2 ± 13.6). Patients were compared with a control group composed of 55 healthy participants matched for age and gender (23 men and 32 women; mean age: 54.2 ± 13.9). Patients underwent an insomnia study protocol that included subjective sleep evaluation, psychometric measures, and home-based polysomnography with evaluation of HRV in wake before sleep, in all sleep stages, and in wake after final awakening. Patients showed modifications of heart rate and HRV parameters, consistent with increased sympathetic activity, while awake before sleep and during Stage-2 non-REM sleep. No significant differences between insomniacs and controls could be detected during slow-wave sleep, REM sleep, and post-sleep wake. These results are consistent with the hypothesis that autonomic hyper-arousal is a major pathogenic mechanism in primary insomnia, and confirm that this condition is associated with an increased cardiovascular risk.

  3. Estimating rice grain protein contents with SPOT/HRV data acquired at maturing stage

    International Nuclear Information System (INIS)

    Asaka, D.; Shiga, H.

    2003-01-01

    Rice grain protein contents that play an important role in the eating quality of rice can be estimated from leaf color in maturing stage. In order to investigate the distribution of paddy rice grain protein of a wide area, we employed SPOT/HRV data from August to September for successive 4 years, selecting the Naganuma town, Hokkaido as the study area. The relationship between each spectral bands and ground survey data were examined. The result showed that the grain protein contents could be estimated using the normalized difference vegetation index (NDVI) with the absolute root mean square error less than 0.4% under the condition that the time lag between the satellite observation date and the maturing stage was within 20 days. In this period, we would have enough chance to get clear observation data every year under the weather conditions in the study area using the SPOT/HRV sensors that has pointing ability. For major rice varieties cultivated in Hokkaido, the same relationship between NDVI and protein contents was observed. Thus, we conclude that the method proposed in this study is operational in rice production

  4. Association between smoking and heart rate variability among individuals with depression.

    Science.gov (United States)

    Harte, Christopher B; Liverant, Gabrielle I; Sloan, Denise M; Kamholz, Barbara W; Rosebrock, Laina E; Fava, Maurizio; Kaplan, Gary B

    2013-08-01

    Both depression and smoking have been independently associated with lower heart rate variability (HRV), suggesting dysregulation of cardiac autonomic function. However, no studies have systematically explored the effects of smoking on HRV among depressed patients. This study examined differences in HRV based on smoking status among depressed individuals. Electrophysiological data were examined among 77 adult outpatients without a history of myocardial infarction, who met criteria for major depressive disorder or dysthymia. Frequency domain [low frequency (LF), high frequency (HF), LF/HF ratio, respiratory sinus arrhythmia (RSA)] parameters of HRV, and heart rate and inter-beat interval (IBI) data were compared between depressed smokers (n = 34) and depressed nonsmokers (n = 44). After controlling for covariates, depressed smokers, compared to depressed nonsmokers, displayed significantly lower LF, HF, and RSA. Among depressed patients, smoking is associated with significantly lower HRV, indicating dysregulated autonomic modulation of the heart.

  5. Social integration prospectively predicts changes in heart rate variability among individuals undergoing migration stress.

    Science.gov (United States)

    Gouin, Jean-Philippe; Zhou, Biru; Fitzpatrick, Stephanie

    2015-04-01

    Poor social integration increases risk for poor health. The psychobiological pathways underlying this effect are not well-understood. This study utilized a migration stress model to prospectively investigate the impact of social integration on change in high-frequency heart rate variability (HF-HRV), a marker of autonomic functioning. Sixty new international students were recruited shortly after their arrival in the host country and assessed 2 and 5 months later. At each assessment period, participants provided information on social integration and loneliness and had their resting HF-HRV evaluated. There was an overall decrease in HF-HRV over time. The magnitude of the within-person and between-person effects of social integration on HRV increased over time, such that greater social integration was associated with higher HF-HRV at later follow-ups. These results suggest that altered autonomic functioning might represent a key pathway linking social integration to health outcomes.

  6. Time-variant partial directed coherence in analysis of the cardiovascular system. A methodological study

    International Nuclear Information System (INIS)

    Milde, T; Schwab, K; Walther, M; Eiselt, M; Witte, H; Schelenz, C; Voss, A

    2011-01-01

    Time-variant partial directed coherence (tvPDC) is used for the first time in a multivariate analysis of heart rate variability (HRV), respiratory movements (RMs) and (systolic) arterial blood pressure. It is shown that respiration-related HRV components which also occur at other frequencies besides the RM frequency (= respiratory sinus arrhythmia, RSA) can be identified. These additional components are known to be an effect of the 'half-the-mean-heart-rate-dilemma' ('cardiac aliasing' CA). These CA components may contaminate the entire frequency range of HRV and can lead to misinterpretation of the RSA analysis. TvPDC analysis of simulated and clinical data (full-term neonates and sedated patients) reveals these contamination effects and, in addition, the respiration-related CA components can be separated from the RSA component and the Traube–Hering–Mayer wave. It can be concluded that tvPDC can be beneficially applied to avoid misinterpretations in HRV analyses as well as to quantify partial correlative interaction properties between RM and RSA

  7. On the Analysis of Recurrence Characteristics at Variable Actions

    Directory of Open Access Journals (Sweden)

    Horea SANDI

    2011-07-01

    Full Text Available The paper is devoted to some methodological problems raised by the analysis of hazards due to variable actions having implications for the risk of damage to structures. The basic recurrence model used is that of Poissonian stochastic processes. The techniques of calibration of specific recurrence characteristics are discussed, adopting a critical point of view versus statistical analyses relying exclusively on data like annual maxima. The adoption of some types of distributions is critically discussed, from the point of view of their compatibility with the Poissonian model referred to. Only the Gumbel and Fréchet distributions are accepted as adequate for the purpose adopted. Starting from their common properties an unbounded family of distributions is proposed. This family makes it possible to adopt calibrations providing an approximation of unlimited closeness to observation samples. The case of a pluri-dimensional characterization of the randomness of observation data is then tackled, considering as an illustrative case the directional statistical analysis of sequences of wind events. Some specific expressions are proposed for the directional analysis, leading to a good approximation of observation samples. A case study relying on the expressions is then presented.

  8. Heart Rate Variability - A Historical Perspective

    Directory of Open Access Journals (Sweden)

    George E Billman

    2011-11-01

    Full Text Available Heart rate variability (HRV, the beat-to-beat variation in either heart rate or the duration of the R-R interval – the heart period, has become a popular clinical and investigational tool. The temporal fluctuations in heart rate exhibit a marked synchrony with respiration (increasing during inspiration and decreasing during expiration – the so called respiratory sinus arrhythmia, RSA and are widely believed to reflect changes in cardiac autonomic regulation. Although the exact contributions of the parasympathetic and the sympathetic divisions of the autonomic nervous system to this variability are controversial and remain the subject of active investigation and debate, a number of time and frequency domain techniques have been developed to provide insight into cardiac autonomic regulation in both health and disease. It is the purpose of this essay to provide an historical overview of the evolution in the concept of heart rate variability. Briefly, pulse rate was first measured by ancient Greek physicians and scientists. However, it was not until the invention of the Physician’s Pulse Watch (a watch with a second hand that could be stopped in 1707 that changes in pulse rate could be accurately assessed. The Rev. Stephen Hales (1733 was the first to note that pulse varied with respiration and in 1847 Carl Ludwig was the first to record RSA. With the measurement of the ECG (1895 and advent of digital signal processing techniques in the 1960’s, investigation of HRV and its relationship to health and disease has exploded. This essay will conclude with a brief description of time domain, frequency domain, and non-linear dynamic analysis techniques (and their limitations that are commonly used to measure heart rate variability.

  9. Heart rate and heart rate variability in dogs with different degrees of myxomatous mitral valve disease

    DEFF Research Database (Denmark)

    Rasmussen, Caroline Elisabeth; Falk, Bo Torkel; Zois, Nora Elisabeth

    2011-01-01

    atrial area using color Doppler mapping) and no murmur, 2) CKCS with mild MR (20%50%) and no clinical signs of HF, 4) CKCS in HF (HF defined as left atrium to aortic root ratio (LA/Ao) >1.5, clinical signs of HF and furosemide responsiveness) and 5) non......-CKCS in HF. Dogs in HF were allowed HF therapy. Both HR and HRV were analysed over a 24-hour period, while HRV were also analysed over a 6-hour nightly period. Analyses of variance were performed with HR or HRV as response variables and the explanatory variables dog group and echocardiographic indices...

  10. Effects of citalopram on heart rate variability in women with generalized anxiety disorder

    Directory of Open Access Journals (Sweden)

    Fatemeh Ranjbar

    2015-07-01

    Full Text Available BACKGROUND: Heart rate variability (HRV is defined as variations in R-R interval with time. Dysautonomia is common in patients with psychiatric disorders such as depression and anxiety. Using HRV analysis, recent studies showed that in anxiety disorders, the vagal cardiac function decreases, and sympathetic function increases. This study aimed at investigating citalopram effects on HRV. METHODS: This before and after study was conducted in 25 generalized anxiety disorder (GAD patients. GAD was diagnosed based on clinical interview according to diagnostic and statistical manual of mental disorders IV-Text revised (DSM-IV-TR criteria using Structured Clinical Interview for DSM Disorders-I questionnaire. A cardiologist studied 24 h ambulatory monitoring of the electrocardiogram (Holter on all patients before the treatment. A volume of 20 mg of citalopram was administered to the subjects on a daily basis. Then, they were studied by Holter monitoring again after 1-month of administration of citalopram. RESULTS: The average age of participants was 35.32 ± 8.7. The average Holter monitoring time was 23.29 ± 1.14 h before treatment and 23.81 ± 0.68 after it. The 3 h low frequency/high frequency ratio was significantly different between 3 h segments of time before treatment (P < 0.001. This difference was even higher after treatment (P = 0.001. Data showed an increase in parasympathetic tone during sleep both before and after treatment. CONCLUSION: These patients showed some impairments of HRV indices that did not improve by citalopram in future, the clinical importance of such disturbances should be evaluated in details with prolonged follow-up and greater sample size.   

  11. Influence of Competitive-Anxiety on Heart Rate Variability in Swimmers.

    Science.gov (United States)

    Fortes, Leonardo S; da Costa, Bruna D V; Paes, Pedro P; do Nascimento Júnior, José R A; Fiorese, Lenamar; Ferreira, Maria E C

    2017-12-01

    The aim of this study was to analyze the relationship between competitive anxiety and heart rate variability (HRV) in swimming athletes. A total of 66 volunteers (41 male and 27 female) who swam the 400-m freestyle in the Brazilian Swimming Championships participated. Thirty minutes before the 400-m freestyle event, the athletes answered the Competitive Anxiety Inventory (CSAI-2R) questionnaire, then underwent anthropometric (body weight, height, and skinfold thickness) and HRV measurements. Then, at a second meeting, held 3 h after the 400-m freestyle event, the athletes returned to the evaluation room for HRV measurement (Polar ® RS800cx, Kempele, Finland). Multiple linear regression was used to evaluate the relationship between competitive anxiety and HRV. The multiple linear regression was performed in three blocks (block 1: cognitive anxiety, block 2: somatic anxiety, and block 3: self-confidence), adopting the forward model. The results indicated a significant association between cognitive anxiety (p = 0.001) and HRV. An increased magnitude of the association was observed when somatic anxiety was inserted in the model (p = 0.001). In contrast, self-confidence showed, which was inserted in block 3, no relationship with HRV (p = 0.27). It was concluded that cognitive and somatic anxieties were associated with the HRV of swimmers. Athletes with a high magnitude of cognitive and/or somatic anxiety demonstrated more significant autonomic nervous system disturbance. Practically, psychological interventions are needed to improve anxiety states that are specific to perform well, and to improve HRV.

  12. The correlation between heart rate variability and improvement in soccer player’s physical performance. http://dx.doi.org/10.5007/1980-0037.2012v14n6p713

    Directory of Open Access Journals (Sweden)

    Ricardo Santos Oliveira

    2012-11-01

    Full Text Available The aim of this study was to analyze whether the heart rate variability (HRV, assessed at the beginning of a soccer preseason, reveals a correlation with the improvement of physical performance over this training period. Ten soccer players took part in the study. Their performance was evaluated by the following tests: the Yo-Yo intermittent recovery test, Level 1(Yo-Yo IR1; the 30-m sprint time, and the vertical jump; all were conducted before and after six weeks of pre-season. The HRV measurements were performed at rest in the supine position for ten minutes. The Spearman Rank Correlation test was used to investigate any possible relationship between HRV and improvements in performance, while the Student’s t-test verified the changes in both performance and HRV. The Magnitude-Based Inferences approach (qualitative analysis was applied to verify the possibilities of the observed values being positive, negative or inconclusive. There were significant improvements in Yo-Yo IR1 performance (P< 0.001 and in the 30-m sprint time (P< 0.001. The qualitative analysis revealed that the differences in Yo-Yo IR1 performance were very likely positive, were almost certainly positive for the sprint, but were inconclusive for the vertical jump. There was a strong correlation between one parasympathetic index and the change in performance [r = 0.85 P = 0.003 (IC95% = 0.49 – 0.97]. In conclusion, this study revealed a strong correlation between parasympathetic indices of HRV (analyzed before the training with the performance improvement in Yo-Yo IR1 in football athletes during pre-season.

  13. Risk Assessment of Diabetes Mellitus by Chaotic Globals to Heart Rate Variability via Six Power Spectra

    Directory of Open Access Journals (Sweden)

    Garner David M.

    2017-09-01

    Full Text Available Background: The priniciple objective here is to analyze cardiovascular dynamics in diabetic subjects by actions related to heart rate variability (HRV. The correlation of chaotic globals is vital to evaluate the probability of dynamical diseases.

  14. Heart rate variability, sleep, and the early detection of post-traumatic stress disorder

    NARCIS (Netherlands)

    van Boxtel, Geert J.M.; Cluitmans, Pierre J.M.; Raymann, Roy J.E.M.; Ouwerkerk, Martin; Denissen, Ad J.M.; Dekker, Marian K.J.; Sitskoorn, Margriet M.; Vermetten, E.; Germain, A.; Neylan, T.C.

    2017-01-01

    Measures of heart rate variability (HRV) are sensitive indices of autonomic nervous system functioning, capable of distinguishing activity of its two constituent branches, the sympathetic and parasympathetic nervous systems. As such, these measures are possibly useful as early markers of

  15. Heart rate variability and QT dispersion study in brain death patients and comatose patients with normal brainstem function

    International Nuclear Information System (INIS)

    Vakilian, A.R.; Iranmanesh, F.; Nadimi, A.E.; Kahnali, J.A.

    2011-01-01

    To compare heart rate variability (HRV) and QT dispersion in comatose patients with normal brainstem function and with brain death. Fourteen brain death patients with clinical signs of imminent brain death and 15 comatose patients were examined by neurologist in intensive care unit. HRV, RR interval and QT dispersion on ECG were assessed for 24 hours in both groups. Independent t-test and chi-square test were used for statistical analysis to determine significance which was set at p < 0.05. According to Holter findings, mean of standard deviation of RR-interval in the comatose and brain death groups was 48.33 and 35 respectively (p = 0.045). Mean of covariance coefficient of RR-interval was 0.065 in the comatose group and 0.043 in the brain deaths (p = 0.006). QT dispersion was not significant difference in two groups. HRV and RR-interval analysis appeared as an early finding for the diagnosis of brainstem death in comparison to comatose patients with normal brainstem function. QT dispersion had not significant in this regard. (author)

  16. Minimizing inter-microscope variability in dental microwear texture analysis

    Science.gov (United States)

    Arman, Samuel D.; Ungar, Peter S.; Brown, Christopher A.; DeSantis, Larisa R. G.; Schmidt, Christopher; Prideaux, Gavin J.

    2016-06-01

    A common approach to dental microwear texture analysis (DMTA) uses confocal profilometry in concert with scale-sensitive fractal analysis to help understand the diets of extinct mammals. One of the main benefits of DMTA over other methods is the repeatable, objective manner of data collection. This repeatability, however, is threatened by variation in results of DMTA of the same dental surfaces yielded by different microscopes. Here we compare DMTA data of five species of kangaroos measured on seven profilers of varying specifications. Comparison between microscopes confirms that inter-microscope differences are present, but we show that deployment of a number of automated treatments to remove measurement noise can help minimize inter-microscope differences. Applying these same treatments to a published hominin DMTA dataset shows that they alter some significant differences between dietary groups. Minimising microscope variability while maintaining interspecific dietary differences requires then that these factors are balanced in determining appropriate treatments. The process outlined here offers a solution for allowing comparison of data between microscopes, which is essential for ongoing DMTA research. In addition, the process undertaken, including considerations of other elements of DMTA protocols also promises to streamline methodology, remove measurement noise and in doing so, optimize recovery of a reliable dietary signature.

  17. Effect of short-term heart rate variability biofeedback on long-term abstinence in alcohol dependent patients - a one-year follow-up.

    Science.gov (United States)

    Penzlin, Ana Isabel; Barlinn, Kristian; Illigens, Ben Min-Woo; Weidner, Kerstin; Siepmann, Martin; Siepmann, Timo

    2017-09-06

    A randomized controlled study (RCT) recently showed that short-term heart rate variability (HRV) biofeedback in addition to standard rehabilitation care for alcohol dependence can reduce craving, anxiety and improve cardiovascular autonomic function. In this one-year follow-up study we aimed to explore whether completion of 2-week HRV-Biofeedback training is associated with long-term abstinence. Furthermore, we sought to identify potential predictors of post-treatment abstinence. We conducted a survey on abstinence in patients with alcohol dependence 1 year after completion of an RCT comparing HRV-biofeedback in addition to inpatient rehabilitation treatment alone (controls). Abstinence rates were compared and analysed for association with demographic data as well as psychometric and autonomic cardiac assessment before and after completion of the biofeedback training using bivariate and multivariate regression analyses. Out of 48 patients who participated in the RCT, 27 patients (9 females, ages 42.9 ± 8.6, mean ± SD) completed our one-year follow-up. When including in the analysis only patients who completed follow-up, the rate of abstinence tended to be higher in patients who underwent HRV-biofeedback 1 year earlier compared to those who received rehabilitative treatment alone (66.7% vs 50%, p = ns). This non-significant trend was also observed in the intention-to-treat analysis where patients who did not participate in the follow-up were assumed to have relapsed (46,7% biofeedback vs. 33.3% controls, p = ns). Neither cardiac autonomic function nor psychometric variables were associated with abstinence 1 year after HRV-biofeedback. Our follow-up study provide a first indication of possible increase in long-term abstinence after HRV-biofeedback for alcohol dependence in addition to rehabilitation. The original randomized controlled trial was registered in the German Clinical Trials Register ( DRKS00004618 ). This one-year follow-up survey has not been

  18. Depressed heart rate variability as an independent predictor of death in chronic congestive heart failure secondary to ischemic or idiopathic dilated cardiomyopathy.

