Parak, Jakub; Tarniceriu, Adrian; Renevey, Philippe; Bertschi, Mattia; Delgado-Gonzalo, Ricard; Korhonen, Ilkka
Heart rate variability (HRV) provides significant information about the health status of an individual. Optical heart rate monitoring is a comfortable alternative to ECG based heart rate monitoring. However, most available optical heart rate monitoring devices do not supply beat-to-beat detection accuracy required by proper HRV analysis. We evaluate the beat-to-beat detection accuracy of a recent wrist-worn optical heart rate monitoring device, PulseOn (PO). Ten subjects (8 male and 2 female; 35.9±10.3 years old) participated in the study. HRV was recorded with PO and Firstbeat Bodyguard 2 (BG2) device, which was used as an ECG based reference. HRV was recorded during sleep. As compared to BG2, PO detected on average 99.57% of the heartbeats (0.43% of beats missed) and had 0.72% extra beat detection rate, with 5.94 ms mean absolute error (MAE) in beat-to-beat intervals (RRI) as compared to the ECG based RRI BG2. Mean RMSSD difference between PO and BG2 derived HRV was 3.1 ms. Therefore, PO provides an accurate method for long term HRV monitoring during sleep. PMID:26738173
Myint, Cho Zin; Barsoum, Nader; Ing, Wong Kiing
The wireless network technology is increasingly important in healthcare as a result of the aging population and the tendency to acquire chronic disease such as heart attack, high blood pressure amongst the elderly. A wireless sensor network system that has the capability to monitor physiological sign such as SpO2 (Saturation of Arterial Oxygen) and heart beat rate in real-time from the human's body is highlighted in this study. This research is to design a prototype sensor network hardware, which consists of microcontroller PIC18F series and transceiver unit. The sensor is corporate into a wearable body sensor network which is small in size and easy to use. The sensor allows a non invasive, real time method to provide information regarding the health of the body. This enables a more efficient and economical means for managing the health care of the population.
Liu Yong Qiang
Full Text Available Purpose: ensure increase of effectiveness of training process’s control by means of operative correction of training loads of different qualification judo wrestlers’ heart beats rate indicators. Material: the research was conducted on the base of Brest SCJSOR № 1. Judo wrestlers of different sport qualification (age 17-19 years old, n=15 participated in the research. Monitoring of judo wrestlers’ heart beats rate was carried out with the help of system “Polar”. Results: we have found factorial structure of functional fitness in every profile of sportsmen. Model characteristics of judo wrestlers were supplemented with the most important sides of functional fitness. Analysis of indicators of restoration effectiveness indicators (REI in both groups of judo wrestlers showed high level of organism’s responsiveness to training load of special and power orientation in comparison with speed power load. We have worked out algorithm of operative correction of training loads by indicators of heart beats rate in training process, depending on orientation and intensity of loads’ physiological influence on judo wrestler. Conclusions: Telemetric on-line monitoring of sportsman’s heart beats rate and calculation of REI permit to objectively assess effectiveness of training’s construction and of micro-cycle in total and detect in due time the trend to development of over-loading and failure of adaptation.
Feng WEN; Fang-tian HE
Heart rate variability (HRV) analysis is affected by ectopic beats.An efficient method was proposed to deal with the ectopic beats.The method was based on trend correlation of the heart timing signal.Predictor of R-R interval (RRI) value at ectopic beat time was constructed by the weight calculation and the slope estimation of preceding normal RRI.The type of ectopic beat was detected and replaced by the predictor of RRI.The performance of the simulated signal after ectopic correction was tested by the standard value using power spectrum density (PSD) estimation,whereas the results of clinical data with ectopic beats were compared with the adjacent ectopic-free data.The result showed the frequency indexes after ectopy corrected had less error than other methods with the test of simulated signal and clinical data.It indicated our method could improve the PSD estimation in HRV analysis.The method had advantages of high accuracy and real time properties to recover the sinus node modulation.
Barad, Lili; Novak, Atara; Ben-Ari, Erez; Lorber, Avraham; Itskovitz-Eldor, Joseph; Rosen, Michael R; Weissman, Amir; Binah, Ofer
Background We previously reported that induced Pluripotent Stem Cell-derived cardiomyocytes (iPSC-CM) manifest beat rate variability (BRV) resembling heart rate variability (HRV) in human sinoatrial node (SAN). We now hypothesized the BRV-HRV continuum originates in pacemaker cells. Objective To investigate whether cellular BRV is a source of HRV dynamics, we hypothesized three-levels of interaction among different cardiomyocyte entities: (1) single pacemaker cells, (2) networks of electrically coupled pacemaker cells and (3) in situ SAN. Methods We measured BRV/HRV properties in single pacemaker cells, iPSC-derived contracting embryoid bodies (EBs) and electrocardiograms from the same individual. Results Pronounced BRV/HRV were present at all three levels. Coefficient of variance (COV) of inter-beat intervals (IBI) and Poincaré plot SD1 and SD2 in single cells were 20x > EBs (P0.05). We also compared BRV magnitude among single cells, small (~5-10 cells) and larger EBs (>10 cells): BRV indices progressively increased (P<0.05) as cell number decreased. Disrupting intracellular Ca2+ handling markedly augmented BRV magnitude, revealing a unique bi-modal firing pattern, suggesting intracellular mechanisms contribute to BRV/HRV and the fractal behavior of heart rhythm. Conclusions The decreased BRV magnitude in transitioning from single cell to EB suggests HRV of hearts in situ originates from summation and integration of multiple cell-based oscillators. Hence, complex interactions among multiple pacemaker cells and intracellular Ca2+ handling determine HRV in humans and isolated cardiomyocyte networks. PMID:25052725
Full Text Available Abstract Background Guidelines recommend maintaining the heart rate (HR of acute stroke patients within physiological limits; data on the frequency and predictors of significant deviations from these limits are scarce. Methods Demographical data, stroke risk factors, NIH stroke scale score, lesion size and location, and ECG parameters were prospectively assessed in 256 patients with ischemic stroke. Patients were continuously monitored for at least 24 hours on a certified stroke unit. Tachycardia (HR ≥120 bpm and bradycardia (HR Results HR ≥120 bpm occurred in 39 patients (15%. Stroke severity (larger lesion size/higher NIHSS-score on admission, atrial fibrillation and HR on admission predicted its occurrence. HR Conclusions Significant tachycardia and bradycardia are frequent phenomena in acute stroke; however they do not independently predict clinical course or outcome. Continuous monitoring allows detecting rhythm disturbances in stroke patients and allows deciding whether urgent medical treatment is necessary.
Kesner, Samuel Benjamin
Compliant and flexible cardiac catheters provide direct access to the inside of the heart via the vascular system without requiring clinicians to stop the heart or open the chest. However, the fast motion of the intracardiac structures makes it difficult to modify and repair the cardiac tissue in a controlled and safe manner. In addition, rigid robotic tools for beating heart surgery require the chest to be opened and the heart exposed, making the procedures highly invasive. The novel robot...
This paper proposes a novel system to classify three types of electrocardiogram beats, namely normal beats and two manifestations of heart arrhythmia. This system includes three main modules: a feature extraction module, a classifier module, and an optimization module. In the feature extraction module, a proper set combining the shape features and timing features is proposed as the efficient characteristic of the patterns. In the classifier module, a multi-class support vector machine (SVM)-b...
... nlm.nih.gov/medlineplus/news/fullstory_158687.html Race May Influence Risk for Irregular Heart Beat Whites ... between the heart rhythm disorder atrial fibrillation and race, a new study says. Whites with heart failure ...
Full Text Available This paper proposes a novel system to classify three types of electrocardiogram beats, namely normal beats and two manifestations of heart arrhythmia. This system includes three main modules: a feature extraction module, a classifier module, and an optimization module. In the feature extraction module, a proper set combining the shape features and timing features is proposed as the efficient characteristic of the patterns. In the classifier module, a multi-class support vector machine (SVM-based classifier is proposed. For the optimization module, a particle swarm optimization algorithm is proposed to search for the best value of the SVM parameters and upstream by looking for the best subset of features that feed the classifier. Simulation results show that the proposed algorithm has very high recognition accuracy. This high efficiency is achieved with only little features, which have been selected using particle swarm optimizer.
Correlation between heart pathology and statistical properties of heart beat data has been studied. It is shown that heart beat data has different scaling behavior for healthy and disease cases. Possibilities to develop new monitoring technique based on the permanent control of the correlations in heart beat data are discussed. copyright 1996 American Institute of Physics
... Keep the Beat": Healthy Blood Pressure Helps Prevent Heart Disease Past Issues / Winter 2010 Table of Contents Your ... a condition that also increases the chance of heart disease and stroke. High blood pressure is especially common ...
Urbanowicz, K; Holyst, J A; Zebrowski, J J
We measure the content of random uncorrelated noise in heart rate variability using a general method of noise level estimation using a coarse grained entropy. We show that usually - except for atrial fibrillation - the level of such noise is within 5 - 15% of the variance of the data and that the variability due to the linearly correlated processes is dominant in all cases analysed but atrial fibrillation. The nonlinear deterministic content of heart rate variability remains significant and may not be ignored.
Background and aim Heart rate (HR) can appear static and regular at rest, during exercise or recovery after exercise. However, HR is constantly adjusted due to factors such as breathing, blood pressure control, thermoregulation and the renin-angiotensin system, leading to a more dynamic response that can be quantified using HRV (heart rate variability). HRV is defined as the deviation in time between successive normal heart beat and is a noninvasive method to measure the total variation in a ...
Full Text Available Soft gentle music accompanies us throughout our lifetime; it is the music of our heart beating. Although at times it is questionable as to who serves as conductor of the orchestra, there is little doubt that our ion channels are the main players. Whenever one of them plays too loudly, too softly or simply off key, disharmony results, sometimes leading to total disruption of the rate and rhythm. Ion channels can disrupt the music of our heart by different mechanisms. Sometimes their function is correct, but their expression is altered by underlying cardiac diseases (i.e. heart failure; sometimes the defect is in their structure, because of an underlying genetic defect, and in this case a channelopathy is present.
Najdoski, Metodija; Mirceski, Valentin; Petrusevski, Vladimir M.; Demiri, Sani
The mercury beating heart (MBH) is a commonly performed experiment, which is based on varying oxidizing agents and substituting other metals for iron. Various modified versions of the classical demonstration of the experiment are presented.
Delius, Juan; Lindenblatt, Ulrike; Lombardi, Celia
The electrocardiogram of pigeons was recorded while they pecked an impact transducer under operant control according to a variable ratio schedule. An analysis of the records in terms of crossaverages between heart beats and pecks. the quasi-equivalents of crosscorrelation functions, revealed that pecks and heart beats tend to coincide temporally at above chance levels according to patterns that vary from individual to individual pigeon. The mechanisms and the functions of the coupling are dis...
Mensch, Arthur; Piuze, Emmanuel; Lehnert, Lucas;
We combine recent work on modeling cardiac mechanics using a finite volume method with the insight that heart wall myofiber orientations exhibit a particular volumetric geometry. In our finite vol- ume mechanical simulation we use Maurer-Cartan one-forms to add a geometrical consistency term to...... control the rate at which myofiber ori- entation changes in the direction perpendicular to the heart wall. This allows us to estimate material properties related to both the passive and active parameters in our model. We have obtained preliminary results on the 4 canine datasets of the 2014 mechanics...
The death of the donor is a mandatory prerequisite for organ transplantation (dead donor rule) worldwide. It is a medical, legal and ethical consensus to accept the concept of brain death, as first proposed in 1968 by the ad hoc committee of the Harvard Medical School, as a certain criterion of death. In isolated cases where the diagnosis of brain death was claimed to be wrong, it could be demonstrated that the diagnostic procedure for brain death had not been correctly performed. In March 2014 a joint statement by the German neuromedical societies emphasized that 1) the diagnosis of brain death is one of the safest diagnoses in medicine if performed according to accepted medical standards and criteria and 2) the concept of non-heart-beating donors (NHBD, i. e. organ donation after an arbitrarily defined duration of circulatory and cardiac arrest) practiced in some European countries must be absolutely rejected because it implicates a high risk of diagnostic error. According to the current literature it is unclear at what time cardiac and circulatory arrest is irreversible and leads to irreversible cessation of all functions of the entire brain including the brainstem, even though clinical signs of cessation of brain functions are always found after 10 min. Furthermore, is it often an arbitrary decision to exactly define the duration of cardiac arrest if continuous echocardiographic monitoring has not been carried out from the very beginning. Last but not least there are ethical concerns against the concept of NHBD because it might influence therapeutic efforts to resuscitate a patient with cardiac arrest. Therefore, the German Medical Council (BÄK) has repeatedly rejected the concept of NHBD for organ transplantation since 1995. PMID:26830897
Ramasamy, Mouli; Oh, Sechang; Varadan, Vijay K.
The present day bio-technical field concentrates on developing various types of innovative ambulatory and wearable devices to monitor several bio-physical, physio-pathological, bio-electrical and bio-potential factors to assess a human body's health condition without intruding quotidian activities. One of the most important aspects of this evolving technology is monitoring heart beat rate and electrocardiogram (ECG) from which many other subsidiary results can be derived. Conventionally, the devices and systems consumes a lot of power since the acquired signals are always processed on the receiver end. Because of this back end processing, the unprocessed raw data is transmitted resulting in usage of more power, memory and processing time. This paper proposes an innovative technique where the acquired signals are processed by a microcontroller in the front end of the module and just the processed signal is then transmitted wirelessly to the display unit. Therefore, power consumption is considerably reduced and clearer data analysis is performed within the module. This also avoids the need for the user to be educated about usage of the device and signal/system analysis, since only the number of heart beats will displayed at the user end. Additionally, the proposed concept also eradicates the other disadvantages like obtrusiveness, high power consumption and size. To demonstrate the above said factors, a commercial controller board was used to extend the monitoring method by using the saved ECG data from a computer.
Wood, Nathan A.; Waugh, Kevin; Liu, Tian Yu Tommy; Zenati, Marco A.; Riviere, Cameron N.
This paper presents a framework for localizing a miniature epicardial crawling robot, HeartLander, on the beating heart using only 6-degree-of-freedom position measurements from an electromagnetic position tracker and a dynamic surface model of the heart. Using only this information, motion and observation models of the system are developed such that a particle filter can accurately estimate not only the location of the robot on the surface of the heart, but also the pose of the heart in the ...
To realize intra-cardiac surgery without cardio-pulmonary bypass, a medical imaging technique with both high image quality and data acquisition rate that is fast enough to follow heart beat movements is required. In this research, we proposed a method that utilized the image quality of MRI and the speed of ultrasound. We developed a 4D image reconstruction method using image registration of 3D MRI and 4D ultrasound images. The registration method consists of rigid registration between 3D MRI and 3D ultrasound with the same heart beat phase, and non-rigid registration between 3D ultrasound images from different heart beat phases. Non-rigid registration was performed with B-spline based registration using variable spring model. In phantom experiment using balloon phantom, registration accuracy was less than 2 mm for total heart volume variation range of 10%. We applied our registration method on 3D MRI and 4D ultrasound images of a volunteer's beating heart data and confirmed through visual observation that heart beat pattern was well reproduced. (orig.)
A. Sarkar; Barat, P.
The heart beat data recorded from samples before and during meditation are analyzed using two different scaling analysis methods. These analyses revealed that mediation severely affects the long range correlation of heart beat of a normal heart. Moreover, it is found that meditation induces periodic behavior in the heart beat. The complexity of the heart rate variability is quantified using multiscale entropy analysis and recurrence analysis. The complexity of the heart beat during mediation ...
The heart beat data recorded from samples before and during meditation are analyzed using two different scaling analysis methods. These analyses revealed that mediation severely affects the long range correlation of heart beat of a normal heart. Moreover, it is found that meditation induces periodic behavior in the heart beat. The complexity of the heart rate variability is quantified using multiscale entropy analysis and recurrence analysis. The complexity of the heart beat during mediation is found to be more.
Howe, Robert D.; Yuen, Shelten G.; Kettler, Daniel T.; Notovny, Paul M.; Plowes, Richard D.
3D ultrasound imaging has enabled minimally invasive, beating heart intracardiac procedures. However, rapid heart motion poses a serious challenge to the surgeon that is compounded by significant time delays and noise in 3D ultrasound. This paper investigates the concept of using a one-degree-of-freedom motion compensation system to synchronize with tissue motions that may be approximated by 1D motion models. We characterize the motion of the mitral valve annulus and show that it is well appr...
Lundby, C; Van Hall, Gerrit
We have measured maximal heart rate during a graded maximal bicycle exercise test to exhaustion in five healthy climbers before and during an expedition to Mt. Everest. Maximal heart rates at sea level were 186 (177-204) beats/min(-1) at sea level and 170 (169-182) beats/min(-1) with acute hypoxia....... After 1, 4 and 6 weeks of acclimatization to 5400 m, maximal heart rates were 155 (135-182), 158 (144-182), and 155 (140-183) beats/min(-1), respectively. Heart rates of two of the climbers were measured during their attempt to reach the summit of Mt. Everest without the use of supplemental oxygen. The...... peak heart rates at 8,750 m for the two climbers were 142 and 144 beats/min(-1), which were similar to their maximal heart rates during exhaustive bicycle exercise at 5,400 m, the values being 144 and 148 beats/min(-1), respectively. The peak heart rates at 8,750 m are in agreement with other field...
The effect of low-dose β-blocker on heart rate and heart rate variability in health subjects wth a resting heart rate of less than 65 beats per minute: Effect on the quality of prospective electrocardiography-gated coronary CT angiography
We assessed the effect of a low-dose β-blocker on heart rate (HR), HR variability (HRV) and image quality of prospective electrocardiography-gated coronary CT angiography (CCTA) in healthy subjects with low HR. CCTA was performed with a 64-slice CT in 75 subjects with a HR of less than 65 beats per minute (bpm). Subjects were divided into 2 groups: Group 1 (G1), 35 with a low dose β-blocker; and Group 2 (G2), 40 without pre-medication. The image quality (IQ) of the CCTA was assessed on a 4-point grading scale (1, poor; 4, excellent). Initial HR (bpm) was not different between the 2 groups. HR during CCTA was lower in G1 than G2 (50.3 ± 5.6 vs. 53.3 ± 4.8, p = 0.016). HRV was not different between the 2 groups. Per-segment analysis showed better IQ at the mid-segment of the right coronary artery (3.0 ± 0.9 vs. 2.5 ± 1.1, p = 0.039) and the first diagonal branch (3.4 ± 0.6 vs. 3.1 ± 0.7, p = 0.024), in the G1 than the G2 group, respectively. The IQ was negatively correlated with HR, but no correlation was found between HRV and IQ. The IQs in the per-vessel analysis were not different between the 2 groups. Low-dose β-blocker reduced HR and improved the IQ of CCTA in a few segments, even at a HR of less than 65 bpm. However the effect was limited.
Wadehn, Federico; Carnal, David; Loeliger, Hans-Andrea
Heart rate variability is one of the key parameters for assessing the health status of a subject's cardiovascular system. This paper presents a local model fitting algorithm used for finding single heart beats in photoplethysmogram recordings. The local fit of exponentially decaying cosines of frequencies within the physiological range is used to detect the presence of a heart beat. Using 42 subjects from the CapnoBase database, the average heart rate error was 0.16 BPM and the standard deviation of the absolute estimation error was 0.24 BPM. PMID:26737125
This study presents a systematic comparison of different approaches to the automated selection of the principal components (PC) which optimise the detection of maternal and fetal heart beats from non-invasive maternal abdominal recordings. A public database of 75 4-channel non-invasive maternal abdominal recordings was used for training the algorithm. Four methods were developed and assessed to determine the optimal PC: (1) power spectral distribution, (2) root mean square, (3) sample entropy, and (4) QRS template. The sensitivity of the performance of the algorithm to large-amplitude noise removal (by wavelet de-noising) and maternal beat cancellation methods were also assessed. The accuracy of maternal and fetal beat detection was assessed against reference annotations and quantified using the detection accuracy score F1 [2*PPV*Se / (PPV + Se)], sensitivity (Se), and positive predictive value (PPV). The best performing implementation was assessed on a test dataset of 100 recordings and the agreement between the computed and the reference fetal heart rate (fHR) and fetal RR (fRR) time series quantified. The best performance for detecting maternal beats (F1 99.3%, Se 99.0%, PPV 99.7%) was obtained when using the QRS template method to select the optimal maternal PC and applying wavelet de-noising. The best performance for detecting fetal beats (F1 89.8%, Se 89.3%, PPV 90.5%) was obtained when the optimal fetal PC was selected using the sample entropy method and utilising a fixed-length time window for the cancellation of the maternal beats. The performance on the test dataset was 142.7 beats2/min2 for fHR and 19.9 ms for fRR, ranking respectively 14 and 17 (out of 29) when compared to the other algorithms presented at the Physionet Challenge 2013. (paper)
Objective: To evaluate the feasibility of dual-source computed tomography (DSCT) coronary angiography in a population with premature heart-beats. Methods: Seventy patients with suspected coronary artery disease and premature heart-beats were routinely imaged on a DSCT scanner (Somatom Definition, Siemens AG, Germany). The images were reconstmcted before and after ECG editing. Two readers independently assessed image quality of all coronary segments using a four-point grading scale from excellent (1) to non-assessable (4). The results of the two groups were compared with a paired t-test, and a P value of less than 0.05 was considered significant. Results: The mean heart rate during examination ranged from 49 to 111 bpm[ mean(70.7±12.4) bpm]. Twenty-eight of 70 patients with relatively small variability of the heart rate [(41.0±18.4) bpm] got diagnostic image quality without ECG editing. In other 42 patients with larger variability of the heart rate [(71.4±28.7) bpm], the mean image quality scores were 2.09±1.27 and 1.50±0.79 before and after ECG editing, there was a significant difference (t= 13.764, P2=121.846, P<0.01). Finally, the diagnostic image accounted 98.0% (1014/1035) in all segments of 70 patients. Conclusion: DSCT can provide diagnostic images for patients with premature heart-beats. The image quality in patients with larger variability of the heart rate can be significantly improved through ECG editing. (authors)
Southall, D P; Johnston, F.; Shinebourne, E. A.; Johnston, P G
Twenty-four hour electrocardiographic recordings were made on 104 randomly selected, healthy 7 to 11-year-old children. Ninety-two were technically adequate and suitable for analysis. The mean highest heart rate measured by direct electrocardiographic analysis over nine beats was 164 +/- 17. The mean lowest heart rates were 49 +/- 6 over three beats', and 56 +/- 6 over nine beats' duration. The maximum duration of heart rates less than 55/minute was 40 minutes. At their lowest heart rates 41 ...
Weis, A.; Bison, G.; Wynands, R.
Stimulated by recent progress in laser-based optical magnetometry and in developments of powerful signal denoising techniques we initiated the development of a low-cost laser-driven optically pumped magnetometer (OPM) for biomagnetic applications. The OPM uses optically pumped cesium atoms in glass cells of a few cm3. Its sensitivity (<70 fT in 1 Hz bandwidth), bandwidth (140 Hz), and spatial resolution (cm) were optimized for the two-dimensional mapping of the magnetic field produced above the chest by the beating human heart. Signal averaging using an electrocardiographic signal as a reference and gradiometric detection reduces residual noise significantly so that the dynamics of the heart field can be displayed a movie. We discuss the principle of the technique and give a status report on ongoing work towards the development of a multichannel device.
João Fabrício Mota Rodrigues
Full Text Available Body size is highly correlated with metabolism, which in turn influences physiological rates such as heart rate. In general, heart rate is negatively influenced by the size of animal's body, but there is insufficient data corroborating this pattern in snakes. This study evaluated how body size affects heart rate in captive Boa constrictor Linnaeus, 1758. We measured the heart rate of 30 snakes using digital palpation and evaluated how this rate is influenced by body mass and sex using Analysis of Covariance (ANCOVA. The heart rate of the snakes was 58.8 ± 6.7 bpm (beats per minute. Body size, estimated as log-transformed body mass, negatively influenced heart rate (F1,28 = 10.27, p = 0.003, slope = -0.00004, R2 = 0.27, but sex had no effect (F1,27 = 0.07, p = 0.80. In conclusion, this result corroborates the negative relationship between body size and heart rate for snakes and reinforces the influence of related metabolic characteristics, such as body size, on the physiological parameters of snakes.
Shi, Cong; Liu, Xiaohua; Kong, Lingqin; Wu, Jizhe; Liu, Ming; Dong, Liquan; Hui, Mei; Zhao, Yuejin
In recent years heart and blood vessel diseases kill more people than everything else combined. The daily test of heart rate for the prevention and treatment of the heart head blood-vessel disease has the vital significance. In order to adapt the transformation of medical model and solve the low accuracy problem of the traditional method of heart rate measuring, we present a new method to monitor heart rate in this paper. The heart rate detection is designed for daily heart rate detection .The heart rate signal is collected by the heart rate sensor. The signal through signal processing circuits converts into sine wave and square wave in turn. And then the signal is transmitted to the computer by data collection card. Finally, we use LABVIEW and MATLAB to show the heart rate wave and calculate the heart rate. By doing contrast experiment with medical heart rate product, experimental results show that the system can realize rapidly and accurately measure the heart rate value. A measurement can be completed within 10 seconds and the error is less than 3beat/min. And the result shows that the method in this paper has a strong anti-interference ability. It can effectively suppress the movement interference. Beyond that the result is insensitive to light.
The rate of heart beat is controlled by autonomic nervous system: accelerated by the sympathetic system and slowed by the parasympathetic system. Scaling properties in heart rate are usually related to the intrinsic dynamics of this physiological regulatory system. The two packages calculating local exponent spectra: Wavelet Transform Modulus Maxima and Multifractal Detrended Fluctuation Analysis (accessible from Physionet home page http://circ.ahajournals.org/cgi/content/full/101/23/e215) are tested, and then used to investigate the spectrum of singularity exponents in series of heart rates obtained from patients suffering from reduced left ventricle systolic function. It occurs that this state of a heart could be connected to some perturbation in the regulatory system, because the heart rate appears to be less controlled than in a healthy human heart. The multifractality in the heart rate signal is weakened: the spectrum is narrower and moved to higher values what indicate the higher activity of the sympatethic nervous system. (author)
Systolic time intervals are highly correlated to fundamental cardiac functions. Several studies have shown that these measurements have significant diagnostic and prognostic value in heart failure condition and are adequate for long-term patient follow-up and disease management. In this paper, we investigate the feasibility of using heart sound (HS) to accurately measure the opening and closing moments of the aortic heart valve. These moments are crucial to define the main systolic timings of the heart cycle, i.e. pre-ejection period (PEP) and left ventricular ejection time (LVET). We introduce an algorithm for automatic extraction of PEP and LVET using HS and electrocardiogram. PEP is estimated with a Bayesian approach using the signal's instantaneous amplitude and patient-specific time intervals between atrio-ventricular valve closure and aortic valve opening. As for LVET, since the aortic valve closure corresponds to the start of the S2 HS component, we base LVET estimation on the detection of the S2 onset. A comparative assessment of the main systolic time intervals is performed using synchronous signal acquisitions of the current gold standard in cardiac time-interval measurement, i.e. echocardiography, and HS. The algorithms were evaluated on a healthy population, as well as on a group of subjects with different cardiovascular diseases (CVD). In the healthy group, from a set of 942 heartbeats, the proposed algorithm achieved 7.66 ± 5.92 ms absolute PEP estimation error. For LVET, the absolute estimation error was 11.39 ± 8.98 ms. For the CVD population, 404 beats were used, leading to 11.86 ± 8.30 and 17.51 ± 17.21 ms absolute PEP and LVET errors, respectively. The results achieved in this study suggest that HS can be used to accurately estimate LVET and PEP. (paper)
Fan Liang; Xiaofeng Meng
Off‐pump coronary artery bypass graft surgery outperforms the traditional on‐pump surgery because the assisted robotic tools can cancel the relative motion between the beating heart and the robotic tools, which reduces post‐surgery complications for patients. The challenge for the robot assisted tool when tracking the beating heart is the abrupt change caused by the nonlinear nature of heart motion and high precision surgery requirements. A characteristic analysis of 3D heart motion data thro...
Serkan Cay; Goksel Cagirci; Ramazan Atak; Yucel Balbay; Ahmet Duran Demir; Sinan Aydogdu
Background Both early repolarization and altered heart rate profile are associated with sudden death. In this study, we aimed to demonstrate an association between early repolarization and heart rate profile during exercise.Methods A total of 84 subjects were included in the study. Comparable 44 subjects with early repolarization and 40 subjects with normal electrocardiogram underwent exercise stress testing. Resting heart rate, maximum heart rate, heart rate increment and decrement were analyzed.Results Both groups were comparable for baseline characteristics including resting heart rate. Maximum heart rate, heart rate increment and heart rate decrment of the subjects in early repolarization group had significantly decreased maximum heart rate, heart rate increment and heart rate decrement compared to control group (all P＜0.05). The lower heart rate increment (＜106 beats/min) and heart rate decrement (＜95 beats/min) were significantly associated with the presence of early repolarization. After adjustment for age and sex, the multiple-adjusted OR of the risk of presence of early repolarization was 2.98 (95% CI 1.21-7.34) (P=0.018) and 7.73 (95% CI 2.84-21.03) (P ＜0.001) for the lower heart rate increment and heart rate decrement compared to higher levels, respectively.Conclusions Subjects with early repolarization have altered heart rate profile during exercise compared to control subjects. This can be related to sudden death.
Singla, Tanu; Montoya, Fernando; Rivera, M.; Tajima, Shunsuke; Nakabayashi, Seiichiro; Parmananda, P.
We report synchronization of Mercury Beating Heart (MBH) oscillators using the environmental coupling mechanism. This mechanism involves interaction of the oscillators with a common medium/environment such that the oscillators do not interact among themselves. In the present work, we chose a modified MBH system as the common environment. In the absence of coupling, this modified system does not exhibit self sustained oscillations. It was observed that, as a result of the coupling of the MBH oscillators with this common environment, the electrical and the mechanical activities of both the oscillators synchronized simultaneously. Experimental results indicate the emergence of both lag and the complete synchronization in the MBH oscillators. Simulations of the phase oscillators were carried out in order to better understand the experimental observations.
Miriam R. Waldeck
Full Text Available Resting heart rate has sometimes been used as a marker of training status. It is reasonable to assume that the relationship between heart rate and training status should be more evident during sleep when extraneous factors that may influence heart rate are reduced. Therefore the aim of the study was to assess the repeatability of monitoring heart rate during sleep when training status remained unchanged, to determine if this measurement had sufficient precision to be used as a marker of training status. The heart rate of ten female subjects was monitored for 24 hours on three occasions over three weeks whilst training status remained unchanged. Average, minimum and maximum heart rate during sleep was calculated. The average heart rate of the group during sleep was similar on each of the three tests (65 ± 9, 63 ± 6 and 67 ± 7 beats·min-1 respectively. The range in minimum heart rate variation during sleep for all subjects over the three testing sessions was from 0 to 10 beats·min-1 (mean = 5 ± 3 beats·min-1 and for maximum heart rate variation was 2 to 31 beats·min-1 (mean = 13 ± 9 beats·min-1. In summary it was found that on an individual basis the minimum heart rate during sleep varied by about 8 beats·min-1. This amount of intrinsic day-to-day variation needs to be considered when changes in heart rate that may occur with changes in training status are interpreted
Geraci, P M; Sepe, V
In 2007 the non-heart-beating organ donation (NHBD) "Programma Alba" (Sunrise Programme) started in Pavia, Italy. The initial plan was to cut down waiting list for kidney transplantation, while its final aim is to shorten organ transplantation waiting lists. When compared to European countries and the USA, the Italian NHBD program has taken longer to get established. Initially Italian physicians were not entirely aware of the NHBD organ viability for transplantation, furthermore ethical issues and the need to regulate medical requirements to Italian law slowed down the NHBD program. In particular, Italian legislation provides for death ascertainment after irreversible cardiac arrest, 20-minute flat electrocardiogram. This no-touch period is longer when compared to worldwide legislation, and organ viability has been a main concern for Italian transplant doctors over the years. However, recent data let up to 40-minute warm ischemia time to preserve organ viability; this has encouraged Pavia's group to establish the NHBD "Programma Alba". It was designed according to Italian legislation from death diagnosis to graft placement, from this perspective must the significant role of the Transplant coordinator be recognized. Since 2007 seven kidneys have been gathered from seven NHBD. Of these, six NHBD kidneys have been transplanted. Currently, four patients are out of dialysis. This report is a detailed description of NHBD "Programma Alba" and its preliminary results. PMID:21617625
Mohamed Abdel Rahman Salem M.D,* Mostafa Elhamamsy M.D
Full Text Available adrenergic agonists decrease sympathetic tone with ensuing attenuation of neuroendocrine and hemodynamic responses to anesthesia and surgery. Also, administration of beta -adrenergic antagonists contributes to prophylaxis against hypertension, tachycardia and myocardial ischemia and myocardial protection during cardiac surgery. The effects of dexmedetomidine (DEX, a highly specific alpha -adrenergic agonist, on these responses have not yet been fully reported in patients undergoing cardiac surgery. Esmolol (ESM is a cardioselective, short-acting -blocking agent. Previous studies have established the effectiveness of esmolol in the reduction of hemodynamic responses during anesthetic induction. Aim: The study of hemodynamic responses of dexmedetomidine and esmolol and their effects on the anesthetic requirements during anesthesia in beating heart surgery. Methods: Forty patients scheduled for elective beating heart surgery received a !thereaf"#$%!&'" end of surgery in the ESM group. Total intravenous anesthesia using fentanyl, cisatracurium a"( -* +of surgery. Hemodynamics measured included heart rate, mean arterial pressure, filling pressures, cardiac index, systemic and pulmonary vascular resistances. The incidence of hypotension, hypertension, tachycardia, bradycardia, dysrhythmias, ST segment changes, total anesthetics requirements, muscle rigidity and postoperative shivering were recorded. Results: #$%",-.&/ 0*! 0 ! l/min/m ( 1 ! + 2
Gert Jan Pelgrim
Full Text Available Objective. To test the feasibility of a CT-compatible, ex vivo, perfused porcine heart model for myocardial perfusion CT imaging. Methods. One porcine heart was perfused according to Langendorff. Dynamic perfusion scanning was performed with a second-generation dual source CT scanner. Circulatory parameters like blood flow, aortic pressure, and heart rate were monitored throughout the experiment. Stenosis was induced in the circumflex artery, controlled by a fractional flow reserve (FFR pressure wire. CT-derived myocardial perfusion parameters were analysed at FFR of 1 to 0.10/0.0. Results. CT images did not show major artefacts due to interference of the model setup. The pacemaker-induced heart rhythm was generally stable at 70 beats per minute. During most of the experiment, blood flow was 0.9–1.0 L/min, and arterial pressure varied between 80 and 95 mm/Hg. Blood flow decreased and arterial pressure increased by approximately 10% after inducing a stenosis with FFR ≤ 0.50. Dynamic perfusion scanning was possible across the range of stenosis grades. Perfusion parameters of circumflex-perfused myocardial segments were affected at increasing stenosis grades. Conclusion. An adapted Langendorff porcine heart model is feasible in a CT environment. This model provides control over physiological parameters and may allow in-depth validation of quantitative CT perfusion techniques.
Maria S Zakynthinaki
Full Text Available The objective of the present study was to formulate a simple and at the same time effective mathematical model of heart rate kinetics in response to movement (exercise. Based on an existing model, a system of two coupled differential equations which give the rate of change of heart rate and the rate of change of exercise intensity is used. The modifications introduced to the existing model are justified and discussed in detail, while models of blood lactate accumulation in respect to time and exercise intensity are also presented. The main modification is that the proposed model has now only one parameter which reflects the overall cardiovascular condition of the individual. The time elapsed after the beginning of the exercise, the intensity of the exercise, as well as blood lactate are also taken into account. Application of the model provides information regarding the individual's cardiovascular condition and is able to detect possible changes in it, across the data recording periods. To demonstrate examples of successful numerical fit of the model, constant intensity experimental heart rate data sets of two individuals have been selected and numerical optimization was implemented. In addition, numerical simulations provided predictions for various exercise intensities and various cardiovascular condition levels. The proposed model can serve as a powerful tool for a complete means of heart rate analysis, not only in exercise physiology (for efficiently designing training sessions for healthy subjects but also in the areas of cardiovascular health and rehabilitation (including application in population groups for which direct heart rate recordings at intense exercises are not possible or not allowed, such as elderly or pregnant women.
Ruttkay, Tamás; Jancsó, Gábor; Gombocz, Károly; Gasz, Balázs
Severe mitral regurgitation due to prolapse of the valve demands early surgical intervention. Recently artificial chord implantation is the prefered solution, which requires cardioplegia and application of cardiopulmonary bypass using the left atrial approach. Transoesophageal echocardiography guided transapical neochord implantation is an emerging new technique for the treatment of mitral regurgitation. It enables the operation through left minithoracotomy on beating heart using a special instrument introduced into the left ventricle. Acute procedural success rates in different centres vary between 86 and 100%. According to reports, 92% of the patients do not require additional intervention at the 3-month follow-up. Continuous integration of data resulting improved outcomes supports the hope that this novel, less-invasive technique will be applied widely for the treatment of mitral regurgitation. PMID:27106725
... Heart failure is a common risk factor for atrial fibrillation. Heart failure affects 5.8 million people in the United ... Services, or federal policy. More Health News on: Atrial Fibrillation Health Disparities Heart Failure Recent Health News Related MedlinePlus Health Topics Atrial ...
de Luca, Elisa; Zaccaria, Gian Maria; Hadhoud, Marwa; Rizzo, Giovanna; Ponzini, Raffaele; Morbiducci, Umberto; Santoro, Massimo Mattia
Heartbeat measurement is important in assesssing cardiac function because variations in heart rhythm can be the cause as well as an effect of hidden pathological heart conditions. Zebrafish (Danio rerio) has emerged as one of the most useful model organisms for cardiac research. Indeed, the zebrafish heart is easily accessible for optical analyses without conducting invasive procedures and shows anatomical similarity to the human heart. In this study, we present a non-invasive, simple, cost-effective process to quantify the heartbeat in embryonic zebrafish. To achieve reproducibility, high throughput and flexibility (i.e., adaptability to any existing confocal microscope system and with a user-friendly interface that can be easily used by researchers), we implemented this method within a software program. We show here that this platform, called ZebraBeat, can successfully detect heart rate variations in embryonic zebrafish at various developmental stages, and it can record cardiac rate fluctuations induced by factors such as temperature and genetic- and chemical-induced alterations. Applications of this methodology may include the screening of chemical libraries affecting heart rhythm and the identification of heart rhythm variations in mutants from large-scale forward genetic screens.
Full Text Available Off‐pump coronary artery bypass graft surgery outperforms the traditional on‐pump surgery because the assisted robotic tools can cancel the relative motion between the beating heart and the robotic tools, which reduces post‐surgery complications for patients. The challenge for the robot assisted tool when tracking the beating heart is the abrupt change caused by the nonlinear nature of heart motion and high precision surgery requirements. A characteristic analysis of 3D heart motion data through bi‐spectral analysis demonstrates the quadratic nonlinearity in heart motion. Therefore, it is necessary to introduce nonlinear heart motion prediction into the motion tracking control procedures. In this paper, the heart motion tracking problem is transformed into a heart motion model following problem by including the adaptive heart motion model into the controller. Moreover, the model following algorithm with the nonlinear heart motion model embedded inside provides more accurate future reference by the quadratic term of sinusoid series, which could enhance the tracking accuracy of sharp change point and approximate the motion with sufficient detail. The experiment results indicate that the proposed algorithm outperforms the linear prediction‐based model following controller in terms of tracking accuracy (root mean square.
Laurson, Kelly R.; Brown, Dale D.; Cullen, Robert W.; Dennis, Karen K.
This study examined how activity type influenced heart rates and time spent in target heart rate zones of high school students participating in physical education classes. Significantly higher average heart rates existed for fitness (142 plus or minus 24 beats per minute [bpm]) compared to team (118 plus or minus 24 bpm) or individual (114 plus or…
Wood, Nathan A.; Liu, Tian Yu Tommy; Waugh, Kevin; Zenati, Marco A.; Riviere, Cameron N.
This paper presents preliminary work toward localizing on a surface which undergoes periodic deformation, as an aspect of research on HeartLander, a miniature epicardial crawling robot. Using only position measurements from the robot, the aim of this work is to use the nonuniform movements of the heart as features to aid in localization. Using a particle filter, with motion and observation models which accurately model the robotic system, registration and localization parameters can be quickl...
Johnson, Alistair E W; Behar, Joachim; Andreotti, Fernando; Clifford, Gari D; Oster, Julien
The electrocardiogram (ECG) is a well studied signal from which many clinically relevant parameters can be derived, such as heart rate. A key component in the estimation of these parameters is the accurate detection of the R peak in the QRS complex. While corruption of the ECG by movement artefact or sensor failure can result in poor delineation of the R peak, use of synchronously measured signals could allow for resolution of the R peak even scenarios with poor quality ECG recordings. Robust estimation of R peak locations from multimodal signals facilitates real time monitoring and is likely to reduce false alarms due to inaccurate derived parameters.We propose a method which fuses R peaks detected on the ECG using an energy detector with those detected on the arterial blood pressure (ABP) waveform using the length transform. A signal quality index (SQI) for the two signals is then derived. The ECG SQI is based upon the agreement between two distinct peak detectors. The ABP SQI estimates the blood pressure at various phases in the cardiac cycle and only accepts the signal as good quality if the values are physiologically plausible. Detections from these two signals were merged by selecting the R peak detections from the signal with a higher SQI. The approach presented in this paper was evaluated on datasets provided for the Physionet/Computing in Cardiology Challenge 2014. The algorithm achieved a sensitivity of 95.1% and positive predictive value of 89.3% on an external evaluation set, and achieved a score of 91.5%.The method here demonstrated excellent performance across a variety of signal morphologies collected during clinical practice. Fusion of R peaks from other signals has the potential to provide informed estimates of the R peak location in situations where the ECG is noisy or completely absent. Source code for the algorithm is made available freely online. PMID:26218060
Mehlsen, J; Pagh, K; Nielsen, J S;
Heart rate responses to stepwise and periodic changes in lung volume were studied in seven young healthy males. Stepwise inspiration and expiration both resulted in an increase in heart rate followed by a rapid decrease in heart rate. The fastest heart rate was reached in 1.6 +/- 0.5 s and in 3.6...... as a measure of vagal function a number of factors have to be taken into consideration and to simplify the analysis of heart rate responses to breathing we recommend, instead, the use of the transient changes in heart rate induced by stepwise changes in lung volume.......Heart rate responses to stepwise and periodic changes in lung volume were studied in seven young healthy males. Stepwise inspiration and expiration both resulted in an increase in heart rate followed by a rapid decrease in heart rate. The fastest heart rate was reached in 1.6 +/- 0.5 s and in 3.......6 +/- 1.4 s in response to inspiration and expiration, respectively (P less than 0.01). The slowest heart rate was reached in 4.8 +/- 1.0 s and in 7.6 +/- 1.9 s in response to inspiration and expiration, respectively (P less than 0.01). Following this biphasic change the heart rate returned to a steady...
Zhang, Jie; Fletcher, Joel G.; Harmsen, W. Scott; Araoz, Philip A.; Williamson, Eric E.; Primak, Andrew N.; McCollough, Cynthia H.
Rationale and Objectives We sought to examine heart rate and heart rate variability during cardiac computed tomography (CT). Materials and Methods Ninety patients (59.0 ± 13.5 years) underwent coronary CT angiography (CTA), with 52 patients also undergoing coronary artery calcium scanning (CAC). Forty-two patients with heart rate greater than 70 bpm were pretreated with oral β-blockers (in five patients, use of β-blocker was not known). Sixty-four patients were given sublingual nitroglycerin. Mean heart rate and percentage of beats outside a ±5 bpm region about the mean were compared between baseline (free breathing), prescan hyperventilation, and scan acquisition (breath-hold). Results Mean scan acquisition time was 13.1 ± 1.5 seconds for CAC scanning and 14.2 ± 2.9 seconds for coronary CTA. Mean heart rate during scan acquisition was significantly lower than at baseline (CAC 58.2 ± 8.5 bpm; CTA 59.2 ± 8.8 bpm; baseline 62.8 ± 8.9 bpm; P .05). Conclusions Breath-holding during cardiac CT scan acquisition significantly lowers the mean heart rate by approximately 4 bpm, but heart rate variability is the same or less compared with normal breathing. PMID:18078905
... beats per minute. - If you have difficulty with math, try doubling the number twice. 25 doubled is ... from going too high. If you are taking medicine for your heart or blood pressure, check with ...
Setareh Rezakhani; Mehdi Aliyari Shoorehdeli; Azam Ghasemi
In this paper, the problem of 3D heart motion in beating heart surgery is resolved by proposing a parallel force-motion controller. Motion controller is designed based on neuro-adaptive approach to compensate 3D heart motion and deal with uncertainity in dynamic parameters, while an implicit force control is implemented by considering a viscoelastic tissue model. Stability analysis is proved through Lypanov’s stability theory and Barballet’s lemma. Simulation results, for D2M2 robot, which is...
Full Text Available In this paper, the problem of 3D heart motion in beating heart surgery is resolved by proposing a parallel force-motion controller. Motion controller is designed based on neuro-adaptive approach to compensate 3D heart motion and deal with uncertainity in dynamic parameters, while an implicit force control is implemented by considering a viscoelastic tissue model. Stability analysis is proved through Lypanov’s stability theory and Barballet’s lemma. Simulation results, for D2M2 robot, which is done in nominal case and viscoelastic parameter mismatches demonstrate the robust performance of the controller.
Kesner, Samuel Benjamin; Howe, Robert D.
Recent developments in cardiac catheter technology promise to allow physicians to perform most cardiac interventions without stopping the heart or opening the chest. However, current cardiac devices, including newly developed catheter robots, are unable to accurately track and interact with the fast moving cardiac tissue without applying potentially damaging forces. This paper examines the challenges of implementing force control on a flexible robotic catheter. In particular, catheter frictio...
Intermittency in time series of the time intervals between heart beats (RR intervals) extracted from 24 hour (portable) ECG is found for some cases of humans with arrhythmia. Laminar phases are found by sweeping a short (5 intervals) time window through the time series and calculating the standard deviation of the series in each window. 8 of the 18 arrhythmia cases studied had a bimodal distribution of the standard deviation values indicating some kind of intermittency. The distribution of lengths of the laminar phases identifies the intermittency obtained in human heart rate variability as Type 1 in the Pomeau and Manneville classification. Although the arrhythmia cases studied were medically very different - in those instances that intermittency did occur the probability distributions of laminar phase lengths were strikingly similar. (author)
Laouini, Ghailen; Meste, Olivier; Meo, Marianna
In this paper, we analyze the heart rate variability (HRV), obtained by using the time-varying integral pulse frequency modulation (TVIPFM) which is well adapted to the exercise stress testing. We consider that the mean heart period is varying function of time, during exercise. This technique allows the estimation of the autonomic nervous system modulation (ANS) from the beat occurrences. The estimated respiratory sinus arrhythmia is then filtered in the time-frequency domain around the respi...
Bhatti, Aftab A.; Navarro, Alex; Gok, Mohammad A.; Wilson, Colin H.; Asher, John; Wong, Yew Toh; Hua, Mi; Talbot, David
A case is described where both kidneys from non-heart-beating (expanded criteria) donors were dual transplanted ipsilaterally. Although both kidneys passed viability tests on the Newcastle machine preservation system and biomarkers' evaluation, there were logistical issues where the cold ischaemic time was too protracted necessitating the transplantation of both kidneys into one recipient. The recipient had satisfactory outcome with the Cockcroft-Gault creatinine clearance of 72.47 (36.29 ml/...
João Fabrício Mota Rodrigues; Roberta da Rocha Braga; Thaís Helena Alencar Ferreira; Estéfanni de Castro Pinheiro; Géssica dos Santos Araújo; Diva Maria Borges-Nojosa
Body size is highly correlated with metabolism, which in turn influences physiological rates such as heart rate. In general, heart rate is negatively influenced by the size of animal's body, but there is insufficient data corroborating this pattern in snakes. This study evaluated how body size affects heart rate in captive Boa constrictor Linnaeus, 1758. We measured the heart rate of 30 snakes using digital palpation and evaluated how this rate is influenced by body mass and sex using Analysi...
Novani, Nefy Puteri; Prihatmanto, Ary Setijadi
Heart Rate Variability (HRV) merupakan variasi dari beat-to-beat denyut jantung yang memberikan gambaran gejala fisiologis dari denyut jantung (heart rate) dengan variasinya dalam interval waktu. Analisis HRV memberikan suatu informasi tentang modulasi otonom jantung dan menjadi alat yang berguna untuk memahami sistem saraf otonom (ANS) yang mengatur proses-proses tertentu di dalam tubuh dengan dua komponen utama yaitu sistem saraf simpatetik dan parasimpatetik. Analisis HRV mencakup anali...
Peng, C K; Mietus, J E; Liu, Y; Khalsa, G; Douglas, P S; Benson, H; Goldberger, A L
We report extremely prominent heart rate oscillations associated with slow breathing during specific traditional forms of Chinese Chi and Kundalini Yoga meditation techniques in healthy young adults. We applied both spectral analysis and a novel analytic technique based on the Hilbert transform to quantify these heart rate dynamics. The amplitude of these oscillations during meditation was significantly greater than in the pre-meditation control state and also in three non-meditation control groups: i) elite athletes during sleep, ii) healthy young adults during metronomic breathing, and iii) healthy young adults during spontaneous nocturnal breathing. This finding, along with the marked variability of the beat-to-beat heart rate dynamics during such profound meditative states, challenges the notion of meditation as only an autonomically quiescent state. PMID:10454297
... Heart patient sheets Arrhythmia • Home • About Arrhythmia Introduction Atrial Fibrillation Bradycardia Conduction Disorders Premature Contractions Tachycardia Ventricular Fibrillation Other Rhythm Disorders Types of ...
Ercan, Abdulkadir; Velioğlu, Yusuf; Ercan, Arzu; Gürbüz, Orçun; Özkan, Hakan; Karal, İlker Hasan; Biçer, Murat; Ener, Serdar
Objectives: This prospective, randomised, controlled, clinical study was planned to determine the effect of trimetazidine and glucose - insulin - potassium (GIK) on myocardial ischemia-reperfusion during beating heart coronary artery bypass surgery. Materials and methods: Patients (n=45) with coronary artery disease who required beating heart coronary artery bypass grafting were randomly allocated into three groups. Patients in group 1 (n=15) was recevied trimetazidine (20 mg x 3...
Abdulkadir Ercan; Yusuf Velioğlu; Arzu Ercan; Orçun Gürbüz; Hakan Özkan; İlker Hasan Karal; Murat Biçer; Serdar Ener
Objectives: This prospective, randomised, controlled, clinical study was planned to determine the effect of trimetazidine and glucose - insulin - potassium (GIK) on myocardial ischemia-reperfusion during beating heart coronary artery bypass surgery.Materials and methods: Patients (n=45) with coronary artery disease who required beating heart coronary artery bypass grafting were randomly allocated into three groups. Patients in group 1 (n=15) was recevied trimetazidine (20 mg x 3 per day) 7 da...
One of the major and significant physiological parameters of human cardiovascular system is the heart rate. Heart rate is represented by the number of times the heart beats per minute. The heart rate data can reflect various physiological states such as stress at work, concentration on tasks, drowsiness, biological workload, and the active state of the autonomic nervous system. Human cardiac dynamics are driven by the complex nonlinear interactions of two competing forces: sym...
Full Text Available This study evaluated the chronotropic and inotropic responses to glucagon in spontaneously beating isolated right atria of rat heart. For comparison, we also investigated the effects resulting from stimulating β-adrenoceptors with isoproterenol in this tissue. Isoproterenol increased both atrial frequency and contractility but glucagon only enhanced atrial rate. The transcript levels of glucagon receptors were about three times higher in sinoatrial node than in the atrial myocardium. Chronotropic responses to glucagon and isoproterenol were blunted by the funny current (If inhibitor ZD 7288. Inhibitors of protein kinase A, H-89 and KT-5720 reduced the chronotropic response to glucagon but not to isoproterenol. Inhibition of ryanodine receptors and calcium/calmodulin dependent protein kinase II (important regulators of sarcoplasmic reticulum Ca2+ release, with ruthenium red and KN-62 respectively, failed to alter chronotropic responses of either glucagon or isoproterenol. Non selective inhibition of phosphodiesterase (PDE with 3-isobutylmethylxantine or selective inhibition of PDE3 or PDE4 with cilostamide or rolipram respectively did not affect chronotropic effects of glucagon or isoproterenol. Our results indicate that glucagon increases beating rate but not contractility in rat right atria which could be a consequence of lower levels of glucagon receptors in atrial myocardium than in sinoatrial node. Chronotropic responses to glucagon or isoproterenol are mediated by If current but not by sarcoplasmic reticulum Ca2+ release, neither are regulated by PDE activity.
王咏; 肖颖彬; 陈林; 王学锋; 钟前进
Objective: To assess the cerebral injury in on-pump beating-heart procedures under mild hypothermia in comparison with traditional on-pump arrested-heart procedures under moderate hypothermia. Methods: Forty patients, 20 with congenital heart disease (CHD) and 20 of rheumatic heart disease (RHD), were divided into 2 groups: Control group (group A, n=20) including 10 patients suffering from CHD as group A1 and the left 10 from RHD as group A2; and experiment group (group B, n=20) which consisting of group B1 (10 with CHD) and group B2 (10 of RHD). The patients in group A underwent traditional arrested-heart procedures, and those in group B were operated on with beating-heart procedures. Arterial blood samples were collected at preoperation (time A), 20 min after cardiopulmonary bypass (CPB) starting (time B), 1 h after CPB (time C) and 24 h postoperation (time D) respectively. Plasma contents of neuron-specific enolase (NSE) and protein S-100b were measured with sensitive ELISA. All the patients received echoencephalography (EEG) before and 1 week after operation. Results: The plasma contents of protein S-100b were increased very significantly at time B, C and D in comparison with those at time A (P<0.01), and that of patients in group A1 was significantly higher than that in group B at time B (P<0.05). There was no significant difference at other time points. At time B, the plasma contents of NSE were significantly higher in group A than in group B, and in group A1 and B1 than in group A2 and B2. What's more, at time B, the former fell back to their preoperative levels, but the latter remained still higher levels than the preoperative ones (P<0.01). No significant difference was found in the abnormality rates of postoperative EEG between 2 groups. Conclusion: The perioperative plasma contents of NSE and protein S-100b are not significantly higher in group B than in group A. On-pump beating-heart procedures do not make more serious cerebral dysfunction than the
Buxton, R. E.; West, M. R.; Kalogera, K. L.; Hanson, A. M.
Heart rate monitoring is required for crewmembers during exercise aboard the International Space Station (ISS) and will be for future exploration missions. The cardiovascular system must be sufficiently stressed throughout a mission to maintain the ability to perform nominal and contingency/emergency tasks. High quality heart rate data are required to accurately determine the intensity of exercise performed by the crewmembers and show maintenance of VO2max. The quality of the data collected on ISS is subject to multiple limitations and is insufficient to meet current requirements. PURPOSE: To evaluate the performance of commercially available Bluetooth heart rate monitors (BT HRM) and their ability to provide high quality heart rate data to monitor crew health aboard the ISS and during future exploration missions. METHODS: Nineteen subjects completed 30 data collection sessions of various intensities on the treadmill and/or cycle. Subjects wore several BT HRM technologies for each testing session. One electrode-based chest strap (CS) was worn, while one or more optical sensors (OS) were worn. Subjects were instrumented with a 12-lead ECG to compare the heart rate data from the Bluetooth sensors. Each BT HRM data set was time matched to the ECG data and a +/-5bpm threshold was applied to the difference between the 2 data sets. Percent error was calculated based on the number of data points outside the threshold and the total number of data points. RESULTS: The electrode-based chest straps performed better than the optical sensors. The best performing CS was CS1 (1.6% error), followed by CS4 (3.3% error), CS3 (6.4% error), and CS2 (9.2% error). The OS resulted in 10.4% error for OS1 and 14.9% error for OS2. CONCLUSIONS: The highest quality data came from CS1, but unfortunately it has been discontinued by the manufacturer. The optical sensors have not been ruled out for use, but more investigation is needed to determine how to obtain the best quality data. CS2 will be
Scharold, J; Lai, N C; Lowell, W R; Graham, J B
Heart rate, metabolic rate, and tailbeat frequency were simultaneously recorded from seven leopard sharks (Triakis semifasciata) during steady swimming at controlled speeds to evaluate the usefulness of heart rate as a measure of field metabolic rate. Heart rate was monitored by acoustic telemetry using a frequency modulated ECG transmitter. Metabolic rate was measured as oxygen consumption in a swimming tunnel respirometer. For instrumented sharks, mean resting oxygen consumption rate and heart rate were 105.3 +/- 35.6 (SE) mg O2.kg-1.h-1 and 36.6 +/- 1.8 (SE) beats.min-1, respectively. While swimming at the maximum sustained speed (0.84 +/- 0.03 lengths.s-1) for 30-60 min, these rates were 229.3 +/- 13.2 mg O2.kg-1.h-1 and 46.9 +/- 0.9 beats.min-1. Although a significant linear regression was obtained between metabolic rate and heart rate, a low overall correlation coefficient may result from the existence of separate individual regressions and confounding changes in stroke volume and/or arteriovenous oxygen difference. Heart rate was approximately as closely correlated with oxygen consumption rate as swimming speed was. A significant linear relationship was obtained between tailbeat frequency and swimming speed to speeds of 0.75 lengths.s-1. PMID:2776865
We propose a novel technique for beat-to-beat heart rate detection based on the ballistocardiographic (BCG) force signal from a subject standing on a common electronic weighing scale. The detection relies on sensing force variations related to the blood acceleration in the aorta, works even if wearing footwear and does not require any sensors attached to the body because it uses the load cells in the scale. We have devised an approach to estimate the sensitivity and frequency response of three commercial weighing scales to assess their capability to detect the BCG force signal. Static sensitivities ranged from 490 nV V−1 N−1 to 1670 nV V−1 N−1. The frequency response depended on the subject's mass but it was broad enough for heart rate estimation. We have designed an electronic pulse detection system based on off-the-shelf integrated circuits to sense heart-beat-related force variations of about 0.24 N. The signal-to-noise ratio of the main peaks of the force signal detected was higher than 30 dB. A Bland–Altman plot was used to compare the RR time intervals estimated from the ECG and BCG force signals for 17 volunteers. The error was ±21 ms, which makes the proposed technique suitable for short-term monitoring of the heart rate
Rosenberg, J; Dirkes, W E; Kehlet, H
In 20 patients undergoing elective major abdominal surgery, heart rate and arterial oxygen saturation were monitored continuously during the night 2 days before operation and during the first and second nights after operation (23:00 to 07:30). Mean heart rate increased by 16 beat min-1 (P less th...