    Science.gov (United States)

    Ponikowski, P; Anker, S D; Chua, T P; Szelemej, R; Piepoli, M; Adamopoulos, S; Webb-Peploe, K; Harrington, D; Banasiak, W; Wrabec, K; Coats, A J

    1997-06-15

    After acute myocardial infarction, depressed heart rate variability (HRV) has been proven to be a powerful independent predictor of a poor outcome. Although patients with chronic congestive heart failure (CHF) have also markedly impaired HRV, the prognostic value of HRV analysis in these patients remains unknown. The aim of this study was to investigate whether HRV parameters could predict survival in 102 consecutive patients with moderate to severe CHF (90 men, mean age 58 years, New York Heart Association [NYHA] class II to IV, CHF due to idiopathic dilated cardiomyopathy in 24 patients and ischemic heart disease in 78 patients, ejection fraction [EF], 26%; peak oxygen consumption, 16.9 ml/kg/min) after exclusion of patients in atrial fibrilation with diabetes or with chronic renal failure. In the prognostic analysis (Cox proportional-hazards model, Kaplan-Meier survival analysis), the following factors were investigated: age, CHF etiology, NYHA class, EF, peak oxygen consumption, presence of ventricular tachycardia on Holter monitoring, and HRV measures derived from 24-hour electrocardiography monitoring, calculated in the time (standard deviation of all normal RR intervals [SDNN], standard deviation of 5-minute RR intervals [SDANN], mean of all 5-minute standard deviations of RR intervals [SD], root-mean-square of difference of successive RR intervals [rMSSD], and percentage of adjacent RR intervals >50 ms different [pNN50]) and frequency domain (total power [TP], power within low-frequency band [LF], and power within high-frequency band [HF]). During follow-up of 584 +/- 405 days (365 days in all who survived), 19 patients (19%) died (mean time to death: 307 +/- 315 days, range 3 to 989). Cox's univariate analysis identified the following factors to be predictors of death: NYHA (p = 0.003), peak oxygen consumption (p = 0.01), EF (p = 0.02), ventricular tachycardia on Holter monitoring (p = 0.05), and among HRV measures: SDNN (p = 0.004), SDANN (p = 0.003), SD

  19. Effect of yoga on short-term heart rate variability measure as a stress index in subjunior cyclists: a pilot study.

    Science.gov (United States)

    Patil, Satish G; Mullur, Lata M; Khodnapur, Jyoti P; Dhanakshirur, Gopal B; Aithala, Manjunatha R

    2013-01-01

    Subjunior athletes experience mental stress due to pressure from the coach, teachers and parents for better performance. Stress, if remains for longer period and not managed appropriately can leads to negative physical, mental and cognitive impact on children. The present study was aimed to evaluate the effect of integrated yoga module on heart rate variability (HRV) measure as a stress index in subjunior cyclists. Fast furrier transform technique of frequency domain method was used for the analysis of HRV. We have found a significant increase in high frequency (HF) component by 14.64% (P activity and causes a shift in the autonomic balance towards parasympathetic dominance indicating a reduction in stress. In conclusion, yoga practice helps to reduce stress by optimizing the autonomic functions. So, it is suggested to incorporate yoga module as a regular feature to keep subjunior athletes both mentally and physically fit.

  20. Volleyball players training intensity monitoring through the use of spectral analysis of heart rate variability during a training microcycle [Kontrola zatížení hráčů volejbalu metodou spektrální analýzy variability srdeční frekvence během týdenního tréninkového mikrocyklu

    Directory of Open Access Journals (Sweden)

    Aleš Jakubec

    2011-09-01

    Full Text Available BACKGROUND: Volleyball players in different specializations are required to meet specific demands in terms of movement behaviour and skills performance. These specific demands need to be individualized according to the training ability level (adaptability to sports training of particular players, which is mainly dependent on the activity of the autonomic nervous system (ANS. Spectral analysis of heart rate variability (SA HRV gives us information on cardiac activity regulation, where the activity of ANS participates in a significant way. Longitudinal assessment of SA HRV within a certain part of a training period can help us to observe the dynamics of the ANS activity and adaptability (training ability changes of an observed player to training. OBJECTIVE: The goal of the work was to verify the possibility of volleyball players' training load optimalization during a one week training microcycle based on the longitudinal observation of dynamics of SA HRV complex indices. METHODS: The SA HRV method was used for the evaluation of autonomic cardiac regulation. The study group consisted of eight volleyball players who took part in 28 training sessions focused on conditioning and volleyball skills development. During the microcycle, there were 7 HRV examinations. RESULTS: The results demonstrated that notable and considerably varied changes in the activity of ANS in players were assessed owing to both training and extra-training stimuli. The results in two players show a high activity of ANS which enables them to increase their training intensity. Four players achieved average values of their ANS activity, which reflects a corresponding training load. In the last two players we found a very low level of their ANS activity and it refers to their reduced adaptability to the training load, which was too high for them. CONCLUSIONS: The presented results support the necessity of the individualization of, at least a part of, team training. Such an

  1. Assessment of Heart Rate Variability Thresholds from Incremental Treadmill Tests in Five Cross-Country Skiing Techniques.

    Directory of Open Access Journals (Sweden)

    Ibai Mendia-Iztueta

    Full Text Available The assessment of heart rate variability (HRV thresholds (HRVTs as an alternative of Ventilatory thresholds (VTs is a relatively new approach with increasing popularity which has not been conducted in cross-country (XC skiing yet. The main purpose of the present study was to assess HRVTs in the five main XC skiing-related techniques, double poling (DP, diagonal striding (DS, Nordic walking (NW, V1 skating (V1, and V2 skating (V2.Ten competitive skiers completed these incremental treadmill tests until exhaustion with a minimum of one to two recovery days in between each test. Ventilatory gases, HRV and poling frequencies were measured. The first HRV threshold (HRVT1 was assessed using two time-domain analysis methods, and the second HRV threshold (HRVT2 was assessed using two non-time varying frequency-domain analysis methods. HRVT1 was assessed by plotting the mean successive difference (MSD and standard deviation (SD of normalized R-R intervals to workload. HRVT1 was assessed by plotting high frequency power (HFP and the HFP relative to respiratory sinus arrhythmia (HFPRSA with workload. HRVTs were named after their methods (HRVT1-SD; HRVT1-MSD; HRVT2-HFP; HRVT2-HFP-RSA. The results showed that the only cases where the proposed HRVTs were good assessors of VTs were the HRVT1-SD of the DS test, the HRVT1-MSD of the DS and V2 tests, and the HRVT2-HFP-RSA of the NW test. The lack of a wider success of the assessment of HRVTs was reasoned to be mostly due to the high entrainment between the breathing and poling frequencies. As secondary finding, a novel Cardiolocomotor coupling mode was observed in the NW test. This new Cardiolocoomtor coupling mode corresponded to the whole bilateral poling cycle instead of corresponding to each poling action as it was reported to the date by the existing literature.

  2. Analysis of Program Obfuscation Schemes with Variable Encoding Technique

    Science.gov (United States)

    Fukushima, Kazuhide; Kiyomoto, Shinsaku; Tanaka, Toshiaki; Sakurai, Kouichi

    Program analysis techniques have improved steadily over the past several decades, and software obfuscation schemes have come to be used in many commercial programs. A software obfuscation scheme transforms an original program or a binary file into an obfuscated program that is more complicated and difficult to analyze, while preserving its functionality. However, the security of obfuscation schemes has not been properly evaluated. In this paper, we analyze obfuscation schemes in order to clarify the advantages of our scheme, the XOR-encoding scheme. First, we more clearly define five types of attack models that we defined previously, and define quantitative resistance to these attacks. Then, we compare the security, functionality and efficiency of three obfuscation schemes with encoding variables: (1) Sato et al.'s scheme with linear transformation, (2) our previous scheme with affine transformation, and (3) the XOR-encoding scheme. We show that the XOR-encoding scheme is superior with regard to the following two points: (1) the XOR-encoding scheme is more secure against a data-dependency attack and a brute force attack than our previous scheme, and is as secure against an information-collecting attack and an inverse transformation attack as our previous scheme, (2) the XOR-encoding scheme does not restrict the calculable ranges of programs and the loss of efficiency is less than in our previous scheme.

  3. Heart Rate Variability in Obstetricians Working 14-Hour Call Compared to 24-Hour Call in Labour and Delivery.

    Science.gov (United States)

    Thurman, Robin H; Yoon, Eugene; Murphy, Kellie E; Windrim, Rory; Farrugia, M Michéle

    2017-12-01

    Obstetricians have stressful and demanding jobs that may impact their health. A physiological measurement of cardiac function which varies with stress is heart rate variability (HRV). By measuring the cyclic variations in R-R intervals, or beat-to-beat differences, HRV reflects the continuous interplay of the controlling forces in the autonomic nervous system. Studies have shown HRV to be reduced during periods of work-induced stress, including 24-hour shifts. Our study aimed to determine if there was a correlation between length of shift worked and HRV. We hypothesised that working for a full 24-hour period is more stressful than a shorter, nighttime-only period, and HRV analyses were used to measure this objectively. Obstetricians wore an HRV monitor for 24 hours during both a regular day followed by a 14-hour night shift and a continuous 24-hour shift in labour and delivery. The 24-hour samples were analysed using standard HRV measurements. HRV measurements obtained from each physician were then compared according to shift type, with each physician acting as his or her own comparator. There were no statistically significant differences in the most important measures of HRV between 24-hour periods which included either a 14-hour overnight shift or a continuous 24-hour shift on labour and delivery. We found no significant differences in key HRV measures in obstetricians working 14 hours versus 24 hours in labour and delivery. An anecdotal increase in physician awareness of his/her own health related to working conditions was noted during the study. Future studies should attempt to control for the hours prior to a night shift, assess associated endocrine variations, and focus upon HRV in the post-shift period. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

  4. Analysis of suspension with variable stiffness and variable damping force for automotive applications

    Directory of Open Access Journals (Sweden)

    Lalitkumar Maikulal Jugulkar

    2016-05-01

    Full Text Available Passive shock absorbers are designed for standard load condition. These give better vibration isolation performance only for the standard load condition. However, if the sprung mass is lesser than the standard mass, comfort and road holding ability is affected. It is demonstrated that sprung mass acceleration increases by 50%, when the vehicle mass varies by 100 kg. In order to obtain consistent damping performance from the shock absorber, it is essential to vary its stiffness and damping properties. In this article, a variable stiffness system is presented, which comprises of two helical springs and a variable fluid damper. Fluid damper intensity is changed in four discrete levels to achieve variable stiffness of the prototype. Numerical simulations have been performed with MATLAB Simscape and Simulink which have been with experimentation on a prototype. Furthermore, the numerical model of the prototype is used in design of real size shock absorber with variable stiffness and damping. Numerical simulation results on the real size model indicate that the peak acceleration will improve by 15% in comparison to the conventional passive solution, without significant deterioration of road holding ability. Arrangement of sensors and actuators for incorporating the system in a vehicle suspension has also been discussed.

  5. HEART RATE VARIABILITY CLASSIFICATION USING SADE-ELM CLASSIFIER WITH BAT FEATURE SELECTION

    Directory of Open Access Journals (Sweden)

    R Kavitha

    2017-07-01

    Full Text Available The electrical activity of the human heart is measured by the vital bio medical signal called ECG. This electrocardiogram is employed as a crucial source to gather the diagnostic information of a patient’s cardiopathy. The monitoring function of cardiac disease is diagnosed by documenting and handling the electrocardiogram (ECG impulses. In the recent years many research has been done and developing an enhanced method to identify the risk in the patient’s body condition by processing and analysing the ECG signal. This analysis of the signal helps to find the cardiac abnormalities, arrhythmias, and many other heart problems. ECG signal is processed to detect the variability in heart rhythm; heart rate variability is calculated based on the time interval between heart beats. Heart Rate Variability HRV is measured by the variation in the beat to beat interval. The Heart rate Variability (HRV is an essential aspect to diagnose the properties of the heart. Recent development enhances the potential with the aid of non-linear metrics in reference point with feature selection. In this paper, the fundamental elements are taken from the ECG signal for feature selection process where Bat algorithm is employed for feature selection to predict the best feature and presented to the classifier for accurate classification. The popular machine learning algorithm ELM is taken for classification, integrated with evolutionary algorithm named Self- Adaptive Differential Evolution Extreme Learning Machine SADEELM to improve the reliability of classification. It combines Effective Fuzzy Kohonen clustering network (EFKCN to be able to increase the accuracy of the effect for HRV transmission classification. Hence, it is observed that the experiment carried out unveils that the precision is improved by the SADE-ELM method and concurrently optimizes the computation time.

  6. Time-varying surrogate data to assess nonlinearity in nonstationary time series: application to heart rate variability.

    Science.gov (United States)

    Faes, Luca; Zhao, He; Chon, Ki H; Nollo, Giandomenico

    2009-03-01

    We propose a method to extend to time-varying (TV) systems the procedure for generating typical surrogate time series, in order to test the presence of nonlinear dynamics in potentially nonstationary signals. The method is based on fitting a TV autoregressive (AR) model to the original series and then regressing the model coefficients with random replacements of the model residuals to generate TV AR surrogate series. The proposed surrogate series were used in combination with a TV sample entropy (SE) discriminating statistic to assess nonlinearity in both simulated and experimental time series, in comparison with traditional time-invariant (TIV) surrogates combined with the TIV SE discriminating statistic. Analysis of simulated time series showed that using TIV surrogates, linear nonstationary time series may be erroneously regarded as nonlinear and weak TV nonlinearities may remain unrevealed, while the use of TV AR surrogates markedly increases the probability of a correct interpretation. Application to short (500 beats) heart rate variability (HRV) time series recorded at rest (R), after head-up tilt (T), and during paced breathing (PB) showed: 1) modifications of the SE statistic that were well interpretable with the known cardiovascular physiology; 2) significant contribution of nonlinear dynamics to HRV in all conditions, with significant increase during PB at 0.2 Hz respiration rate; and 3) a disagreement between TV AR surrogates and TIV surrogates in about a quarter of the series, suggesting that nonstationarity may affect HRV recordings and bias the outcome of the traditional surrogate-based nonlinearity test.

  7. [Effects of Monochord Music on Heart Rate Variability and Self-Reports of Relaxation in Healthy Adults].

    Science.gov (United States)

    Gäbel, Christine; Garrido, Natalia; Koenig, Julian; Hillecke, Thomas Karl; Warth, Marco

    Music-based interventions are considered an effective and low-cost treatment option for stress-related symptoms. The present study aimed to examine the trajectories of the psychophysiological response in apparently healthy participants during a music-based relaxation intervention compared to a verbal relaxation exercise. 70 participants were assigned to either receptive live music (experimental group) or a prerecorded verbal relaxation exercise (control group). Self-ratings of relaxation were assessed before and after each intervention on visual analogue scales and the Relaxation Inventory (RI). The heart rate variability (HRV) was continuously recorded throughout the sessions. Statistical analysis focused on HRV parameters indicative of parasympathetic cardiovascular outflow. We found significant quadratic main effects for time on the mean R-R interval (heart rate), the high-frequency power of HRV (indicative of parasympathetic activity), and the self-ratings of relaxation in both groups. A significant group × time interaction was observed for the cognitive tension subscale of the RI. Participants in both groups showed psychophysiological changes indicative of greater relaxation over the course of the interventions. However, differences between groups were only marginal. Music might be effective in relieving stress and promoting relaxation by altering the autonomic nervous system function. Future studies need to explore the long-term outcomes of such interventions. © 2017 S. Karger GmbH, Freiburg.

  8. Analysis of time variable gravity data over Africa

    International Nuclear Information System (INIS)

    Barletta, Valentina R.; Aoudia, Abdelkarim

    2010-01-01

    phenomena, climate and even to human activities. The time analysis approach proposed in this work is used to discriminate signals from different possible geographical sources mostly in the low latitude regions, where hydrology is strongest, as for example Africa. By applying our approach to hydrological models we can show similarities and differences with GRACE data. The similarities lie almost all in the geographical signatures of the periodic component even if there are differences in amplitudes and phase. While differences in the non-periodic component can be explained with the presence of other phenomena, the differences in the periodic component can be explained with missing groundwater or other defects in the hydrological models. In this way we tested the adequacy of some hydrological models commonly combined with gravity data to retrieve solid Earth geophysical signatures. Thus we show that analysis of time variable gravity data over Africa strongly requires a correct and reliable hydrological model. (author)

  9. An improved and explicit surrogate variable analysis procedure by coefficient adjustment.

    Science.gov (United States)

    Lee, Seunggeun; Sun, Wei; Wright, Fred A; Zou, Fei

    2017-06-01

    Unobserved environmental, demographic, and technical factors can negatively affect the estimation and testing of the effects of primary variables. Surrogate variable analysis, proposed to tackle this problem, has been widely used in genomic studies. To estimate hidden factors that are correlated with the primary variables, surrogate variable analysis performs principal component analysis either on a subset of features or on all features, but weighting each differently. However, existing approaches may fail to identify hidden factors that are strongly correlated with the primary variables, and the extra step of feature selection and weight calculation makes the theoretical investigation of surrogate variable analysis challenging. In this paper, we propose an improved surrogate variable analysis using all measured features that has a natural connection with restricted least squares, which allows us to study its theoretical properties. Simulation studies and real data analysis show that the method is competitive to state-of-the-art methods.

  10. Analysis of cataclysmic variable GSC02197-00886 evolution

    Science.gov (United States)

    Mitrofanova, A. A.; Borisov, N. V.; Shimansky, V. V.