M. Sh. Hubutija
Full Text Available Aim. To compare the effectiveness of different methods for bone marrow (BM harvesting from non-heart beating donors taking into account the number and the quality of collected hematopoietic stem cells (HSC. Materials and methods. The study was performed on 43 non-heart beating donors. For BM harvesting two bone marrow aspiration needles were installed in each iliac bone. The needles were installed in one bone connected to closed system, combined with surgical suction and volumetric pump. BM aspiration was performed using different values for vacuum and combining with perfusion solution into the bone. The volume, the number of nucleated cells (NC, HSC and cell viability were evaluated in the obtained samples. Results. Compared with the standard mode the usage of vacuum 0.6–0.7 atm increased the collection of NC by 65.6%, HSC 87%, and did not reduce their viability. Using a vacuum of 0.9 atm reduced the amount of collected HSC and damaged cells. While using combined aspiration and perfusion of BM HSC were prepared at more than 86.2%, but the viability of the cells was lower than under the standard aspiration. Having coherently performed a standard aspiration and aspiration with perfusion from one iliac bone 407.2 ± 46.7 ml BM, 8.0 ± 0.8 × 109 NC and 194.2 ± 20.8 × 106 HSC were harvested. The proportion of viable cells was not less than 75.2 ± 3.2%. Conclusion. Method of BM harvesting implying coherently performing aspiration and aspiration-perfusion with the usage of vacuum 0.6–0.7 atm allows to prepare more progenitor cells without losing their quality. As a result, from one non-heart beating donor different types of progenitor cells can be collected in the amount sufficient for systemic infusion in adult patient.
Full Text Available Abstract Objectives On-pump beating heart technique for myocardial revascularization has been used successfully among both low and high risk patients. Its application among low ejection fraction patients is limited. The aim of our study is to evaluate this technique among patients with low ejection fraction and to compare results with off-pump bypass technique. Methods This retrospective study includes 137 patients with ejection fraction below 0.35 who underwent isolated coronary artery bypass surgery. 39 patients underwent myocardial revascularization using on-pump beating heart (ONCAB/BH, while 98 patients had off-pump beating heart (OPCAB. Different preoperative, operative and postoperative variables were evaluated among both groups. Results Patients profiles and risk factors were similar among both groups, except for the number of patients undergoing redo CABG which was significantly higher among ONCAB/BH (13% vs 3%; p = 0.025. Ejection fraction (EF varied from 10-34%. The mean EF for patients who underwent ONCAB/BH was 28 ± 6 in comparison to 26 ± 5 for OPCAB patients (P = 0.093. Predicted risk for surgery according to EuroSCORE was similar among both groups (P = 0.443. The number of grafts performed per patient was significantly more among patients who underwent ONCAB/BH (2.2 ± 0.7 Vs 1.7 ± 0.7; P = 0.002. Completeness of revascularization was significantly greater in the ONCAB/BH patients (72% Vs 46%, P = 0.015. The incidence of hospital mortality and combined major morbidity was more among ONCAB/BH in comparison to OPCAB, but the difference was not significant. However, the incidence of blood loss, ventricular arrythmias, inotropic support, ICU, hospital stay and blood transfusion were significantly greater among patients who underwent ONCAB/BH. Conclusions On-pump beating heart technique can be used in myocardial revascularization among patients with left ventricular dysfunction. The technique was found to be associated with better
Jurák, Pavel; Halámek, Josef; Kára, T.; Lanfranchi, P.; Souček, M.
Brno: University of Technology VUTIUM Press, 2002 - (Kozumplík, J.; Provazník, I.; Jan, J.), s. 226 - 229 ISBN 80-214-2633-0. ISSN 1211-412X. [BIOSIGNAL 2002. Brno (CZ), 25.06.2002-28.06.2002] R&D Projects: GA ČR GA102/00/1262; GA ČR GA102/02/1339 Institutional research plan: CEZ:AV0Z2065902 Keywords : heart beat interactions * autonomic nervous system * respiration monitoring Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery
Karaşen, Rıza Murat; ÇİFTÇİ, Bülent; Acar, Baran; YALÇIN, Ahmet Arif; GÜVEN, Selma FIRAT
To demonstrate the effects of obstructive sleep apnea syndrome (OSAS) on baroregulatory function by using heart rate recovery (HRR) parameters. Materials and methods: Fifty-four moderate and severe OSAS patients were included in the study. HRR was defined as the difference in heart rate between peak exercise and 1 min later; a value of 18 beats/min was considered abnormal. OSAS patients were enrolled in the study as group 1 (normal HRR; n = 12) and group 2 (abnormal HRR, n = 42). Left ventr...
Galeotti, Loriano; Scully, Christopher G; Vicente, Jose; Johannesen, Lars; Strauss, David G
Alarm fatigue is a top medical device hazard in patient monitoring that could be reduced by merging physiological information from multiple sensors, minimizing the impact of a single sensor failing. We developed a heart beat detection algorithm that utilizes multi-modal physiological signals (e.g. electrocardiogram, blood pressure, stroke volume, photoplethysmogram and electro-encephalogram) by merging the heart beats obtained from signal-specific detectors. We used the PhysioNet/Computing in Cardiology Challenge 2014 training set to develop the algorithm, and we refined it with a mix of signals from the multiparameter intelligent monitoring in intensive care (MIMIC II) database and artificially disrupted waveforms. The algorithm had an average sensitivity of 95.67% and positive predictive value (PPV) of 92.28% when applied to the PhysioNet/Computing in Cardiology Challenge 2014 200 record training set. On a refined dataset obtained by removing 5 records with arrhythmias and inconsistent reference annotations we obtained an average sensitivity of 97.43% and PPV of 94.17%. Algorithm performance was assessed with the Physionet Challenge 2014 test set that consisted of 200 records (each up to 10 min length) containing multiple physiological signals and reference annotations verified by the PhysioNet/Computing in Cardiology Challenge 2014 organizers. Our algorithm had a sensitivity of 92.74% and PPV of 87.37% computed over all annotated beats, and a record average sensitivity of 91.08%, PPV of 86.96% and an overall score (average of all 4 measures) of 89.53%. Our algorithm is an example of a data fusion approach that can improve patient monitoring and reduce false alarms by reducing the effect of individual signal failures. PMID:26218439
Full Text Available Abstract Background Rupture of aneurysms of the sinus of Valsalva results in abrupt onset of congestive heart failure. On-pump beating-heart surgery may reduce cardiac impairment by maintaining coronary blood flow and avoiding cardioplegia. Herein, we report the operative correction of thirty-one patients of ruptured aneurysms of the sinus of Valsalva, using the on-pump beating-heart technique. Methods Thirty-one patients with ruptured aneurysms of the sinus of Valsalva underwent operative corrections using the on-pump beating-heart technique. In patients with fistula diameter less than 1 cm and no aortic regurgitation, the aorta was unclamped throughout cardiopulmonary bypass(CPB while receiving antegrade heart perfusion. In remainder of patients, retrograde perfusion was used. Results After intracardiac manipulation was complete and the nasopharyngeal temperature was raised to 36-37°C, the patients were smoothly weaned off CPB. There were no early or late postoperative deaths. All patients were in New York Heart Association functional class I at follow-up (range, 0.5-1 year. Mild-to-moderate aortic valve regurgitation was observed in one patient. No recurrence of the left-to-right shunt from ruptured aneurysms of the sinus of Valsalva was observed. Conclusions Beating heart on pump allows adequate examination of the aortic lesion under near-physiologic conditions, allows decrease in ischemia-reperfusion injury and potentially decreases the risk of serious or fatal rhythm disturbances. On-pump beating-heart technique for repair of ruptured aneurysm of sinus of Valsalva is feasible and promising. Antegrade heart perfusion is suitable for patients with a fistula diameter
Pace, Danielle F.; Wiles, Andrew D.; Moore, John; Wedlake, Chris; Gobbi, David G.; Peters, Terry M.
Ultrasound is garnering significant interest as an imaging modality for surgical guidance, due to its affordability, real-time temporal resolution and ease of integration into the operating room. Minimally-invasive intracardiac surgery performed on the beating-heart prevents direct vision of the surgical target, and procedures such as mitral valve replacement and atrial septal defect closure would benefit from intraoperative ultrasound imaging. We propose that placing 4D ultrasound within an augmented reality environment, along with a patient-specific cardiac model and virtual representations of tracked surgical tools, will create a visually intuitive platform with sufficient image information to safely and accurately repair tissue within the beating heart. However, the quality of the imaging parameters, spatial calibration, temporal calibration and ECG-gating must be well characterized before any 4D ultrasound system can be used clinically to guide the treatment of moving structures. In this paper, we describe a comprehensive accuracy assessment framework that can be used to evaluate the performance of 4D ultrasound systems while imaging moving targets. We image a dynamic phantom that is comprised of a simple robot and a tracked phantom to which point-source, distance and spherical objects of known construction can be attached. We also follow our protocol to evaluate 4D ultrasound images generated in real-time by reconstructing ECG-gated 2D ultrasound images acquired from a tracked multiplanar transesophageal probe. Likewise, our evaluation framework allows any type of 4D ultrasound to be quantitatively assessed.
Rahul Pitale; Kapil Tajane
In today’s era Heart Rate Variability becomes an important characteristic to determine the condition of heart. That’s why the calculation of HRV and classification to generate rules is necessary. Human Heart Generates the electrical signal. ECG is used to detect the heart beat. ECG signal contains lots of noise. To classify the signals first to decompose the signals using wavelet transform. Many Mother wavelet are used to denoise the signals. Support Vector Machine is used to ...
Orhan Saim Demirtürk
Full Text Available An operation on the beating heart was planned for a 60-year-old woman who applied to our clinic with aortic stenosis, three vessel coronary artery disease and poor left ventricular function. There are reports about beating heart valve surgery perfomed alone or combined with coronary artery bypass operations using continuous retrograde coronary sinus isothermic blood perfusion in patients with poor ventricle. We performed a coronary revascularization process for three-vessel disease on the pump beating heart and aortic valve replacement under cross-clamp using continuous retrograde coronary sinus isothermic blood perfusion in the same session. She was discharged on the sixth postoperative day after an uneventful recovery. She is well and active 24 months after the operation. Valve replacement using the retrograde coronary sinus isothermic blood perfusion technique due to its protective effect on the already borderline myocardial functions in patients with poor ventricles is a useful and clinically successful method.
von Lewinski, Mareike; Biau, Sophie; Erber, Regina; Ille, Natascha; Aurich, Jörg; Faure, Jean-Michel; Möstl, Erich; Aurich, Christine
Although some information exists on the stress response of horses in equestrian sports, the horse-rider team is much less well understood. In this study, salivary cortisol concentrations, heart rate (HR) and heart rate variability (HRV), SDRR (standard deviation of beat-to-beat interval) and RMSSD (root mean square of successive beat-to-beat intervals) were analysed in horses and their riders (n=6 each) at a public performance and an identical rehearsal that was not open to the public. Cortisol concentrations increased in both horses and riders (Pequestrian tasks in riders (P<0.001), but not in their horses. The RMSSD decreased in horses and riders (P<0.001) during rehearsal and performance, indicating a decrease in parasympathetic tone. The decrease in RMSSD in the riders was more pronounced (P<0.05) during the performance (from 32.6 ± 6.6 to 3.8 ± 0.3 ms) than during the rehearsal (from 27.5 ± 4.2 to 6.6 ± 0.6 ms). The study has shown that the presence of spectators caused more pronounced changes in cardiac activity in the riders than it did in their horses. PMID:23380228
Smith Michael L
Full Text Available Abstract Background Heart rate variability (HRV is known to be impaired in patients with congestive heart failure (CHF. Time-domain analysis of ECG signals traditionally relies heavily on linear indices of an essentially non-linear phenomenon. Poincaré plots are commonly used to study non-linear behavior of physiologic signals. Lagged Poincaré plots incorporate autocovariance information and analysis of Poincaré plots for various lags can provide interesting insights into the autonomic control of the heart. Methods Using Poincaré plot analysis, we assessed whether the relation of the lag between heart beats and HRV is altered in CHF. We studied the influence of lag on estimates of Poincaré plot indices for various lengths of beat sequence in a public domain data set (PhysioNet of 29 subjects with CHF and 54 subjects with normal sinus rhythm. Results A curvilinear association was observed between lag and Poincaré plot indices (SD1, SD2, SDLD and SD1/SD2 ratio in normal subjects even for a small sequence of 50 beats (p value for quadratic term 3 × 10-5, 0.002, 3.5 × 10-5 and 0.0003, respectively. This curvilinearity was lost in patients with CHF even after exploring sequences up to 50,000 beats (p values for quadratic term > 0.5. Conclusion Since lagged Poincaré plots incorporate autocovariance information, these analyses provide insights into the autonomic control of heart rate that is influenced by the non-linearity of the signal. The differences in lag-response in CHF patients and normal subjects exist even in the face of the treatment received by the CHF patients.
Kristiansen, N. K.; Fleischer, J.; Jensen, M. S.;
the reference method. Agreement between the two methods in measuring heart rate and root mean square of successive differences in the heart beat interval (RMSSD) was analysed using correlation coefficients (Pearson's R-2), mean differences with 95% confidence intervals and 95% limits of agreement, and...
Lin, D C
Evidence of discrete scale invariance (DSI) in daytime healthy heart rate variability (HRV) is presented based on the log-periodic power law scaling of the heart beat interval increment. Our analysis suggests multiple DSI groups and a dynamic cascading process. A cascade model is presented to simulate such a property.
Data saving capability of "Compressed sensing (sampling)" in signal discretization is disputed and found to be far below the theoretical upper bound defined by the signal sparsity. On a simple and intuitive example, it is demonstrated that, in a realistic scenario for signals that are believed to be sparse, one can achieve a substantially larger saving than compressing sensing can. It is also shown that frequent assertions in the literature that "Compressed sensing" can beat the Nyquist sampling approach are misleading substitution of terms and are rooted in misinterpretation of the sampling theory.
Vora, Shrenik; Dandekar, Kapil; Kurzweg, Timothy
In this paper, we propose a monitoring system that employs a passive RFID tag to transmit heart rate using an ECG signal as its source. This system operates without a battery and has been constructed with easily available commercial components. Here, an RFID tag is used as an on-off keying device, wherein it is normally transmitting, but turns off every time a heart beat is detected. Heart beats ranging from 30BPM through 300BPM are successfully measured using our device. It is shown that the system is capable of providing accurate heart rate measurements up to a distance of ten feet with a standard deviation of less than one beat per minute without a local power source. The proposed system is also found to be resilient in the presence of an additional RFID tag. PMID:26737271
Heart rate variability (HRV) indices based on 24-hour electrocardiograph recordings have been used in clinical research studies to assess the aggregate activity of the autonomic nervous system. While 24-hour HRV is generally considered non-invasive, use in research protocols typically involves cons...
Deschodt-Arsac, Véronique; Calmettes, Guillaume; Gouspillou, Gilles; Chapolard, Mathilde; Raffard, Gérard; Rouland, Richard; Jais, Pierre; Haissaguerre, Michel; Dos Santos, Pierre; Diolez, Philippe
The comprehensive study of human pathologies has revealed the complexity of the interactions involved in cardiovascular physiology. The recent validation of system's biology approaches - like our Modular Control and Regulation Analysis (MoCA) - motivates the current interest for new integrative and non-invasive analyses that could be used for medical study of human heart contraction energetics. By considering heart energetics as a supply-demand system, MoCA gives access to integrated organ function and brings out a new type of information, the "elasticities", which describe in situ the regulation of both energy demand and supply by cellular energetic status. These regulations determine the internal control of contraction energetics and may therefore be a key to the understanding of the links between molecular events in pathologies and whole organ function/dysfunction. A wider application to the effects of cardiac drugs in conjunction with the direct study of heart pathologies may be considered in the near future. MoCA can potentially be used not only to detect the origin of the defects associated with the pathology (elasticity analyses), but also to provide a quantitative description of how these defects influence global heart function (regulation analysis) and therefore open new therapeutic perspectives. Several key examples of current applications to intact isolated beating heart are presented in this paper. The future application to human pathologies will require the use of non-invasive NMR techniques for the simultaneous measurement of energy status ((31)P NMR) and heart contractile activity (3D MRI). This article is part of a Directed Issue entitled: Bioenergetic dysfunction, adaptation and therapy. PMID:22789933
Hensey, Mark; O'Neill, James
There has been an increased focus on heart rate as a target in the management of cardiovascular disease and more specifically in heart failure with preserved ejection fraction in recent years with several studies showing the benefit of a lower resting heart rate on outcomes. This review paper examines the pathophysiology behind the benefits of lowering heart rate in heart failure and also the evidence for and against the pharmacological agents available to achieve this. PMID:27457085
Full Text Available AIMS: Cardiac grafts from non-heartbeating donors (NHBDs could significantly increase organ availability and reduce waiting-list mortality. Reluctance to exploit hearts from NHBDs arises from obligatory delays in procurement leading to periods of warm ischemia and possible subsequent contractile dysfunction. Means for early prediction of graft suitability prior to transplantation are thus required for development of heart transplantation programs with NHBDs. METHODS AND RESULTS: Hearts (n = 31 isolated from male Wistar rats were perfused with modified Krebs-Henseleit buffer aerobically for 20 min, followed by global, no-flow ischemia (32°C for 30, 50, 55 or 60 min. Reperfusion was unloaded for 20 min, and then loaded, in working-mode, for 40 min. Left ventricular (LV pressure was monitored using a micro-tip pressure catheter introduced via the mitral valve. Several hemodynamic parameters measured during early, unloaded reperfusion correlated significantly with LV work after 60 min reperfusion (p<0.001. Coronary flow and the production of lactate and lactate dehydrogenase (LDH also correlated significantly with outcomes after 60 min reperfusion (p<0.05. Based on early reperfusion hemodynamic measures, a composite, weighted predictive parameter, incorporating heart rate (HR, developed pressure (DP and end-diastolic pressure, was generated and evaluated against the HR-DP product after 60 min of reperfusion. Effective discriminating ability for this novel parameter was observed for four HR*DP cut-off values, particularly for ≥20 *10(3 mmHg*beats*min(-1 (p<0.01. CONCLUSION: Upon reperfusion of a NHBD heart, early evaluation, at the time of organ procurement, of cardiac hemodynamic parameters, as well as easily accessible markers of metabolism and necrosis seem to accurately predict subsequent contractile recovery and could thus potentially be of use in guiding the decision of accepting the ischemic heart for transplantation.
... Pressure High Blood Pressure Tools & Resources Stroke More Blood Pressure vs. Heart Rate Updated:Aug 30,2016 Blood ... was last reviewed on 08/04/2014. High Blood Pressure • Home • About High Blood Pressure (HBP) Introduction What ...
Ryan, S. M.; Goldberger, A. L.; Pincus, S. M.; Mietus, J.; Lipsitz, L. A.
OBJECTIVES. This study aimed to quantify the complex dynamics of beat-to-beat sinus rhythm heart rate fluctuations and to determine their differences as a function of gender and age. BACKGROUND. Recently, measures of heart rate variability and the nonlinear "complexity" of heart rate dynamics have been used as indicators of cardiovascular health. Because women have lower cardiovascular risk and greater longevity than men, we postulated that there are important gender-related differences in beat-to-beat heart rate dynamics. METHODS. We analyzed heart rate dynamics during 8-min segments of continuous electrocardiographic recording in healthy young (20 to 39 years old), middle-aged (40 to 64 years old) and elderly (65 to 90 years old) men (n = 40) and women (n = 27) while they performed spontaneous and metronomic (15 breaths/min) breathing. Relatively high (0.15 to 0.40 Hz) and low (0.01 to 0.15 Hz) frequency components of heart rate variability were computed using spectral analysis. The overall "complexity" of each heart rate time series was quantified by its approximate entropy, a measure of regularity derived from nonlinear dynamics ("chaos" theory). RESULTS. Mean heart rate did not differ between the age groups or genders. High frequency heart rate power and the high/low frequency power ratio decreased with age in both men and women (p gender-as well as age-related differences in heart rate dynamics. Whether these gender differences are related to lower cardiovascular disease risk and greater longevity in women requires further study.
Ryan, S. M.; Goldberger, A. L.; Pincus, S. M.; Mietus, J.; Lipsitz, L. A.
OBJECTIVES. This study aimed to quantify the complex dynamics of beat-to-beat sinus rhythm heart rate fluctuations and to determine their differences as a function of gender and age. BACKGROUND. Recently, measures of heart rate variability and the nonlinear "complexity" of heart rate dynamics have been used as indicators of cardiovascular health. Because women have lower cardiovascular risk and greater longevity than men, we postulated that there are important gender-related differences in beat-to-beat heart rate dynamics. METHODS. We analyzed heart rate dynamics during 8-min segments of continuous electrocardiographic recording in healthy young (20 to 39 years old), middle-aged (40 to 64 years old) and elderly (65 to 90 years old) men (n = 40) and women (n = 27) while they performed spontaneous and metronomic (15 breaths/min) breathing. Relatively high (0.15 to 0.40 Hz) and low (0.01 to 0.15 Hz) frequency components of heart rate variability were computed using spectral analysis. The overall "complexity" of each heart rate time series was quantified by its approximate entropy, a measure of regularity derived from nonlinear dynamics ("chaos" theory). RESULTS. Mean heart rate did not differ between the age groups or genders. High frequency heart rate power and the high/low frequency power ratio decreased with age in both men and women (p age and was higher in women than men (p gender-as well as age-related differences in heart rate dynamics. Whether these gender differences are related to lower cardiovascular disease risk and greater longevity in women requires further study.
Liu, Z; Zhu, B; Yun, P; Wang, P; Wang, X; Xu, H
The concept of brain death has not been accepted by the majority of Chinese. Importantly, it is not recognized as a legal entity. We have developed a non-heart-beating donation protocol based on literature searches (Medline, Ovid, and CNKI) and issues related to Chinese customs and ethics. The principles guiding protocol development included: separation of the decision to terminate life support from the donation decision, family-centered donation, freedom of conflict interest, and prohibition of organ sales. This protocol covers donation policy, potential donor identification and evaluation, family consent, determination of death, procurement, and special legal documents/organ distribution policy. A random survey was performed regarding donation. There have been several arguments about the development of this protocol. First, do donor family members have the right to make a decision to withdraw life support? Another issue is whether family members have the right to consent to donation without a will from the donor. Our survey found that over 96.1% of people do not have a will and have not discussed their interests in donation with family members. The last issue is whether the hospital can financially help for the funeral after donation. We have debated these issues nationwide with various opinions. We hope to find the right solutions through international debate. We believe that the use of non-heart-beating-donor organs has potential in China. We are hopeful that it will become a major organ source that is developed in such a way so as to be accepted internationally as well as in China. PMID:18555104
Dudkowska, A.; Makowiec, D.
In order to determine differences between healthy patients and patients with congestive heart failure we apply the artificial insymmetrised pattern (AIP) method. The AIP method by exploring a human eye ability to extract regularities and read symmetries in a dot pattern, serves a tool for qualitative discrimination of heart rate states.
Matchett, Gerald; Wood, Philip
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.
Lin, D. C.; Sharif, A.
The influence from the central nervous system on the human multifractal heart rate variability (HRV) is examined under the autonomic nervous system perturbation induced by the head-up-tilt body maneuver. We conducted the multifractal factorization analysis to factor out the common multifractal factor in the joint fluctuation of the beat-to-beat heart rate and electroencephalography data. Evidence of a central link in the multifractal HRV was found, where the transition towards increased (decreased) HRV multifractal complexity is associated with a stronger (weaker) multifractal correlation between the central and autonomic nervous systems.
A F Pimentel, Marco; Santos, Mauro D; Springer, David B; Clifford, Gari D
Accurate heart beat detection in signals acquired from intensive care unit (ICU) patients is necessary for establishing both normality and detecting abnormal events. Detection is normally performed by analysing the electrocardiogram (ECG) signal, and alarms are triggered when parameters derived from this signal exceed preset or variable thresholds. However, due to noisy and missing data, these alarms are frequently deemed to be false positives, and therefore ignored by clinical staff. The fusion of features derived from other signals, such as the arterial blood pressure (ABP) or the photoplethysmogram (PPG), has the potential to reduce such false alarms. In order to leverage the highly correlated temporal nature of the physiological signals, a hidden semi-Markov model (HSMM) approach, which uses the intra- and inter-beat depolarization interval, was designed to detect heart beats in such data. Features based on the wavelet transform, signal gradient and signal quality indices were extracted from the ECG and ABP waveforms for use in the HSMM framework. The presented method achieved an overall score of 89.13% on the hidden/test data set provided by the Physionet/Computing in Cardiology Challenge 2014: Robust Detection of Heart Beats in Multimodal Data. PMID:26218536
Rohmer, Damien; Sitek, Arkadiusz; Gullberg, Grant T.
The motion of the beating heart is complex and createsartifacts in SPECT and x-ray CT images. Phantoms such as the JaszczakDynamic Cardiac Phantom are used to simulate cardiac motion forevaluationof acquisition and data processing protocols used for cardiacimaging. Two concentric elastic membranes filled with water are connectedto tubing and pump apparatus for creating fluid flow in and out of theinner volume to simulate motion of the heart. In the present report, themovement of two concentric balloons is solved numerically in order tocreate a computer simulation of the motion of the moving membranes in theJaszczak Dynamic Cardiac Phantom. A system of differential equations,based on the physical properties, determine the motion. Two methods aretested for solving the system of differential equations. The results ofboth methods are similar providing a final shape that does not convergeto a trivial circular profile. Finally,a tomographic imaging simulationis performed by acquiring static projections of the moving shape andreconstructing the result to observe motion artifacts. Two cases aretaken into account: in one case each projection angle is sampled for ashort time interval and the other case is sampled for a longer timeinterval. The longer sampling acquisition shows a clear improvement indecreasing the tomographic streaking artifacts.
The motion of the beating heart is complex and creates artifacts in SPECT and x-ray CT images. Phantoms such as the Jaszczak Dynamic Cardiac Phantom are used to simulate cardiac motion for evaluation of acquisition and data processing protocols used for cardiac imaging. Two concentric elastic membranes filled with water are connected to tubing and pump apparatus for creating fluid flow in and out of the inner volume to simulate motion of the heart. In the present report, the movement of two concentric balloons is solved numerically in order to create a computer simulation of the motion of the moving membranes in the Jaszczak Dynamic Cardiac Phantom. A system of differential equations, based on the physical properties, determine the motion. Two methods are tested for solving the system of differential equations. The results of both methods are similar providing a final shape that does not converge to a trivial circular profile. Finally, a tomographic imaging simulation is performed by acquiring static projections of the moving shape and reconstructing the result to observe motion artifacts. Two cases are taken into account: in one case each projection angle is sampled for a short time interval and the other case is sampled for a longer time interval. The longer sampling acquisition shows a clear improvement in decreasing the tomographic streaking artifacts
Full Text Available Purpose: of this paper: Heart rate is a reliable indicator of the stress. Non-invasive methods have advantage over the methods that have a negative influence on the condition of an animal. When breeding sport horses, which undergo stressful training every day, it is required, from an ethical aspect, to monitor their capabilities by using most advanced electronic devices Polar Sport Tester and Polar Equine RS800cx G3.Design/methodology/approach: The original Polar ProTrainer 5 Equine edition software facilitates the analysis of individual training phases and gives the number of heart beats, average heart rate, average speed and distance covered in individual training phases.Findings: Heart rate increased, in warming up phase, from the value associated with a resting horse (30 to 40 bpm approximately in one minute, while, during the slow cooling down phase, ten minutes were required for the heart rate to reach the afore-mentioned value. During quick trotting heart rate are 112 heart beats per minute, while during steeplechase phase, it increased to the value of 160 to 170 heart beats per minute.Research limitations/implications: To receive heart rate without disturbances already we moisten the skin on the contact spots, using a mixture of water and electrolytes (Salvana Nutrilyt. Placing receiver on the saddle close by the T56H transmitter was the optimal choice.Practical implications: Modern equipment makes monitoring the horse’s heart rate accurately and to perform, safely and without disturbances, exercises required during training. It also checks the heart rate, which indicates the horse’s health.Originality/value: Polar Sport Tester and Polar Equine RS800cx G3 are state of the art products that facilitate the receipt of the horse’s heart rate signals. The accuracy of the acquired results can be compared with those obtained with ECG measurements.
We have studied three-dimensionally (3-D) reconstructed images of atrioventricular (AV) annuli based on four-chamber magnetic resonance (MR) images for total artificial heart (TAH) implantation. To assess the interrelationship among the AV annuli and the thorax, we applied the frame of reference of the vertebral canal to these images. The Z-axis was along the vertebral canal, the Y-axis in the anteroposterior direction. The angle alpha was defined as the angle between the X-axis and the intersection between the plane of the annulus and the X-Y plane. The angle beta was defined as the angle between the Z-axis and the intersection between the plane of annulus and X-Z plane. The angle gamma was defined as the angle between the plane of the annulus and the anterior thoracic wall. We determined each angle for the mitral annulus (MVA) and tricuspid annulus (TVA) in four normal subjects to be as follows: alpha-MVA, 20.5-39.5 degrees; alpha-TVA, 26.1-43.5 degrees; beta-MVA, 4.7-49.4 degrees; beta-TVA, 4.4-40.9 degrees; and gamma-TVA, 35.2-44.1 degrees. It is suggested that reconstruction of the thoracic wall and AV annuli using the frame of reference of the diaphragmatic surface of the heart would facilitate evaluation of the spacial requirements for TAH implantation. Research to define this new frame of reference is in progress. (author)
E. I. Tarlovskaya
Full Text Available Aim. To compare the efficacy and cost/effectiveness ratio of the original and generic bisoprolol in achieving target heart rate (HR in patients with ischemic heart disease.Material and methods. Patients with ischemic heart disease (n=60; 36 males and 24 females aged from 35 to 75 years were included into the study. Patients were randomized into group A (received therapy based on the original bisoprolol or into group B (received therapy based on of generic bisoprolol. Ivabradine was added, if the effect was insufficient. The duration of follow-up was 6 weeks. The HR dynamics was assessed during the study period. Cost/effectiveness ratio was calculated.Results. Significant HR slowing was found in both groups by the end of observation. In group A baseline HR was 70.0±5.6 beats/min and in 6 weeks - 58.1±3.8 beats/min, while in group B - 69.5±5.2 and 60.5±3.9 beats/min respectively. HR slowing was significantly higher in group A than that in group B. Direct costs in order to achieve a target HR in 1 patient for 6 weeks of therapy in group A were 663.75 rubles, while this in group B - 1093.58 rubles. Direct costs for HR deceleration by 1 beat in group A were 48.46 rubles vs 69.40 rubles in group B. The effect of therapy based on the original bisoprolol, is superior to that when generic bisoprolol used.Conclusion. HR-slowing effect of therapy based on the original bisoprolol was superior to that when generic bisoprolol was used. Pharmacoeconomic analysis revealed that HR deceleration was more economically profitable in treatment based on the original bisoprolol.
Ferrari, Roberto; Fox, Kim
Elevated heart rate is known to induce myocardial ischaemia in patients with coronary artery disease (CAD), and heart rate reduction is a recognized strategy to prevent ischaemic episodes. In addition, clinical evidence shows that slowing the heart rate reduces the symptoms of angina by improving microcirculation and coronary flow. Elevated heart rate is an established risk factor for cardiovascular events in patients with CAD and in those with chronic heart failure (HF). Accordingly, reducing heart rate improves prognosis in patients with HF, as demonstrated in SHIFT. By contrast, data from SIGNIFY indicate that heart rate is not a modifiable risk factor in patients with CAD who do not also have HF. Heart rate is also an important determinant of cardiac arrhythmias; low heart rate can be associated with atrial fibrillation, and high heart rate after exercise can be associated with sudden cardiac death. In this Review, we critically assess these clinical findings, and propose hypotheses for the variable effect of heart rate reduction in cardiovascular disease. PMID:27226153
The purpose of the study was to determine the association between of preoperative heart rate and post spinal hypotension in women undergoing cesarean section, Two hundred patients undergoing caesarean were included in the study selected on non probability convenience sampling technique, The patients were divided into two groups depending upon their pre operative heart rate. Spinal anesthesia was administered and number of patients developing hypotension was noted. Among 200 patients, who were included in the study; 112 were placed in group A and 88 were placed in group B depending on mean heart rate of 90 beats per minute or less or 91 beats per minute or more respectively. In group A 14 (11.86%) patients developed hypotension where as in group B 28 (31,82%) patients developed hypotension. Pre operative heart rate is significantly associated with post spinal hypotension in obstetric patients undergoing cesarean section. (author)
Obeid, Dany; Sadek, Sawsan; Zaharia, Gheorghe,; El Zein, Ghais
International audience This paper provides a validation approach for a microwave Doppler Radar system used for heartbeat detection. The proposed system is tested at 16 GHz with several transmitted power, simultaneously with a pc-based electrocardiogram. Obtained results show accurate detection for the heartbeat signal in terms of heartbeat rate and heart rate variability.
In order to assess the influence of change in heart rate on left ventricular diastolic function indices, ECG gated cardiac pool study was performed in 6 patients with implanted programmable AAI pacemakers. Heart rate was changed by atrial pacing from 50 to 120 beats/min, every 10 beats/min. The filling fraction during first third of diastole (1/3FF), the peak filling rate (PFR), mean first third filling rate (1/3FR-mean) and early filling volume ratio (%EFV), being used as the indices of left ventricular diastolic performance, were assessed. In accordance with increase in heart rate, 1/3FF decreased significantly. PFR were fairly stable from 50 to 80 beats/min, but increased significantly from 90 to 120 beats/min. 1/3FR-mean and %EFV did not change significantly, but 1/3FR-mean showed decreasing tendency and %EFV showed increasing tendency as the heart rate was increased. %EFV was more changeable index than other indices among clinical cases. These results indicate that PFR and 1/3FR-mean were appropriate diastolic phase indices at rest. (author)
Blanksby, B A; Reidy, P W
Ten competitive ballroom dance couples performed simulated competitive sequences of Modern and Latin American dance. Heart rate was telemetered during the dance sequences and related to direct measures of oxygen uptake and heart rate obtained while walking on a treadmill. Linear regression was employed to estimate gross and net energy expenditures of the dance sequences. A multivariate analysis of variance with repeated measures on the dance factor was applied to the data to test for interaction and main effects on the sex and dance factors. Overall mean heart rate values for the Modern dance sequence were 170 beats.min-1 and 173 beats.min-1 for males and females respectively. During the Latin American sequence mean overall heart rate for males was 168 beats.min-1 and 177 beats.min-1 for females. Predicted mean gross values of oxygen consumption for the males were 42.8 +/- 5.7 ml.kg-1 min-1 and 42.8 +/- 6.9 ml.kg-1 min-1 for the Modern and Latin American sequences respectively. Corresponding gross estimates of oxygen consumption for the females were 34.7 +/- 3.8 ml.kg-1 min-1 and 36.1 +/- 4.1 ml.kg-1 min-1. Males were estimated to expand 54.1 +/- 8.1 kJ.min-1 of energy during the Modern sequence and 54.0 +/- 9.6 kJ.min-1 during the Latin American sequence, while predicted energy expenditure for females was 34.7 +/- 3.8 kJ.min-1 and 36.1 +/- 4.1 kJ.min-1 for Modern and Latin American dance respectively. The results suggested that both males and females were dancing at greater than 80% of their maximum oxygen consumption. A significant difference between males and females was observed for predicted gross and net values of oxygen consumption (in L.min-1 and ml.kg-1 min-1). PMID:3167503
Huang, Chenxi; Alamili, Mahdi; Rosenberg, Jacob; Gögenur, Ismail
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...... HRV indices were decreased both in time and frequency domains during acute diverticulitis compared to baseline. In particular, the indices reflecting the balance of sympathetic and parasympathetic activities were affected: standard deviation of normal-to-normal beats (P = .003), low-frequency power (P...
Marsano, Anna; Conficconi, Chiara; Lemme, Marta; Occhetta, Paola; Gaudiello, Emanuele; Votta, Emiliano; Cerino, Giulia; Redaelli, Alberto; Rasponi, Marco
In the past few years, microfluidic-based technology has developed microscale models recapitulating key physical and biological cues typical of the native myocardium. However, the application of controlled physiological uniaxial cyclic strains on a defined three-dimension cellular environment is not yet possible. Two-dimension mechanical stimulation was particularly investigated, neglecting the complex three-dimensional cell-cell and cell-matrix interactions. For this purpose, we developed a heart-on-a-chip platform, which recapitulates the physiologic mechanical environment experienced by cells in the native myocardium. The device includes an array of hanging posts to confine cell-laden gels, and a pneumatic actuation system to induce homogeneous uniaxial cyclic strains to the 3D cell constructs during culture. The device was used to generate mature and highly functional micro-engineered cardiac tissues (μECTs), from both neonatal rat and human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM), strongly suggesting the robustness of our engineered cardiac micro-niche. Our results demonstrated that the cyclic strain was effectively highly uniaxial and uniformly transferred to cells in culture. As compared to control, stimulated μECTs showed superior cardiac differentiation, as well as electrical and mechanical coupling, owing to a remarkable increase in junction complexes. Mechanical stimulation also promoted early spontaneous synchronous beating and better contractile capability in response to electric pacing. Pacing analyses of hiPSC-CM constructs upon controlled administration of isoprenaline showed further promising applications of our platform in drug discovery, delivery and toxicology fields. The proposed heart-on-a-chip device represents a relevant step forward in the field, providing a standard functional three-dimensional cardiac model to possibly predict signs of hypertrophic changes in cardiac phenotype by mechanical and biochemical co
Full Text Available Abstract Background Both the act of competing, which can create a kind of mental stress, and participation in motor sports, which induces physical stress from intense g-forces, are known to increase heart rate dramatically. However, little is known about the specific effect of competition on heart rate during motor sports, particularly during four-wheel car driving. The goal of this preliminary study, therefore, was to investigate whether competition increases heart rate under such situations. Findings The participants drove an entry-level formula kart during two competitive races and during solo driving against the clock while heart rate and g-forces were measured. Analyses showed that heart rate values during the races (168.8 beats/min were significantly higher than those during solo driving (140.9 beats/min and rest (75.1 beats/min. Conclusions The results of this preliminary study indicate that competition heightens heart rate during four-wheel car driving. Kart drivers should be concerned about maintaining good health and developing physical strength.
Peter Van Leeuwen
Full Text Available It has been shown that short-term direct interaction between maternal and fetal heart rates may take place and that this interaction is affected by the rate of maternal respiration. The aim of this study was to determine the effect of maternal aerobic exercise during pregnancy on the occurrence of fetal-maternal heart rate synchronization.In 40 pregnant women at the 36th week of gestation, 21 of whom exercised regularly, we acquired 18 min. RR interval time series obtained simultaneously in the mothers and their fetuses from magnetocardiographic recordings. The time series of the two groups were examined with respect to their heart rate variability, the maternal respiratory rate and the presence of synchronization epochs as determined on the basis of synchrograms. Surrogate data were used to assess whether the occurrence of synchronization was due to chance.In the original data, we found synchronization occurred less often in pregnancies in which the mothers had exercised regularly. These subjects also displayed higher combined fetal-maternal heart rate variability and lower maternal respiratory rates. Analysis of the surrogate data showed shorter epochs of synchronization and a lack of the phase coordination found between maternal and fetal beat timing in the original data.The results suggest that fetal-maternal heart rate coupling is present but generally weak. Maternal exercise has a damping effect on its occurrence, most likely due to an increase in beat-to-beat differences, higher vagal tone and slower breathing rates.
Bazylev, V V; Nemchenko, E V; Karnakhin, V A; Pavlov, A A; Mikulyak, A I
Advantages and shortcomings of aortocoronary bypass grafting on the beating heart and in the conditions of artificial circulation (AC) have long been discussed. The data on patency of bypass grafts in the remote period are indicative of comparable results of operations with and without AC or advantages of using AC. In order to determine benefits of each method it is necessary to reveal intraoperative predictors of bypass grafts occlusion in the remote period. We analyzed the results of ultrasound flowmetry of the blood flow through the left internal thoracic artery during bypass grafting of the anterior descending artery with the use of AC and on the beating heart. A retrospective study included a total of 352 patients subdivided into 2 groups: Group One was composed of 120 patients undergoing surgery in the conditions of AC and Group Two comprised 232 patients subjected to similar operations on the beating heart. Blood flow was measured with the help of flowmeter VeryQ MediStim® after termination of AC and inactivation of heparin by protamine, with systolic pressure of 100-110 mm Hg. There were no statistically significant differences between the groups by the diameter and degree of stenosis of the anterior descending artery, diameter of the left internal thoracic artery. The mean volumetric blood flow velocity (Qmean) along the shunts in Group One was higher (p=0.01). No statistically significant differences by the pulsatility index (PI) between the groups were revealed (p=0.2). A conclusion was drawn that coronary bypass grafting of the anterior descending artery by the left internal thoracic artery in the conditions of artificial circulation made it possible to achieve higher volumetric velocity of blood flow through the conduit as compared with operations on the beating heart, with similar resistance index. The immediate results of the operations with the use of the both techniques did not differ. PMID:27100540
... July 2015. Cardiovascular Conditions • Conditions Home • Arrhythmia and Atrial Fibrillation • Cardiac Arrest • Cardiac Rehab • Cardiomyopathy • Cardiovascular Conditions of Childhood • Cholesterol • Congenital Heart Defects • Diabetes • Heart Attack • Heart Failure (HF) • Heart Valve Problems and Disease • High Blood ...
Schulze Westerath, Heike; Probst, Johanna; Gygox, Lorenz; Hillmann, Edna
A good animal-human relationship is one important aspect concerning cattle welfare. The aim of this study was to investigate the effect of gentle handling at head and neck on behaviour and heart beat parameters in beef cattle.
Araoz, Philip A; Kirsch, Jacobo; Primak, Andrew N.; Braun, Natalie N.; Saba, Osama; Williamson, Eric E.; Harmsen, W. Scott; Mandrekar, Jayawant N.; McCollough, Cynthia H.
The purpose of this study was to determine the cardiac phase having the highest coronary sharpness for low and high heart rate patients scanned with dual source CT (DSCT) and to compare coronary image sharpness over different cardiac phases. DSCT coronary CT scans for 30 low heart rate (≤ 70 beats per minute- bpm) and 30 high heart rate (>70 bpm) patients were reconstructed into different cardiac phases, starting at 30% and increasing at 5% increments until 70%. A blinded observer graded imag...
Goutam Kumar Sahoo, Samit Ari, Sarat Kumar Patra
Electrocardiogram (ECG) is generally used fordiagnosis ofcardiovascularabnormalitiesanddisorders.Anefficient method for analysingtheECG signal towards the detection ofheartrate(HR)andischemic episodesfollows mainly fivestages:pre-processing, feature extraction,heart ratedetection,beat classification and ischemicepisoderecognition.Theheart rate is calculatedusing theextracted featuresoftheECG signal. Thecalculated HRvaluecan beanalysedforthedetectionofvariouscardiovascularabnormalities.Theabil...
The asymmetry in heart rate variability is a visibly obvious phenomenon in the Poincaré plot of normal sinus rhythm. It shows the unevenness in the distribution of points above and below the line of identity, which indicates instantaneous changes in the beat to beat heart rate. The major limitation of the existing asymmetry definition is that it considers only the instantaneous changes in the beat to beat heart rate rather than the pattern (increase/decrease). In this paper, a novel definition of asymmetry is proposed considering the geometry of a 2D Poincaré plot. Based on the proposed definition, traditional asymmetry indices—Guzik's index (GI), Porta's index (PI) and Ehlers' index (EI)—have been redefined. In order to compare the effectiveness of the new definition, all indices have been calculated for RR interval series of 54 subjects with normal sinus rhythm of 5 min and 30 min duration. The new definition resulted in a higher prevalence of normal subjects showing asymmetry in heart rate variability
DeVore, Adam D; Schulte, Phillip J; Mentz, Robert J; Hardy, N Chantelle; Kelly, Jacob P; Velazquez, Eric J; Maya, Juan F; Kielhorn, Adrian; Patel, Harshali K; Reed, Shelby D; Hernandez, Adrian F
There are limited data describing outcomes associated with an elevated heart rate in patients with heart failure with reduced ejection fraction (HFrEF) in routine clinical practice. We identified patients with HFrEF at Duke University Hospital undergoing echocardiograms and heart rate assessments without paced rhythms or atrial fibrillation. Outcomes (all-cause mortality or hospitalization and medical costs per day alive) were assessed using electronic medical records, hospital cost accounting data, and national death records. Patients were stratified by heart rate (<70 and ≥70 beats/min) and compared using generalized linear models specified with gamma error distributions and log links for costs and proportional hazard models for mortality/hospitalization. Of 722 eligible patients, 582 patients (81%) were treated with β blockers. The median heart rate was 81 beats/min (25th and 75th percentiles 69 to 96) and 527 patients (73%) had a heart rate ≥70 beats/min. After multivariate adjustment, a heart rate ≥70 beats/min was associated with increased 1-year all-cause mortality or hospitalization, hazard ratio 1.37 (95% CI 1.07 to 1.75) and increased medical costs per day alive, cost ratio 2.03 (95% CI 1.53 to 2.69). In conclusion, at a large tertiary care center, despite broad use of β blockers, a heart rate ≥70 beats/min was observed in 73% of patients with HFrEF and associated with worse 1-year outcomes and increased direct medical costs per day alive. PMID:26805662
de Leon-Lomeli, R; Murguia, J S; Chouvarda, I; Mendez, M O; Gonzalez-Galvan, E; Alba, A; Milioli, G; Grassi, A; Terzano, M G; Parrino, L
Insomnia is a condition that affects the nervous and muscular system. Thirty percent of the population between 18 and 60 years suffers from insomnia. The effects of this disorder involve problems such as poor school or job performance and traffic accidents. In addition, patients with insomnia present changes in the cardiac function during sleep. Furthermore, the structure of electroencephalographic A-phases, which builds up the Cyclic Alternating Pattern during sleep, is related to the insomnia events. Therefore, the relationship between these brain activations (A-phases) and the autonomic nervous system would be of interest, revealing the interplay of central and autonomic activity during insomnia. With this goal, a study of the relationship between A-phases and heart rate fluctuations is presented. Polysomnography recording of five healthy subjects, five sleep misperception patients and five patients with psychophysiological insomnia were used in the study. Detrended Fluctuation Analysis (DFA) was used in order to evaluate the heart rate dynamics and this was correlated with the number of A-phases. The results suggest that pathological patients present changes in the dynamics of the heart rate. This is reflected in the modification of A-phases dynamics, which seems to modify of heart rate dynamics. PMID:25570435
Flower, Abigail A.; Moorman, J. Randall; Lake, Douglas E.; Delos, John B.
The pacemaking system of the heart is complex; a healthy heart constantly integrates and responds to extracardiac signals, resulting in highly complex heart rate patterns with a great deal of variability. In the laboratory and in some pathological or age-related states, however, dynamics can show reduced complexity that is more readily described and modeled. Reduced heart rate complexity has both clinical and dynamical significance – it may provide warning of impending illness or clues about ...
Jahandardoost, Mehdi; Fradet, Guy; Mohammadi, Hadi
To date, to the best of the authors' knowledge, in almost all of the studies performed around the hemodynamics of bileaflet mechanical heart valves, a heart rate of 70-72 beats/min has been considered. In fact, the heart rate of ~72 beats/min does not represent the entire normal physiological conditions under which the aortic or prosthetic valves function. The heart rates of 120 or 50 beats/min may lead to hemodynamic complications, such as plaque formation and/or thromboembolism in patients. In this study, the hemodynamic performance of the bileaflet mechanical heart valves in a wide range of normal and physiological heart rates, that is, 60-150 beats/min, was studied in the opening phase. The model considered in this study was a St. Jude Medical bileaflet mechanical heart valve with the inner diameter of 27 mm in the aortic position. The hemodynamics of the native valve and the St. Jude Medical valve were studied in a variety of heart rates in the opening phase and the results were carefully compared. The results indicate that peak values of the velocity profile downstream of the valve increase as heart rate increases, as well as the location of the maximum velocity changes with heart rate in the St. Jude Medical valve model. Also, the maximum values of shear stress and wall shear stresses downstream of the valve are proportional to heart rate in both models. Interestingly, the maximum shear stress and wall shear stress values in both models are in the same range when heart rate is St. Jude Medical valve model when heart rate is >90 beats/min (up to ~40% growth compared to that of the native valve). The findings of this study may be of importance in the hemodynamic performance of bileaflet mechanical heart valves. They may also play an important role in design improvement of conventional prosthetic heart valves and the design of the next generation of prosthetic valves, such as percutaneous valves. PMID:26786673
Kiljander, Toni; Toikka, Jyri; Koskenvuo, Juha; Jaakkola, Ilkka
The effect of public defense of a doctoral thesis on the heart rate of the doctoral candidate Most doctoral candidates find the public defense of a doctoral thesis an exciting and stressful experience. In this study, Holter recording during the defense was made for four doctoral candidates of the Faculty of Medicine. Maximum heart rate among the subjects was on the average 172 beats/min with a median heart rate of 116 beats/min. Sympathicotonia and release of stress hormones associated with the defense raise the heart rate to levels that may be very high for several hours. This is a risk factor for a coronary event and should be considered, if the doctoral candidate has coronary heart disease, carries risk factors for coronary heart disease, or is an elderly person. PMID:21805898
Full Text Available The shortage of available organs is the limiting factor for kidney transplantation (Ktx. One of the strategies to increase access to Ktx is the use of non-heart beating (NHB donors. We herein present a successful Ktx from an NHB (Maastricht Category-4 donor. The donor was a 21-year-old woman who had brain death due to cerebrovascular accident. She had severe hypotension for three hours despite 30 μg/kg/min dopamine infusion, followed by cardio-pulmonary arrest just before the operation began. Cardio-pulmonary resuscitation was consequently initiated and continued during the operation. Donor organ harvesting (hepatectomy and bilateral nephrectomy was performed after direct aortic cannulation. The warm ischemia time was 35 minutes. The recipient was a 54-year-old man who had undergone hemodialysis for four years. There were 3/6 mismatches, and the lymphocyte cross-match was negative. The induction immunosuppressive was anti-thymocyte globulin, followed by tacrolimus/ MMF/steroid after the 12th day. He had delayed graft function and hemodialysis was required at the third and sixth days. The urine output gradually increased and sCr slowly declined afterwards and he discharged with sCr 1.5 mg/dl on the 24th day. At the first year of transplantation, he is in good clinical condition with a stable baseline sCr of 1.5 mg/dl. NHB donors can be an alternative and important source to expand the kidney donation pool, and successful long-term outcomes favor this modality.
Ogliari, Giulia; Mahinrad, Simin; Stott, David J;
BACKGROUND: Heart rate and heart rate variability, markers of cardiac autonomic function, have been linked with cardiovascular disease. We investigated whether heart rate and heart rate variability are associated with functional status in older adults, independent of cardiovascular disease. METHODS...... < 0.05). All associations were independent of sex, medications, cardiovascular risk factors and comorbidities. INTERPRETATION: Higher resting heart rate and lower heart rate variability were associated with worse functional status and with higher risk of future functional decline in older adults......: We obtained data from the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER). A total of 5042 participants were included in the present study, and mean followup was 3.2 years. Heart rate and heart rate variability were derived from baseline 10-second electrocardiograms. Heart rate...
Herry, Christophe L; Frasch, Martin; Seely, Andrew JE; Wu, Hau-Tieng
The processing of ECG signal provides a wealth of information on cardiac function and overall cardiovascular health. While multi-lead ECG recordings are often necessary for a proper assessment of cardiac rhythms, they are not always available or practical, for example in fetal ECG applications. Moreover, a wide range of small non-obtrusive single-lead ECG ambulatory monitoring devices are now available, from which heart rate variability (HRV) and other health-related metrics are derived. Prop...
Bruno Gouvêa de Barros; Rodrigo Weber dos Santos; Marcelo Lobosco; Sergio Alonso
The inclusion of nonconducting media, mimicking cardiac fibrosis, in two models of cardiac tissue produces the formation of ectopic beats. The fraction of nonconducting media in comparison with the fraction of healthy myocytes and the topological distribution of cells determines the probability of ectopic beat generation. First, a detailed subcellular microscopic model that accounts for the microstructure of the cardiac tissue is constructed and employed for the numerical simulation of action...
Teich, M C; Jost, B M; Vibe-Rheymer, K; Heneghan, C; Teich, Malvin C.; Lowen, Steven B.; Jost, Bradley M.; Vibe-Rheymer, Karin; Heneghan, Conor
We focus on various measures of the fluctuations of the sequence of intervals between beats of the human heart, and how such fluctuations can be used to assess the presence or likelihood of cardiovascular disease. We examine sixteen such measures and their suitability for correctly classifying heartbeat records of various lengths as normal or revealing the presence of cardiac dysfunction, particularly congestive heart failure. Using receiver-operating-characteristic analysis we demonstrate that scale-dependent measures prove substantially superior to scale-independent ones. The wavelet-transform standard deviation at a scale near 32 heartbeat intervals, and its spectral counterpart near 1/32 cycles/interval, turn out to provide reliable results using heartbeat records just minutes long. We further establish for all subjects that the human heartbeat has an underlying stochastic origin rather than arising from a chaotic attractor. Finally, we develop a mathematical point process that emulates the human heartbea...
Xu, Binbin; Dubois, Rémi; Pont, Oriol; Yahia, Hussein
• Background : In Heart rate variability analysis, the rate-rate time series suffer often from aperiodic non-stationarity, presence of ectopic beats etc. It would be hard to extract helpful information from the original signals. 10 • Problem : Trend removal methods are commonly practiced to reduce the influence of the low frequency and aperiodic non-stationary in RR data. This can unfortunately affect the signal and make the analysis on detrended data less appropriate. • Objective : Investiga...
Xu, Binbin; Dubois, Rémi; Pont, Oriol; Yahia, Hussein
$\\bullet$ Background : In Heart rate variability analysis, the rate-rate time series suffer often from aperiodic non-stationarity, presence of ectopic beats etc. It would be hard to extract helpful information from the original signals. 10 $\\bullet$ Problem : Trend removal methods are commonly practiced to reduce the influence of the low frequency and aperiodic non-stationary in RR data. This can unfortunately affect the signal and make the analysis on detrended data less appropriate. $\\bulle...
Full Text Available Chagas' myocardiopathy, caused by the intracellular protozoan Trypanosoma cruzi, is characterized by microvascular alterations, heart failure and arrhythmias. Ischemia and arrythmogenesis have been attributed to proteins shed by the parasite, although this has not been fully demonstrated. The aim of the present investigation was to study the effect of substances shed by T. cruzi on ischemia/reperfusion-induced arrhythmias. We performed a triple ischemia-reperfusion (I/R protocol whereby the isolated beating rat hearts were perfused with either Vero-control or Vero T. cruzi-infected conditioned medium during the different stages of ischemia and subsequently reperfused with Tyrode's solution. ECG and heart rate were recorded during the entire experiment. We observed that triple I/R-induced bradycardia was associated with the generation of auricular-ventricular blockade during ischemia and non-sustained nodal and ventricular tachycardia during reperfusion. Interestingly, perfusion with Vero-infected medium produced a delay in the reperfusion-induced recovery of heart rate, increased the frequency of tachycardic events and induced ventricular fibrillation. These results suggest that the presence of parasite-shed substances in conditioned media enhances the arrhythmogenic effects that occur during the I/R protocol.
Jarbas Jakson Dinkhuysen
implantation of the donor heart in the bicaval bipulmonary orthotopic position using normothermic beating heart and thus, facilitate the transplanted heart adaptation to the recipient. This study presents a small experience about a new strategy of myocardial protection during heart transplant. METHODS: In cardiopulmonary bypass, the aorta anastomosis was done first, allowing the coronary arteries to receive blood flow and the recovering of the beats. The rest of the anastomosis is performed on a beating heart in sinus rhythm. The pulmonary anastomosis is the last to be done. This methodology was applied in 10 subjects: eight males, age 16-69 (mean 32.7 years, SPAo 90-100 mmHg (mean 96 mmHg, SPAP 25-65 mmHg (mean 46.1 mmHg, PVR 0.9 to 5.0 Wood (mean 3.17 Wood, GTP 4-13 mmHg (mean 7.9 mmHg, and eight male donors, age 15-48 years (mean 27.7 years, weight 65-114 kg (mean 83.1 kg. Causes of brain coma: encephalic trauma in five hemorrhagic stroke in four, and brain tumor in one. RESULTS: The ischemic time ranged from 58-90 minutes (mean 67.6 minutes and 8 donors were in hospitals of Sao Paulo and two in distant cities. All grafts assumed the cardiac output requiring low-dose inotropic therapy and maintained these conditions in the postoperative period. There were no deaths and all were discharged. The late evolution goes from 20 days to 10 months with one death occurred after 4 months due to sepsis. CONCLUSION: This method, besides reducing the ischemic time of the procedure, allows the donated organ to regain and maintain their beats without pre or after load during implantation entailing the physiological recovery of the graft.