    2014-01-01

    We present the spectral analysis of the physical state and evolution of the WZSge-type cataclysmic variable GSC02197-00886. The spectra of the system, covering the total orbital period at the time of the outburst on May 8, 2010, at the late relaxation stage, and in the quiescent state, were obtained at the SAO RAS 6-m BTA telescope in 2010-2012. From the absorption and emission HI, He I, and Fe II lines, we have determined the radial velocities for all the nights of observations and constructed the maps of Doppler tomography for the quiescent state. It was found that during the outburst the spectra of the object were formed in an optically thick accretion disk with an effective temperature of T eff ≈ 45 000 K and in a hotter boundary layer. During the relaxation of the system, the accretion disk gradually became optically thinner in the continuum and in the emission lines. In the quiescent state (July 2012), the continuous spectrum was dominated by the radiation of the cooling white dwarf with T eff = 18 000 K. The emission lines are formed on the surface of the cool star by the X-ray irradiation of the 1RXSJ213807.1+261958 source. We propose a method for determining the parameters of the white dwarf, based on the numerical modeling of the system spectra in the quiescent state and their comparison with the observed spectra. It is shown that the effective temperature of white dwarf has decreased by Δ T eff = 6000 K during the relaxation from August 2010 to July 2012. We have obtained a set of parameters for GSC02197-00886 and shown their good agreement with the average parameters of the W Z Sge-type systems, presented in the literature.

  11. An Analysis of Social Class Classification Based on Linguistic Variables

    Institute of Scientific and Technical Information of China (English)

    QU Xia-sha

    2016-01-01

    Since language is an influential tool in social interaction, the relationship of speech and social factors, such as social class, gender, even age is worth studying. People employ different linguistic variables to imply their social class, status and iden-tity in the social interaction. Thus the linguistic variation involves vocabulary, sounds, grammatical constructions, dialects and so on. As a result, a classification of social class draws people’s attention. Linguistic variable in speech interactions indicate the social relationship between people. This paper attempts to illustrate three main linguistic variables which influence the social class, and further sociolinguistic studies need to be more concerned about.

  12. Prognostic value of left ventricular diastolic function and association with heart rate variability after a first acute myocardial infarction

    DEFF Research Database (Denmark)

    Poulsen, S H; Jensen, S E; Møller, J E

    2001-01-01

    deceleration time (chi(2) = 6.4, p 4, p ... and control subjects. Mitral deceleration time and isovolumetric relaxation time correlated weakly but significantly with all indices of HRV whereas ejection fraction correlated weakly with the long term HRV indices. The mean follow up time was 14.9 (8.7) months. Multivariate analysis showed that mitral...

  13. Heart rate variability at limiting stationarity: evidence of neuro-cardiac control mechanisms operating at ultra-low frequencies

    International Nuclear Information System (INIS)

    Fisher, A C; Groves, D; Eleuteri, A; Mesum, P; Patterson, D; Taggart, P

    2014-01-01

    This study considers the linkage of exogenously stimulated emotional stress with the neurogenic regulation of heart rate operating at very low frequencies. The objectives were three-fold: to consider the present evidence that such a linkage exists as a primary phenomenon; to compare the potential of a frequency-domain method and a time-domain method in revealing this phenomenon by characterizing heart rate variability (HRV) at frequencies of [0.0005…0.4] Hz and to design, implement and report a physiological experiment in which alternating periods of exposure to bland and high valence visual stimuli might reveal this phenomenon. A methodical challenge was to optimize the length of exposure to the stimulus such that subjects did not have time to habituate to stimuli, whilst acquiring sufficient data (heart beats) such that the ultra-low frequency (ULF) components of HRV could be described. With exposure times set to approximately 5 min, during which time the strength of the stimulus and the corresponding evoked response were considered stationary, the lowest HRV frequency component that could be characterized was 0.003 Hz. In trials with parametrically defined test data, the time-domain method based on the Ornstein–Uhlenbeck Gaussian process (OU-GP) was shown to be better than the frequency-domain method in describing the ULF components of the HRV. In an experimental cohort of 16 subjects, analysis using the OU-GP revealed evidence of cardiac regulatory mechanisms influenced by emotional valence operating in the bandwidth (ULF*) [0.002…0.01] Hz. (paper)

  14. Economic analysis of variables affecting the plantain ( Musa sp ...

    African Journals Online (AJOL)

    Journal of Agriculture, Forestry and the Social Sciences ... The study examined variables affecting plantain (Musa sp) mono cropping system of production by ... land fragmentation, wrong application of fertilizer, high cost of fertilizers, lack of ...

  15. HRV changes before and after radiofrequency ablation in patients with different origin of right ventricular outflow tract ventricular premature contraction

    Directory of Open Access Journals (Sweden)

    Yi-Ming Ma

    2017-04-01

    Full Text Available Objective: To observe the HRV changes before and after the radiofrequency current catheter ablationventricular premature beats originated from different site of right ventricular outflow tract. Methods: A total of 102 patients with frequent RVOT-VPC admitted to our hospital were accepted radiofrequency current catheter ablation (RF. According to the origin of RVOT-VPC, it was divided into 2 groups, one is from ventricular septum, and the other one is from free wall, and in each group, male and female are observed separately. Results: (1 HRV before RF ablation: 1 rMSSD in the female patients with RVOT-VPC from free wall was significantly lower than those from septum; 2 frequency domain index (W, LF were higher than normal range, and in male patients, LF/HF1. (2 HRV after RF ablation: 1 Significant changes were found in female patients with RVOT-VPC from septum, rMSSD, PNN50, HF and LF decreased; 2 In female patients with RVOT-VPC from free wall, rMSSD decreased; 3 In male patients, there were no significant HRV changes found before and after RF ablation. (3 Heart rate changes: 1 In female patients with RVOT-VPC from septum, heart rate decreased significantly [(76.47±9.47 bpm vs (69.29±14.59 bpm]. 2 No significant changes were found in male patients. Conclusion: In patients with RVOT-PVC sympathetic and vagus excitability increased, and after catheter ablation, in female patients with RVOT-PVC originated from septum, the HRV index relating to sympathetic and vagus excitability significantly decreased.

  16. Impact analysis of flow variability in sizing kanbans

    Directory of Open Access Journals (Sweden)

    Isaac Pergher

    2014-02-01

    Full Text Available The aim of this paper is to analyze the effects of variability flow, advocated by Factory Physics, in sizing Kanban production systems. The variability of flow presupposes that the variability of activities performed by a process is dissipated throughout the productive flow system, causing variations in the lead time, the work-in-process levels and the equipment availability, among others. To conduct the research, we created a didactic model of discrete event computer simulation. The proposed model aims to present the possible impacts caused by the variability flow in a production system regarding the sizing of the number of Kanbans cards, by using the results supplied by two different investigated scenarios. The main results of the research allow concluding that, by comparing the two scenarios developed in the model, the presence of variability in the production system caused an average increase of 32% in the number of Kanban cards (p=0,000. This implies that, in real productive systems, the study of Kanban sizing should consider the variability of individual operations, a fact often relegated as an assumption in the formulation from classical literature on the definition of the number of Kanbans, thus providing opportunities for the development of future research.

  17. Heart Rate Variability Interventions for Concussion and Rehabilitation

    Directory of Open Access Journals (Sweden)

    Robert Lake Conder

    2014-08-01

    Full Text Available The study of Heart Rate Variability (HRV has emerged as an essential component of cardiovascular health, as well as a physiological mechanism by which one can increase the interactive communication between the cardiac and the neurocognitive systems (i.e., the body and the brain. It is well-established that lack of heart rate variability implies cardiopathology, morbidity, reduced quality-of-life, and precipitous mortality. On the positive, optimal heart rate variability has been associated with good cardiovascular health, autonomic nervous system (ANS control, emotional regulation, and enhanced neurocognitive processing. In addition to health benefits, optimal HRV has been shown to improve neurocognitive performance by enhancing focus, visual acuity and readiness, and by promoting emotional regulation needed for peak performance. In concussed athletes and soldiers, concussions not only alter brain connectivity, but also alter cardiac functioning and impair cardiovascular performance upon exertion. Altered sympathetic and parasympathetic balance in the ANS has been postulated as a critical factor in refractory Post Concussive Syndrome (PCS. This article will review both the pathological aspects of reduced heart rate variability on athletic performance, as well as the cardiovascular and cerebrovascular components of concussion and PCS. Additionally, this article will review interventions with HRV biofeedback (HRV BFB training as a promising and underutilized treatment for sports and military-related concussion. Finally, this article will review research and promising case studies pertaining to use of HRV BFB for enhancement of cognition and performance, with applicability to concussion rehabilitation.

  18. The 2 Hz and 15 Hz electroacupuncture induced reverse effect on autonomic function in healthy adult using a heart rate variability analysis

    Directory of Open Access Journals (Sweden)

    Bor-An Jia

    2011-10-01

    Full Text Available The purpose of the present study was to investigate effect of electro-acupuncture (EA at different frequencies on autonomic function. Twenty healthy adult volunteers were studied, and underwent 4 sessions of EA (sham, 2 Hz, 15 Hz, and 50 Hz. Sham, 2 Hz, 15 Hz, and 50 Hz EA was applied to the bilateral Leg Three Li (足三里 zú sān lǐ, ST-36 and Upper Great Hollow (上巨虛 shàng jù xū, ST-37 acupoints. The intensity of electrical stimulation was adjusted to obtain visible twitching of the anterior tibial muscle about 2.0-2.5 mA except sham without electrical stimulation. The components of heart rate variability (HRV and blood pressure were measured before EA (BLP, EA (EAP, and post-EA periods (PEP. The results indicated that the natural logarithmic high frequency power (lnHF of HRV was greater during PEP than during the BLP in the 2 Hz EA sessions. The natural logarithmic low frequency power (lnLF of HRV was greater during the PEP than during the BLP in 15 Hz EA sessions, suggesting that 2 Hz EA apply to Leg Three Li (足三里 zú sān lǐ, ST-36 and Upper Great Hollow (上巨虛 shàng jù xū, ST-37 acupoints increased vagal activity, whereas 15 Hz EA increased sympathetic activity.

  19. Variability search in M 31 using principal component analysis and the Hubble Source Catalogue

    Science.gov (United States)

    Moretti, M. I.; Hatzidimitriou, D.; Karampelas, A.; Sokolovsky, K. V.; Bonanos, A. Z.; Gavras, P.; Yang, M.

    2018-06-01

    Principal component analysis (PCA) is being extensively used in Astronomy but not yet exhaustively exploited for variability search. The aim of this work is to investigate the effectiveness of using the PCA as a method to search for variable stars in large photometric data sets. We apply PCA to variability indices computed for light curves of 18 152 stars in three fields in M 31 extracted from the Hubble Source Catalogue. The projection of the data into the principal components is used as a stellar variability detection and classification tool, capable of distinguishing between RR Lyrae stars, long-period variables (LPVs) and non-variables. This projection recovered more than 90 per cent of the known variables and revealed 38 previously unknown variable stars (about 30 per cent more), all LPVs except for one object of uncertain variability type. We conclude that this methodology can indeed successfully identify candidate variable stars.

  20. Experimental Analysis of Linear Induction Motor under Variable Voltage Variable Frequency (VVVF Power Supply

    Directory of Open Access Journals (Sweden)

    Prasenjit D. Wakode

    2016-07-01

    Full Text Available This paper presents the complete analysis of Linear Induction Motor (LIM under VVVF. The complete variation of LIM air gap flux under ‘blocked Linor’ condition and starting force is analyzed and presented when LIM is given VVVF supply. The analysis of this data is important in further understanding of the equivalent circuit parameters of LIM and to study the magnetic circuit of LIM. The variation of these parameters is important to know the LIM response at different frequencies. The simulation and application of different control strategies such as vector control thus becomes quite easy to apply and understand motor’s response under such strategy of control.

  1. Clinical Trials With Large Numbers of Variables: Important Advantages of Canonical Analysis.

    Science.gov (United States)

    Cleophas, Ton J

    2016-01-01

    Canonical analysis assesses the combined effects of a set of predictor variables on a set of outcome variables, but it is little used in clinical trials despite the omnipresence of multiple variables. The aim of this study was to assess the performance of canonical analysis as compared with traditional multivariate methods using multivariate analysis of covariance (MANCOVA). As an example, a simulated data file with 12 gene expression levels and 4 drug efficacy scores was used. The correlation coefficient between the 12 predictor and 4 outcome variables was 0.87 (P = 0.0001) meaning that 76% of the variability in the outcome variables was explained by the 12 covariates. Repeated testing after the removal of 5 unimportant predictor and 1 outcome variable produced virtually the same overall result. The MANCOVA identified identical unimportant variables, but it was unable to provide overall statistics. (1) Canonical analysis is remarkable, because it can handle many more variables than traditional multivariate methods such as MANCOVA can. (2) At the same time, it accounts for the relative importance of the separate variables, their interactions and differences in units. (3) Canonical analysis provides overall statistics of the effects of sets of variables, whereas traditional multivariate methods only provide the statistics of the separate variables. (4) Unlike other methods for combining the effects of multiple variables such as factor analysis/partial least squares, canonical analysis is scientifically entirely rigorous. (5) Limitations include that it is less flexible than factor analysis/partial least squares, because only 2 sets of variables are used and because multiple solutions instead of one is offered. We do hope that this article will stimulate clinical investigators to start using this remarkable method.

  2. CADDIS Volume 4. Data Analysis: Advanced Analyses - Controlling for Natural Variability

    Science.gov (United States)

    Methods for controlling natural variability, predicting environmental conditions from biological observations method, biological trait data, species sensitivity distributions, propensity scores, Advanced Analyses of Data Analysis references.

  3. CADDIS Volume 4. Data Analysis: Advanced Analyses - Controlling for Natural Variability: SSD Plot Diagrams

    Science.gov (United States)

    Methods for controlling natural variability, predicting environmental conditions from biological observations method, biological trait data, species sensitivity distributions, propensity scores, Advanced Analyses of Data Analysis references.

  4. Variability, correlation and path coefficient analysis of seedling traits ...

    African Journals Online (AJOL)

    use

    2011-12-12

    Dec 12, 2011 ... Indirect selection is a useful means for improving yield in cotton crop. The objective of the present study was to determine the genetic variability, broad sense heritability, genetic advance and correlation among the six seedling traits and their direct and indirect effects on cotton yield by using path coefficient ...

  5. Genetic variability, correlation and path analysis in sponge gourd ...

    African Journals Online (AJOL)

    Windows-7

    2013-02-06

    Feb 6, 2013 ... fiber used in industries for filter and cleaning the motor car, glass wares, kitchen ... The fibrous vascular system inside the fruit after been separated from the skin, ... was carried out to gather information on genetic variability ...

  6. Analysis of North Sea Offshore Wind Power Variability

    NARCIS (Netherlands)

    Buatois, A.; Gibescu, M.; Rawn, B.G.; Van der Meijden, M.A.M.M.

    2014-01-01

    This paper evaluates, for a 2030 scenario, the impact on onshore power systems in terms of the variability of the power generated by 81 GW of offshore wind farms installed in the North Sea. Meso-scale reanalysis data are used as input for computing the hourly power production for offshore wind

  7. An Analysis of the Interactive Effects of Demographic Variables on ...

    African Journals Online (AJOL)

    This study investigated the influence of two environmental variables (social density and overcrowding) on students' learning and academic performance in selected Nigerian Universities. 150 undergraduates drawn from two universities within the middle belt region of Nigeria made up of 90 males and 60 females responded ...

  8. Predicting travel time variability for cost-benefit analysis

    NARCIS (Netherlands)

    Peer, S.; Koopmans, C.; Verhoef, E.T.

    2010-01-01

    Unreliable travel times cause substantial costs to travelers. Nevertheless, they are not taken into account in many cost-benefit-analyses (CBA), or only in very rough ways. This paper aims at providing simple rules on how variability can be predicted, based on travel time data from Dutch highways.

  9. Perceptual mapping of mulitiple variable batteries by plotting supplementary variables in correspondence analysis of rating data

    NARCIS (Netherlands)

    A. Torres (Antoni); M. van de Velden (Michel)

    2005-01-01

    textabstractIn this paper we consider the use of correspondence analysis (CA) of rating data. CA of rating data allows a joint representation of the rated items (e.g. attributes or products) and individuals. However, as the number of individuals increases, the interpretation of the CA map becomes

  10. Yoga and heart rate variability: A comprehensive review of the literature

    Directory of Open Access Journals (Sweden)

    Anupama Tyagi

    2016-01-01

    Full Text Available Heart rate variability (HRV has been used as a proxy for health and fitness and indicator of autonomic regulation and therefore, appears well placed to assess the changes occurring with mind.-body practices that facilitate autonomic balance. While many studies suggest that yoga influences HRV, such studies have not been systematically reviewed. We aimed to systematically review all published papers that report on yoga practices and HRV. A comprehensive search of multiple databases was conducted and all studies that reported a measure of HRV associated with any yoga practice were included. Studies were categorized by the study design and type of yoga practice. A total of 59 studies were reviewed involving a total of 2358 participants. Most studies were performed in India on relatively small numbers of healthy male yoga practitioners during a single laboratory session. Of the reviewed studies, 15 were randomized controlled trials with 6 having a Jadad score of 3. The reviewed studies suggest that yoga can affect cardiac autonomic regulation with increased HRV and vagal dominance during yoga practices. Regular yoga practitioners were also found to have increased vagal tone at rest compared to non-yoga practitioners. It is premature to draw any firm conclusions about yoga and HRV as most studies were of poor quality, with small sample sizes and insufficient reporting of study design and statistical methods. Rigorous studies with detailed reporting of yoga practices and any corresponding changes in respiration are required to determine the effect of yoga on HRV.

  11. Pattern of brain injury and depressed heart rate variability in newborns with hypoxic ischemic encephalopathy.

    Science.gov (United States)

    Metzler, Marina; Govindan, Rathinaswamy; Al-Shargabi, Tareq; Vezina, Gilbert; Andescavage, Nickie; Wang, Yunfei; du Plessis, Adre; Massaro, An N

    2017-09-01

    BackgroundDecreased heart rate variability (HRV) is a measure of autonomic dysfunction and brain injury in newborns with hypoxic ischemic encephalopathy (HIE). This study aimed to characterize the relationship between HRV and brain injury pattern using magnetic resonance imaging (MRI) in newborns with HIE undergoing therapeutic hypothermia.MethodsHRV metrics were quantified in the time domain (α S , α L , and root mean square at short (RMS S ) and long (RMS L ) timescales) and frequency domain (relative low-(LF) and high-frequency (HF) power) over 24-27 h of life. The brain injury pattern shown by MRI was classified as no injury, pure cortical/white matter injury, mixed watershed/mild basal ganglia injury, predominant basal ganglia or global injury, and death. HRV metrics were compared across brain injury pattern groups using a random-effects mixed model.ResultsData from 74 infants were analyzed. Brain injury pattern was significantly associated with the degree of HRV suppression. Specifically, negative associations were observed between the pattern of brain injury and RMS S (estimate -0.224, SE 0.082, P=0.006), RMS L (estimate -0.189, SE 0.082, P=0.021), and LF power (estimate -0.044, SE 0.016, P=0.006).ConclusionDegree of HRV depression is related to the pattern of brain injury. HRV monitoring may provide insights into the pattern of brain injury at the bedside.