Nakajima, K; Tamura, T; Miike, H
An apparatus for simultaneously monitoring heart and respiratory rates was developed using photoplethysmography (PPG) and digital filters, and compared with conventional methods. The PPG signal, which includes both heart and respiratory components, was measured at the earlobe with an original transmission mode photoplethysmographic device. A digital filtering technique was used to distinguish heart and respiratory signals from the PPG signal. The cut-off frequency of the respiratory signal filter was selected automatically depending on the heart rate. Using digital filtering techniques, heart and respiratory signals were separated at rest and during exercise. The digital signal processor was employed to realize an adaptive and real-time filtering. The heart rate was calculated by the zero-crossing method and the respiratory rate from the peak interval of the filtered signal. To evaluate the newly developed monitor, an ECG for heart rate and a transthoracic impedance plethysmogram for respiratory rate were monitored simultaneously. To obtain higher heart and respiratory rates, exercise was performed on an electrical bicycle ergometer. Heart and respiratory rates calculated by the new method compare to those obtained from ECG and the transthoracic impedance plethysmogram. The maximum error of heart and respiratory rates was 10 beats/min and 7 breaths/min, respectively. PMID:8818134
HUANG XiaoLin; NING XinBao; WANG XinLong
Analysis of multiscale entropy (MSE) and multiscale standard deviation (MSD) are performed for both the heart rate interval series and the interval increment series. For the interval series, it is found that, it is impractical to discriminate the diseases of atrial fibrillation (AF) and congestive heart failure (CHF) unambiguously from the healthy. A clear discrimination from the healthy, both young and old, however, can be made in the MSE analysis of the increment series where we find that both CHF and AF sufferers have significantly low MSE values in the whole range of time scales investigated, which reveals that there are common dynamic characteristics underlying these two different diseases. In addition, we propose the sample entropy (SE) corresponding to time scale factor 4 of increment series as a diag-nosis index of both AF and CHF, and the reference threshold is recommended. Further indication that this index can help discriminate sensitively the mild heart failure (cardiac function classes 1 and 2) from the healthy gives a clue to early clinic diagnosis of CHF.
The simultaneous study of the cardiac and respiratory activities and their interactions is of great physiological and clinical interest. For this purpose, we want to investigate if respiratory inductive plethysmography (RIP) can be used for cardiac functional exploration. We propose a system, based on RIP technology and time-scale approaches of signal processing, for the extraction of cardiac information. This study focuses on the monitoring of blood volume shift due to heart beat, noted ▵Vtrc and investigates RIP for the detection of ▵Vtrc variations by comparison to stroke volume (SV) variations estimated by impedance cardiography (IMP). We proposed a specific respiratory protocol assumed to induce significant variations of the SV. Fifteen healthy volunteers in the seated and supine positions were asked to alternate rest respiration and maneuvers, consisting in blowing into a manometer. A multi-step treatment including a variant of empirical mode decomposition was applied on RIP signals to extract cardiac volume signals and estimate beat-to-beat ▵Vtrc. These were averaged in quasi-stationary states at rest and during the respiratory maneuvers, and analysed in view of SV estimations from IMP signals simultaneously acquired. Correlation and statistical tests over the data show that RIP can be used to detect variations of the cardiac blood shift in healthy young subjects. (paper)
Gemma, Karen Erickson; Wells, Christine L.
Heart rates were recorded by radiotelemetry in ten elite and national-class synchronized swimmers as they performed competitive figures of high degrees of difficulty. The focus was on changes in heart rates and electrocardiogram patterns for each body position, especially those requiring facial immersion and breath-holding. (Author/MT)
Adriano L. Roque
Full Text Available OBJECTIVES: There are no data in the literature with regard to the acute effects of different styles of music on the geometric indices of heart rate variability. In this study, we evaluated the acute effects of relaxant baroque and excitatory heavy metal music on the geometric indices of heart rate variability in women. METHODS: We conducted this study in 21 healthy women ranging in age from 18 to 35 years. We excluded persons with previous experience with musical instruments and persons who had an affinity for the song styles. We evaluated two groups: Group 1 (n = 21, who were exposed to relaxant classical baroque musical and excitatory heavy metal auditory stimulation; and Group 2 (n = 19, who were exposed to both styles of music and white noise auditory stimulation. Using earphones, the volunteers were exposed to baroque or heavy metal music for five minutes. After the first music exposure to baroque or heavy metal music, they remained at rest for five minutes; subsequently, they were re-exposed to the opposite music (70-80 dB. A different group of women were exposed to the same music styles plus white noise auditory stimulation (90 dB. The sequence of the songs was randomized for each individual. We analyzed the following indices: triangular index, triangular interpolation of RR intervals and Poincaré plot (standard deviation of instantaneous beat-by-beat variability, standard deviation of the long-term RR interval, standard deviation of instantaneous beat-by-beat variability and standard deviation of the long-term RR interval ratio, low frequency, high frequency, low frequency/high frequency ratio, standard deviation of all the normal RR intervals, root-mean square of differences between the adjacent normal RR intervals and the percentage of adjacent RR intervals with a difference of duration greater than 50 ms. Heart rate variability was recorded at rest for 10 minutes. RESULTS: The triangular index and the standard deviation of
Nader - Rahnama
Full Text Available ABSTRACT. The aim of this study was to investigate the effects of exercise training on maximum aerobic capacity, rest heart beat, blood pressure and anthropometric variables of postmenopausal women with breast cancer. Twenty nine women with breast cancer who received surgery, chemotherapy and radiotherapy with current hormone therapy divided into two groups; intervention and control. Subjects of intervention group performed 15 weeks combination exercise training including walking (2 sessions per week and resistance training (2 sessions per week that different from walking days. Before and after 15 weeks, Vo2max, rest heart beat, blood pressure, body weight, body mass index (BMI and waist to hip ratio (WHR were measured in two groups. Data analyzed by using t- test. Significant differences were observed for Vo2max, rest heart beat, body weight, BMI and WHR between intervention and control groups (P< 0.05, after 15 weeks. In fact, exercise training had positive effects on the Vo2max, rest heart beat, body weight, BMI and WHR in postmenopausal women with breast cancer. No significant different was founded for blood pressure between two groups (P=0.193. In conclusion, exercise training can improve maximum aerobic capacity, rest heart beat and anthropometric variables in postmenopausal women with breast cancer.
Lipsitz, L. A.; Hashimoto, F.; Lubowsky, L. P.; Mietus, J.; Moody, G. B.; Appenzeller, O.; Goldberger, A. L.
OBJECTIVE--To investigate the alterations in autonomic control of heart rate at high altitude and to test the hypothesis that hypoxaemic stress during exposure to high altitude induces non-linear, periodic heart rate oscillations, similar to those seen in heart failure and the sleep apnoea syndrome. SUBJECTS--11 healthy subjects aged 24-64. MAIN OUTCOME MEASURES--24 hour ambulatory electrocardiogram records obtained at baseline (1524 m) and at 4700 m. Simultaneous heart rate and respiratory dynamics during 2.5 hours of sleep by fast Fourier transform analysis of beat to beat heart rate and of an electrocardiographically derived respiration signal. RESULTS--All subjects had resting hypoxaemia at high altitude, with an average oxyhaemoglobin saturation of 81% (5%). There was no significant change in mean heart rate, but low frequency (0.01-0.05 Hz) spectral power was increased (P high altitude. Time series analysis showed a complex range of non-linear sinus rhythm dynamics. Striking low frequency (0.04-0.06 Hz) heart rate oscillations were observed during sleep in eight subjects at high altitude. Analysis of the electrocardiographically derived respiration signal indicated that these heart rate oscillations correlated with low frequency respiratory oscillations. CONCLUSIONS--These data suggest (a) that increased low frequency power during high altitude exposure is not simply attributable to increased sympathetic modulation of heart rate, but relates to distinctive cardiopulmonary oscillations at approximately 0.05 Hz and (b) that the emergence of periodic heart rate oscillations at high altitude is consistent with an unstable cardiopulmonary control system that may develop on acute exposure to hypoxaemic stress.
Buxton, Roxanne E.; West, Michael R.; Kalogera, Kent L.; Hanson, Andrea M.
Heart rate monitoring is required during exercise for crewmembers aboard the International Space Station (ISS) and will be for future exploration missions. The cardiovascular system must be sufficiently stressed throughout a mission to maintain the ability to perform nominal and contingency/emergency tasks. High quality heart rate data is required to accurately determine the intensity of exercise performed by the crewmembers and show maintenance of VO2max. The quality of the data collected on ISS is subject to multiple limitations and is insufficient to meet current requirements. PURPOSE: To evaluate the performance of commercially available Bluetooth® heart rate monitors (BT_HRM) and their ability to provide high quality heart rate data to monitor crew health on board ISS and during future exploration missions. METHODS: Nineteen subjects completed 30 data collection sessions of various intensities on the treadmill and/or cycle. Subjects wore several BT_HRM technologies for each testing session. One electrode-based chest strap (CS) was worn, while one or more optical sensors (OS) was worn. Subjects were instrumented with a 12-lead ECG to compare the heart rate data from the Bluetooth sensors. Each BT_RHM data set was time matched to the ECG data and a +/-5bpm threshold was applied to the difference between the two data sets. Percent error was calculated based on the number of data points outside the threshold and the total number of data points. REULTS: The electrode-based chest straps performed better than the optical sensors. The best performing CS was CS1 (1.6%error), followed by CS4 (3.3%error), CS3 (6.4%error), and CS2 (9.2%error). The OS resulted in 10.4% error for OS1 and 14.9% error for OS2. CONCLUSIONS: The highest quality data came from CS1, unfortunately it has been discontinued by the manufacturer. The optical sensors have not been ruled out for use, but more investigation is needed to determine how to get the best quality data. CS2 will be used in an
Sakamoto, Kentaro Q; Takahashi, Akinori; Iwata, Takashi; Yamamoto, Takashi; Yamamoto, Maki; Trathan, Philip N
Albatrosses are known to expend only a small amount of energy during flight. The low energy cost of albatross flight has been attributed to energy-efficient gliding (soaring) with sporadic flapping, although little is known about how much time and energy albatrosses expend in flapping versus gliding during cruising flight. Here, we examined the heart rates (used as an instantaneous index of energy expenditure) and flapping activities of free-ranging black-browed albatrosses (Thalassarche melanophrys) to estimate the energy cost of flapping as well as time spent in flapping activities. The heart rate of albatrosses during flight (144 beats min(-1)) was similar to that while sitting on the water (150 beats min(-1)). In contrast, heart rate was much higher during takeoff and landing (ca. 200 beats min(-1)). Heart rate during cruising flight was linearly correlated with the number of wing flaps per minute, suggesting an extra energy burden of flapping. Albatrosses spend only 4.6±1.4% of their time flapping during cruising flight, which was significantly lower than during and shortly after takeoff (9.8±3.5%). Flapping activity, which amounted to just 4.6% of the time in flight, accounted for 13.3% of the total energy expenditure during cruising flight. These results support the idea that albatrosses achieve energy-efficient flight by reducing the time spent in flapping activity, which is associated with high energy expenditure. PMID:23661772
An unconstrained method for the long-term monitoring of heart and breath rates during sleep is proposed. The system includes a sensor unit and a web-based network module. The sensor unit is set beneath a pillow to pick up the pressure variations from the head induced by inhalation/exhalation movements and heart pulsation during sleep. The measured pressure signal was digitized and transferred to a remote database server via the network module. A wavelet-based algorithm was employed to detect the heart and breath rates, as well as body movement, during sleep. The overall system was utilized for a total six-month trial operation delivered to a female subject. The profiles of the heart and breath rates on a beat-by-beat and daily basis were obtained. Movements during sleep were also estimated. The results show that the daily average percentage of undetectable periods (UPs) during 881.6 sleep hours over a 180 day period was 17.2%. A total of 89.2% of sleep hours had a UP of not more than 25%. The profile of the heart rate revealed a periodic property that corresponded to the female monthly menstrual cycle. Our system shows promise as a long-term unconstrained monitor for heart and breath rates, and for other physiological parameters related to the quality of sleep and the regularity of the menstrual cycle. (note)
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 123I-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)
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
Panigrahy, D; Rakshit, M; Sahu, P K
This paper describes a field programmable gate array (FPGA) implementation of a system that calculates the heart rate from Electrocardiogram (ECG) signal. After heart rate calculation, tachycardia, bradycardia or normal heart rate can easily be detected. ECG is a diagnosis tool routinely used to access the electrical activities and muscular function of the heart. Heart rate is calculated by detecting the R peaks from the ECG signal. To provide a portable and the continuous heart rate monitoring system for patients using ECG, needs a dedicated hardware. FPGA provides easy testability, allows faster implementation and verification option for implementing a new design. We have proposed a five-stage based methodology by using basic VHDL blocks like addition, multiplication and data conversion (real to the fixed point and vice-versa). Our proposed heart rate calculation (R-peak detection) method has been validated, using 48 first channel ECG records of the MIT-BIH arrhythmia database. It shows an accuracy of 99.84%, the sensitivity of 99.94% and the positive predictive value of 99.89%. Our proposed method outperforms other well-known methods in case of pathological ECG signals and successfully implemented in FPGA. PMID:26643079
ZHAO Song; WANG Jia-xiang; YANG Yang; HE Zhan-feng; LIAO Qiu-ming
Background Non-heart-beating donor lung has been a promising source of lung transplantation. Many studies on non-heart-beating donor lungs are based on animal lung transplantation. In this study, we assessed by organ bath the effect of one-hour warm ischemia on the non-heart-beating donor lung in terms of the integrity of contractile and relaxant functions and tissue structures of pulmonic arteries and bronchi.Methods Sixteen Swedish pigs were randomly classified into two groups: heart-beating donor group and 1-hour warm ischemia non-heart-beating donor group. Pulmonic and bronchial rings were taken from the isolated left lungs of the pigs. The pulmonic rings were stimulated by U-46619 (5.7 mol/L) and acetylcholine (10~(-4) mmol/L) to assess the contractile abilities of smooth muscle and the endothelium-dependent relaxation response, respectively. As such, acetylcholine (10~(-5) mmol/L) and natrium arachidonic acid (0.01%) were used to detect the contraction of bronchial smooth muscle and epithelium-dependent relaxation response. Meanwhile, the variances of precontraction tension of control groups were recorded to measure whether there was spontaneous relaxation during endothelium/epithelium-dependent relaxation course. Finally, papaverine solution (10~(-4) mmol/L) was used to detect the non-endothelium/epithelium-dependent relaxant abilities of pulmonic and bronchial smooth muscles.Results There was no significant difference in the tension values of precontraction of pulmonic rings (P＞0.05), endothelium-dependent relaxation (P＞0.05), precontraction of bronchial rings (P＞0.05) and epithelium-dependent relaxation (P＞0.05) between the heart-beating donor group and the 1-hour warm ischemia non-heart-beating donor group. And the pulmonic and bronchial rings of each subgroup B had no spontaneous relaxation. Finally, papaverine solution relaxed the smooth muscle of all the rings completely.Conclusions The results of this experiment suggest that the contractile
Guede-Fernandez, F; Ferrer-Mileo, V; Ramos-Castro, J; Fernandez-Chimeno, M; Garcia-Gonzalez, M A
The aim of this paper is to present a smartphone based system for real-time pulse-to-pulse (PP) interval time series acquisition by frame-to-frame camera image processing. The developed smartphone application acquires image frames from built-in rear-camera at the maximum available rate (30 Hz) and the smartphone GPU has been used by Renderscript API for high performance frame-by-frame image acquisition and computing in order to obtain PPG signal and PP interval time series. The relative error of mean heart rate is negligible. In addition, measurement posture and the employed smartphone model influences on the beat-to-beat error measurement of heart rate and HRV indices have been analyzed. Then, the standard deviation of the beat-to-beat error (SDE) was 7.81 ± 3.81 ms in the worst case. Furthermore, in supine measurement posture, significant device influence on the SDE has been found and the SDE is lower with Samsung S5 than Motorola X. This study can be applied to analyze the reliability of different smartphone models for HRV assessment from real-time Android camera frames processing. PMID:26737985
Lundby, C; Møller, P; Kanstrup, I L;
This study examined the effects of dopamine D(2)-receptor blockade on the early decrease in maximal heart rate at high altitude (4559 m). We also attempted to clarify the time-dependent component of this reduction and the extent to which it is reversed by oxygen breathing. Twelve subjects performed...... breathing completely reversed the decrease in maximal heart rate to values not different from those at sea level. In conclusion, dopamine D(2)-receptor blockade with domperidone demonstrates that hypoxic exercise in humans activates D(2)-receptors, resulting in a decrease in circulating levels...... progressively decreased the maximal heart rate from day 1 and onwards; also, hypoxia by itself increased plasma noradrenaline levels after maximal exercise. Domperidone further increased maximal noradrenaline concentrations, but had no effect on maximal heart rate. On each study day at altitude, oxygen...
Zupan, Manja; Buskas, Julia; Altimiras, Jordi; Keeling, Linda J
Since most animal species have been recognized as sentient beings, emotional state may be a good indicator of welfare in animals. The goal of this study was to manipulate the environment of nine beagle research dogs to highlight physiological responses indicative of different emotional experiences. Stimuli were selected to be a more or a less positive food (meatball or food pellet) or social reward (familiar person or less familiar person). That all the stimuli were positive and of different reward value was confirmed in a runway motivation test. Dogs were tested individually while standing facing a display theatre where the different stimuli could be shown by lifting a shutter. The dogs approached and remained voluntarily in the test system. They were tested in four sessions (of 20s each) for each of the four stimuli. A test session consisted of four presentation phases (1st exposure to stimulus, post exposure, 2nd exposure, and access to reward). Heart rate (HR) and heart rate variability (HRV) responses were recorded during testing in the experimental room and also when lying resting in a quiet familiar room. A new method of 'stitching' short periods of HRV data together was used in the analysis. When testing different stimuli, no significant differences were observed in HR and LF:HF ratio (relative power in low frequency (LF) and the high-frequency (HF) range), implying that the sympathetic tone was activated similarly for all the stimuli and may suggest that dogs were in a state of positive arousal. A decrease of HF was associated with the meatball stimulus compared to the food pellet and the reward phase (interacting with the person or eating the food) was associated with a decrease in HF and RMSSD (root mean square of successive differences of inter-beat intervals) compared to the preceding phase (looking at the person or food). This suggests that parasympathetic deactivation is associated with a more positive emotional state in the dog. A similar reduction
Humen, D P; Boughner, D R
The accuracy and tracking ability of nine commercially available heart rate monitors were assessed. The heart rate of 16 young healthy men was continuously monitored by a single-lead electrocardiograph while they exercised on a stationary bicycle ergometer. Readings were obtained from the devices during exercise. The devices that measured the cardiac electrical potential with a three-electrode system or that incorporated a light transmission device attached to the earlobe were the most accura...
Current guidelines regarding recommended exercise in pregnancy appear consistent with reported research regarding fetal heart changes in response to maternal exercise. Fetal heart rate increases during pregnancy, but maternal exercise appears well tolerated if performed in uncomplicated pregnancies and not in the supine position. Maximal levels of exercise that are well tolerated by the fetus have not yet been well defined; however, recent literature suggests that sustained exercise during pregnancy may have beneficial effects on autonomic control of fetal heart rate and variability that may lead to long-term health benefits. PMID:27388963
Simko, Fedor; Baka, Tomas; Paulis, Ludovit; Reiter, Russel J
Elevated heart rate is a risk factor for cardiovascular and all-cause mortalities in the general population and various cardiovascular pathologies. Insufficient heart rate decline during the night, that is, nondipping heart rate, also increases cardiovascular risk. Abnormal heart rate reflects an autonomic nervous system imbalance in terms of relative dominance of sympathetic tone. There are only a few prospective studies concerning the effect of heart rate reduction in coronary heart disease and heart failure. In hypertensive patients, retrospective analyses show no additional benefit of slowing down the heart rate by beta-blockade to blood pressure reduction. Melatonin, a secretory product of the pineal gland, has several attributes, which predict melatonin to be a promising candidate in the struggle against elevated heart rate and its consequences in the hypertensive population. First, melatonin production depends on the sympathetic stimulation of the pineal gland. On the other hand, melatonin inhibits the sympathetic system in several ways representing potentially the counter-regulatory mechanism to normalize excessive sympathetic drive. Second, administration of melatonin reduces heart rate in animals and humans. Third, the chronobiological action of melatonin may normalize the insufficient nocturnal decline of heart rate. Moreover, melatonin reduces the development of endothelial dysfunction and atherosclerosis, which are considered a crucial pathophysiological disorder of increased heart rate and pulsatile blood flow. The antihypertensive and antiremodeling action of melatonin along with its beneficial effects on lipid profile and insulin resistance may be of additional benefit. A clinical trial investigating melatonin actions in hypertensive patients with increased heart rate is warranted. PMID:27264986
Hayley Young; David Benton
Both heart rate (HR) and brain functioning involve the integrated output of a multitude of regulatory mechanisms, that are not quantified adequately by linear approximations such as means and standard deviations. It was therefore considered whether non-linear measures of HR complexity are more strongly associated with cognition and mood. Whilst resting, the inter-beat (R-R) time series of twenty-one males and twenty-four females were measured for five minutes. The data were summarised using t...
Just, C. L.; Vial, D. P.; Kruger, A.; Niemeier, J. J.; Lee, H. W.; Schroer, H. W.
Researchers have long been interested the cardiac activity of mollusks. First, it is important as a basic measure of the animal's metabolism. Further, activities such as feeding and burrowing affect heart rate, as do environmental factors such as water salinity, water temperature, exposure, and predation. We have developed a small, noninvasive sensor for measuring freshwater mussel heart rate. Its working principle is as follows. An infrared (IR) light-emitting diode is placed in contact with the mussel shell. Some of the IR penetrates through the shell, reflects off internal organs, and traverses back. A photodetector detects this IR, and electronics condition the signal. The heartbeat of the animal modulates the IR, allowing one to measure the heart rate. The technique is widely-used in finger heart-rate monitors in humans. The sensors do not have to be positioned above the heart and several locations on the mussel shell work well. The sensor is small (8 mm × 10 mm) and consumes less than 1 mA, and has a simple one-wire interface that allows for easy integration into data acquisition hardware. We present heart rate measurements for the common pocketbook (lampsilis cardium) freshwater mussel.
Brock, David L.
Among the many ideas and theories in anatomy and physiology, one particular topic provides all the potential benefits of learning about the human body: the circulatory system, specifically the heart. Describes a distinctive way to study circulation and the heart that allows students to explore the basic principles of vertebrate anatomy and…
Full Text Available Objectives: This prospective, randomised, controlled, clinical study was planned to determine the effect of trimetazidine and glucose - insulin - potassium (GIK on myocardial ischemia-reperfusion during beating heart coronary artery bypass surgery.Materials and methods: Patients (n=45 with coronary artery disease who required beating heart coronary artery bypass grafting were randomly allocated into three groups. Patients in group 1 (n=15 was recevied trimetazidine (20 mg x 3 per day 7 days before surgery. Patients in group 2 (n=15 received GIK infusion after induction of anesthesia through the first 12 hours of intensive care unit convalescence. Patients in group 3 (n=15 were control group. Measurements of blood glucose, circulating creatine kinase MB (CK-MB and Troponin I (TnI concentrations were obtained before surgery, 5 minutes after completion of operation and at 12, 24, and 48 hours postoperatively. Mean pulmonary artery pressure, cardiac index, morbidity and data associated with operation were recorded in all patients preoperatively and postoperatively.Results: Preoperative risk profiles and operative variables were statistically similar when the groups were compared. The concentration of circulating CK-MB and Tn I significantly increased over time after off - pump coronary artery surgery, with no significant intergroup differences. Cardiac index and mean pulmonary artery pressure did not differ significantly between groups.Conclusion: Pretreatment with trimetazidine and GIK infusion protocol were used as an adjunct to ischemic - reperfusion therapy in off - pump coronary artery bypass surgery. These results suggested that pretreatment with trimetazidine and GIK infusion protocol do not significantly reduce ischemic reperfusion damage.
Poelker, Matt; Grames, Joseph; Hansknecht, John; Kazimi, Reza; Musson, John
Even at a continuous wave facility such as CEBAF at Jefferson Lab, an electron beam with long time intervals (tens of ns) between individual bunches can be useful, for example to isolate sources of background via time of flight detection or to measure the energy of neutral particles that cannot be separated with a magnetic field. This paper describes a demonstrated method to quickly and easily deliver bunches with repetition rates of 20 to 100 MHz corresponding to time intervals between 10 to 50 ns (respectively). This is accomplished by changing the ON/OFF frequency of the RF-pulsed drive laser by a small amount (f/f < 20%), resulting in a bunch frequency equal to the beat frequency between the radio frequencies of the drive laser and the photoinjector chopper system.
Franzmann, A W; Schwartz, C C; Johnson, D C
Baseline body temperatures (BT), heart rates (HR) and respiratory rates (RR) were obtained from Alaskan moose (Alces alces gigas Miller) at the Moose Research Center (MRC), Alaska. Excitability, seasons and drugs influenced the values to varying degrees. Excitability was the most influential factor. Safe expected ranges were: BT 38.4 to 38.9 C, HR 70 to 91 beats/min (b/min), and RR 13 to 40 respirations/min (r/min). These ranges incorporated all seasons, a central nervous system depressant drug and a paralyzing drug. Values which may be considered critical and an indication that corrective action should be taken include: BT 40.2 C, HR 102 b/min, and RR 40 r/min. It is recommended that persons trained in monitoring vital signs be on hand during moose capture and immobilization procedures. PMID:6530720
Direct data collection from ventricular blood-pool studies were stored in frame mode in a computer and by means of a modified tape recorder, the blood-pool image and ECG were recorded on tape. At the end of the study the tape data were replayed into the computer. The ECG signal was passed through a trigger circuit that detected the R wave which was sampled by the computer once every msec. Contractions outside of the desired range could be rejected along with the subsequent contraction. Of seven patients whose calculated ejection fractions were changed by more than 0.03, all had frequent (one in 20) ectopic contractions. The distorted ventricular volume curves were effectively restructured by the constraining procedure, changing the end-systolic volume and EF. Computer modeling showed a linear relationship between the percent of ectopic contractions and the underestimate of ejection fraction. One ectopic beat in ten led to a 5% underestimate of EF
Cagirci, Goksel; Cay, Serkan; Karakurt, Ozlem;
BACKGROUND: Cigarette smoking increases the risk of cardiovascular events related with several mechanisms. The most suggested mechanism is increased activity of sympathetic nervous system. Heart rate variability (HRV) and heart rate turbulence (HRT) has been shown to be independent and powerful...
Yamazaki, Aiko; Yashiro, Masateru; Mii, Sumiyuki; Aki, Ryoichi; Hamada, Yuko; Arakawa, Nobuko; Kawahara, Katsumasa; Hoffman, Robert M; Amoh, Yasuyuki
Nestin-expressing hair-follicle-associated pluripotent (HAP) stem cells are located in the bulge area of the follicle. Previous studies have shown that HAP stem cells can differentiate to neurons, glia, keratinocytes, smooth muscle cells, and melanocytes in vitro. HAP stem cells effected nerve and spinal cord regeneration in mouse models. Recently, we demonstrated that HAP stem cells differentiated to beating cardiac muscle cells. The differentiation potential to cardiac muscle cells was greatest in the upper part of the follicle. The beat rate of the cardiac muscle cells was stimulated by isoproterenol. In the present study, we observed that isoproterenol directs HAP stem cells to differentiate to cardiac muscle cells in large numbers in culture compared to HAP stem cells not supplemented with isoproterenol. The addition of activin A, bone morphogenetic protein 4, and basic fibroblast growth factor, along with isoproternal, induced the cardiac muscle cells to form tissue sheets of beating heart muscle cells. These results demonstrate that HAP stem cells have great potential to form beating cardiac muscle cells in tissue sheets. PMID:27104748
Objectives: To evaluate foetal heart rate pattern during antepartum period in pregnancies suffering from intra-uterine growth restriction. Methods: The case control study was conducted at the Alzahra Hospital, Tabriz, Iran from April 2008 to April 2011. It comprised 100 pregnancies with intra-uterine growth restriction and 92 normal pregnancies. The foetal heart rate pattern including basal heart rate, beat-to-beat variation, non-stress test (NST) result and acceleration and deceleration patterns of the heart rate were determined in both groups during the antepartum period. Findings were compared between the two groups and their relation with pregnancy-foetal outcomes was specified in the case group. SPSS 15 was used for statistical analysis. Results: There was no statistically significant difference between the foetus mean basal heart rate in the two groups (p <0.960). Frequency of cases with non-reactive non-stress test in the Cases was significantly higher than Controls (p <0.005). The difference in heart rate acceleration was also not statistically significant (p <0.618). Frequency of cases with low birth weight and caesarian was non-significantly but borderline higher among the Cases (p <0.081 and 0.060, respectively). Conclusion: Abnormal foetal heart rate pattern is more common in pregnancies marked by intra-uterine growth restriction and is directly associated with worse pregnancy/foetal outcomes. (author)
Zia, Sonia; Mozafari, Masoud; Natasha, G; Tan, Aaron; Cui, Zhanfeng; Seifalian, Alexander M
Whole-organ decellularization and tissue engineering approaches have made significant inroads during recent years. If proven to be successful and clinically viable, it is highly likely that this field would be poised to revolutionize organ transplantation surgery. In particular, whole-heart decellularization has captured the attention and imagination of the scientific community. This technique allows for the generation of a complex three-dimensional (3D) extracellular matrix scaffold, with the preservation of the intrinsic 3D basket-weave macroarchitecture of the heart itself. The decellularized scaffold can then be recellularized by seeding it with cells and incubating it in perfusion bioreactors in order to create functional organ constructs for transplantation. Indeed, research into this strategy of whole-heart tissue engineering has consequently emerged from the pages of science fiction into a proof-of-concept laboratory undertaking. This review presents current trends and advances, and critically appraises the concepts involved in various approaches to whole-heart decellularization and tissue engineering. PMID:25739987
Mouridsen, Mette Rauhe; Bendsen, Nathalie Tommerup; Astrup, Arne;
Purpose: To evaluate the effects of weight loss on heart rate (HR) and heart rate variability (HRV) parameters in overweight postmenopausal women. Design and Methods: Forty-nine overweight postmenopausal women with an average body mass index of 28.8 1.9 kg/m2 underwent a 12-week dietary weight......-slice MRI at L3. Results: The weight loss of 3.9 2.0 kg was accompanied by an improvement of HRV. SDNN increased by 9.2% (p ¼ 0.003) and SDNNindex increased by 11.4% (p ¼ 0.0003). MeanNN increased by 2.4%, reflecting a decrease in mean heart rate from 74.1 to 72.3 beats/min (p ¼ 0.033). Systolic blood...
Full Text Available In today’s era Heart Rate Variability becomes an important characteristic to determine the condition of heart. That’s why the calculation of HRV and classification to generate rules is necessary. Human Heart Generates the electrical signal. ECG is used to detect the heart beat. ECG signal contains lots of noise. To classify the signals first to decompose the signals using wavelet transform. Many Mother wavelet are used to denoise the signals. Support Vector Machine is used to classify the denoise signal and recognize pattern for better classification of ECG signal. Various methods have been done using different classification tools like Neural Network, Support Vector Machine, and Wavelet transform. Among them Support Vector Machine is very successful in many research areas such as pattern recognition, bioinformatics, etc. This paper gives Brief Survey on Support Vector Machine and Combination of Wavelet Transform & PCA for better Feature Extraction of ECG signals
Burattini, L; Zareba, W
There is growing evidence that beat-to-beat changes in ventricular repolarization contribute to increased vulnerability to ventricular arrhythmias. Beat-to-beat repolarization variability is usually measured in the electrocardiogram (ECG) by tracking consecutive QT or RT intervals. However, these measurements strongly depend on the accurate identification of T-wave endpoints, and they do not reflect changes in repolarization morphology. In this article, we propose a new computerized time-domain method to measure beat-to-beat variability of repolarization morphology without the need to identify T-wave endpoints. The repolarization correlation index (RCI) is computed for each beat to determine the difference between the morphology of repolarization within a heart-rate dependent repolarization window compared to a template (median) repolarization morphology. The repolarization variability index (RVI) describes the mean value of repolarization correlation in a studied ECG recording. To validate our method, we analyzed repolarization variability in 128-beat segments from Holter ECG recordings of 42 ischemic cardiomyopathy (ICM) patients compared to 36 healthy subjects. The ICM patients had significantly higher values of RVI than healthy subjects (in lead X: 0.045 +/- 0.035 vs. 0.024 +/- 0.010, respectively; P 0.044). No significant correlation was found between the RVI values and the magnitude of heart rate, heart rate variability, QTc interval duration, or ejection fraction in studied ICM patients. In conclusion, our time-domain method, based on computation of repolarization correlation indices for consecutive beats, provides a new approach to quantify beat-to-beat variability of repolarization morphology without the need to identify T-wave endpoints. PMID:10688321
Murphy, Olive H.; Borghi, Alessandro; Bahmanyar, Mohammad Reza; McLeod, Christopher N.; Navaratnarajah, Manoraj; Yacoub, Magdi; Toumazou, Christofer
The frequency response of an implantable antenna is key to the performance of a wireless implantable sensor. If the antenna detunes significantly, there are substantial power losses resulting in loss of accuracy. One reason for detuning is because of a change in the surrounding environment of an antenna. The pulsating anatomy of the human heart constitutes such a changing environment, so detuning is expected but this has not been quantified dynamically before. Four miniature implantable anten...
Lu Wang; Weiping Cheng; Zhongren Sun; Yangyang Xu; Guangyu Cheng; Ingrid Gaischek; Haixue Kuang; Gerhard Litscher
This high-tech “teleacupuncture study” describes a neurovegetative ear acupressure effect in patients with chronic insomnia by using heart rate variability analysis. Heart rate (HR) and heart rate variability (HRV) measurements in 31 patients (mean age ± SD: 54.3 ± 10.6 years) were performed under standardized conditions in Harbin, China, and the data analysis was performed in Graz, Austria. Similar to our previous clinical and basic teleacupuncture research works, the electrocardiograms (ECG...
Crandall, C. G.; Zhang, R.; Levine, B. D.
The purpose of this project was to identify whether dynamic baroreflex regulation of heart rate (HR) is altered during whole body heating. In 14 subjects, dynamic baroreflex regulation of HR was assessed using transfer function analysis. In normothermic and heat-stressed conditions, each subject breathed at a fixed rate (0. 25 Hz) while beat-by-beat HR and systolic blood pressure (SBP) were obtained. Whole body heating significantly increased sublingual temperature, HR, and forearm skin blood flow. Spectral analysis of HR and SBP revealed that the heat stress significantly reduced HR and SBP variability within the high-frequency range (0.2-0.3 Hz), reduced SBP variability within the low-frequency range (0.03-0.15 Hz), and increased the ratio of low- to high-frequency HR variability (all P humans during heat stress.
Crandall, C. G.; Zhang, R.; Levine, B. D.
The purpose of this project was to identify whether dynamic baroreflex regulation of heart rate (HR) is altered during whole body heating. In 14 subjects, dynamic baroreflex regulation of HR was assessed using transfer function analysis. In normothermic and heat-stressed conditions, each subject breathed at a fixed rate (0. 25 Hz) while beat-by-beat HR and systolic blood pressure (SBP) were obtained. Whole body heating significantly increased sublingual temperature, HR, and forearm skin blood flow. Spectral analysis of HR and SBP revealed that the heat stress significantly reduced HR and SBP variability within the high-frequency range (0.2-0.3 Hz), reduced SBP variability within the low-frequency range (0.03-0.15 Hz), and increased the ratio of low- to high-frequency HR variability (all P blood pressure. Reduced vagal baroreflex regulation of HR may contribute to reduced orthostatic tolerance known to occur in humans during heat stress.
Full Text Available Choir singing is known to promote wellbeing. One reason for this may be that singing demands a slower than normal respiration which may in turn affect heart activity. Coupling of heart rate variability (HRV to respiration is called Respiratory sinus arrhythmia (RSA. This coupling has a subjective as well as a biologically soothing effect, and it is beneficial for cardiovascular function. RSA is seen to be more marked during slow-paced breathing and at lower respiration rates (0.1 Hz and below. In this study, we investigate how singing, which is a form of guided breathing, affects HRV and RSA. The study comprises a group of healthy 18 year olds of mixed gender. The subjects are asked to; (1 hum a single tone and breathe whenever they need to; (2 sing a hymn with free, unguided breathing; and (3 sing a slow mantra and breathe solely between phrases. Heart rate (HR is measured continuously during the study. The study design makes it possible to compare above three levels of song structure. In a separate case study, we examine five individuals performing singing tasks (1-(3. We collect data with more advanced equipment, simultaneously recording HR, respiration, skin conductance and finger temperature. We show how song structure, respiration and heart rate are connected. Unison singing of regular song structures makes the hearts of the singers accelerate and decelerate simultaneously. Implications concerning the effect on wellbeing and health are discussed as well as the question how this inner entrainment may affect perception and behavior.
The purpose of this study is to estimate radiation dose and image quality of electrocardiogram (ECG)-gated coronary 320-area detector CT (ADCT) angiography which was acquired using the protocols that were considered as optimal methods for different heart rates (HR) in 1031 consecutive patients (M/F =580/451, 65±12 yr) without arrhythmias. We set up 5 protocols for 320-ADCT based on the relationship among heart rates, temporal resolution, gantry rotation speed, optimal reconstruction phase and slow filling phase on 64-multidetector-row computed tomography (MDCT), id est (ie), 1) mid-diastolic (75% of risk ratio (RR)) 1 beat scan (moderate disability (MD) 1 beat, N=761 (73.8%)) for HR ≤60, 2) mid-diastolic (75% of RR) 2 beat scan (MD 2 beat, N=135) for 61≤ HR ≤65, 3) end-systolic and mid-diastolic (37-80% of RR) 2 beat scan (embryonic stem (ES)-MD 2 beat, N=92) for 66≤ HR ≤75, 4) end-systolic (R +280-430 ms) 2 beat scan (ES 2 beat, N=21) for 76≤ HR ≤80, and 5) end-systolic (R +250-400 ms) 3 beat scan (ES 3 beat, N=22) for 81≤ HR ≤105. Image quality was classified into 3 categories (excellent (3 points), acceptable (2 points), and unacceptable (1 point)). Scanning time, DLP.e and image quality score were 1.4±0.1 s, 220±59 mGy·cm, 3.0±0.2 points in MD 1 beat, 2.2±0.2 s, 434±118 mGy·cm, 2.9±0.3 points in MD 2 beat, 2.1±0.2 s, 729±229 mGy·cm, 2.7±0.5 points in ES-MD 2 beat, 1.9±0.1 s, 432±148 mGy·cm, 2.2±0.6 points in ES 2 beat, and 2.4±0.2 s, 669±152 mGy·cm, 2.3±0.6 points in ES 3 beat respectively. In conclusion, the prospective ECG-gated scan protocol for coronary 320-ADCT angiography in any HR group was considered reasonable and proper for image quality and radiation dose. (author)
Rasmussen, Caroline Elisabeth; Falk, Bo Torkel; Zois, Nora Elisabeth;
moderate/severe MR and in HF compared to CKCS with no/minimal and mild MR (all P<0.02). Another 10 HRV variables showed the same groupwise differences (all P<0.02), except that the difference between CKCS with mild MR and CKCS with moderate/severe MR did not reach statistical significance. Minimum HR, mean......HEART RATE AND HEART RATE VARIABILITY IN DOGS WITH DIFFERENT DEGREES OF MYXOMATOUS MITRAL VALVE DISEASE. CE Rasmussen1, T Falk1, NE Zois1, SG Moesgaard1, HD Pedersen2, J Häggström3 and LH Olsen1. 1. Department of Basic Animal and Veterinary Sciences, Faculty of Life Sciences, University of...... Copenhagen, Frederiksberg, Denmark. 2. Novo Nordic A/S, Maaloev, Denmark. 3. Department of Clinical Sciences, Swedish University of Agricultural Science, Uppsala, Sweden. Heart rate variability (HRV) is an indirect measurement of the autonomic modulation of heart rate (HR). Reduced HRV measured from short...
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)
Aydın, Gülay; Sarıkaya, Savaş; Turgut, Okan Onur; Şahin, Şafak; Çakmak, Nuray Yılmaz; Yılmaz, Mehmet Birhan; Tandoğan, İzzet
Background and objective: Metabolic syndrome (MetS) is described as a group of various abnormal metabolic risk factors such as obesity, dyslipidemia, increased blood pressure, increased plasma glucose levels, prothrombotic condition and proinflammatory state. These parameters are related to decreased parasympathetic and increased sympathetic activity. We aimed to evaluate autonomic function using a combination with heart rate variability (HRV) and heart rate turbulence (HRT) in metabolic sy...
Quantification of cardiac autonomic activity and control via heart rate (HR) and heart rate variability (HRV) is known to provide prognostic information in clinical populations. Issues with regard to standardisation and interpretation of HRV data make the use of the more easily accessible HR on its own as an indicator of autonomic cardiac control very appealing. The aim of this study was to investigate the strength of associations between an important cardio vascular health metric such as VO2...
Grant, Catharina C.; Murray, Carien; Janse van Rensburg, Dina C.; Fletcher, Lizelle
Quantification of cardiac autonomic activity and control via heart rate (HR) and heart rate variability (HRV) is known to provide prognostic information in clinical populations. Issues with regard to standardization and interpretation of HRV data make the use of the more easily accessible HR on its own as an indicator of autonomic cardiac control very appealing. The aim of this study was to investigate the strength of associations between an important cardio vascular health metric such as VO2...
Wilson, C H; Asher, J F; Gupta, A; Vijayanand, D; Wyrley-Birch, H; Stamp, S; Rix, D A; Soomro, N; Manas, D M; Jaques, B C; Peaston, R; Talbot, D
Intraarterial cooling (IAC) of non-heart-beating donors (NHBD) for renal donation requires a cheap, low-viscosity solution. HTK contains a high hydrogen ion buffer level that theoretically should reduce the observable acidosis associated with ongoing anaerobic metabolism. A retrospective comparison of all retrieved NHBD kidneys as well as of viability on the Organ Recovery Systems Lifeporter machine perfusion circuit was performed with respect to the preservation solution HTK or Marshall's HOC. Forty-two NHBD kidneys (19 HTK and 23 HOC) were machine perfused between February 2004 and May 2005. Most of the HTK kidneys were obtained from uncontrolled donors (12 vs 5; Fisher exact test, P = .01). As a consequence, the glutathione-s-transferase viability assay (411 vs 292 IU/L, P = .12) and the lactate concentrations (2.33 vs 1.94 mmol/L, P = .13) were higher among the HTK cohort. There was evidence of greater buffering capacity in HTK, since the lactate:hydrogen ion ratios were consistently lower during the first 2 perfusion hours (1 hour P = .03, 2 hour P = .02). A linear regression analysis confirmed that this was related to the IAC solution (ANCOVA, P advantages of improved pH buffering with HTK appear to have clinical relevance. PMID:17362727
Williams, T M; Kooyman, G L; Croll, D A
Respiratory, metabolic, and cardiovascular responses to swimming were examined in two species of pinniped, the harbor seal (Phoca vitulina) and the California sea lion (Zalophus californianus). 1. Harbor seals remained submerged for 82-92% of the time at swimming speeds below 1.2 m.s-1. At higher speeds, including simulated speeds above 1.4 m.s-1, the percentage of time spent submerged decreased, and was inversely related to body weight. In contrast, the percentage of time spent submerged did not change with speed for sea lions swimming from 0.5 m.s-1 to 4.0 m.s-1. 2. During swimming, harbor seals showed a distinct breathhold bradycardia and ventilatory tachycardia that were independent of swimming speed. Average heart rate was 137 beats.min-1 when swimming on the water surface and 50 beats.min-1 when submerged. A bimodal pattern of heart rate also occurred in sea lions, but was not as pronounced as in the seals. 3. The weighted average heart rate (WAHR), calculated from measured heart rate and the percentage time spent on the water surface or submerged, increased linearly with swimming speed for both species. The graded increase in heart rate with exercise load is similar to the response observed for terrestrial mammals. 4. The rate of oxygen consumption increased exponentially with swimming speed in both seals and sea lions. The minimum cost of transport calculated from these rates ranged from 2.3 to 3.6 J.m-1.kg-1, and was 2.5-4.0 times the level predicted for similarly-sized salmonids. Despite different modes of propulsion and physiological responses to swimming, these pinnipeds demonstrate similar transport costs. PMID:2045544
Linneberg, Allan; Jacobsen, Rikke K.; Skaaby, Tea; Taylor, Amy E.; Fluharty, Meg E.; Jeppesen, Jørgen L.; Bjorngaard, Johan H.; Åsvold, Bjørn O.; Gabrielsen, Maiken E.; Campbell, Archie; Marioni, Riccardo E.; Kumari, Meena; Marques-Vidal, Pedro; Kaakinen, Marika; Cavadino, Alana; Postmus, Iris; Ahluwalia, Tarunveer S.; Wannamethee, S. Goya; Lahti, Jari; Räikkönen, Katri; Palotie, Aarno; Wong, Andrew; Dalgård, Christine; Ford, Ian; Ben-Shlomo, Yoav; Christiansen, Lene; Kyvik, Kirsten O.; Kuh, Diana; Eriksson, Johan G.; Whincup, Peter H.; Mbarek, Hamdi; de Geus, Eco J.C.; Vink, Jacqueline M.; Boomsma, Dorret I.; Smith, George Davey; Lawlor, Debbie A.; Kisialiou, Aliaksei; McConnachie, Alex; Padmanabhan, Sandosh; Jukema, J. Wouter; Power, Chris; Hyppönen, Elina; Preisig, Martin; Waeber, Gerard; Vollenweider, Peter; Korhonen, Tellervo; Laatikainen, Tiina; Salomaa, Veikko; Kaprio, Jaakko; Kivimaki, Mika; Smith, Blair H.; Hayward, Caroline; Sørensen, Thorkild I.A.; Thuesen, Betina H.; Sattar, Naveed; Morris, Richard W.; Romundstad, Pål R.; Munafò, Marcus R.; Jarvelin, Marjo-Riitta; Husemoen, Lise Lotte N.
Background Smoking is an important cardiovascular disease risk factor, but the mechanisms linking smoking to blood pressure are poorly understood. Methods and Results Data on 141,317 participants (62,666 never, 40,669 former, 37,982 current smokers) from 23 population-based studies were included in observational and Mendelian randomisation (MR) meta-analyses of the associations of smoking status and smoking heaviness with systolic and diastolic blood pressure (SBP, DBP), hypertension, and resting heart rate. For the MR analyses, a genetic variant rs16969968/rs1051730 was used as a proxy for smoking heaviness in current smokers. In observational analyses, current as compared with never smoking was associated with lower SBP, DBP, and lower hypertension risk, but with higher resting heart rate. In observational analyses amongst current smokers, one cigarette/day higher level of smoking heaviness was associated with higher (0.21 beats/minute; 95% CI 0.19; 0.24) resting heart rate, and slightly higher DBP (0.05 mmHg; 95% CI 0.02; 0.08) and SBP (0.08 mmHg; 95% CI 0.03; 0.13). However, in MR analyses amongst current smokers, while each smoking increasing allele of rs16969968/rs1051730 was associated with higher resting heart rate (0.36 beats/minute/allele; 95% CI 0.18; 0.54), there was no strong association with DBP, SBP, or hypertension. This would suggest a 7 beats/minute higher heart rate in those who smoke 20 cigarettes/day. Conclusions This MR meta-analysis supports a causal association of smoking heaviness with higher level of resting heart rate, but not with blood pressure. These findings suggest that part of the cardiovascular risk of smoking may operate through increasing resting heart rate. PMID:26538566
Courter, B. J.; Jex, H. R.
Some persons can control their pulse rate with the aid of a biofeedback display. If the biofeedback display is modified to show the error between a command pulse-rate and the measured rate, a compensatory (error correcting) heart rate tracking control loop can be created. The dynamic response characteristics of this control loop when subjected to step and quasi-random disturbances were measured. The control loop includes a beat-to-beat cardiotachmeter differenced with a forcing function from a quasi-random input generator; the resulting error pulse-rate is displayed as feedback. The subject acts to null the displayed pulse-rate error, thereby closing a compensatory control loop. McRuer's Law should hold for this case. A few subjects already skilled in voluntary pulse-rate control were tested for heart-rate control response. Control-law properties are derived, such as: crossover frequency, stability margins, and closed-loop bandwidth. These are evaluated for a range of forcing functions and for step as well as random disturbances.
Keiichi Sato; Isamu Kanemoto; Kippei Mihara; Koudai Kawase; Takuya Mori; Misato Ohashi; Hirokazu Abe; Shuichi Chimura
Double-chambered right ventricle was diagnosed in two dogs, one of them a pup and the other full grown. Both dogs underwent surgery using the novel approach of right ventricular outflow chamber ventriculotomy via left intercostal thoracotomy with moderate hypothermia and moderate pump flow cardiopulmonary bypass under beating heart. No major complication occurred during and after the operation. On continuous wave Doppler echocardiography, the pressure gradient across the stenosis in the right...
Full Text Available Physical exercise is associated with parasympathetic withdrawal and increased sympathetic activity resulting in heart rate increase. The rate of post-exercise cardiodeceleration is used as an index of cardiac vagal reactivation. Analysis of heart rate variability (HRV and complexity can provide useful information about autonomic control of the cardiovascular system. The aim of the present study was to ascertain the association between heart rate decrease after exercise and HRV parameters. Heart rate was monitored in 17 healthy male subjects (mean age: 20 years during the pre-exercise phase (25 min supine, 5 min standing, during exercise (8 min of the step test with an ascending frequency corresponding to 70% of individual maximal power output and during the recovery phase (30 min supine. HRV analysis in the time and frequency domains and evaluation of a newly developed complexity measure - sample entropy - were performed on selected segments of heart rate time series. During recovery, heart rate decreased gradually but did not attain pre-exercise values within 30 min after exercise. On the other hand, HRV gradually increased, but did not regain rest values during the study period. Heart rate complexity was slightly reduced after exercise and attained rest values after 30-min recovery. The rate of cardiodeceleration did not correlate with pre-exercise HRV parameters, but positively correlated with HRV measures and sample entropy obtained from the early phases of recovery. In conclusion, the cardiodeceleration rate is independent of HRV measures during the rest period but it is related to early post-exercise recovery HRV measures, confirming a parasympathetic contribution to this phase.
OBJECTIVE: Research regarding communication between pediatricians and parents in pediatric consultation has mainly focused on parental satisfaction, on its influence on compliance and on communication techniques used by pediatricians. However, there is paucity in research regarding parental stress levels during pediatric consultation. Therefore, the aim of our study was to measure parental heart rate variability related as a measure of stress levels during pediatric consultation. METHODS: Vid...
Zeng, Peng; Liu, Hongxing; Ni, Huangjing; Zhou, Jing; Xia, Lan; Ning, Xinbao
We first introduce multiscale power (MSP) method to assess the power distribution of physiological signals on multiple time scales. Simulation on synthetic data and experiments on heart rate variability (HRV) are tested to support the approach. Results show that both physical and psychological changes influence power distribution significantly. A quantitative parameter, termed power difference (PD), is introduced to evaluate the degree of power distribution alteration. We find that dynamical correlation of HRV will be destroyed completely when PD>0.7.
Stephanie Pildner von Steinburg
Full Text Available Aim. There is no consensus about the normal fetal heart rate. Current international guidelines recommend for the normal fetal heart rate (FHR baseline different ranges of 110 to 150 beats per minute (bpm or 110 to 160 bpm. We started with a precise definition of “normality” and performed a retrospective computerized analysis of electronically recorded FHR tracings. Methods. We analyzed all recorded cardiotocography tracings of singleton pregnancies in three German medical centers from 2000 to 2007 and identified 78,852 tracings of sufficient quality. For each tracing, the baseline FHR was extracted by eliminating accelerations/decelerations and averaging based on the “delayed moving windows” algorithm. After analyzing 40% of the dataset as “training set” from one hospital generating a hypothetical normal baseline range, evaluation of external validity on the other 60% of the data was performed using data from later years in the same hospital and externally using data from the two other hospitals. Results. Based on the training data set, the “best” FHR range was 115 or 120 to 160 bpm. Validation in all three data sets identified 120 to 160 bpm as the correct symmetric “normal range”. FHR decreases slightly during gestation. Conclusions. Normal ranges for FHR are 120 to 160 bpm. Many international guidelines define ranges of 110 to 160 bpm which seem to be safe in daily practice. However, further studies should confirm that such asymmetric alarm limits are safe, with a particular focus on the lower bound, and should give insights about how to show and further improve the usefulness of the widely used practice of CTG monitoring.
Full Text Available Mia Skov-Madsen, My Svensson, Jeppe Hagstrup ChristensenDepartment of Nephrology, Aarhus University Hospital, Aalborg, DenmarkIntroduction: Twenty four-hour ambulatory blood pressure monitoring is a clinically validated procedure in evaluation of blood pressure (BP. We hypothesised that the discomfort during cuff inflation would increase the heart rate (HR measured with 24-h ambulatory BP monitoring compared to a following HR measurement with a 24-h Holter monitor.Methods: The study population (n = 56 were recruited from the outpatient’s clinic at the Department of Nephrology, Aalborg Hospital, Aarhus University Hospital at Aalborg, Denmark. All the patients had chronic kidney disease (CKD. We compared HR measured with a 24-h Holter monitor with a following HR measured by a 24-h ambulatory BP monitoring.Results: We found a highly significant correlation between the HR measured with the Holter monitor and HR measured with 24-h ambulatory blood pressure monitoring (r = 0.77, p < 0.001. Using the Bland-Altman plot, the mean difference in HR was only 0.5 beat/min during 24 hours with acceptable limits of agreement for both high and low HR levels. Dividing the patients into groups according to betablocker treatment, body mass index, age, sex, angiotensin-converting enzyme inhibitor treatment, statins treatment, diuretic treatment, or calcium channel blocker treatment revealed similar results as described above.Conclusion: The results indicate that the discomfort induced by cuff inflation during 24-h ambulatory BP monitoring does not increase HR. Thus, 24-h ambulatory BP monitoring may be a reliable measurement of the BP among people with CKD.Keywords: ambulatory blood pressure monitoring, Holter monitoring, heart rate, chronic kidney disease, hypertension
Hill, M; Talbot, C; Price, M
Age-predicted maximal heart rate (HRMAX ) equations are commonly used for the purpose of prescribing exercise regimens, as criteria for achieving maximal exertion and for diagnostic exercise testing. Despite the growing popularity of upper body exercise in both healthy and clinical settings, no recommendations are available for exercise modes using the smaller upper body muscle mass. The purpose of this study was to determine how well commonly used age-adjusted prediction equations for HRMAX estimate actual HRMAX for upper body exercise in healthy young and older adults. A total of 30 young (age: 20 ± 2 years, height: 171·9 ± 32·8 cm, mass: 77·7 ± 12·6 kg) and 20 elderly adults (age: 66 ± 6 years, height: 162 ± 8·1 cm, mass: 65·3 ± 12·3 kg) undertook maximal incremental exercise tests on a conventional arm crank ergometer. Age-adjusted maximal heart rate was calculated using prediction equations based on leg exercise and compared with measured HRMAX data for the arms. Maximal HR for arm exercise was significantly overpredicted compared with age-adjusted prediction equations in both young and older adults. Subtracting 10-20 beats min(-1) from conventional prediction equations provides a reasonable estimate of HRMAX for upper body exercise in healthy older and younger adults. PMID:25319169
Ghasemi, F; Peinke, J; Tabar, M R R; Sahimi, Muhammad
We describe a method for analyzing the stochasticity in the non-stationary data for the beat-to-beat fluctuations in the heart rates of healthy subjects, as well as those with congestive heart failure. The method analyzes the returns time series of the data as a Markov process, and computes the Markov time scale, i.e., the time scale over which the data are a Markov process. We also construct an effective stochastic continuum equation for the return series. We show that the drift and diffusion coefficients, as well as the amplitude of the returns time series for healthy subjects are distinct from those with CHF. Thus, the method may potentially provide a diagnostic tool for distinguishing healthy subjects from those with congestive heart failure, as it can distinguish small differences between the data for the two classes of subjects in terms of well-defined and physically-motivated quantities.