  12. Can illness perceptions predict lower heart rate variability following acute myocardial infarction?

    Directory of Open Access Journals (Sweden)

    Mary Princip

    2016-11-01

    Full Text Available Objective: Decreased heart rate variability (HRV has been reported to be a predictor of mortality after myocardial infarction (MI. Patients’ beliefs and perceptions concerning their illness may play a role in decreased HRV. This study investigated if illness perceptions predict HRV at three months following acute MI. Methods: 130 patients referred to a tertiary cardiology centre, were examined within 48 hours and three months following acute MI. At admission, patients’ cognitive representations of their MI were assessed using the German version of the self-rated Brief Illness Perception Questionnaire (Brief IPQ. At admission and after three months (follow-up, frequency and time domain measures of HRV were obtained from 5-min electrocardiogram (ECG recordings during stable supine resting. Results: Linear hierarchical regression showed that the Brief IPQ dimensions timeline (β coefficient = -0.29; p = .044, personal control (β = 0.47; p = .008 and illness understanding (β = 0.43; p = .014 were significant predictors of HRV, adjusted for age, gender, baseline HRV, diabetes, beta-blockers, left ventricular ejection fraction (LVEF, attendance of cardiac rehabilitation, and depressive symptoms. Conclusions: As patients’ negative perceptions of their illness are associated with lower HRV following acute MI, a brief illness perception questionnaire may help to identify patients who might benefit from a specific illness perceptions intervention.

  13. Using variable transformations to perform common event analysis

    International Nuclear Information System (INIS)

    Worrell, R.B.

    1977-01-01

    Any analytical method for studying the effect of common events on the behavior of a system is considered as being a form of common event analysis. The particular common events that are involved often represent quite different phenomena, and this has led to the development of different kinds of common event analysis. For example, common mode failure analysis, common cause analysis, critical location analysis, etc., are all different kinds of common event analysis for which the common events involved represent different phenomena. However, the problem that must be solved for each of these different kinds of common event analysis is essentially the same: Determine the effect of common events on the behavior of a system. Thus, a technique that is useful in achieving one kind of common event analysis is often useful in achieving other kinds of common event analysis

  14. Bias and Bias Correction in Multi-Site Instrumental Variables Analysis of Heterogeneous Mediator Effects

    Science.gov (United States)

    Reardon, Sean F.; Unlu, Faith; Zhu, Pei; Bloom, Howard

    2013-01-01

    We explore the use of instrumental variables (IV) analysis with a multi-site randomized trial to estimate the effect of a mediating variable on an outcome in cases where it can be assumed that the observed mediator is the only mechanism linking treatment assignment to outcomes, as assumption known in the instrumental variables literature as the…

  15. Influence of mercury exposure on blood pressure, resting heart rate and heart rate variability in French Polynesians: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Valera Beatriz

    2011-11-01

    Full Text Available Abstract Background Populations which diet is rich in seafood are highly exposed to contaminants such as mercury, which could affect cardiovascular risk factors Objective To assess the associations between mercury and blood pressure (BP, resting heart rate (HR and HR variability (HRV among French Polynesians Methods Data were collected among 180 adults (≥ 18 years and 101 teenagers (12-17 years. HRV was measured using a two-hour ambulatory electrocardiogram (Holter and BP was measured using a standardized protocol. The association between mercury and HRV and BP parameters was studied using analysis of variance (ANOVA and analysis of covariance (ANCOVA Results Among teenagers, the high frequency (HF decreased between the 2nd and 3rd tertile (380 vs. 204 ms2, p = 0.03 and a similar pattern was observed for the square root of the mean squared differences of successive R-R intervals (rMSSD (43 vs. 30 ms, p = 0.005 after adjusting for confounders. In addition, the ratio low/high frequency (LF/HF increased between the 2nd and 3rd tertile (2.3 vs. 3.0, p = 0.04. Among adults, the standard deviation of R-R intervals (SDNN tended to decrease between the 1st and 2nd tertile (84 vs. 75 ms, p = 0.069 after adjusting for confounders. Furthermore, diastolic BP tended to increase between the 2nd and 3rd tertile (86 vs. 91 mm Hg, p = 0.09. No significant difference was observed in resting HR or pulse pressure (PP Conclusions Mercury was associated with decreased HRV among French Polynesian teenagers while no significant association was observed with resting HR, BP, or PP among teenagers or adults

  16. Daily heart rate variability of Paralympic gold medallist swimmers: A 17-week investigation

    OpenAIRE

    Edmonds, Rohan; Leicht, Anthony; McKean, Mark; Burkett, Brendan

    2015-01-01

    Objectives: Heart rate variability (HRV) can be a simple, non-invasive method of gauging cardiac autonomic nervous system fluctuations across periodised training workloads and taper in elite athlete populations. The purpose of these three case studies was to examine daily cardiac autonomic variations in Paralympic athletes leading in to the Paralympic games. Methods: Three Paralympic gold medallist swimmers were monitored daily for their resting HRV over a 17-week monitoring period leading...

  17. Heart Rate Variability as a Measure of Airport Ramp-Traffic Controllers Workload

    Science.gov (United States)

    Hayashi, Miwa; Dulchinos, Victoria Lee

    2016-01-01

    Heart Rate Variability (HRV) has been reported to reflect the person's cognitive and emotional stress levels, and may offer an objective measure of human-operator's workload levels, which are recorded continuously and unobtrusively to the task performance. The present paper compares the HRV data collected during a human-in-the-loop simulation of airport ramp-traffic control operations with the controller participants' own verbal self-reporting ratings of their workload.

  18. Variable structure control of complex systems analysis and design

    CERN Document Server

    Yan, Xing-Gang; Edwards, Christopher

    2017-01-01

    This book systematizes recent research work on variable-structure control. It is self-contained, presenting necessary mathematical preliminaries so that the theoretical developments can be easily understood by a broad readership. The text begins with an introduction to the fundamental ideas of variable-structure control pertinent to their application in complex nonlinear systems. In the core of the book, the authors lay out an approach, suitable for a large class of systems, that deals with system uncertainties with nonlinear bounds. Its treatment of complex systems in which limited measurement information is available makes the results developed convenient to implement. Various case-study applications are described, from aerospace, through power systems to river pollution control with supporting simulations to aid the transition from mathematical theory to engineering practicalities. The book addresses systems with nonlinearities, time delays and interconnections and considers issues such as stabilization, o...

  19. Load flow analysis for variable speed offshore wind farms

    DEFF Research Database (Denmark)

    Chen, Zhe; Zhao, Menghua; Blaabjerg, Frede

    2009-01-01

    factors such as the different wind farm configurations, the control of wind turbines and the power losses of pulse width modulation converters are considered. The DC/DC converter model is proposed and integrated into load flow algorithm by modifying the Jacobian matrix. Two iterative methods are proposed...... and integrated into the load flow algorithm: one takes into account the control strategy of converters and the other considers the power losses of converters. In addition, different types of variable speed wind turbine systems with different control methods are investigated. Finally, the method is demonstrated......A serial AC-DC integrated load flow algorithm for variable speed offshore wind farms is proposed. It divides the electrical system of a wind farm into several local networks, and different load flow methods are used for these local networks sequentially. This method is fast, more accurate, and many...

  20. Attribute Analysis of Aridity Variability in North Xinjiang, China

    Directory of Open Access Journals (Sweden)

    Yanfeng Wu

    2016-01-01

    Full Text Available Identifying the dominant meteorological factors affecting aridity variability can improve our understanding of climate change and its future trend in arid and semiarid regions. This study investigated the spatiotemporal aridity variability in North Xinjiang, China, from 1961 to 2013, based on the UNESCO aridity index (precipitation/potential evapotranspiration, and analyzed its association with meteorological factors. The results suggest that North Xinjiang is becoming more humid with an increasing trend in aridity index. Precipitation, temperature, and relative humidity have positive correlation with aridity, and evapotranspiration, sunshine hours, and wind speed have negative correlation with aridity. Wind speed and sunshine hours have a higher sensitivity and more contribution to aridity. This study provides an understanding of the effect of recent climate change on drought in northwest China.

  1. Analysis models for variables associated with breastfeeding duration

    Directory of Open Access Journals (Sweden)

    Edson Theodoro dos S. Neto

    2013-09-01

    Full Text Available OBJECTIVE To analyze the factors associated with breastfeeding duration by two statistical models. METHODS A population-based cohort study was conducted with 86 mothers and newborns from two areas primary covered by the National Health System, with high rates of infant mortality in Vitória, Espírito Santo, Brazil. During 30 months, 67 (78% children and mothers were visited seven times at home by trained interviewers, who filled out survey forms. Data on food and sucking habits, socioeconomic and maternal characteristics were collected. Variables were analyzed by Cox regression models, considering duration of breastfeeding as the dependent variable, and logistic regression (dependent variables, was the presence of a breastfeeding child in different post-natal ages. RESULTS In the logistic regression model, the pacifier sucking (adjusted Odds Ratio: 3.4; 95%CI 1.2-9.55 and bottle feeding (adjusted Odds Ratio: 4.4; 95%CI 1.6-12.1 increased the chance of weaning a child before one year of age. Variables associated to breastfeeding duration in the Cox regression model were: pacifier sucking (adjusted Hazard Ratio 2.0; 95%CI 1.2-3.3 and bottle feeding (adjusted Hazard Ratio 2.0; 95%CI 1.2-3.5. However, protective factors (maternal age and family income differed between both models. CONCLUSIONS Risk and protective factors associated with cessation of breastfeeding may be analyzed by different models of statistical regression. Cox Regression Models are adequate to analyze such factors in longitudinal studies.

  2. Analysis on electronic control unit of continuously variable transmission

    Science.gov (United States)

    Cao, Shuanggui

    Continuously variable transmission system can ensure that the engine work along the line of best fuel economy, improve fuel economy, save fuel and reduce harmful gas emissions. At the same time, continuously variable transmission allows the vehicle speed is more smooth and improves the ride comfort. Although the CVT technology has made great development, but there are many shortcomings in the CVT. The CVT system of ordinary vehicles now is still low efficiency, poor starting performance, low transmission power, and is not ideal controlling, high cost and other issues. Therefore, many scholars began to study some new type of continuously variable transmission. The transmission system with electronic systems control can achieve automatic control of power transmission, give full play to the characteristics of the engine to achieve optimal control of powertrain, so the vehicle is always traveling around the best condition. Electronic control unit is composed of the core processor, input and output circuit module and other auxiliary circuit module. Input module collects and process many signals sent by sensor and , such as throttle angle, brake signals, engine speed signal, speed signal of input and output shaft of transmission, manual shift signals, mode selection signals, gear position signal and the speed ratio signal, so as to provide its corresponding processing for the controller core.

  3. Ventilatory thresholds determined from HRV: comparison of 2 methods in obese adolescents.

    Science.gov (United States)

    Quinart, S; Mourot, L; Nègre, V; Simon-Rigaud, M-L; Nicolet-Guénat, M; Bertrand, A-M; Meneveau, N; Mougin, F

    2014-03-01

    The development of personalised training programmes is crucial in the management of obesity. We evaluated the ability of 2 heart rate variability analyses to determine ventilatory thresholds (VT) in obese adolescents. 20 adolescents (mean age 14.3±1.6 years and body mass index z-score 4.2±0.1) performed an incremental test to exhaustion before and after a 9-month multidisciplinary management programme. The first (VT1) and second (VT2) ventilatory thresholds were identified by the reference method (gas exchanges). We recorded RR intervals to estimate VT1 and VT2 from heart rate variability using time-domain analysis and time-varying spectral-domain analysis. The coefficient correlations between thresholds were higher with spectral-domain analysis compared to time-domain analysis: Heart rate at VT1: r=0.91 vs. =0.66 and VT2: r=0.91 vs. =0.66; power at VT1: r=0.91 vs. =0.74 and VT2: r=0.93 vs. =0.78; spectral-domain vs. time-domain analysis respectively). No systematic bias in heart rate at VT1 and VT2 with standard deviations <6 bpm were found, confirming that spectral-domain analysis could replace the reference method for the detection of ventilatory thresholds. Furthermore, this technique is sensitive to rehabilitation and re-training, which underlines its utility in clinical practice. This inexpensive and non-invasive tool is promising for prescribing physical activity programs in obese adolescents. © Georg Thieme Verlag KG Stuttgart · New York.

  4. An Overview of Heart Rate Variability Metrics and Norms

    Directory of Open Access Journals (Sweden)

    Fred Shaffer

    2017-09-01

    Full Text Available Healthy biological systems exhibit complex patterns of variability that can be described by mathematical chaos. Heart rate variability (HRV consists of changes in the time intervals between consecutive heartbeats called interbeat intervals (IBIs. A healthy heart is not a metronome. The oscillations of a healthy heart are complex and constantly changing, which allow the cardiovascular system to rapidly adjust to sudden physical and psychological challenges to homeostasis. This article briefly reviews current perspectives on the mechanisms that generate 24 h, short-term (~5 min, and ultra-short-term (<5 min HRV, the importance of HRV, and its implications for health and performance. The authors provide an overview of widely-used HRV time-domain, frequency-domain, and non-linear metrics. Time-domain indices quantify the amount of HRV observed during monitoring periods that may range from ~2 min to 24 h. Frequency-domain values calculate the absolute or relative amount of signal energy within component bands. Non-linear measurements quantify the unpredictability and complexity of a series of IBIs. The authors survey published normative values for clinical, healthy, and optimal performance populations. They stress the importance of measurement context, including recording period length, subject age, and sex, on baseline HRV values. They caution that 24 h, short-term, and ultra-short-term normative values are not interchangeable. They encourage professionals to supplement published norms with findings from their own specialized populations. Finally, the authors provide an overview of HRV assessment strategies for clinical and optimal performance interventions.

  5. Activity Monitoring and Heart Rate Variability as Indicators of Fall Risk: Proof-of-Concept for Application of Wearable Sensors in the Acute Care Setting.

    Science.gov (United States)

    Razjouyan, Javad; Grewal, Gurtej Singh; Rishel, Cindy; Parthasarathy, Sairam; Mohler, Jane; Najafi, Bijan

    2017-07-01

    Growing concern for falls in acute care settings could be addressed with objective evaluation of fall risk. The current proof-of-concept study evaluated the feasibility of using a chest-worn sensor during hospitalization to determine fall risk. Physical activity and heart rate variability (HRV) of 31 volunteers admitted to a 29-bed adult inpatient unit were recorded using a single chest-worn sensor. Sensor data during the first 24-hour recording were analyzed. Participants were stratified using the Hendrich II fall risk assessment into high and low fall risk groups. Univariate analysis revealed age, daytime activity, nighttime side lying posture, and HRV were significantly different between groups. Results suggest feasibility of wearable technology to consciously monitor physical activity, sleep postures, and HRV as potential markers of fall risk in the acute care setting. Further study is warranted to confirm the results and examine the efficacy of the proposed wearable technology to manage falls in hospitals. [Journal of Gerontological Nursing, 43(7), 53-62.]. Copyright 2017, SLACK Incorporated.

  6. Microsatellite marker analysis of the genetic variability in Hanoverian Hounds.

    Science.gov (United States)

    Lüpke, L; Distl, O

    2005-04-01

    Genetic variability of the dog breed Hanoverian Hound was analysed using a set of 16 microsatellites. The sample of 92 dogs was representative for the total current population [n=334, inbreeding coefficient 9.2%, relationship coefficient 11.2%] with respect to the level and distribution of the inbreeding and relationship coefficients. All microsatellites used were in Hardy-Weinberg equilibrium. The average number of alleles was 6.4. The average observed heterozygosity (H(O)) was slightly higher than the expected heterozygosity (H(E)). Dinucleotide microsatellites exhibited lower polymorphism information content (PIC) than tetranucleotide microsatellites (0.52 versus 0.66). The average PIC was 0.61. The individual inbreeding coefficient was negatively related to the average H(O) of all microsatellites, whereas the proportion of genes from introducing of Hanoverian Hounds from abroad showed no relationships to H(O). We found that the genetic variability in the Hanoverian Hounds analysed here was unexpectedly higher than that previously published for dog breeds of similar population size. Even in dog breeds of larger population size heterogyzosity was seldom higher than that observed here. The rather high genetic variability as quantified by polymorphic microsatellites in Hanoverian Hounds may be due to a large genetic variation in the founder animals of this breed and to the fact that this genetic diversity could be maintained despite genetic bottlenecks experienced by this breed in the 1920s and 1950s and despite the presence of high inbreeding and relationship coefficients for more than 50 years.

  7. Internet Gamblers Differ on Social Variables: A Latent Class Analysis.

    Science.gov (United States)

    Khazaal, Yasser; Chatton, Anne; Achab, Sophia; Monney, Gregoire; Thorens, Gabriel; Dufour, Magali; Zullino, Daniele; Rothen, Stephane

    2017-09-01

    Online gambling has gained popularity in the last decade, leading to an important shift in how consumers engage in gambling and in the factors related to problem gambling and prevention. Indebtedness and loneliness have previously been associated with problem gambling. The current study aimed to characterize online gamblers in relation to indebtedness, loneliness, and several in-game social behaviors. The data set was obtained from 584 Internet gamblers recruited online through gambling websites and forums. Of these gamblers, 372 participants completed all study assessments and were included in the analyses. Questionnaires included those on sociodemographics and social variables (indebtedness, loneliness, in-game social behaviors), as well as the Gambling Motives Questionnaire, Gambling Related Cognitions Scale, Internet Addiction Test, Problem Gambling Severity Index, Short Depression-Happiness Scale, and UPPS-P Impulsive Behavior Scale. Social variables were explored with a latent class model. The clusters obtained were compared for psychological measures and three clusters were found: lonely indebted gamblers (cluster 1: 6.5%), not lonely not indebted gamblers (cluster 2: 75.4%), and not lonely indebted gamblers (cluster 3: 18%). Participants in clusters 1 and 3 (particularly in cluster 1) were at higher risk of problem gambling than were those in cluster 2. The three groups differed on most assessed variables, including the Problem Gambling Severity Index, the Short Depression-Happiness Scale, and the UPPS-P subscales (except the sensation seeking subscore). Results highlight significant between-group differences, suggesting that Internet gamblers are not a homogeneous group. Specific intervention strategies could be implemented for groups at risk.