This paper reports a novel contactless monitoring method to record photoplethysmogram (PPG) on a mattress for the continuous measurement of heart rate (HR). PPGs were obtained from subjects' fingers and backs with and without making a direct contact between the PPG sensor and their skin when they rested in a supine position on the mattress. Electrocardiograms (ECGs) were measured from the subjects' limbs for reference. Clear PPG waveforms were obtained from the subjects' backs. Beat-to-beat HR derived from contactless PPG measurement was comparable to those measured from contact PPG and ECG measurements. Thus we found that contactless PPG could be captured from the subjects' backs and it was sufficient to provide accurate HR measurements. This contactless monitoring of PPG has the potential to reduce obstruction in sleep and provide clinical evaluation in sleep study
Javorka, Michal; Turianikova, Zuzana; Tonhajzerova, Ingrid; Lazarova, Zuzana; Czippelova, Barbora; Javorka, Kamil
Obesity is accompanied by many severe complications including various cardiovascular disorders. An impairment of cardiovascular control by autonomic nervous system could be one of the possible links between obesity and cardiovascular complications development. The aim of this study was to compare spontaneous heart rate and systolic blood pressure oscillations reflecting cardiovascular autonomic control of young obese subjects with normal control subjects by linear and nonlinear methods and to find sensitive markers of early autonomic dysregulation. Continuous recordings of beat-to-beat systolic blood pressure and RR intervals from ECG were obtained from 40 obese subjects (25 female, age 14·2 [13·1-16·1] (median [interquartile range]) years) and gender and age matched non-obese control subjects. In addition to linear measures (time and frequency domain), we performed recurrence quantification analysis (RQA) and multiscale entropy analysis for both signals. While no significant differences in heart rate and systolic blood pressure dynamics were detected by linear measures and MSE, analysis of recurrence plots from RR intervals time series showed significant differences - indices trapping time and maximal length of vertical from RQA were significantly higher in obese compared to control group. We conclude that heart rate and blood pressure control by autonomic nervous system in young obese subjects is relatively well preserved. However, novel RQA-related measures are able to detect early subtle abnormalities in cardiac autonomic control in obese subjects indicating decreased signal complexity. PMID:25684329
Zurbuchen, A; Pfenniger, A; Stahel, A; Stoeck, C T; Vandenberghe, S; Koch, V M; Vogel, Rolf
Energy-harvesting devices attract wide interest as power supplies of today's medical implants. Their long lifetime will spare patients from repeated surgical interventions. They also offer the opportunity to further miniaturize existing implants such as pacemakers, defibrillators or recorders of bio signals. A mass imbalance oscillation generator, which consists of a clockwork from a commercially available automatic wrist watch, was used as energy harvesting device to convert the kinetic energy from the cardiac wall motion to electrical energy. An MRI-based motion analysis of the left ventricle revealed basal regions to be energetically most favorable for the rotating unbalance of our harvester. A mathematical model was developed as a tool for optimizing the device's configuration. The model was validated by an in vitro experiment where an arm robot accelerated the harvesting device by reproducing the cardiac motion. Furthermore, in an in vivo experiment, the device was affixed onto a sheep heart for 1 h. The generated power in both experiments-in vitro (30 μW) and in vivo (16.7 μW)-is sufficient to power modern pacemakers. PMID:22805983
Background: During computed tomography coronary angiography (CTCA) unexpected changes in heart rate while scanning may affect image quality. Purpose: To evaluate whether an iso-osmolar contrast medium (IOCM, iodixanol) and a low-osmolar contrast medium (LOCM, iomeprol) affect heart rate and experienced heat sensation differently. Material and Methods: One hundred patients scheduled for CTCA were randomized to receive either iodixanol 320 mgI/ml or iomeprol 400 mgI/ml. Depending on their heart rate, the patients were assigned to one of five scanning protocols, each optimized for different heart rate ranges. During scanning the time between each heart beat (hb) was recorded, and the corresponding heart rate was calculated. For each contrast medium (CM) the average heart rate, the variation in heart rate from individual mean heart rate, and the mean deviation from the predefined scanning protocol were calculated. Experience of heat was obtained immediately after scanning by using a visual analog scale (VAS). Examination quality was rated by two radiologists on a three-point scale. Results: The mean variation in heart rate after IOCM was 1.4 hb/min and after LOCM it was 4.4 hb/min (NS). The mean deviations in heart rate from that in the predefined scanning protocol were 2.0 hb/min and 4.7 hb/min, respectively (NS). A greater number of arrhythmic hb were observed after LOCM compared with IOCM (P<0.001). There was no statistically significant difference in image quality. The LOCM group reported a stronger heat sensation after CM injection than the IOCM group (VAS =36 mm and 18 mm, P<0.05). Conclusion: At clinically used concentrations the IOCM, iodixanol 320 mgI/ml, does not increase the heart rate during CTCA and causes less heart arrhythmia and less heat sensation than the LOCM, iomeprol 400 mgI/ml
This study examines signal availability in fetal electrocardiogram (FECG) beat-to-beat acquisition and the accuracy of fetal heart rate variability (HRV) analysis in the clinical setting using a commercially available FECG monitor. Signal availability was examined in 130 FECG recordings of 0.3–17.5 h duration collected in 63 fetuses (25th–42nd week of gestation) under uncontrolled conditions. Identification of R-peaks demonstrated a signal loss of 30% ± 24% with 3.6 ± 1.7 signal gaps per minute. Median duration of the gaps within a recording was 1.8 ± 0.2 s. Per hour of recording, 1.8 ± 2.1 episodes of 5 min of uninterrupted data were found. Signal availability improved with gestational age and was poorer in women with high body-mass index. Fetal HRV between weeks 36–42 was examined on the basis of 5 min RR-interval episodes obtained under controlled quiet conditions in 55 FECG compared to 46 high quality fetal magnetocardiograms. There were no differences in RR-interval duration, its standard deviation and low frequency power. However, various measures of short-term HRV were significantly higher in the FECG data: root mean square of successive differences (10.0 ± 1.8 versus 6.6 ± 3.0 ms, p < 0.001, high frequency spectral power (24 ± 12 versus 13 ± 13 ms2, p < 0.001) and approximate entropy (0.86 ± 0.16 versus 0.73 ± 0.24, p = 0.007). We conclude that, in spite of considerable signal loss, FECG recordings can accurately estimate heart rate and its overall variance. However, measures that quantify short-term beat-to-beat HRV will be compromised due to possible recurring inappropriate detection of single R-peaks. (paper)
The methods and device for estimation of cardiac output and measurement of pulse wave velocity simultaneously is presented here. The beat-to-beat cardiac output as well as pulse wave velocity measurement is based on application of electrical impedance method on the thorax and calf. The results are demonstrated in a study of 24 subjects. The dependence of pulse wave velocity and cardiac output on heart rate during rest in patients with an implanted pacemaker was evaluated. The heart rate was changed by pacemaker programming while neither exercise nor drugs were applied. The most important result is that the pulse wave velocity, cardiac output and blood pressure do not depend significantly on heart rate, while the stroke volume is reciprocal proportionally to the heart rate.
Cardiovascular control acts over multiple time scales, which introduces a significant amount of complexity to heart rate and blood pressure time series. Multiscale entropy (MSE) analysis has been developed to quantify the complexity of a time series over multiple time scales. In previous studies, MSE analyses identified impaired cardiovascular control and increased cardiovascular risk in various pathological conditions. Despite the increasing acceptance of the MSE technique in clinical research, information underpinning the involvement of the autonomic nervous system in the MSE of heart rate and blood pressure is lacking. The objective of this study is to investigate the effect of orthostatic challenge on the MSE of heart rate and blood pressure variability (HRV, BPV) and the correlation between MSE (complexity measures) and traditional linear (time and frequency domain) measures. MSE analysis of HRV and BPV was performed in 28 healthy young subjects on 1000 consecutive heart beats in the supine and standing positions. Sample entropy values were assessed on scales of 1–10. We found that MSE of heart rate and blood pressure signals is sensitive to changes in autonomic balance caused by postural change from the supine to the standing position. The effect of orthostatic challenge on heart rate and blood pressure complexity depended on the time scale under investigation. Entropy values did not correlate with the mean values of heart rate and blood pressure and showed only weak correlations with linear HRV and BPV measures. In conclusion, the MSE analysis of heart rate and blood pressure provides a sensitive tool to detect changes in autonomic balance as induced by postural change
Turianikova, Zuzana; Javorka, Kamil; Baumert, Mathias; Calkovska, Andrea; Javorka, Michal
Cardiovascular control acts over multiple time scales, which introduces a significant amount of complexity to heart rate and blood pressure time series. Multiscale entropy (MSE) analysis has been developed to quantify the complexity of a time series over multiple time scales. In previous studies, MSE analyses identified impaired cardiovascular control and increased cardiovascular risk in various pathological conditions. Despite the increasing acceptance of the MSE technique in clinical research, information underpinning the involvement of the autonomic nervous system in the MSE of heart rate and blood pressure is lacking. The objective of this study is to investigate the effect of orthostatic challenge on the MSE of heart rate and blood pressure variability (HRV, BPV) and the correlation between MSE (complexity measures) and traditional linear (time and frequency domain) measures. MSE analysis of HRV and BPV was performed in 28 healthy young subjects on 1000 consecutive heart beats in the supine and standing positions. Sample entropy values were assessed on scales of 1-10. We found that MSE of heart rate and blood pressure signals is sensitive to changes in autonomic balance caused by postural change from the supine to the standing position. The effect of orthostatic challenge on heart rate and blood pressure complexity depended on the time scale under investigation. Entropy values did not correlate with the mean values of heart rate and blood pressure and showed only weak correlations with linear HRV and BPV measures. In conclusion, the MSE analysis of heart rate and blood pressure provides a sensitive tool to detect changes in autonomic balance as induced by postural change. PMID:21799239
Heart rate distribution and predictors of resting heart rate after initiation of beta-blocker treatment in patients with coronary artery disease: REsults of Sympathetic Evaluation And Research of China(RESEARCH) study
ZHAO Ying-xin; LI Yue-ping; GAO Fei; MA Han-ying; WANG Zhi-jian; HAN Hong-ya; SHEN Hua
Background The importance of heart rate as secondary prevention strategies for patients with coronary artery disease (CAD) is emphasized by multiple guidelines.However,limited information is available on the heart rate distribution and the change patterns of resting heart rate when initiating beta-blocker therapy among Chinese patients with CAD.Methods The REsults of Sympathetic Evaluation And Research of China (RESEARCH) study is a multi-centre,prospective,observational study involving 147 centers in 23 cities across China.All eligible beta-blocker naive patients were prescribed with metroprolol succinate.Initial dosage and target heart rate were selected at the discretion of their physicians in charge according to their usual institutional practice.The heart rate distribution and the change patterns of resting heart rate after initiation of beta-blocker therapy were observed.Results The majority of patients (63.6％) were prescribed with 47.5 mg metroprolol succinate.At baseline,there were only 17.4％ of patients whose heart rate was less than 70 beats per minute,and the proportion reached 42.5％ and 79.1％,one month and two months after initiation of beta-blockers,respectively.Multivariate linear regression analysis showed that baseline heart rate (B=0.900,SE=0.006,t=141.787,P＜0.0001) and the dosage (B=-0.007,SE=0.002,t=-3.242,P=0.001) were independent predictors of resting heart rate 2 months after beta-blocker therapy.Conclusions Resting heart rate is not optimally controlled in a broadly representative cohort of Chinese outpatients with CAD even after initiation of β-blocker therapy,and baseline heart rate and the dosage of beta-blocker are both independent predictors of resting heart rate after β-blocker therapy.
Pinna, Gian Domenico; Maestri, Roberto; La Rovere, Maria Teresa
The baroreceptor-heart rate reflex (baroreflex sensitivity, BRS) is a key mechanism contributing to the neural regulation of the cardiovascular system. Several methods have been proposed so far to assess BRS by analyzing the spontaneous beat-to-beat fluctuations of arterial blood pressure and heart rate. These methods are inherently simple, non-invasive and low-cost. This study is an attempt to address the question of whether spontaneous baroreflex methods have proven to be of value in the clinical setting. In the first part of this article, we critically review most representative clinical studies using spontaneous BRS techniques either for risk stratification or treatment evaluation, these being major issues in the clinical management of the patients. In the second part, we address two important aspects of spontaneous BRS measurements: measurability and reliability. Estimation of BRS in the studies selected for the review was performed according to the sequence, transfer function, alpha-index and phase-rectified signal averaging method. Arterial blood pressure was recorded non-invasively during supine, short-term (Measurability and reliability can be a major issue in the measurement of spontaneous BRS, particularly in some patient populations like post-myocardial infarction and heart failure patents. Main causes of poor measurability are: non-sinus rhythm, a high rate of ectopic beats and the need for recorded time series of RR interval and arterial blood pressure to satisfy the constraints of the different BRS estimation algorithms. As for reliability, within-subject variability is rather high in the measurements of spontaneous BRS and, therefore, should be carefully taken into account when BRS measurements are used to detect treatment effects in individual patients. PMID:25798657
Naemat Mohamed H.ELDin Shiry
Full Text Available Objective : To assess the correlation between fetal heart rate and the fate of pregnancy in women with first trimester bleeding. Methods : This prospective observational study included 281 consecutive women with first trimester bleeding and Singleton pregnancies. The embryonic heart rate measured at the time of first trans-vaginal scan as per protocol in our university hospital for the evaluation of pregnancy. The heart rate was classified as slow if it was fewer than 110 beats per minute. The primary outcome measure is the occurrence of spontaneous early pregnancy loss prior to 12 weeks. Other outcome measures included the occurrence of late pregnancy loss (prior to 24 weeks, gestational age at birth, and fetal weight at birth. Results : Embryonic heart rate at less than 110 bpm was associated with a high likelihood of pregnancy loss. The sensitivity, specificity, positive and negative predictive value, and accuracy were 43.1%, 86%, 40.7%, 87.2%, and 78.2%, respectively. The OR (95% CI of first-trimester pregnancy. Conclusion: embryonic heart rate can be an independent predictor of the outcome of pregnancy in women with intrauterine pregnancy complaining of first trimester bleeding.
Waldeck, Miriam R.; Lambert, Michael I.
Resting heart rate has sometimes been used as a marker of training status. It is reasonable to assume that the relationship between heart rate and training status should be more evident during sleep when extraneous factors that may influence heart rate are reduced. Therefore the aim of the study was to assess the repeatability of monitoring heart rate during sleep when training status remained unchanged, to determine if this measurement had sufficient precision to be used as a marker of train...
Aoyagi, Naoko; Kiyono, Ken; Struzik, Zbigniew R.; Yamamoto, Yoshiharu
We examine fractal scaling properties of heart rate variability using detrended fluctuation analysis (DFA), during physical activity in healthy subjects. We analyze 11 records of healthy subjects, which include both usual daily activity and experimental exercise. The subjects were asked to ride on a bicycle ergometer for 2.5 hours, and maintained a heartbeat interval of 500-600 ms. In order to estimate the long-range correlation in the series of heartbeat intervals during controlled physical activity, we apply DFA to the data set with the third-order polynomial trend removed. For all records during exercise, we observe a characteristic crossover phenomenon at ≈ 300 beats. The scaling exponent in the range > 300 beats (> 3 minutes) during exercise decreases and tends to be closer to white noise (≈ 0.5), which corresponds to uncorrelated behavior. The long-range scaling exponent during exercise is significantly lower than that during daily activity in this range. Contrary to the currently held view, our results indicate a breakdown in long-range correlations and 1/f-like scaling, rather than the increase in the Hurst exponent characteristic of a (congestive) increase in afterload and observed, e.g., in congestive heart failure (CHF) patients. Further, our results suggest an increased load imbalance induced departure from critical-like behavior, which has recently been reported in healthy human heart rate during daily activity.
Park, Young-Sun; Hoh, Jeong-Kyu; Park, Moon-il
The purpose of this study was to investigate the feasibility of different fetal heart rate (FHR) ranges in the nonstress test (NST) and to better understand the meaning of mild bradycardia and/or tachycardia without non-reassuring patterns. We employed the heredity to show that mild bradycardia (100-119 beats per minute, bpm) and mild tachycardia (161-180 bpm) regressed to the normal FHR range (120-160 bpm). We used linear regression to analyze FHR data from FHR tracings recorded 10 min befor...
Reliable and accurate estimation of instantaneous frequencies of physiological rhythms, such as heart rate, is critical for many healthcare applications. Robust estimation is especially challenging when novel unobtrusive sensors are used for continuous health monitoring in uncontrolled environments, because these sensors can create significant amounts of potentially unreliable data. We propose a new flexible algorithm for the robust estimation of local (beat-to-beat) intervals from cardiac vibration signals, specifically ballistocardiograms (BCGs), recorded by an unobtrusive bed-mounted sensor. This sensor allows the measurement of motions of the body which are caused by cardiac activity. Our method requires neither a training phase nor any prior knowledge about the morphology of the heart beats in the analyzed waveforms. Instead, three short-time estimators are combined using a Bayesian approach to continuously estimate the inter-beat intervals. We have validated our method on over-night BCG recordings from 33 subjects (8 normal, 25 insomniacs). On this dataset, containing approximately one million heart beats, our method achieved a mean beat-to-beat interval error of 0.78% with a coverage of 72.69%. (paper)
Fabrício E. Rossi
Full Text Available Abstract This study examined the relationship between resting heart rate (RHRr and anthropometric, metabolic and hemodynamic parameters in subjects aged 80 years and over. One hundred thirteen individuals were divided into two groups (RHR:<66 beats/min and ≥66 beats/min. Anthropometric parameters (weight, height, body mass index and waist circumference (WC were measured. Hemodynamic parameters (systolic (SBP and diastolic (DBP pressure were measured and pulse pressures (PP were obtained. Metabolic parameters were fasting blood glucose, triglycerides and total cholesterol. In elderly aged 80 and over, RHR influenced the changes observed in DBP, PP and triglycerides. Additionally, subjects with RHR≥66 beats/min had higher DBP, glucose, total cholesterol and lower PP as compared with elderly with RHR<66 beats/min. Men demonstrated greater weight, height, and WC than women while women had higher percentage of body fat, trunk fat, and higher total cholesterol. Thus, subjects with 80 years old and over who present RHR≥66 have higher DBP and lower PP and heart rate variability compared with the elderly with RHR<66.
Maycon Jr Ferreira; Angelina Zanesco
Abstract Alterations in the heart rate recovery and heart rate variability have been associated with greater risk of mortality and early prognosis of cardiac diseases. Thus, strategies for assessing autonomic nervous system and its modulation to the heart are crucial for preventing cardiovascular events in healthy subjects as well as in cardiac patients. In this review, an update of studies examining heart rate variability (HRV) and its use as indicator of cardiac autonomic modulation will be...
We assessed adherence to European Society of Cardiology heart rate guidelines (i.e. heart rates less than 70bpm) in patients with chronic stable heart failure. We also investigated the percent of patients on target doses of rate controlling drugs.
Full Text Available Autonomic disorders of the cardiovascular system, such as orthostatic hypotension and elevated resting heart rate, predict mortality and cardiovascular events in the population. Low-energy-fractures constitute a substantial clinical problem that may represent an additional risk related to such autonomic dysfunction.To test the association between orthostatic hypotension, resting heart rate and incidence of low-energy-fractures in the general population.Using multivariable-adjusted Cox regression models we investigated the association between orthostatic blood pressure response, resting heart rate and first incident low-energy-fracture in a population-based, middle-aged cohort of 33 000 individuals over 25 years follow-up. The median follow-up time from baseline to first incident fracture among the subjects that experienced a low energy fracture was 15.0 years. A 10 mmHg orthostatic decrease in systolic blood pressure at baseline was associated with 5% increased risk of low-energy-fractures (95% confidence interval 1.01-1.10 during follow-up, whereas the resting heart rate predicted low-energy-fractures with an effect size of 8% increased risk per 10 beats-per-minute (1.05-1.12, independently of the orthostatic response. Subjects with a resting heart rate exceeding 68 beats-per-minute had 18% (1.10-1.26 increased risk of low-energy-fractures during follow-up compared with subjects with a resting heart rate below 68 beats-per-minute. When combining the orthostatic response and resting heart rate, there was a 30% risk increase (1.08-1.57 of low-energy-fractures between the extremes, i.e. between subjects in the fourth compared with the first quartiles of both resting heart rate and systolic blood pressure-decrease.Orthostatic blood pressure decline and elevated resting heart rate independently predict low-energy fractures in a middle-aged population. These two measures of subclinical cardiovascular dysautonomia may herald increased risks many years
Wallot, Sebastian; Fusaroli, Riccardo; Tylén, Kristian;
on variability of the data, different choices regarding the kind of measures can have a substantial impact on the results. In this article we compare linear and non-linear statistics on two prominent types of heart beat data, beat-to-beat intervals (R-R interval) and beats-per-minute (BPM). As a proof...... dynamics, but their power to do so critically depends on the type data that is employed: While R-R intervals are very susceptible to nonlinear analyses, the success of nonlinear methods for BPM data critically depends on their construction. Generally, ‘oversampled’ BPM time-series can be recommended...
Seebacher, F; Franklin, C E
During thermoregulation in the bearded dragon Pogona barbata, heart rate when heating is significantly faster than when cooling at any given body temperature (heart rate hysteresis), resulting in faster rates of heating than cooling. However, the mechanisms that control heart rate during heating and cooling are unknown. The aim of this study was to test the hypothesis that changes in cholinergic and adrenergic tone on the heart are responsible for the heart rate hysteresis during heating and cooling in P. barbata. Heating and cooling trials were conducted before and after the administration of atropine, a muscarinic antagonist, and sotalol, a beta-adrenergic antagonist. Cholinergic and beta-adrenergic blockade did not abolish the heart rate hysteresis, as the heart rate during heating was significantly faster than during cooling in all cases. Adrenergic tone was extremely high (92.3 %) at the commencement of heating, and decreased to 30.7 % at the end of the cooling period. Moreover, in four lizards there was an instantaneous drop in heart rate (up to 15 beats min(-1)) as the heat source was switched off, and this drop in heart rate coincided with either a drop in beta-adrenergic tone or an increase in cholinergic tone. Rates of heating were significantly faster during the cholinergic blockade, and least with a combined cholinergic and beta-adrenergic blockade. The results showed that cholinergic and beta-adrenergic systems are not the only control mechanisms acting on the heart during heating and cooling, but they do have a significant effect on heart rate and on rates of heating and cooling. PMID:11815660
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
Scharff-Olson, M; Williford, H N; Smith, F H
The purpose of this study was to examine the relationship between heart rate (HR) and oxygen consumption (VO2) for aerobic dance exercise. Therefore, eleven females completed 20 minutes of aerobic dance with continuous monitoring of HR and VO2. These physiological responses were analyzed with correlation/regression techniques. The results showed that for aerobic dance to produce a response in excess of 50% of VO2 max, the target HR must be approximately 80% of the age-predicted HR max or greater. In contrast, previously reported data for treadmill running shows that 50% of VO2 max is achieved at approximately 65% of age-predicted HR max in females. The maximum heart rate reserve (Karvonen) method was also found to underestimate the actual VO2 of AD. With the Karvonen method, the target heart rate must approximate 65% of maximum HR reserve in order to elicit a VO2 response which is representative of 50% of VO2 max. These data support recent research which illustrates that target heart rate prescriptions derived from treadmill testing may fail to accurately place AD participants in the recommended training zone. PMID:1293420
Stuckey, Melanie I; Kiviniemi, Antti; Gill, Dawn P; Shoemaker, J Kevin; Petrella, Robert J
The purpose of this study was to examine differences in heart rate variability (HRV) in metabolic syndrome (MetS) and to determine associations between HRV parameters, MetS risk factors, and insulin resistance (homeostasis model assessment for insulin resistance (HOMA-IR)). Participants (n = 220; aged 23-70 years) were assessed for MetS risk factors (waist circumference, blood pressure, fasting plasma glucose, triglycerides, and high-density lipoprotein cholesterol) and 5-min supine HRV (time and frequency domain and nonlinear). HRV was compared between those with 3 or more (MetS+) and those with 2 or fewer MetS risk factors (MetS-). Multiple linear regression models were built for each HRV parameter to investigate associations with MetS risk factors and HOMA-IR. Data with normal distribution are presented as means ± SD and those without as median [interquartile range]. In women, standard deviation of R-R intervals 38.0 [27.0] ms, 44.5 [29.3] ms; p = 0.020), low-frequency power (5.73 ± 1.06 ln ms(2), 6.13 ± 1.05 ln ms(2); p = 0.022), and the standard deviation of the length of the Poincaré plot (46.8 [31.6] ms, 58.4 [29.9] ms; p = 0.014) were lower and heart rate was higher (68  beats/min, 64  beats/min; p = 0. 018) in MetS+ compared with MetS-, with no differences in men. Waist circumference was most commonly associated with HRV, especially frequency domain parameters. HOMA-IR was associated with heart rate. In conclusion, MetS+ women had a less favourable HRV profile than MetS- women, but there were no differences in men. HOMA-IR was associated with heart rate, not HRV. PMID:26140416
Parker, S B; Hurley, B F; Hanlon, D P; Vaccaro, P
Fourteen untrained females (age 19 +/- 1, range 18-21) were studied to examine the heart rate-VO2 relationship during a single aerobic dance training session. These findings were used to help explain the changes in VO2max resulting from an aerobic dance training program. VO2max and body composition were determined before and after an 8 wk training period. In addition, the heart rate-VO2 responses to an aerobic dance training session were monitored and compared to the heart rate responses of treadmill jogging performed at the same VO2. The aerobic dance session elicited a significantly lower oxygen pulse than did treadmill exercise (7.2 +/- 0.3 vs 8.1 +/- 0.8 ml.beat-1; P less than 0.01). There were no significant changes in percent body fat, whereas VO2max increased by 11% (34.4 +/- 0.9 vs 38.1 +/- 0.8 ml.kg-1.min-1; P less than 0.05). No significant changes in any of the parameters tested were observed in 10 untrained controls. These findings indicate that the heart rate elicited from aerobic dance represents a lower relative exercise intensity (VO2) than that of running. Therefore, the assumption that aerobic dance training produces the same cardiovascular adaptations as running training when performed at the same target rate may be unwarranted. PMID:2709986
Objective: To report the clinical applicability of coronary angiography for patients with high heart rate, arrhythmia or cardiac pacing using the new-generation of electron-beam CT (e-Speed). Methods: EBCT (GE e-Speed) coronary angiography was performed in 36 eases (male 27, female 9, mean age 58), including the heart rate more than 90 bpm in 20 patients, frequent ectopic beats in 11 cases, implantation of cardiac pacemaker in 4 patients and the unacceptable MSCT image quality due to variability of interscan heart rate (from 82 bpm to 104 bpm) in 1 case. After volume data set was acquired using spiral mode with prospective ECG-gating, the reconstructions of MIP, CPR, VR and Cine were performed. The VR quality was evaluated using a five-point scale. Results: The quality of coronary imaging in all of 36 cases were acceptable. The total visualization rate of coronary artery branches was 80.0%. Left main, left anterior artery and right coronary artery were visualized in all patients and in 94.3% of all cases circumflex artery were visible. Conclusion: EBCT (e-Speed) is applicable in noninvasive coronary angiography for patients with high heart rate, arrhythmia or implanted cardiac pacemaker', and this examination can obtain satisfied diagnosis. (authors)
Mansikka, Heikki; Virtanen, Kai; Harris, Don; Simola, Petteri
Increased task demand will increase the pilot mental workload (PMWL). When PMWL is increased, mental overload may occur resulting in degraded performance. During pilots' instrument flight rules (IFR) proficiency test, PMWL is typically not measured. Therefore, little is known about workload during the proficiency test and pilots' potential to cope with higher task demands than those experienced during the test. In this study, fighter pilots' performance and PMWL was measured during a real IFR proficiency test in an F/A-18 simulator. PMWL was measured using heart rate (HR) and heart rate variation (HRV). Performance was rated using Finnish Air Force's official rating scales. Results indicated that HR and HRV differentiate varying task demands in situations where variations in performance are insignificant. It was concluded that during a proficiency test, PMWL should be measured together with the task performance measurement. PMID:27109324
Deng, Yilei; Zhao, Longshuan; Lu, Xu
Ischemic-type biliary lesions (ITBL) are the most troublesome biliary complication after liver transplantation (LT) from non-heart-beating donors (NHBD) and frequently result in death or re-transplantation. In transplantation process, warm ischemia (WI) in the donor, cold ischemia and reperfusion injury in the recipient altogether inducing ischemia-reperfusion injury (IRI) is strongly associated with ITBL. This is a cascading injury process, involving in a complex series of inter-connecting events causing variety of cells activation and damage associated with the massive release of inflammatory cytokines and generation of reactive oxygen species (ROS). These damaged cells such as sinusoidal endothelial cells (SECs), Kupffer cells (KCs), hepatocytes and biliary epithelial cells (BECs), coupled with immunological injury and bile salt toxicity altogether contribute to ITBL in NHBD LT. Developed therapeutic strategies to attenuate IRI are essential to improve outcome after LT. Among them, single pharmaceutical interventions blocking a specific pathway of IRI in rodent models play an absolutely dominant role, and show a beneficial effect in some given controlled experiments. But this will likely prove ineffective in complex clinical setting in which more risk parameters are involved. Therefore, we intend to design a multidrug cocktail approach to block different pathways on more than one stage (WI, cold ischemia and reperfusion) of the process of IRI-induced ITBL simultaneously. This multidrug cocktail will include six drugs containing streptokinase, epoprostenol, thiazolidinediones (TZDs), N-Acetylcysteine (NAC), hemin and tauroursodeoxycholic acid (TUDC). These drugs show protective effects by targeting the different key events of IRI, such as anti-inflammatory, anti-fibrosis, anti-oxidation, anti-apoptosis and reduced bile salt toxicity. Ideally, the compounds, dosage, and method of application of drugs included in cocktail should not be definitive. We can consider
Miriam J Warnier
Full Text Available BACKGROUND: Although it is known that patients with chronic obstructive pulmonary disease (COPD generally do have an increased heart rate, the effects on both mortality and non-fatal pulmonary complications are unclear. We assessed whether heart rate is associated with all-cause mortality, and non-fatal pulmonary endpoints. METHODS: A prospective cohort study of 405 elderly patients with COPD was performed. All patients underwent extensive investigations, including electrocardiography. Follow-up data on mortality were obtained by linking the cohort to the Dutch National Cause of Death Register and information on complications (exacerbation of COPD or pneumonia by scrutinizing patient files of general practitioners. Multivariable cox regression analysis was performed. RESULTS: During the follow-up 132 (33% patients died. The overall mortality rate was 50/1000 py (42-59. The major causes of death were cardiovascular and respiratory. The relative risk of all-cause mortality increased with 21% for every 10 beats/minute increase in heart rate (adjusted HR: 1.21 [1.07-1.36], p = 0.002. The incidence of major non-fatal pulmonary events was 145/1000 py (120-168. The risk of a non-fatal pulmonary complication increased non-significantly with 7% for every 10 beats/minute increase in resting heart rate (adjusted HR: 1.07 [0.96-1.18], p = 0.208. CONCLUSIONS: Increased resting heart rate is a strong and independent risk factor for all-cause mortality in elderly patients with COPD. An increased resting heart rate did not result in an increased risk of exacerbations or pneumonia. This may indicate that the increased mortality risk of COPD is related to non-pulmonary causes. Future randomized controlled trials are needed to investigate whether heart-rate lowering agents are worthwhile for COPD patients.