  8. Homogeneity analysis with k sets of variables: An alternating least squares method with optimal scaling features

    NARCIS (Netherlands)

    van der Burg, Eeke; de Leeuw, Jan; Verdegaal, Renée

    1988-01-01

    Homogeneity analysis, or multiple correspondence analysis, is usually applied tok separate variables. In this paper we apply it to sets of variables by using sums within sets. The resulting technique is called OVERALS. It uses the notion of optimal scaling, with transformations that can be multiple

  9. Transient analysis of a variable speed rotary compressor

    International Nuclear Information System (INIS)

    Park, Youn Cheol

    2010-01-01

    A transient simulation model of a rolling piston type rotary compressor is developed to predict the dynamic characteristics of a variable speed compressor. The model is based on the principles of conservation, real gas equations, kinematics of the crankshaft and roller, mass flow loss due to leakage, and heat transfer. For the computer simulation of the compressor, the experimental data were obtained from motor performance tests at various operating frequencies. Using the developed model, re-expansion loss, friction loss, mass flow loss and heat transfer loss is estimated as a function of the crankshaft speed in a variable speed compressor. In addition, the compressor efficiency and energy losses are predicted at various compressor-operating frequencies. Since the transient state of the compressor strongly depends on the system, the developed model is combined with a transient system simulation program to get transient variations of the compression process in the system. Motor efficiency, mechanical efficiency, motor torque and volumetric efficiency are calculated with respect to variation of the driving frequency in a rotary compressor.

  10. Effect of laughter on mood and heart rate variability in patients awaiting organ transplantation: a pilot study.

    Science.gov (United States)

    Dolgoff-Kaspar, Rima; Baldwin, Ann; Johnson, Scott; Edling, Nancy; Sethi, Gulshan K

    2012-01-01

    Research shows that laughter has myriad health benefits, yet the medical community has not implemented it formally as a treatment. Patients awaiting organ transplantation have significant physical disabilities and are at risk for psychological distress. Attenuated heart rate variability (HRV) is a risk factor for a negative long-term outcome in some patients. The study intended to evaluate the clinical utility of laughter yoga in improving psychological and physiological measures in outpatients awaiting organ transplantation. Positive results would indicate promising areas to pursue in a follow-up study. Six participants met for 10 sessions over 4 weeks. The research team measured each participant's heart rate, HRV, blood pressure (BP), and immediate mood before and after the laughter and control interventions. The team assessed participants' longer-term mood (anxiety and depression) at the study's initiation, after a no-treatment control week, and at the end of the study. The study occurred at the Department of Surgery and Medicine at the University of Arizona Health Sciences Center, Tucson. Participants were patients awaiting transplants (three heart and three lung), two women and four men (ages 51-69 y). Participants had received no major surgery in the 3 months prior to the intervention, did not have a hernia or uncontrolled hypertension, and did not fall into the New York Heart Association function class 4. The 20-minute laughter intervention involved breathing and stretching exercises, simulated laughter (ie, unconditional laughter that is not contingent on the environment), chanting, clapping, and a meditation. The 20-minute control intervention involved the study's personnel discussing health and study-related topics with the participants. The research team measured BP, heart rate, and HRV and administered the Profile of Mood States, Beck Anxiety Inventory, and Beck Depression Inventory-II to evaluate immediate and longer-term mood. The team had planned

  11. Effect of laughter yoga on mood and heart rate variability in patients awaiting organ transplantation: a pilot study.

    Science.gov (United States)

    Dolgoff-Kaspar, Rima; Baldwin, Ann; Johnson, M Scott; Edling, Nancy; Sethi, Gulshan K

    2012-01-01

    Research shows that laughter has myriad health benefits, yet the medical community has not implemented it formally as a treatment. Patients awaiting organ transplantation have significant physical disabilities and are at risk for psychological distress. Attenuated heart rate variability (HRV) is a risk factor for a negative long-term outcome in some patients. The study intended to evaluate the clinical utility of laughter yoga in improving psychological and physiological measures in outpatients awaiting organ transplantation. Positive results would indicate promising areas to pursue in a follow-up study. Six participants met for 10 sessions over 4 weeks. The research team measured each participant's heart rate, HRV, blood pressure (BP), and immediate mood before and after the laughter and control interventions. The team assessed participants' longer-term mood (anxiety and depression) at the study's initiation, after a no-treatment control week, and at the end of the study. The study occurred at the Department of Surgery and Medicine at the University of Arizona Health Sciences Center, Tucson. Participants were patients awaiting transplants (three heart and three lung), two women and four men (ages 51-69 y). Participants had received no major surgery in the 3 months prior to the intervention, did not have a hernia or uncontrolled hypertension, and did not fall into the New York Heart Association function class 4. The 20-minute laughter intervention involved breathing and stretching exercises, simulated laughter (ie, unconditional laughter that is not contingent on the environment), chanting, clapping, and a meditation. The 20-minute control intervention involved the study's personnel discussing health and study-related topics with the participants. The research team measured BP, heart rate, and HRV and administered the Profile of Mood States, Beck Anxiety Inventory, and Beck Depression Inventory-II to evaluate immediate and longer-term mood. The team had planned

  12. A comparative analysis of alternative approaches for quantifying nonlinear dynamics in cardiovascular system.

    Science.gov (United States)

    Chen, Yun; Yang, Hui

    2013-01-01

    Heart rate variability (HRV) analysis has emerged as an important research topic to evaluate autonomic cardiac function. However, traditional time and frequency-domain analysis characterizes and quantify only linear and stationary phenomena. In the present investigation, we made a comparative analysis of three alternative approaches (i.e., wavelet multifractal analysis, Lyapunov exponents and multiscale entropy analysis) for quantifying nonlinear dynamics in heart rate time series. Note that these extracted nonlinear features provide information about nonlinear scaling behaviors and the complexity of cardiac systems. To evaluate the performance, we used 24-hour HRV recordings from 54 healthy subjects and 29 heart failure patients, available in PhysioNet. Three nonlinear methods are evaluated not only individually but also in combination using three classification algorithms, i.e., linear discriminate analysis, quadratic discriminate analysis and k-nearest neighbors. Experimental results show that three nonlinear methods capture nonlinear dynamics from different perspectives and the combined feature set achieves the best performance, i.e., sensitivity 97.7% and specificity 91.5%. Collectively, nonlinear HRV features are shown to have the promise to identify the disorders in autonomic cardiovascular function.

  13. Approaches for modeling within subject variability in pharmacometric count data analysis: dynamic inter-occasion variability and stochastic differential equations.

    Science.gov (United States)

    Deng, Chenhui; Plan, Elodie L; Karlsson, Mats O

    2016-06-01

    Parameter variation in pharmacometric analysis studies can be characterized as within subject parameter variability (WSV) in pharmacometric models. WSV has previously been successfully modeled using inter-occasion variability (IOV), but also stochastic differential equations (SDEs). In this study, two approaches, dynamic inter-occasion variability (dIOV) and adapted stochastic differential equations, were proposed to investigate WSV in pharmacometric count data analysis. These approaches were applied to published count models for seizure counts and Likert pain scores. Both approaches improved the model fits significantly. In addition, stochastic simulation and estimation were used to explore further the capability of the two approaches to diagnose and improve models where existing WSV is not recognized. The results of simulations confirmed the gain in introducing WSV as dIOV and SDEs when parameters vary randomly over time. Further, the approaches were also informative as diagnostics of model misspecification, when parameters changed systematically over time but this was not recognized in the structural model. The proposed approaches in this study offer strategies to characterize WSV and are not restricted to count data.

  14. [The exercise training restores the heart rate variability in heart failure patients. A systematic review].

    Science.gov (United States)

    Segovia, Victoria; Manterola, Carlos; González, Marcelo; Rodríguez-Núñez, Iván

    Cardiovascular diseases are a significant cause of morbidity and mortality in the general population. In this sense, the autonomic imbalance is the cornerstone of the pathophysiology underlying the development of these diseases. The aim of this study was to determine the efficacy of exercise training on heart rate variability (HRV) in adult patients with chronic heart failure. A systematic literature review was conducted in electronic databases. The considered studies were randomised clinical trials, quasi-experimental studies with non-randomised control group, quasi-experimental studies with analysis of pre- and post- intervention, and crossover studies with randomly assigned training and non-training periods. The standardised mean differences were calculated between pre- and post-intervention in both the control and experimental group. Within-subject analysis of the control group showed no statistical significance in the standardised mean differences of HRV. In the experimental group, the standardised mean differences were positive for the root mean square of successive difference (+0.468±0.215; P=.032), high frequency band (HF) (0.934±0.256; P < .001) and low frequency band (LF) (< 0.415±0.096; P=.001). Moreover, the standardised mean difference was negative for LF/HF (-0.747±0.369, P=<.044). On the other hand, only 3 studies entered the comparative meta-analysis. The effect of exercise training was favourable for the experimental group in LF/HF (-2.21±95% CI: -3.83 to -0.60), HF, and LF. The exercise training was effective in increasing HRV and restoring the autonomic balance in patients with heart failure. Copyright © 2016 Instituto Nacional de Cardiología Ignacio Chávez. Publicado por Masson Doyma México S.A. All rights reserved.

  15. Heart Rate Variability in Patients with Chronic Obstructive Pulmonary Disease Treated by Noninvasive Mechanic Ventilation

    Directory of Open Access Journals (Sweden)

    Zekeriya Küçükdurmaz

    2011-08-01

    Full Text Available Aims: This study aimed to investigate heart rate variability (HRV of patients with severe COPD who are treated by noninvasive mechanic ventilation (NIMV.Patients and Method: Twenty-seven patient (58±8 years, 9 F with severe COPD treated by nocturnal NIMV at home and 23 sex and age matched volunteers (56±8 years, 11 F who has not dyspnea as a control group recruited in the study. Subjects underwent spirometry, blood gas analysis, transthoracic echocardiography, 24 hours ambulatory ECG analysis. Time domain HRV analysis performed from ambulatory ECG records. Results: 52% of patients at NYHA functional class II, 36% at class III, and 12% at class IV when they have been treated by NIMV. Groups were similar for age and sex (p>0.05 for both. Heart rates of patients were higher significantly than controls’ (p0.05. But, systolic pulmonary pressures were higher of COPD group (p<0.01. 24 hours heart rate was higher, and standard deviation of normal R-R intervals (SDNN 24 hours, SDNN night, SDNN day, SDNN index (SDNNI and standard deviation of mean R-R intervals (SDANNI values were lower in COPD group significantly. SDNN was inversely correlated with duration of daily NIMV usage, intensive care unit administration and entubation rate and PaCO2. SDNNI was inversely correlated with functional class, duration of daily NIMV usage, intensive care unit administration rate and PaCO2. Else, SDNNI was correlated with predicted forced vital capacity % (FVC% and predicted forced expiratory volume at 1 second % (FEV1%.Conclusion: Time domain HRV decreases in patients with severe COPD. Decrease is correlated with severity of disease, and it presents in despite of the chronic nocturnal NIMV application. These patients have high risk for cardiovascular morbidity and mortality and should be monitored and manegement for cardiovascular events.

  16. Heart-Rate Variability During Deep Sleep in World-Class Alpine Skiers: A Time-Efficient Alternative to Morning Supine Measurements.

    Science.gov (United States)

    Herzig, David; Testorelli, Moreno; Olstad, Daniela Schäfer; Erlacher, Daniel; Achermann, Peter; Eser, Prisca; Wilhelm, Matthias

    2017-05-01

    It is increasingly popular to use heart-rate variability (HRV) to tailor training for athletes. A time-efficient method is HRV assessment during deep sleep. To validate the selection of deep-sleep segments identified by RR intervals with simultaneous electroencephalography (EEG) recordings and to compare HRV parameters of these segments with those of standard morning supine measurements. In 11 world-class alpine skiers, RR intervals were monitored during 10 nights, and simultaneous EEGs were recorded during 2-4 nights. Deep sleep was determined from the HRV signal and verified by delta power from the EEG recordings. Four further segments were chosen for HRV determination, namely, a 4-h segment from midnight to 4 AM and three 5-min segments: 1 just before awakening, 1 after waking in supine position, and 1 in standing after orthostatic challenge. Training load was recorded every day. A total of 80 night and 68 morning measurements of 9 athletes were analyzed. Good correspondence between the phases selected by RR intervals vs those selected by EEG was found. Concerning root-mean-squared difference of successive RR intervals (RMSSD), a marker for parasympathetic activity, the best relationship with the morning supine measurement was found in deep sleep. HRV is a simple tool for approximating deep-sleep phases, and HRV measurement during deep sleep could provide a time-efficient alternative to HRV in supine position.

  17. Dimensional analysis of heart rate variability in heart transplant recipients

    Energy Technology Data Exchange (ETDEWEB)

    Zbilut, J.P.; Mayer-Kress, G.; Geist, K.

    1987-01-01

    We discuss periodicities in the heart rate in normal and transplanted hearts. We then consider the possibility of dimensional analysis of these periodicities in transplanted hearts and problems associated with the record.

  18. GIS and correlation analysis of geo-environmental variables ...

    African Journals Online (AJOL)

    Key words: Correlation, GIS, malaria geography, malaria incidence ... problems, as it has created the possibility for geocoding, extracting and spatial analysis of health ...... Bulletin of the World Health Organization, 78(12), 1438–1444. Carter ...

  19. INFLUENCE OF ALPHAEEG/EMG BIOFEEDBACK AND SELF-REGULATION PSYCHO TECHNIQUES ON THE HEART RATE VARIABILITY INDICES

    Directory of Open Access Journals (Sweden)

    O. M. Bazanova

    2013-01-01

    Full Text Available With the purpose to study the impact of the upper frequency alpha EEG power increasing neurofeedback training (ANFT on the cognitive performance, EEG alpha-activity and heart rate variability (HRV 27 healthy men aged 18–34 years in pre, post and follow up one month 10 sessions ANFT time were investigated. The AFNT enhanced the fluency in cognitive performance, alpha frequency and power in upper frequency range and HRV only in participants with low baseline alpha frequency. While mock AFNT did change neither cognitive performance, nor alpha-activity, nor HRV indices. ANT reduces activation in cognitive load, and this effect persists for a month.

  20. Resting heart rate variability is associated with ex-Gaussian metrics of intra-individual reaction time variability.

    Science.gov (United States)

    Spangler, Derek P; Williams, DeWayne P; Speller, Lassiter F; Brooks, Justin R; Thayer, Julian F

    2018-03-01

    The relationships between vagally mediated heart rate variability (vmHRV) and the cognitive mechanisms underlying performance can be elucidated with ex-Gaussian modeling-an approach that quantifies two different forms of intra-individual variability (IIV) in reaction time (RT). To this end, the current study examined relations of resting vmHRV to whole-distribution and ex-Gaussian IIV. Subjects (N = 83) completed a 5-minute baseline while vmHRV (root mean square of successive differences; RMSSD) was measured. Ex-Gaussian (sigma, tau) and whole-distribution (standard deviation) estimates of IIV were derived from reaction times on a Stroop task. Resting vmHRV was found to be inversely related to tau (exponential IIV) but not to sigma (Gaussian IIV) or the whole-distribution standard deviation of RTs. Findings suggest that individuals with high vmHRV can better prevent attentional lapses but not difficulties with motor control. These findings inform the differential relationships of cardiac vagal control to the cognitive processes underlying human performance. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  1. Variability in microbiological degradation experiments, analysis and case study

    DEFF Research Database (Denmark)

    Sommer, Helle Mølgaard

    1997-01-01

    and describes analysis techniques for testing the reproducibility of a given experiment. The parameter estimation method employed for the experiments in this study is based on an iterative maximum likelihood method and the test statistic is an approximated likelihood ratio test. The estimations were carried out...

  2. Individual differences in heart rate variability are associated with the avoidance of negative emotional events.

    Science.gov (United States)

    Katahira, Kentaro; Fujimura, Tomomi; Matsuda, Yoshi-Taka; Okanoya, Kazuo; Okada, Masato

    2014-12-01

    Although the emotional outcome of a choice generally affects subsequent decisions, humans can inhibit the influence of emotion. Heart rate variability (HRV) has emerged as an objective measure of individual differences in the capacity for inhibitory control. In the present study, we investigated how individual differences in HRV at rest are associated with the emotional effects of the outcome of a choice on subsequent decision making using a decision-making task in which emotional pictures appeared as decision outcomes. We used a reinforcement learning model to characterize the observed behaviors according to several parameters, namely, the learning rate and the motivational value of positive and negative pictures. Consequently, we found that individuals with a lower resting HRV exhibited a greater negative motivational value in response to negative pictures, suggesting that these individuals tend to avoid negative pictures compared with individuals with a higher resting HRV. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. The role of physical activity and heart rate variability for the control of work related stress.

    Science.gov (United States)

    Tonello, Laís; Rodrigues, Fábio B; Souza, Jeniffer W S; Campbell, Carmen S G; Leicht, Anthony S; Boullosa, Daniel A

    2014-01-01

    Physical activity (PA) and exercise are often used as tools to reduce stress and therefore the risk for developing cardiovascular diseases (CVD). Meanwhile, heart rate variability (HRV) has been utilized to assess both stress and PA or exercise influences. The objective of the present review was to examine the current literature in regards to workplace stress, PA/exercise and HRV to encourage further studies. We considered original articles from known databases (PubMed, ISI Web of Knowledge) over the last 10 years that examined these important factors. A total of seven studies were identified with workplace stress strongly associated with reduced HRV in workers. Longitudinal workplace PA interventions may provide a means to improve worker stress levels and potentially cardiovascular risk with mechanisms still to be clarified. Future studies are recommended to identify the impact of PA, exercise, and fitness on stress levels and HRV in workers and their subsequent influence on cardiovascular health.

  4. Heart Rate Variability in Cavalier King Charles Spaniels with Different Degree of Myxomatous Mitral Valve Disease

    DEFF Research Database (Denmark)

    Rasmussen, Caroline Elisabeth; Falk, Bo Torkel; Zois, Nora Elisabeth

    2010-01-01

    Sciences, University of Copenhagen, Frederiksberg, Denmark, 2Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden; and 3Novo Nordic A/S, Maaloev, Denmark. Introduction: Modulation of heart rate by the autonomic nervous system can indirectly be measured by heart rate...... variability (HRV). Reduced HRV is seen in dogs with heart failure secondary to myxomatous mitral valve disease (MMVD). However, HRV is suggested to increase with disease progression in dogs with early stages of MMVD. Comparable results are found in people with primary mitral valve prolapse, a disease...... resembling canine MMVD. Aim: To associate progression of MMVD in dogs with time and frequency domain HRV, analysed from 24-hour electrocardiography. Materials and Methods: Eighty-one Cavalier King Charles Spaniels (CKCS) were examined by echocardiography and 24-hour electrocardiography. CKCS were divided...

  5. Heart rate variability reflects self-regulatory strength, effort, and fatigue.

    Science.gov (United States)

    Segerstrom, Suzanne C; Nes, Lise Solberg

    2007-03-01

    Experimental research reliably demonstrates that self-regulatory deficits are a consequence of prior self-regulatory effort. However, in naturalistic settings, although people know that they are sometimes vulnerable to saying, eating, or doing the wrong thing, they cannot accurately gauge their capacity to self-regulate at any given time. Because self-regulation and autonomic regulation colocalize in the brain, an autonomic measure, heart rate variability (HRV), could provide an index of self-regulatory strength and activity. During an experimental manipulation of self-regulation (eating carrots or cookies), HRV was elevated during high self-regulatory effort (eat carrots, resist cookies) compared with low self-regulatory effort (eat cookies, resist carrots). The experimental manipulation and higher HRV at baseline independently predicted persistence at a subsequent anagram task. HRV appears to index self-regulatory strength and effort, making it possible to study these phenomena in the field as well as the lab.

  6. Relation between emotional distress and heart rate variability in patients with an implantable cardioverter-defibrillator

    DEFF Research Database (Denmark)

    Hoogwegt, Madelein T; Pedersen, Susanne S.; Theuns, Dominic A M J

    2014-01-01

    We investigated the relationship between Type D personality, depression, and anxiety, and heart rate variability (HRV) in 64 patients with an implantable cardioverter-defibrillator (ICD). HRV was obtained via 24-h Holter monitoring, and 24-h, 30-min daytime rest and 30-min nighttime sleep HRV were...... analyzed. In adjusted analyses, significant associations (standard deviation of normal-to-normal [NN] intervals [SDNN]: p = .043; standard deviation of NN intervals over 5-min periods [SDANN]: p = .010) and a trend (HRV triangular index: p = .09) were found for Type D personality, and trends were found...... = .043). A Benjamini-Hochberg correction for multiple testing led to reduction of the number of significant relationships, but there was still support for lower autonomic control patients with Type D personality and depression. Future research with larger sample sizes is warranted....

  7. The role of physical activity and heart rate variability for the control of work related stress

    Directory of Open Access Journals (Sweden)

    Laís eTonello

    2014-02-01

    Full Text Available Physical activity (PA and exercise are often used as tools to reduce stress and therefore the risk for developing cardiovascular diseases. Meanwhile, heart rate variability (HRV has been utilised to assess both stress and PA or exercise influences. The objective of the present mini review was to examine the current literature in regards to workplace stress, PA/exercise and HRV to encourage further studies. We considered original articles from known databases (PubMed, ISI Web of Knowledge over the last 10 years that examined these important factors. A total of 7 studies were identified with workplace stress strongly associated with reduced HRV in workers. Longitudinal workplace PA interventions may provide a means to improve worker stress levels and potentially cardiovascular risk with mechanisms still to be clarified. Future studies are recommended to identify the impact of PA, exercise and fitness on stress levels and HRV in workers and their subsequent influence on cardiovascular health.

  8. Analysis of Secret Key Randomness Exploiting the Radio Channel Variability

    Directory of Open Access Journals (Sweden)

    Taghrid Mazloum

    2015-01-01

    Full Text Available A few years ago, physical layer based techniques have started to be considered as a way to improve security in wireless communications. A well known problem is the management of ciphering keys, both regarding the generation and distribution of these keys. A way to alleviate such difficulties is to use a common source of randomness for the legitimate terminals, not accessible to an eavesdropper. This is the case of the fading propagation channel, when exact or approximate reciprocity applies. Although this principle has been known for long, not so many works have evaluated the effect of radio channel properties in practical environments on the degree of randomness of the generated keys. To this end, we here investigate indoor radio channel measurements in different environments and settings at either 2.4625 GHz or 5.4 GHz band, of particular interest for WIFI related standards. Key bits are extracted by quantizing the complex channel coefficients and their randomness is evaluated using the NIST test suite. We then look at the impact of the carrier frequency, the channel variability in the space, time, and frequency degrees of freedom used to construct a long secret key, in relation to the nature of the radio environment such as the LOS/NLOS character.

  9. Analysis of North Sea Offshore Wind Power Variability

    Directory of Open Access Journals (Sweden)

    Aymeric Buatois

    2014-05-01

    Full Text Available This paper evaluates, for a 2030 scenario, the impact on onshore power systems in terms of the variability of the power generated by 81 GW of offshore wind farms installed in the North Sea. Meso-scale reanalysis data are used as input for computing the hourly power production for offshore wind farms, and this total production is analyzed to identify the largest aggregated hourly power variations. Based on publicly available information, a simplified representation of the coastal power grid is built for the countries bordering the North Sea. Wind farms less than 60 km from shore are connected radially to the mainland, while the rest are connected to a hypothetical offshore HVDC (High-Voltage Direct Current power grid, designed such that wind curtailment does not exceed 1% of production. Loads and conventional power plants by technology and associated cost curves are computed for the various national power systems, based on 2030 projections. Using the MATLAB-based MATPOWER toolbox, the hourly optimal power flow for this regional hybrid AC/DC grid is computed for high, low and medium years from the meso-scale database. The largest net load variations are evaluated per market area and related to the extra load-following reserves that may be needed from conventional generators.

  10. VAM2D: Variably saturated analysis model in two dimensions

    International Nuclear Information System (INIS)

    Huyakorn, P.S.; Kool, J.B.; Wu, Y.S.

    1991-10-01

    This report documents a two-dimensional finite element model, VAM2D, developed to simulate water flow and solute transport in variably saturated porous media. Both flow and transport simulation can be handled concurrently or sequentially. The formulation of the governing equations and the numerical procedures used in the code are presented. The flow equation is approximated using the Galerkin finite element method. Nonlinear soil moisture characteristics and atmospheric boundary conditions (e.g., infiltration, evaporation and seepage face), are treated using Picard and Newton-Raphson iterations. Hysteresis effects and anisotropy in the unsaturated hydraulic conductivity can be taken into account if needed. The contaminant transport simulation can account for advection, hydrodynamic dispersion, linear equilibrium sorption, and first-order degradation. Transport of a single component or a multi-component decay chain can be handled. The transport equation is approximated using an upstream weighted residual method. Several test problems are presented to verify the code and demonstrate its utility. These problems range from simple one-dimensional to complex two-dimensional and axisymmetric problems. This document has been produced as a user's manual. It contains detailed information on the code structure along with instructions for input data preparation and sample input and printed output for selected test problems. Also included are instructions for job set up and restarting procedures. 44 refs., 54 figs., 24 tabs

  11. Determination of heart rate variability with an electronic stethoscope.

    Science.gov (United States)

    Kamran, Haroon; Naggar, Isaac; Oniyuke, Francisca; Palomeque, Mercy; Chokshi, Priya; Salciccioli, Louis; Stewart, Mark; Lazar, Jason M

    2013-02-01

    Heart rate variability (HRV) is widely used to characterize cardiac autonomic function by measuring beat-to-beat alterations in heart rate. Decreased HRV has been found predictive of worse cardiovascular (CV) outcomes. HRV is determined from time intervals between QRS complexes recorded by electrocardiography (ECG) for several minutes to 24 h. Although cardiac auscultation with a stethoscope is performed routinely on patients, the human ear cannot detect heart sound time intervals. The electronic stethoscope digitally processes heart sounds, from which cardiac time intervals can be obtained. Accordingly, the objective of this study was to determine the feasibility of obtaining HRV from electronically recorded heart sounds. We prospectively studied 50 subjects with and without CV risk factors/disease and simultaneously recorded single lead ECG and heart sounds for 2 min. Time and frequency measures of HRV were calculated from R-R and S1-S1 intervals and were compared using intra-class correlation coefficients (ICC). The majority of the indices were strongly correlated (ICC 0.73-1.0), while the remaining indices were moderately correlated (ICC 0.56-0.63). In conclusion, we found HRV measures determined from S1-S1 are in agreement with those determined by single lead ECG, and we demonstrate and discuss differences in the measures in detail. In addition to characterizing cardiac murmurs and time intervals, the electronic stethoscope holds promise as a convenient low-cost tool to determine HRV in the hospital and outpatient settings as a practical extension of the physical examination.

  12. A method for calorimetric analysis in variable conditions heating

    International Nuclear Information System (INIS)

    Berthier, G.

    1965-01-01

    By the analysis of the thermal transition conditions given by the quenching of a sample in a furnace maintained at a high temperature, it is possible to study the thermal diffusivity of some materials and those of solid state structure transformation on a qualitative as well as a quantitative standpoint. For instance the transformation energy of α-quartz into β-quartz and the Wigner energy stored within neutron-irradiated beryllium oxide have been measured. (author) [fr

  13. Short-term association between personal exposure to noise and heart rate variability: The RECORD MultiSensor Study.

    Science.gov (United States)

    El Aarbaoui, Tarik; Méline, Julie; Brondeel, Ruben; Chaix, Basile

    2017-12-01

    Studies revealed long-term associations between noise exposure and cardiovascular health, but the underlying short-term mechanisms remain uncertain. To explore the concomitant and lagged short-term associations between personal exposure to noise and heart rate variability (HRV) in a real life setting in the Île-de-France region. The RECORD MultiSensor Study collected between July 2014 and June 2015 noise and heart rate data for 75 participants, aged 34-74 years, in their living environments for 7 days using a personal dosimeter and electrocardiography (ECG) sensor on the chest. HRV parameters and noise levels were calculated for 5-min windows. Short-term relationships between noise level and log-transformed HRV parameters were assessed using mixed effects models with a random intercept for participants and a temporal autocorrelation structure, adjusted for heart rate, physical activity (accelerometry), and short-term trends. An increase by one dB(A) of A-weighted equivalent sound pressure level (Leq) was associated with a 0.97% concomitant increase of the Standard deviation of normal to normal intervals (SDNN) (95% CI: 0.92, 1.02), of 2.08% of the Low frequency band power (LF) (95% CI: 1.97, 2.18), of 1.30% of the High frequency band power (HF) (95% CI: 1.17, 1.43), and of 1.16% of the LF/HF ratio (95% CI: 1.10, 1.23). The analysis of lagged exposures to noise adjusted for the concomitant exposure illustrates the dynamic of recovery of the autonomic nervous system. Non-linear associations were documented with all HRV parameters with the exception of HF. Piecewise regression revealed that the association was almost 6 times stronger below than above 65 Leq dB(A) for the SDNN and LF/HF ratio. Personal noise exposure was found to be related to a concomitant increase of the overall HRV, with evidence of imbalance of the autonomic nervous system towards sympathetic activity, a pathway to increased cardiovascular morbidity and mortality. Copyright © 2017 Elsevier Ltd

  14. Hippotherapy acute impact on heart rate variability non-linear dynamics in neurological disorders.

    Science.gov (United States)

    Cabiddu, Ramona; Borghi-Silva, Audrey; Trimer, Renata; Trimer, Vitor; Ricci, Paula Angélica; Italiano Monteiro, Clara; Camargo Magalhães Maniglia, Marcela; Silva Pereira, Ana Maria; Rodrigues das Chagas, Gustavo; Carvalho, Eliane Maria

    2016-05-15

    Neurological disorders are associated with autonomic dysfunction. Hippotherapy (HT) is a therapy treatment strategy that utilizes a horse in an interdisciplinary approach for the physical and mental rehabilitation of people with physical, mental and/or psychological disabilities. However, no studies have been carried out which evaluated the effects of HT on the autonomic control in these patients. Therefore, the objective of the present study was to investigate the effects of a single HT session on cardiovascular autonomic control by time domain and non-linear analysis of heart rate variability (HRV). The HRV signal was recorded continuously in twelve children affected by neurological disorders during a HT session, consisting in a 10-minute sitting position rest (P1), a 15-minute preparatory phase sitting on the horse (P2), a 15-minute HT session (P3) and a final 10-minute sitting position recovery (P4). Time domain and non-linear HRV indices, including Sample Entropy (SampEn), Lempel-Ziv Complexity (LZC) and Detrended Fluctuation Analysis (DFA), were calculated for each treatment phase. We observed that SampEn increased during P3 (SampEn=0.56±0.10) with respect to P1 (SampEn=0.40±0.14, p<0.05), while DFA decreased during P3 (DFA=1.10±0.10) with respect to P1 (DFA=1.26±0.14, p<0.05). A significant SDRR increase (p<0.05) was observed during the recovery period P4 (SDRR=50±30ms) with respect to the HT session period P3 (SDRR=30±10ms). Our results suggest that HT might benefit children with disabilities attributable to neurological disorders by eliciting an acute autonomic response during the therapy and during the recovery period. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Iterative Strain-Gage Balance Calibration Data Analysis for Extended Independent Variable Sets

    Science.gov (United States)

    Ulbrich, Norbert Manfred

    2011-01-01

    A new method was developed that makes it possible to use an extended set of independent calibration variables for an iterative analysis of wind tunnel strain gage balance calibration data. The new method permits the application of the iterative analysis method whenever the total number of balance loads and other independent calibration variables is greater than the total number of measured strain gage outputs. Iteration equations used by the iterative analysis method have the limitation that the number of independent and dependent variables must match. The new method circumvents this limitation. It simply adds a missing dependent variable to the original data set by using an additional independent variable also as an additional dependent variable. Then, the desired solution of the regression analysis problem can be obtained that fits each gage output as a function of both the original and additional independent calibration variables. The final regression coefficients can be converted to data reduction matrix coefficients because the missing dependent variables were added to the data set without changing the regression analysis result for each gage output. Therefore, the new method still supports the application of the two load iteration equation choices that the iterative method traditionally uses for the prediction of balance loads during a wind tunnel test. An example is discussed in the paper that illustrates the application of the new method to a realistic simulation of temperature dependent calibration data set of a six component balance.

  16. Partial differential equations with variable exponents variational methods and qualitative analysis

    CERN Document Server

    Radulescu, Vicentiu D

    2015-01-01

    Partial Differential Equations with Variable Exponents: Variational Methods and Qualitative Analysis provides researchers and graduate students with a thorough introduction to the theory of nonlinear partial differential equations (PDEs) with a variable exponent, particularly those of elliptic type. The book presents the most important variational methods for elliptic PDEs described by nonhomogeneous differential operators and containing one or more power-type nonlinearities with a variable exponent. The authors give a systematic treatment of the basic mathematical theory and constructive meth

  17. Anxiety, attention, and decision making: The moderating role of heart rate variability.

    Science.gov (United States)

    Ramírez, Encarnación; Ortega, Ana Raquel; Reyes Del Paso, Gustavo A

    2015-12-01

    The current exploratory research examined whether high frequency heart rate variability (HF-HRV) modulates the association between anxiety and (1) executive attentional control during situations involving neutral stimuli, in which the distractor stimuli are in conflict with the target stimulus, and (2) risk aversion in decision making. Forty-five participants (21 with low and 24 with high trait-anxiety) performed a modified version of the Attention Network Test to measure attentional control, and the Balloon Analog Risk Task to measure risk aversion. HF-HRV was recorded during a rest period before completion of the tasks. Results showed that individuals with high anxiety and low HF-HRV have worse attentional control in the face of conflicting information as well as greater risk aversion, in comparison with individuals with both high anxiety and high HF-HRV or low anxiety (regardless of HF-HRV). HF-HRV was positively associated with attentional control and negatively associated with risk aversion. Furthermore, a strong negative association was observed between attentional control and risk aversion. These results suggest that HF-HRV modulates the influence of anxiety on both attentional control to neutral stimuli, and risk aversion in decision making. Greater HF-HRV appears to fulfill a protective role in highly anxious individuals. The associations observed also suggest that executive control of attention plays a relevant role in decision making. These results support the relevance of the autonomic nervous system in sustained cognition and are in accordance with theories in which vagal-mediated heart rate variability is taken as an indicator of prefrontal cortex inhibitory influences. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. The Effect of Heart Rate on the Heart Rate Variability Response to Autonomic Interventions

    Directory of Open Access Journals (Sweden)

    George E Billman

    2013-08-01

    Full Text Available Heart rate variability (HRV, the beat-to-beat variation in either heart rate (HR or heart period (R-R interval, has become a popular clinical and investigational tool to quantify cardiac autonomic regulation. However, it is not widely appreciated that, due to the inverse curvilinear relationship between HR and R-R interval, HR per se can profoundly influence HRV. It is, therefore, critical to correct HRV for the prevailing HR particularly, as HR changes in response to autonomic neural activation or inhibition. The present study evaluated the effects of HR on the HRV response to autonomic interventions that either increased (submaximal exercise, n = 25 or baroreceptor reflex activation, n = 20 or reduced (pharmacological blockade: β-adrenergic receptor, muscarinic receptor antagonists alone and in combination, n = 25, or bilateral cervical vagotomy, n = 9 autonomic neural activity in a canine model. Both total (RR interval standard deviation, RRSD and the high frequency variability (HF, 0.2 to 1.04 Hz were determined before and in response to an autonomic intervention. All interventions that reduced or abolished cardiac parasympathetic regulation provoked large reductions in HRV even after HR correction [division by mean RRsec or (mean RRsec2 for RRSD and HF, respectively] while interventions that reduced HR yielded mixed results. β-adrenergic receptor blockade reduced HRV (RRSD but not HF while both RRSD and HF increased in response to increases in arterial blood (baroreceptor reflex activation even after HR correction. These data suggest that the physiological basis for HRV is revealed after correction for prevailing HR and, further, that cardiac parasympathetic activity is responsible for a major portion of the HRV in the dog.

  19. Effect of the Stroop test performed in supine position on the heart rate variability in both genders.

    Science.gov (United States)

    Vazan, Rastislav; Filcikova, Diana; Mravec, Boris

    2017-12-01

    The effect of Stroop test (ST)-induced stress on autonomic nervous system activity is often examined via measurement of heart rate variability (HRV). However, HRV may be significantly affected by interfering factors, including vocalization and inappropriate body position. Surprisingly, published studies ignore these issues, so the aim of our study was to test the innovative procedure for correct HRV measurement in individuals exposed to ST. Moreover, we examined possible gender differences in HRV and heart rate (HR) during ST. Healthy participants (21 men, 34 women) were placed in a supine position (no orthostatic activation) and then exposed to a 5 min relaxation period and a 5 min period of computerized ST (no vocalization). We found significant differences in HR and HRV parameters in both genders during ST when compared to relaxation (baseline) values. On the other hand, there were no significant differences in HR and HRV between males and females (except for a higher baseline HR in women). Also, reactivity to ST stress (difference between baseline and ST value) showed no gender differences. In conclusion, when performed in a supine position and without vocalization, the ST induces significant stress-related changes of HR and HRV in both genders, with no gender differences in the magnitude of reaction to ST stress. This experimental procedure can be used for correct examination of mental stress-related changes in the autonomic nervous system, and is particularly useful for examining mixed-gender experimental groups. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Low to high frequency ratio of heart rate variability spectra fails to describe sympatho-vagal balance in cardiac patients.

    Science.gov (United States)

    Milicević, Goran

    2005-06-01

    Heart rate variability (HRV) reflects an influence of autonomic nervous system on heart work. In healthy subjects, ratio between low and high frequency components (LF/HF ratio) of HRV spectra represents a measure of sympatho-vagal balance. The ratio was defined by the authorities as an useful clinical tool, but it seems that it fails to summarise sympatho-vagal balance in a clinical setting. Value of the method was re-evaluated in several categories of cardiac patients. HRV was analysed from 24-hour Holter ECGs in 132 healthy subjects, and 2159 cardiac patients dichotomised by gender, median of age, diagnosis of myocardial infarction or coronary artery surgery, left ventricular systolic function and divided by overall HRV into several categories. In healthy subjects, LF/HF ratio correlated with overall HRV negatively, as expected. The paradoxical finding was obtained in cardiac patients; the lower the overall HRV and the time-domain indices of vagal modulation activity were the lower the LF/HF ratio was. If used as a measure of sympatho-vagal balance, long-term recordings of LF/HF ratio contradict to clinical finding and time-domain HRV indices in cardiac patients. The ratio cannot therefore be used as a reliable marker of autonomic activity in a clinical setting.

  1. DNA flow cytometric analysis in variable types of hydropic placentas

    Directory of Open Access Journals (Sweden)

    Fatemeh Atabaki pasdar

    2015-05-01

    Full Text Available Background: Differential diagnosis between complete hydatidiform mole, partial hydatidiform mole and hydropic abortion, known as hydropic placentas is still a challenge for pathologists but it is very important for patient management. Objective: We analyzed the nuclear DNA content of various types of hydropic placentas by flowcytometry. Materials and Methods: DNA ploidy analysis was performed in 20 non-molar (hydropic and non-hydropic spontaneous abortions and 20 molar (complete and partial moles, formalin-fixed, paraffin-embedded tissue samples by flow cytometry. The criteria for selection were based on the histopathologic diagnosis. Results: Of 10 cases histologically diagnosed as complete hydatiform mole, 9 cases yielded diploid histograms, and 1 case was tetraploid. Of 10 partial hydatidiform moles, 8 were triploid and 2 were diploid. All of 20 cases diagnosed as spontaneous abortions (hydropic and non-hydropic yielded diploid histograms. Conclusion: These findings signify the importance of the combined use of conventional histology and ploidy analysis in the differential diagnosis of complete hydatidiform mole, partial hydatidiform mole and hydropic abortion.

  2. Physiologic variability at the verge of systemic inflammation: multi-scale entropy of heart rate variability is affected by very low doses of endotoxin

    Science.gov (United States)

    Herlitz, Georg N.; Sanders, Renee L.; Cheung, Nora H.; Coyle, Susette M.; Griffel, Benjamin; Macor, Marie A.; Lowry, Stephen F.; Calvano, Steve E.; Gale, Stephen C.

    2014-01-01

    Introduction Human injury or infection induces systemic inflammation with characteristic neuro-endocrine responses. Fluctuations in autonomic function during inflammation are reflected by beat-to-beat variation in heart rate, termed heart rate variability (HRV). In the present study, we determine threshold doses of endotoxin needed to induce observable changes in markers of systemic inflammation, we investigate whether metrics of HRV exhibit a differing threshold dose from other inflammatory markers, and we investigate the size of data sets required for meaningful use of multi-scale entropy (MSE) analysis of HRV. Methods Healthy human volunteers (n=25) were randomized to receive placebo (normal saline) or endotoxin/lipopolysaccharide (LPS): 0.1, 0.25, 0.5, 1.0, or 2.0 ng/kg administered intravenously. Vital signs were recorded every 30 minutes for 6 hours and then at 9, 12, and 24 hours after LPS. Blood samples were drawn at specific time points for cytokine measurements. HRV analysis was performed using EKG epochs of 5 minutes. MSE for HRV was calculated for all dose groups to scale factor 40. Results The lowest significant threshold dose was noted in core temperature at 0.25ng/kg. Endogenous TNF-α and IL-6 were significantly responsive at the next dosage level (0.5ng/kg) along with elevations in circulating leukocytes and heart rate. Responses were exaggerated at higher doses (1 and 2 ng/kg). Time domain and frequency domain HRV metrics similarly suggested a threshold dose, differing from placebo at 1.0 and 2.0 ng/kg, below which no clear pattern in response was evident. By applying repeated-measures ANOVA across scale factors, a significant decrease in MSE was seen at 1.0 and 2.0 ng/kg by 2 hours post exposure to LPS. While not statistically significant below 1.0 ng/kg, MSE unexpectedly decreased across all groups in an orderly dose-response pattern not seen in the other outcomes. Conclusions By usingrANOVA across scale factors, MSE can detect autonomic change

  3. Statistical methods and regression analysis of stratospheric ozone and meteorological variables in Isfahan

    Science.gov (United States)

    Hassanzadeh, S.; Hosseinibalam, F.; Omidvari, M.

    2008-04-01

    Data of seven meteorological variables (relative humidity, wet temperature, dry temperature, maximum temperature, minimum temperature, ground temperature and sun radiation time) and ozone values have been used for statistical analysis. Meteorological variables and ozone values were analyzed using both multiple linear regression and principal component methods. Data for the period 1999-2004 are analyzed jointly using both methods. For all periods, temperature dependent variables were highly correlated, but were all negatively correlated with relative humidity. Multiple regression analysis was used to fit the meteorological variables using the meteorological variables as predictors. A variable selection method based on high loading of varimax rotated principal components was used to obtain subsets of the predictor variables to be included in the linear regression model of the meteorological variables. In 1999, 2001 and 2002 one of the meteorological variables was weakly influenced predominantly by the ozone concentrations. However, the model did not predict that the meteorological variables for the year 2000 were not influenced predominantly by the ozone concentrations that point to variation in sun radiation. This could be due to other factors that were not explicitly considered in this study.

  4. Periodic radio variability in NRAO 530: phase dispersion minimization analysis

    International Nuclear Information System (INIS)

    Lu Junchao; Lin Jiming; Qiu Hongbing; Wang Junyi; An Tao

    2012-01-01

    A periodicity analysis of the radio light curves of the blazar NRAO 530 at 14.5, 8.0, and 4.8 GHz is presented employing an improved phase dispersion minimization technique. The result, which shows two persistent periodic components of ∼ 6 and ∼ 10 yr at all three frequencies, is consistent with the results obtained with the Lomb-Scargle periodogram and weighted wavelet Z-transform algorithms. The reliability of the derived periodicities is confirmed by the Monte Carlo numerical simulations which show a high statistical confidence. (Quasi-)Periodic fluctuations of the radio luminosity of NRAO 530 might be associated with the oscillations of the accretion disk triggered by hydrodynamic instabilities of the accreted flow. (research papers)

  5. Bias and Bias Correction in Multisite Instrumental Variables Analysis of Heterogeneous Mediator Effects

    Science.gov (United States)

    Reardon, Sean F.; Unlu, Fatih; Zhu, Pei; Bloom, Howard S.

    2014-01-01

    We explore the use of instrumental variables (IV) analysis with a multisite randomized trial to estimate the effect of a mediating variable on an outcome in cases where it can be assumed that the observed mediator is the only mechanism linking treatment assignment to outcomes, an assumption known in the IV literature as the exclusion restriction.…

  6. Variables predicting elevated portal pressure in alcoholic liver disease. Results of a multivariate analysis

    DEFF Research Database (Denmark)

    Krogsgaard, K; Christensen, E; Gluud, C

    1987-01-01

    In 46 alcoholic patients the association of wedged-to-free hepatic-vein pressure with other variables (clinical, histologic, hemodynamic, and liver function data) was studied by means of multiple regression analysis, taking the wedged-to-free hepatic-vein pressure as the dependent variable. Four ...

  7. Methods for the Quasi-Periodic Variability Analysis in Blazars Y. Liu ...

    Indian Academy of Sciences (India)

    the variability analysis in blazars in optical and radio bands, to search for possible quasi-periodic signals. 2. Power spectral density (PSD). In statistical signal processing and physics, the power spectral density (PSD) is a positive real function of a frequency variable associated with a stationary stochas- tic process. Intuitively ...

  8. Analysis, Test and Verification in The Presence of Variability (Dagstuhl Seminar 13091)

    DEFF Research Database (Denmark)

    2014-01-01

    -aware tool chains. We brought together 46 key researchers from three continents, working on quality assurance challenges that arise from introducing variability, and some who do not work with variability, but that are experts in their respective areas in the broader domain of software analysis or testing...

  9. Dispositional Variables and Work-Family Conflict: A Meta-Analysis

    Science.gov (United States)

    Allen, Tammy D.; Johnson, Ryan C.; Saboe, Kristin N.; Cho, Eunae; Dumani, Soner; Evans, Sarah

    2012-01-01

    Meta-analysis was used to comprehensively summarize the relationship between dispositional variables and both directions of work-family conflict. The largest effects detected were those associated with negative affect, neuroticism, and self-efficacy; all were in expected directions. In general, negative trait-based variables (e.g., negative affect…

  10. Increased heart rate variability during nondirective meditation.

    Science.gov (United States)

    Nesvold, Anders; Fagerland, Morten W; Davanger, Svend; Ellingsen, Øyvind; Solberg, Erik E; Holen, Are; Sevre, Knut; Atar, Dan

    2012-08-01

    Meditation practices are in use for relaxation and stress reduction. Some studies indicate beneficial cardiovascular health effects of meditation. The effects on the autonomous nervous system seem to vary among techniques. The purpose of the present study was to identify autonomic nerve activity changes during nondirective meditation. Heart rate variability (HRV), blood pressure variability (BPV), and baroreflex sensitivity (BRS) were monitored in 27 middle-aged healthy participants of both genders, first during 20 min regular rest with eyes closed, thereafter practising Acem meditation for 20 min. Haemodynamic and autonomic data were collected continuously (beat-to-beat) and non-invasively. HRV and BPV parameters were estimated by power spectral analyses, computed by an autoregressive model. Spontaneous activity of baroreceptors were determined by the sequence method. Primary outcomes were changes in HRV, BPV, and BRS between rest and meditation. HRV increased in the low-frequency (LF) and high-frequency (HF) bands during meditation, compared with rest (p = 0.014, 0.013, respectively). Power spectral density of the RR-intervals increased as well (p = 0.012). LF/HF ratio decreased non-significantly, and a reduction of LF-BPV power was observed during meditation (p < 0.001). There was no significant difference in BRS. Respiration and heart rates remained unchanged. Blood pressure increased slightly during meditation. There is an increased parasympathetic and reduced sympathetic nerve activity and increased overall HRV, while practising the technique. Hence, nondirective meditation by the middle aged may contribute towards a reduction of cardiovascular risk.

  11. A brief review and clinical application of heart rate variability biofeedback in sports, exercise, and rehabilitation medicine.

    Science.gov (United States)

    Prinsloo, Gabriell E; Rauch, H G Laurie; Derman, Wayne E

    2014-05-01

    An important component of the effective management of chronic noncommunicable disease is the assessment and management of psychosocial stress. The measurement and modulation of heart rate variability (HRV) may be valuable in this regard. To describe the measurement and physiological control of HRV; to describe the impact of psychosocial stress on cardiovascular disease, metabolic syndrome, and chronic respiratory disease, and the relationship between these diseases and changes in HRV; and to describe the influence of biofeedback and exercise on HRV and the use of HRV biofeedback in the management of chronic disease. The PubMed, Medline, and Embase databases were searched (up to August 2013). Additional articles were obtained from the reference lists of relevant articles and reviews. Articles were individually selected for further review based on the quality and focus of the study, and the population studied. Heart rate variability is reduced in stress and in many chronic diseases, and may even predict the development and prognosis of some diseases. Heart rate variability can be increased with both exercise and biofeedback. Although the research on the effect of exercise is conflicting, there is evidence that aerobic training may increase HRV and cardiac vagal tone both in healthy individuals and in patients with disease. Heart rate variability biofeedback is also an effective method of increasing HRV and cardiac vagal tone, and has been shown to decrease stress and reduce the morbidity and mortality of disease. The assessment and management of psychosocial stress is a challenging but important component of effective comprehensive lifestyle interventions for the management of noncommunicable disease. It is, therefore, important for the sports and exercise physician to have an understanding of the therapeutic use of HRV modulation, both in the reduction of stress and in the management of chronic disease.

  12. Fourier analysis of the light curves of eclipsing variables, XXIV

    International Nuclear Information System (INIS)

    Edalati, M.T.

    1978-01-01

    The aim of the present paper will be to evaluate numerically Jacobian and other functions which have been discussed in more detail in a previous paper of this series, and also choose the most convenient moments to obtain a good determination for the unknown eclipse parameters a and c 0 . More than 12 different pairs of g-functions for real values of m have been investigated numerically and diagrammatically. The behaviour of g-functions depends but very little on different combination of the moments, and related diagrams are approximately the same as g 2 and g 4 . The behaviour of the vanishing Jacobian, arising from different pairs of g-functions for real values of m>= 0 . Accordingly, the author obtains the optimum combination of the moments (i.e., A 6 , A 7 , A 8 and A 9 ) in g-functions g 7 and g 8 . It has been noted that the behaviour of the g-functions which depend on the combinations of the higher order moments (i.e., m>= 5) have been ruled out, because the proportional error of the moments Asub(2m) increases with increasing values of real m. The automated method has been tested successfully on the light curve of RT Per. Finally, a comparison is given of the elements of RT Per arising from two different pairs of g-functions, i.e. g 2 , g 4 and g 7 , g 8 for the light curves analysis. (Auth.)

  13. Sensitivity, specificity and predictive values of linear and nonlinear indices of heart rate variability in stable angina patients

    Directory of Open Access Journals (Sweden)

    Pivatelli Flávio

    2012-10-01

    Full Text Available Abstract Background Decreased heart rate variability (HRV is related to higher morbidity and mortality. In this study we evaluated the linear and nonlinear indices of the HRV in stable angina patients submitted to coronary angiography. Methods We studied 77 unselected patients for elective coronary angiography, which were divided into two groups: coronary artery disease (CAD and non-CAD groups. For analysis of HRV indices, HRV was recorded beat by beat with the volunteers in the supine position for 40 minutes. We analyzed the linear indices in the time (SDNN [standard deviation of normal to normal], NN50 [total number of adjacent RR intervals with a difference of duration greater than 50ms] and RMSSD [root-mean square of differences] and frequency domains ultra-low frequency (ULF ≤ 0,003 Hz, very low frequency (VLF 0,003 – 0,04 Hz, low frequency (LF (0.04–0.15 Hz, and high frequency (HF (0.15–0.40 Hz as well as the ratio between LF and HF components (LF/HF. In relation to the nonlinear indices we evaluated SD1, SD2, SD1/SD2, approximate entropy (−ApEn, α1, α2, Lyapunov Exponent, Hurst Exponent, autocorrelation and dimension correlation. The definition of the cutoff point of the variables for predictive tests was obtained by the Receiver Operating Characteristic curve (ROC. The area under the ROC curve was calculated by the extended trapezoidal rule, assuming as relevant areas under the curve ≥ 0.650. Results Coronary arterial disease patients presented reduced values of SDNN, RMSSD, NN50, HF, SD1, SD2 and -ApEn. HF ≤ 66 ms2, RMSSD ≤ 23.9 ms, ApEn ≤−0.296 and NN50 ≤ 16 presented the best discriminatory power for the presence of significant coronary obstruction. Conclusion We suggest the use of Heart Rate Variability Analysis in linear and nonlinear domains, for prognostic purposes in patients with stable angina pectoris, in view of their overall impairment.

  14. Digital Heart-Rate Variability Parameter Monitoring and Assessment ASIC.

    Science.gov (United States)

    Massagram, W; Hafner, N; Mingqi Chen; Macchiarulo, L; Lubecke, V M; Boric-Lubecke, O

    2010-02-01

    This paper describes experimental results for an application-specific integrated circuit (ASIC), designed for digital heart rate variability (HRV) parameter monitoring and assessment. This ASIC chip measures beat-to-beat (RR) intervals and stores HRV parameters into its internal memory in real time. A wide range of short-term and long-term ECG signals obtained from Physionet was used for testing. The system detects R peaks with millisecond accuracy, and stores up to 2 min of continuous RR interval data and up to 4 min of RR interval histogram. The prototype chip was fabricated in a 0.5 ¿m complementary metal-oxide semiconductor technology on a 3×3 mm(2) die area, with a measured dynamic power consumption of 10 ¿W and measured leakage current of 2.62 nA. The HRV monitoring system including this HRV ASIC, an analog-to-digital converter, and a low complexity microcontroller was estimated to consume 32.5 ¿V, which is seven times lower power than a stand-alone microcontroller performing the same functions. Compact size, low cost, and low power consumption make this chip suitable for a miniaturized portable HRV monitoring system.

  15. Omega-3 Polyunsaturated Fatty Acids and Heart Rate Variability

    Directory of Open Access Journals (Sweden)

    Jeppe Hagstrup Christensen

    2011-11-01

    Full Text Available Omega-3 polyunsaturated fatty acids (PUFA may modulate autonomic control of the heart because omega-3 PUFA is abundant in the brain and other nervous tissue as well as in cardiac tissue. This might partly explain why omega-3 PUFA offer some protection against sudden cardiac death (SCD. The autonomic nervous system is involved in the pathogenesis of SCD. Heart rate variability (HRV can be used as a non-invasive marker of cardiac autonomic control and a low HRV is a predictor for SCD and arrhythmic events. Studies on HRV and omega-3 PUFA have been performed in several populations such as patients with ischemic heart disease, patients with diabetes mellitus, patients with chronic renal failure, and in healthy subjects as well as in children.. The studies have demonstrated a positive association between cellular content of omega-3 PUFA and HRV and supplementation with omega-3 PUFA seems to increase HRV which could be a possible explanation for decreased risk of arrhythmic events and SCD sometimes observed after omega-3 PUFA supplementation. However, the results are not consistent and further research is needed

  16. Heart Rate Variability Discriminates Competitive Levels in Professional Soccer Players.

    Science.gov (United States)

    Proietti, Riccardo; di Fronso, Selenia; Pereira, Lucas A; Bortoli, Laura; Robazza, Claudio; Nakamura, Fabio Y; Bertollo, Maurizio

    2017-06-01

    Heart rate variability (HRV) has been increasingly used to monitor team sports athletes. Besides the traditional time domain indices (i.e., the SD of successive RR intervals [SDNN] and the root mean square difference of successive normal RR intervals [RMSSD]), recently the use of the stress score (SS), which is an inverse function of the SD2 index derived from the Poincaré plot, and the sympathetic/parasympathetic ratio (S/PS) to monitor soccer players has been proposed. However, the reliability of these new indices and the ability of HRV to differentiate between soccer competitive levels are unknown. The aim of this study was to analyze the reliability of the different HRV-derived indices in professional soccer players during the competitive period and to compare HRV of professional soccer players from 3 teams of distinct competitive levels (i.e., Italian Second Division [2D], European League [EL], and Champions League [CL]). Fifty-four male professional soccer players from 3 different teams of 2 European countries (Italy and Germany) participated in the study. The intraclass correlation coefficient values of the HRV indices varied from 0.78 (very large) to 0.90 (near perfect). The coefficient of variation (CV) values for RMSSD and SDNN were all soccer players and is able to differentiate between international- and national-level players.

  17. Analysis of Design Variables of Annular Linear Induction Electromagnetic Pump using an MHD Model

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Jae Sik; Kim, Hee Reyoung [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2015-05-15

    The generated force is affected by lots of factors including electrical input, hydrodynamic flow, geometrical shape, and so on. These factors, which are the design variables of an ALIP, should be suitably analyzed to optimally design an ALIP. Analysis on the developed pressure and efficiency of the ALIP according to the change of design variables is required for the ALIP satisfying requirements. In this study, the design variables of the ALIP are analyzed by using ideal MHD analysis model. Electromagnetic force and efficiency are derived by analyzing the main design variables such as pump core length, inner core diameter, flow gap and turns of coils. The developed pressure and efficiency of the ALIP were derived and analyzed on the change of the main variables such as pump core length, inner core diameter, flow gap, and turns of coils of the ALIP.

  18. PISA 2012 Analysis of School Variables Affecting Problem-Solving Competency: Turkey-Serbia Comparison

    Directory of Open Access Journals (Sweden)

    Emine YAVUZ

    2017-12-01

    Full Text Available According to the OECD's PISA 2012 Turkey problem-solving report, Turkey and Serbia are at the same mathematical literacy level. However, Serbia's average of problem-solving competency is said to be higher than Turkey's. In this study, school variables that affect problem-solving competency of the two countries were examined and compared. The method of the study was causal comparison method, and HLM analysis was performed on data of 4494 students from 147 schools in Turkey sample and 4059 students from 132 schools in Serbia sample separately. As a result of HLM analysis, "obstacle and family donation" variable for Serbia and "abandon, teacher morale and mathematics competition" variable for Turkey were statistically significant. Although it was found that for each countries different variables influence the problem-solving competency, it was quite remarkable that these variables are in common in that they are components of the school climate concept.

  19. Heart Rate Variability, Insulin Resistance, and Insulin Sensitivity in Japanese Adults: The Toon Health Study

    Directory of Open Access Journals (Sweden)

    Isao Saito

    2015-09-01

    Full Text Available Background: Although impaired cardiac autonomic function is associated with an increased risk of type 2 diabetes in Caucasians, evidence in Asian populations with a lower body mass index is limited. Methods: Between 2009–2012, the Toon Health Study recruited 1899 individuals aged 30–79 years who were not taking medication for diabetes. A 75-g oral glucose tolerance test was used to diagnose type 2 diabetes, and fasting and 2-h-postload glucose and insulin concentrations were measured. We assessed the homeostasis model assessment index for insulin resistance (HOMA-IR and Gutt’s insulin sensitivity index (ISI. Pulse was recorded for 5 min, and time-domain heart rate variability (HRV indices were calculated: the standard deviation of normal-to-normal intervals (SDNN and the root mean square of successive difference (RMSSD. Power spectral analysis provided frequency domain measures of HRV: high frequency (HF power, low frequency (LF power, and the LF:HF ratio. Results: Multivariate-adjusted logistic regression models showed decreased SDNN, RMSSD, and HF, and increased LF:HF ratio were associated significantly with increased HOMA-IR and decreased ISI. When stratified by overweight status, the association of RMSSD, HF, and LF:HF ratio with decreased ISI was also apparent in non-overweight individuals. The interaction between LF:HF ratio and decreased ISI in overweight individuals was significant, with the odds ratio for decreased ISI in the highest quartile of LF:HF ratio in non-overweight individuals being 2.09 (95% confidence interval, 1.41–3.10. Conclusions: Reduced HRV was associated with insulin resistance and lower insulin sensitivity. Decreased ISI was linked with parasympathetic dysfunction, primarily in non-overweight individuals.

  20. Short-term heart rate variability in asthmatic obese children: effect of exhaustive exercise and different humidity conditions.

    Science.gov (United States)

    Rezvan, K; Dabidi Roshan, V; Mahmudi, S A

    2015-11-01

    Asthmatic obese children experience changes in functional capacity and autonomic control. Previous heart rate variability (HRV) studies were based on 24-hour recordings, little research has been conducted on the short-term HRV in asthmatic obese children, primarily during physical effort indifferent environmental humidity conditions. The aim of this study was to evaluate the effect of aerobic activity on short-term HRV in asthmatic obese children under two different environmental humidity conditions. Ten obese boys with mild asthma as experimental group and 15 obese healthy boys with the same conditions were involved as a control group. Protocol included progressive and exhaustive aerobic activities on a calibrated ergometer pedal bicycle in two various environmental humidity 35±5% and 65±5%. HRV was measured by PADSY MEDSET Holter monitoring device during three phases; pre-test, mid-test and post-test. Then, short-term HRV was assessed from calculation of the mean R-R interval measured on HRV at each phases. HRV significantly decreased at mid-test and post-test among asthmatic and health children. However, the aforesaid changes were significantly higher in the asthmatic than health children following. Moreover, decrease of short-term HRV was significantly greater in the 35±5% than 65±5% environmental humidity. Our findings suggest from the autonomic standpoint, asthmatic and non-asthmatic children respond differently to exhaustive exercise induced stress. Aerobic exercise at an environment with high humidity compared with the low humidity appears to have additional benefits on short-term HRV in that it enhances the parasympathetic and autonomic modulation of the heart in asthmatic obese children.

  1. Depression, comorbid anxiety disorders, and heart rate variability in physically healthy, unmedicated patients: implications for cardiovascular risk.

    Science.gov (United States)

    Kemp, Andrew H; Quintana, Daniel S; Felmingham, Kim L; Matthews, Slade; Jelinek, Herbert F

    2012-01-01

    There is evidence that heart rate variability (HRV) is reduced in major depressive disorder (MDD), although there is debate about whether this effect is caused by medication or the disorder per se. MDD is associated with a two to fourfold increase in the risk of cardiac mortality, and HRV is a robust predictor of cardiac mortality; determining a direct link between HRV and not only MDD, but common comorbid anxiety disorders, will point to psychiatric indicators for cardiovascular risk reduction. To determine in physically healthy, unmedicated patients whether (1) HRV is reduced in MDD relative to controls, and (2) HRV reductions are driven by MDD alone, comorbid generalized anxiety disorder (GAD, characterized by anxious anticipation), or comorbid panic and posttraumatic stress disorders (PD/PTSD, characterized by anxious arousal). A case-control study in 2006 and 2007 on 73 MDD patients, including 24 without anxiety comorbidity, 24 with GAD, and 14 with PD/PTSD. Seventy-three MDD and 94 healthy age- and sex-matched control participants were recruited from the general community. Participants had no history of drug addiction, alcoholism, brain injury, loss of consciousness, stroke, neurological disorder, or serious medical conditions. There were no significant differences between the four groups in age, gender, BMI, or alcohol use. HRV was calculated from electrocardiography under a standardized short-term resting state condition. HRV was reduced in MDD relative to controls, an effect associated with a medium effect size. MDD participants with comorbid generalized anxiety disorder displayed the greatest reductions in HRV relative to controls, an effect associated with a large effect size. Unmedicated, physically healthy MDD patients with and without comorbid anxiety had reduced HRV. Those with comorbid GAD showed the greatest reductions. Implications for cardiovascular risk reduction strategies in otherwise healthy patients with psychiatric illness are discussed.

  2. Neuro-immune relationships at patients with chronic pyelonephrite and cholecystite. Communication 2. Correlations between parameters EEG, HRV and Phagocytosis

    OpenAIRE

    Kul’chyns’kyi, Andriy B; Kovbasnyuk, Marta M; Korolyshyn, Tetyana A; Kyjenko, Valeriy M; Zukow, Walery; Popovych, Igor L

    2016-01-01

    Kul’chyns’kyi Andriy B, Kovbasnyuk Marta M, Korolyshyn Tetyana A, Kyjenko Valeriy M, Zukow Walery, Popovych Igor L. Neuro-immune relationships at patients with chronic pyelonephrite and cholecystite. Communication 2. Correlations between parameters EEG, HRV and Phagocytosis. Journal of Education, Health and Sport. 2016;6(10):377-401. eISSN 2391-8306. DOI http://dx.doi.org/10.5281/zenodo.163221 http://ojs.ukw.edu.pl/index.php/johs/article/view/3957 The journal h...

  3. Modeling Psychological Attributes in Psychology – An Epistemological Discussion: Network Analysis vs. Latent Variables

    Science.gov (United States)

    Guyon, Hervé; Falissard, Bruno; Kop, Jean-Luc

    2017-01-01

    Network Analysis is considered as a new method that challenges Latent Variable models in inferring psychological attributes. With Network Analysis, psychological attributes are derived from a complex system of components without the need to call on any latent variables. But the ontological status of psychological attributes is not adequately defined with Network Analysis, because a psychological attribute is both a complex system and a property emerging from this complex system. The aim of this article is to reappraise the legitimacy of latent variable models by engaging in an ontological and epistemological discussion on psychological attributes. Psychological attributes relate to the mental equilibrium of individuals embedded in their social interactions, as robust attractors within complex dynamic processes with emergent properties, distinct from physical entities located in precise areas of the brain. Latent variables thus possess legitimacy, because the emergent properties can be conceptualized and analyzed on the sole basis of their manifestations, without exploring the upstream complex system. However, in opposition with the usual Latent Variable models, this article is in favor of the integration of a dynamic system of manifestations. Latent Variables models and Network Analysis thus appear as complementary approaches. New approaches combining Latent Network Models and Network Residuals are certainly a promising new way to infer psychological attributes, placing psychological attributes in an inter-subjective dynamic approach. Pragmatism-realism appears as the epistemological framework required if we are to use latent variables as representations of psychological attributes. PMID:28572780

  4. 24-Hour Blood Pressure Variability Assessed by Average Real Variability: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Mena, Luis J; Felix, Vanessa G; Melgarejo, Jesus D; Maestre, Gladys E

    2017-10-19

    Although 24-hour blood pressure (BP) variability (BPV) is predictive of cardiovascular outcomes independent of absolute BP levels, it is not regularly assessed in clinical practice. One possible limitation to routine BPV assessment is the lack of standardized methods for accurately estimating 24-hour BPV. We conducted a systematic review to assess the predictive power of reported BPV indexes to address appropriate quantification of 24-hour BPV, including the average real variability (ARV) index. Studies chosen for review were those that presented data for 24-hour BPV in adults from meta-analysis, longitudinal or cross-sectional design, and examined BPV in terms of the following issues: (1) methods used to calculate and evaluate ARV; (2) assessment of 24-hour BPV determined using noninvasive ambulatory BP monitoring; (3) multivariate analysis adjusted for covariates, including some measure of BP; (4) association of 24-hour BPV with subclinical organ damage; and (5) the predictive value of 24-hour BPV on target organ damage and rate of cardiovascular events. Of the 19 assessed studies, 17 reported significant associations between high ARV and the presence and progression of subclinical organ damage, as well as the incidence of hard end points, such as cardiovascular events. In all these cases, ARV remained a significant independent predictor ( P <0.05) after adjustment for BP and other clinical factors. In addition, increased ARV in systolic BP was associated with risk of all cardiovascular events (hazard ratio, 1.18; 95% confidence interval, 1.09-1.27). Only 2 cross-sectional studies did not find that high ARV was a significant risk factor. Current evidence suggests that ARV index adds significant prognostic information to 24-hour ambulatory BP monitoring and is a useful approach for studying the clinical value of BPV. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

  5. Heart Rate Variability: Effect of Exercise Intensity on Postexercise Response

    Science.gov (United States)

    James, David V. B.; Munson, Steven C.; Maldonado-Martin, Sara; De Ste Croix, Mark B. A.

    2012-01-01

    The purpose of the present study was to investigate the influence of two exercise intensities (moderate and severe) on heart rate variability (HRV) response in 16 runners 1 hr prior to (-1 hr) and at +1 hr, +24 hr, +48 hr, and +72 hr following each exercise session. Time domain indexes and a high frequency component showed a significant decrease…

  6. Heart rate variability is reduced during acute uncomplicated diverticulitis

    DEFF Research Database (Denmark)

    Huang, Chenxi; Alamili, Mahdi; Rosenberg, Jacob

    2016-01-01

    BACKGROUND: The aim of the present study was to report the trajectory of heart rate variability (HRV) indices during a low-grade acute inflammation and their associations to biomarkers for infection. METHODS: Twelve patients with uncomplicated acute diverticulitis completed this observational study...

  7. Heart rate variability and cognitive processing: The autonomic response to task demands.

    Science.gov (United States)

    Luque-Casado, Antonio; Perales, José C; Cárdenas, David; Sanabria, Daniel

    2016-01-01

    This study investigated variations in heart rate variability (HRV) as a function of cognitive demands. Participants completed an execution condition including the psychomotor vigilance task, a working memory task and a duration discrimination task. The control condition consisted of oddball versions (participants had to detect the rare event) of the tasks from the execution condition, designed to control for the effect of the task parameters (stimulus duration and stimulus rate) on HRV. The NASA-TLX questionnaire was used as a subjective measure of cognitive workload across tasks and conditions. Three major findings emerged from this study. First, HRV varied as a function of task demands (with the lowest values in the working memory task). Second, and crucially, we found similar HRV values when comparing each of the tasks with its oddball control equivalent, and a significant decrement in HRV as a function of time-on-task. Finally, the NASA-TLX results showed larger cognitive workload in the execution condition than in the oddball control condition, and scores variations as a function of task. Taken together, our results suggest that HRV is highly sensitive to overall demands of sustained attention over and above the influence of other cognitive processes suggested by previous literature. In addition, our study highlights a potential dissociation between objective and subjective measures of mental workload, with important implications in applied settings. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Heart rate variability in prediction of individual adaptation to endurance training in recreational endurance runners.

    Science.gov (United States)

    Vesterinen, V; Häkkinen, K; Hynynen, E; Mikkola, J; Hokka, L; Nummela, A

    2013-03-01

    The aim of this study was to investigate whether nocturnal heart rate variability (HRV) can be used to predict changes in endurance performance during 28 weeks of endurance training. The training was divided into 14 weeks of basic training (BTP) and 14 weeks of intensive training periods (ITP). Endurance performance characteristics, nocturnal HRV, and serum hormone concentrations were measured before and after both training periods in 28 recreational endurance runners. During the study peak treadmill running speed (Vpeak ) improved by 7.5 ± 4.5%. No changes were observed in HRV indices after BTP, but after ITP, these indices increased significantly (HFP: 1.9%, P=0.026; TP: 1.7%, P=0.007). Significant correlations were observed between the change of Vpeak and HRV indices (TP: r=0.75, PHRV among recreational endurance runners, it seems that moderate- and high-intensity training are needed. This study showed that recreational endurance runners with a high HRV at baseline improved their endurance running performance after ITP more than runners with low baseline HRV. © 2011 John Wiley & Sons A/S.

  9. Influence diagram of physiological and environmental factors affecting heart rate variability: an extended literature overview

    Directory of Open Access Journals (Sweden)

    Julien Fatisson

    2016-09-01

    Full Text Available Heart rate variability (HRV corresponds to the adaptation of the heart to any stimulus. In fact, among the pathologies affecting HRV the most, there are the cardiovascular diseases and depressive disorders, which are associated with high medical cost in Western societies. Consequently, HRV is now widely used as an index of health.In order to better understand how this adaptation takes place, it is necessary to examine which factors directly influence HRV, whether they have a physiological or environmental origin. The primary objective of this research is therefore to conduct a literature review in order to get a comprehensive overview of the subject.The system of these factors affecting HRV can be divided into the following five categories: physiological and pathological factors, environmental factors, lifestyle factors, non-modifiable factors and effects. The direct interrelationships between these factors and HRV can be regrouped into an influence diagram. This diagram can therefore serve as a basis to improve daily clinical practice as well as help design even more precise research protocols.

  10. The Relationship between Heart Rate Variability and Adiposity Differs for Central and Overall Adiposity

    Directory of Open Access Journals (Sweden)

    B. Gwen Windham

    2012-01-01

    Full Text Available While frank obesity is associated with reduced HRV, indicative of poorer autonomic nervous system (ANS function, the association between body mass index (BMI and HRV is less clear. We hypothesized that effects of adiposity on ANS are mostly mediated by visceral fat and less by subcutaneous fat; therefore, centrally distributed adipose tissue, that is, waist circumference (WC, should be more strongly associated with HRV than overall adiposity (BMI. To examine this hypothesis, we used data collected in a subset of the Baltimore Longitudinal Study of Aging to compare strength of association between HRV and WC to that of HRV and BMI. Time domain HRV variables SDNN (standard deviation of successive differences in normal-to-normal (