Diobel M. Castner
Full Text Available Heart rate recovery (HRR is an indicator of all-cause mortality in children and adults. We aimed to determine the effect of adiposity and Prader-Willi Syndrome (PWS, a congenital form of obesity, on HRR. Sixteen children of normal weight (NW = body fat % ≤85th percentile, 9.4 ± 1.1 y, 18 children with obesity (OB = body fat % >95th percentile, 9.3 ± 1.1 y, and 11 PWS youth (regardless of body fat %; 11.4 ± 2.5 y completed peak and submaximal bike tests on separate visits. HRR was recorded one minute following peak and submaximal exercises. All groups displayed similar HRR from peak exercise, while NW (54 ± 16 beats and OB (50 ± 12 beats exhibited a significantly faster HRR from submaximal exercise than PWS (37 ± 14 beats. These data suggest that excess adiposity does not influence HRR in children, but other factors such as low cardiovascular fitness and/or autonomic dysfunction might be more influential.
Rabbia, F; Grosso, T; Cat Genova, G; Conterno, A; De Vito, B; Mulatero, P; Chiandussi, L; Veglio, F
The aim of this study was to evaluate the distribution of resting heart rate and its biological and environmental determinants in adolescents. The study was cross- sectional and the population consisted of 2230 children and adolescents, age range 12-18 years, enrolled randomly from state schools in Turin, Italy. In all participants the following parameters were evaluated: heart rate, blood pressure (BP), weight, height, degree of sexual development, physical activity, parental socio-cultural level. Heart rate and BP were measured after 5, 10 and 15 min in a sitting position. Furthermore, to obtain regression equations to define heart rate as a function of the other variables available, a multiple regression analysis was performed. In both sexes BP, but not heart rate, declined significantly from the first to the last determination. Heart rate was positively and significantly correlated to BP level in both sexes; heart rate was higher in girls (3 bpm) and followed a progressive decreasing trend with age in both sexes, that was opposite to BP values. Age, sexual maturation, height, physical activity and parental socio-cultural level were independent determinants of resting heart rate. In conclusion, resting heart rate in adolescents is related to several methodological, constitutional and environmental factors that have to be taken into account when assessing heart rate values and constructing tables of normal values. PMID:12082493
Højgaard, Michael V; Agner, Erik; Kanters, Jørgen K; Holstein-Rathlou, N.-H.
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...... (RR) interval and finger blood pressure (Finapres) in 14 healthy individuals on three different days. The protocol was 1 h of supine rest and 1 h of 60-degree head-up tilt. Time-series of consecutive 300-s segments as well as 1024-s segments of RR intervals and systolic, diastolic and mean blood...
Siebenmann, C; Rasmussen, P; Sørensen, H; Bonne, T C; Zaar, M; Aachmann-Andersen, N J; Nordsborg, N B; Secher, N H; Lundby, C
Hypoxia increases the heart rate response to exercise, but the mechanism(s) remains unclear. We tested the hypothesis that the tachycardic effect of hypoxia persists during separate, but not combined, inhibition of β-adrenergic and muscarinic receptors. Nine subjects performed incremental exercise to exhaustion in normoxia and hypoxia (fraction of inspired O2 = 12%) after intravenous administration of 1) no drugs (Cont), 2) propranolol (Prop), 3) glycopyrrolate (Glyc), or 4) Prop + Glyc. HR increased with exercise in all drug conditions (P hypoxia than normoxia (P hypoxia and normoxia was 19.8 ± 13.8 beats/min during Cont and similar (17.2 ± 7.7 beats/min, P = 0.95) during Prop but smaller (P hypoxia (P 0.4) but larger during Prop (3.4 ± 1.6 l/min, P = 0.004). Our results demonstrate that the tachycardic effect of hypoxia during exercise partially relies on vagal withdrawal. Conversely, sympathoexcitation either does not contribute or increases heart rate through mechanisms other than β-adrenergic transmission. A potential candidate is α-adrenergic transmission, which could also explain why a tachycardic effect of hypoxia persists during combined β-adrenergic and muscarinic receptor inhibition. PMID:25888515
Zhang, Henggui; Aziz, Wajid; Monfredi, Oliver; Abbas, Syed Ali; Shah, Saeed Arif; Kazmi, Syeda Sobia Hassan; Butt, Wasi Haider
The dynamical fluctuations in the rhythms of biological systems provide valuable information about the underlying functioning of these systems. During the past few decades analysis of cardiac function based on the heart rate variability (HRV; variation in R wave to R wave intervals) has attracted great attention, resulting in more than 17000-publications (PubMed list). However, it is still controversial about the underling mechanisms of HRV. In this study, we performed both linear (time domain and frequency domain) and nonlinear analysis of HRV data acquired from humans and animals to identify the relationship between HRV and heart rate (HR). The HRV data consists of the following groups: (a) human normal sinus rhythm (n = 72); (b) human congestive heart failure (n = 44); (c) rabbit sinoatrial node cells (SANC; n = 67); (d) conscious rat (n = 11). In both human and animal data at variant pathological conditions, both linear and nonlinear analysis techniques showed an inverse correlation between HRV and HR, supporting the concept that HRV is dependent on HR, and therefore, HRV cannot be used in an ordinary manner to analyse autonomic nerve activity of a heart. PMID:27336907
Background: Computed tomography coronary angiography (CTCA) has been widely used since the introduction of 64-slice scanners and dual-source CT technology, but the relatively high radiation dose remains a major concern. Purpose: To evaluate the relationship between radiation exposure and heart rate (HR), in dual-source CTCA. Material and Methods: Data from 218 CTCA examinations, performed with a dual-source 64-slices scanner, were statistically evaluated. Effective radiation dose, expressed in mSv, was calculated as the product of the dose-length product (DLP) times a conversion coefficient for the chest (mSv = DLPx0.017). Heart rate range and mean heart rate, expressed in beats per minute (bpm) of each individual during CTCA, were also provided by the system. Statistical analysis of effective dose and heart rate data was performed by using Pearson correlation coefficient and two-sample t-test. Results: Mean HR and effective dose were found to have a borderline positive relationship. Individuals with a mean HR >65 bpm observed to receive a statistically significant higher effective dose as compared to those with a mean HR =65 bpm. Moreover, a strong correlation between effective dose and variability of HR of more than 20 bpm was observed. Conclusion: Dual-source CT scanners are considered to have the capability to provide diagnostic examinations even with high HR and arrhythmias. However, it is desirable to keep the mean heart rate below 65 bpm and heart rate fluctuation less than 20 bpm in order to reduce the radiation exposure
Laukkanen, R M; Kalaja, M K; Kalaja, S P; Holmala, E B; Paavolainen, L M; Tummavuori, M; Virtanen, P; Rusko, H K
This study measured heart rate during floor and step aerobic classes at three intensity levels. A group of 20 female occasional exercisers [mean age 33 (SD 8) years, mean body mass index 21 (SD 2) kg.m-2 volunteered to participate in six aerobic classes (three floor classes, three step classes) and in a laboratory test as members of one of two groups according to their prestudy regular participation in aerobics classes. Subjects in group A had participated four or more times a week and those of group B less than twice a week. The characteristics of the groups were as follows: group A, n = 10, mean maximal oxygen uptake (VO2max) 38.7 (SD 3.6) ml.kg-1.min-1, mean maximal heart rate (HRmax) 183 (SD 8) beats.min-1; group B, n = 10, VO2max 36.1 (SD 3.6) ml.kg-1.min-1, HRmax 178 (SD 7) beats.min-1. Each class consisted of a warm-up, a 20 min period of structured aerobic exercise (cardiophase) and a cool-down. The cardiophase was planned and guided as light, (rate of perceived exertion, RPE 11-12), moderate (RPE 13-14) or heavy (RPE 15-17) by an experienced instructor. The mean heart rates during the light classes were 72 (step) and 74 (floor) %HRmax in group A and 75 (step) and 79 (floor) %HRmax in group B; during the moderate classes, 84 (step) and 80 (floor) %HRmax in group A and 82 (step) and 83 (floor) %HRmax in group B, and during the heavy classes 89 (step and floor) %HRmax in group A and 88 (step) and 92 (floor) %HRmax in group B. Differences in heart rate and %HRmax were not statistically significant between the groups. However, differences in heart rate and %HRmax between the intensities (light vs moderate, moderate vs heavy and light vs heavy) were significant within both groups (all, P < 0.01). Based on the results, we conclude that intensity management during the aerobics classes was generally successful regardless of the participants' prior participation in aerobics. However, some individuals who were older and/or had less prior participation tended to
龚倩; 葛建军; 葛圣林; 林敏; 周汝元; 高晴云
目的 探讨β1受体阻滞剂艾司洛尔在不停跳心内直视手术中对心肌的保护作用.方法 选择22例择期行房间隔修补手术患者,随机分为两组,每组11例,两组均在常温体外循环心脏不停跳心内直视下进行房间隔修补手术.实验组在体外循环开始前于预冲液中加入艾司洛尔1 mg/kg,转机过程中再以300 μg·kg-1·min-1的速度从静脉持续输注艾司洛尔,直到手术完成.对照组给予等量的生理盐水代替艾司洛尔,其余和实验组相同.监测两组病例在各个时间点的血流动力学、血气分析、心肌损伤标志物及围手术期各项临床指标,并进行对比.结果 在转机过程中,实验组心率(56±8)次/min显著低于对照组(64±9)次/min(P＜0.05),实验组cTnI和CK-MB在术后6、12、24 h各个时间点均显著低于对照组(均为P＜0.001),两组病例在手术开始前、转机开始前、转机过程中、停机后和手术结束后各个时间点的血气分析指标差异无统计学意义(均为P>0.05).结论 在常温体外循环心脏不停跳心内直视手术中应用艾司洛尔可以显著保护心肌并改善手术操作条件.%Objective To investigate the cardiac protective effect of esmolol during open heart beating surgery. Methods Twenty-two patients with atrial septal defect ( ASD ) undergoing elective open heart beating surgery were randomly divided into two groups. Each group had 11 patients. Experimental group received open heart beating surgery with normothermia cardiopulmonary bypass ( CPB ). Esmolol was added into the cardioplegic solution with 1 mg·kg-1 , and then esmolol was continuous infusion intravenously with 300 μg · kg-1·min-1 during CPB until the end of surgery. Control group received saline instead of esmolol. The hemodynamics, blood gas analysis and cardiac injury markers of different time and clinical parameters of peri-operative period were recorded and compared. Results The heart rate ( HR ) during
Eighteen patients with atrial fibrillation were given digoxin 0.13 mg twice daily for 3 weeks and β-methyldigoxin 0.10 mg twice daily for another 3 weeks. At the end of each 3 week period an exercise test was performed and the effects on the heart rate of the two drugs were compared. No difference in heart rate was obtained at rest, wheareas the heart rate after 6 min of exercise was higher during treatment with digoxin (131 beats/min) than when the patients were taking β-methyldigoxin (124 beats/min). There were no significant differences between digoxin and β-methyldigoxin in their effects on the ECT (R-R intervals, T-wave, Q-T duration). The plasma concentrations of the two glycosides were determined by radioimmunoassay and by 86Rb-uptake inhibition assay. Comparable plasma concentration values (1.0 ng/ml for digoxin, 1.1 ng/ml for β-methyldigoxin, mean values) were obtained by radioimmunoassay, but the 86Rb-technique gave significantly higher values (mean 1.5 ng/ml) for β-methyldigoxin. It is concluded that β-methyldigoxin is equal to digoxin for producing slowing of the heart rate in patients with atrial fibrillation. (orig.)
Full Text Available BACKGROUND: Many avian species soar and glide over land. Evidence from large birds (m(b>0.9 kg suggests that soaring-gliding is considerably cheaper in terms of energy than flapping flight, and costs about two to three times the basal metabolic rate (BMR. Yet, soaring-gliding is considered unfavorable for small birds because migration speed in small birds during soaring-gliding is believed to be lower than that of flapping flight. Nevertheless, several small bird species routinely soar and glide. METHODOLOGY/PRINCIPAL FINDINGS: To estimate the energetic cost of soaring-gliding flight in small birds, we measured heart beat frequencies of free-ranging migrating European bee-eaters (Merops apiaster, m(b∼55 g using radio telemetry, and established the relationship between heart beat frequency and metabolic rate (by indirect calorimetry in the laboratory. Heart beat frequency during sustained soaring-gliding was 2.2 to 2.5 times lower than during flapping flight, but similar to, and not significantly different from, that measured in resting birds. We estimated that soaring-gliding metabolic rate of European bee-eaters is about twice their basal metabolic rate (BMR, which is similar to the value estimated in the black-browed albatross Thalassarche (previously Diomedea melanophrys, m(b∼4 kg. We found that soaring-gliding migration speed is not significantly different from flapping migration speed. CONCLUSIONS/SIGNIFICANCE: We found no evidence that soaring-gliding speed is slower than flapping flight in bee-eaters, contradicting earlier estimates that implied a migration speed penalty for using soaring-gliding rather than flapping flight. Moreover, we suggest that small birds soar and glide during migration, breeding, dispersal, and other stages in their annual cycle because it may entail a low energy cost of transport. We propose that the energy cost of soaring-gliding may be proportional to BMR regardless of bird size, as theoretically deduced by
Peira, Nathalie; Fredrikson, Mats; Pourtois, Gilles
When regulating negative emotional reactions, one goal is to reduce physiological reactions. However, not all regulation strategies succeed in doing that. We tested whether heart rate biofeedback helped participants reduce physiological reactions in response to negative and neutral pictures. When viewing neutral pictures, participants could regulate their heart rate whether the heart rate feedback was real or not. In contrast, when viewing negative pictures, participants could regulate heart rate only when feedback was real. Ratings of task success paralleled heart rate. Participants' general level of anxiety, emotion awareness, or cognitive emotion regulation strategies did not influence the results. Our findings show that accurate online heart rate biofeedback provides an efficient way to down-regulate autonomic physiological reactions when encountering negative stimuli. PMID:24373886
Mahomed, K.; Nyoni, R.; Mulambo, T.; Kasule, J.; Jacobus, E.
OBJECTIVE--To compare effectiveness of different methods of monitoring intrapartum fetal heart rate. DESIGN--Prospective randomised controlled trial. SETTING--Referral maternity hospital, Harare, Zimbabwe. SUBJECTS--1255 women who were 37 weeks or more pregnant with singleton cephalic presentation and normal fetal heart rate before entry into study. INTERVENTIONS--Intermittent monitoring of fetal heart rate by electronic monitoring, Doppler ultrasound, use of Pinard stethoscope by a research ...
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 ...
Kiyono, Ken; Struzik, Zbigniew R.; Aoyagi, Naoko; Sakata, Seiichiro; Hayano, Junichiro; Yamamoto, Yoshiharu
We demonstrate the robust scale-invariance in the probability density function (PDF) of detrended healthy human heart rate increments, which is preserved not only in a quiescent condition, but also in a dynamic state where the mean level of heart rate is dramatically changing. This scale-independent and fractal structure is markedly different from the scale-dependent PDF evolution observed in a turbulent-like, cascade heart rate model. These results strongly support the view that healthy huma...
Kiyono, Ken; Struzik, Zbigniew R.; Aoyagi, Naoko; Sakata, Seiichiro; Hayano, Junichiro; Yamamoto, Yoshiharu
We demonstrate the robust scale-invariance in the probability density function (PDF) of detrended healthy human heart rate increments, which is preserved not only in a quiescent condition, but also in a dynamic state where the mean level of the heart rate is dramatically changing. This scale-independent and fractal structure is markedly different from the scale-dependent PDF evolution observed in a turbulentlike, cascade heart rate model. These results strongly support the view that a healthy human heart rate is controlled to converge continually to a critical state.
This study investigated the interaction between heart rate (HR) and blood pressure (BP) during conscious control under visual biofeedback and background noise conditions. Normotensive volunteers were instructed to (i) decrease and (ii) increase HR (group A, n = 16) or BP (group B, n = 16). After instructions to lower HR or BP there was no significant change in HR or BP for either group. After instructions to raise HR, HR increased significantly (13.8 ± 1.3 beats min−1, P < 0.0001) and BP did not change. However, following instructions to raise BP, both HR and BP increased significantly: systolic BP (5.2 ± 1.5 mmHg, P < 0.001), diastolic BP (3.5 ± 0.9 mmHg, P < 0.001) and HR (8.6 ± 1.3 beats min−1, P < 0.0001). Biofeedback and background noise did not alter the relative change in HR or BP. In conclusion, normotensive subjects were unable to reduce BP or HR under conscious control. Subjects were able to increase both HR and BP, and voluntary increases in HR did not alter BP, while voluntary increases in BP also increased HR indicating distinct HR/BP interactions during conscious control
Heusch, Gerd; Kleinbongard, Petra
Ivabradine inhibits hyperpolarization-activated cyclic nucleotide-gated channels in the sinus node, thereby reducing heart rate, and heart rate reduction improves regional myocardial blood flow and contractile function in ischemic myocardium. Accordingly, ivabradine reduces anginal symptoms in patients with stable coronary artery disease but does not improve their clinical outcome. Heart rate reduction with ivabradine in patients with symptomatic heart failure reduces symptoms, attenuates remodeling, and improves clinical outcome. In pigs and mice, ivabradine reduces infarct size from myocardial ischemia/reperfusion, even when heart rate reduction is abrogated by atrial pacing. Improved viability is also observed in isolated ventricular cardiomyocytes subjected to simulated ischemia/reperfusion. These beneficial effects are attributed to reduced reactive oxygen species formation from the mitochondria. There is also evidence for a heart rate-independent benefit from ivabradine in the vasculature of mice and humans, and in left ventricular contractile function of pigs. Finally, in mice, ivabradine also has anti-aging potential. PMID:27041289
Tomas A Salerno
Full Text Available OBJECTIVE: Mitral valve surgery can be performed through the trans-atrial or the trans-septal approach. Although the trans-atrial is the preferred method, the trans-septal approach has also been used recently and has a particular value in beating-heart mitral valve surgery. Herein we report our experience with beating-heart mitral valve surgery via trans-septal approach, and discuss its advantages and pitfalls. METHODS: Between 2000 and 2007, 214 consecutive patients were operated upon utilizing beating heart technique for mitral valve surgery. The operation was performed via transseptal approach with the aorta unclamped, the heart beating, with normal electrocardiogram and in sinus rhythm. RESULTS: Mean age was 56.03 ± 13.93 years (range: 19-86 years; median: 56 years. There were 131 (61.2% males and 83 (38.8% females. Of the prostheses used, 108 (50.5% were biological, and 39 (18.2% were mechanical. Mitral repairs were performed in 67 (31.3% patients. Mean hospital stay was 17.4 ± 20.0 days (range: 3-135 days; median: 11 days. Intra-aortic balloon pump (IABP utilization was required in 12 (5.6% of 214 patients. One-month mortality was 7.4%, and re-operation for bleeding was needed in 15 (7% patients. CONCLUSIONS: Beating-heart mitral valve surgery is an option for myocardial protection in patients undergoing mitral valve surgery. This technique is facilitated by the trans-septal approach due to reduced aortic insufficiency and improved visualization of the mitral apparatus.OBJETIVO: A cirurgia da valva mitral pode ser feita via transatrial ou transeptal. Embora a transatrial seja a preferida, a via transeptal tem sido utilizada mais recentemente e tido um grande valor nas operações com o coração batendo. Mostramos a nossa experiência na cirurgia da valva mitral via transeptal com coração batendo e discutimos seus benefícios e problemas. MÉTODOS: Entre 2000 e 2007, 214 pacientes consecutivos foram operados com o coração batendo. A
Vicente, José; Laguna, Pablo; Bartra, Ariadna; Bailón, Raquel
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. PMID:26780463
Wilson, Scott T; Chesin, Megan; Fertuck, Eric; Keilp, John; Brodsky, Beth; Mann, J John; Sönmez, Cemile Ceren; Benjamin-Phillips, Christopher; Stanley, Barbara
Identification of biological indicators of suicide risk is important given advantages of biomarker-based models. Decreased high frequency heart rate variability (HF HRV) may be a biomarker of suicide risk. The aim of this research was to determine whether HF HRV differs between suicide attempters and non-attempters. Using the Trier Social Stress Test (TSST), we compared HF HRV between females with and without a history of suicide attempt, all with a lifetime diagnosis of a mood disorder. To investigate a potential mechanism explaining association between HF HRV and suicide, we examined the association between self-reported anger and HF HRV. Results of an Area under the Curve (AUC) analysis showed attempters had a lower cumulative HF HRV during the TSST than non-attempters. In addition, while there was no difference in self-reported anger at baseline, the increase in anger was greater in attempters, and negatively associated with HF HRV. Results suggest that suicide attempters have a reduced capacity to regulate their response to stress, and that reduced capacity to regulate anger may be a mechanism through which decreased HF HRV can lead to an increase in suicide risk. Our results have implications for the prevention of suicidal behavior in at-risk populations. PMID:27124209
The use of heart rate variability (HRV) parameters during exercise is not supported by appropriate reliability studies. In 80 healthy adults, ECG was recorded during three 6 min bouts of exercise, separated by 6 min of unloaded cycling. Two bouts were at a moderate intensity while the final bout was at a heavy exercise intensity. This protocol was repeated under the same conditions on three occasions, with a controlled start time (pre-determined at the first visit). Standard time and frequency domain indices of HRV were derived. Reliability was assessed by Bland–Altman plots, 95% limits of agreement and intraclass correlation coefficients (ICC). The sample size required to detect a mean difference ≥30% of the between-subject standard deviation was also estimated. There was no systematic change between days. All HRV parameters demonstrated a high degree of reproducibility during baseline (ICC range: 0.58–0.75), moderate (ICC: 0.58–0.85) and heavy intensity exercise (ICC range: 0.40–0.76). The reproducibility was slightly diminished during heavy intensity exercise relative to both unloaded baseline cycling and moderate exercise. This study indicates that HRV parameters can be reliably determined during exercise, and it underlines the importance of standardizing exercise intensity with regard to fitness levels if HRV is to be reliably determined. (paper)
van Andel, Judith; Ungureanu, Constantin; Aarts, Ronald; Leijten, Frans; Arends, Johan
Heart rate is a useful neurophysiological sign when monitoring seizures in patients with epilepsy. In an ambulatory setting, heart rate is measured with ECG involving electrodes on the skin. This method is uncomfortable which is burdensome for patients and is sensitive to motion artifacts, which dec
Tendais, Iva; Visser, Gerard H. A.; Figueiredo, Barbara; Montenegro, Nuno; Mulder, Eduard J. H.
Fetal movements and fetal heart rate (FHR) are well-established markers of fetal well-being and maturation of the fetal central nervous system. The purpose of this paper is to review and discuss the available knowledge on fetal movements and heart rate patterns in twin pregnancies. There is some evi
Tan, Isabella; Spronck, Bart; Kiat, Hosen; Barin, Edward; Reesink, Koen D; Delhaas, Tammo; Avolio, Alberto P; Butlin, Mark
Carotid-femoral pulse wave velocity (cfPWV) quantifies large artery stiffness, it is used in hemodynamic research and is considered a useful cardiovascular clinical marker. cfPWV is blood pressure (BP) dependent. Intrinsic heart rate (HR) dependency of cfPWV is unknown because increasing HR is commonly accompanied by increasing BP. This study aims to quantify cfPWV dependency on acute, sympathovagal-independent changes in HR, independent of BP. Individuals (n=52, age 40-93 years, 11 female) with in situ cardiac pacemakers or cardioverter defibrillators were paced at 60, 70, 80, 90, and 100 bpm. BP and cfPWV were measured at each HR. Both cfPWV (mean [95% CI], 0.31 [0.26-0.37] m/s per 10 bpm; Parea; and (3) using measured BP dependency of cfPWV derived from changes in BP induced by orthostatic changes (seated and supine) in a subset of subjects (n=17). The BP-independent effects of HR on cfPWV were quantified as 0.20 [0.11-0.28] m/s per 10 bpm (P<0.001, method 1), 0.16 [0.11-0.22] m/s per 10 bpm (P<0.001, method 2), and 0.16 [0.11-0.21] m/s per 10 bpm (P<0.001, method 3). With a mean HR dependency in the range of 0.16 to 0.20 m/s per 10 bpm, cfPWV may be considered to have minimal physiologically relevant changes for small changes in HR, but larger differences in HR must be considered as contributing to significant differences in cfPWV. PMID:27245180
The purpose of this study was to examine the effect different cycling cadences have on heart rate variability (HRV) when exercising at constant power outputs. Sixteen males had ECG and respiratory measurements recorded at rest and during 8, 10 min periods of cycling at four different cadences (40, 60, 80 and 100 revs min−1) and two power outputs (0 W (unloaded) and 100 W (loaded)). The cycling periods were performed following a Latin square design. Spectral analyses of R–R intervals by fast Fourier transforms were used to quantify absolute frequency domain HRV indices (ms2) during the final 5 min of each bout, which were then log transformed using the natural logarithm (Ln). HRV indices of high frequency (HF) power were reduced when cadence was increased (during unloaded cycling (0 W) log transformed HF power decreased from a mean [SD] of 6.3 [1.4] Ln ms2 at 40 revs min−1 to 3.9 [1.3] Ln ms2 at 100 revs min−1). During loaded cycling (at 100 W), the low to high frequency (LF:HF) ratio formed a 'J' shaped curve as cadence increased from 40 revs min−1 (1.4 [0.4]) to 100 revs min−1 (1.9 [0.7]), but dipped below the 40 revs min−1 values during the 60 revs min−1 1.1 (0.3) and 80 revs min−1 1.2 (0.6) cadence conditions. Cardiac frequency (fC) and ventilatory variables were strongly correlated with frequency domain HRV indices (r = −0.80 to −0.95). It is concluded that HRV indices are influenced by both cycling cadence and power output; this is mediated by the fC and ventilatory changes that occur as cadence or exercise intensity is increased. Consequently, if HRV is assessed during exercise, both power output/exercise intensity and cadence should be standardized
Full Text Available The aim of the present study was to compare the modulation of heart rate in a group of postmenopausal women to that of a group of young women under resting conditions on the basis of R-R interval variability. Ten healthy postmenopausal women (mean ± SD, 58.3 ± 6.8 years and 10 healthy young women (mean ± SD, 21.6 ± 0.82 years were submitted to a control resting electrocardiogram (ECG in the supine and sitting positions over a period of 6 min. The ECG was obtained from a one-channel heart monitor at the CM5 lead and processed and stored using an analog to digital converter connected to a microcomputer. R-R intervals were calculated on a beat-to-beat basis from the ECG recording in real time using a signal-processing software. Heart rate variability (HRV was expressed as standard deviation (RMSM and mean square root (RMSSD. In the supine position, the postmenopausal group showed significantly lower (P<0.05 median values of RMSM (34.9 and RMSSD (22.32 than the young group (RMSM: 62.11 and RMSSD: 49.1. The same occurred in the sitting position (RMSM: 33.0 and RMSSD: 18.9 compared to RMSM: 57.6 and RMSSD: 42.8 for the young group. These results indicate a decrease in parasympathetic modulation in postmenopausal women compared to young women which was possibly due both to the influence of age and hormonal factors. Thus, time domain HRV proved to be a noninvasive and sensitive method for the identification of changes in autonomic modulation of the sinus node in postmenopausal women.
Full Text Available Quantification of cardiac autonomic activity and control via heart rate (HR and heart rate variability (HRV is known to provide prognostic information in clinical populations. Issues with regard to standardisation and interpretation of HRV data make the use of the more easily accessible HR on its own as an indicator of autonomic cardiac control very appealing. The aim of this study was to investigate the strength of associations between an important cardio vascular health metric such as VO2max and the following: HR, HRV indicators and heart rate normalised HRV indicators. A cross sectional descriptive study was done including 145 healthy volunteers aged between 18 and 22 years. HRV was quantified by time domain, frequency domain and Poincaré plot analysis. Indirect VO2max was determined using the Multistage Coopers test. The Pearson correlation coefficient was calculated to quantify the strength of the associations. Both simple linear and multiple stepwise regressions were performed to be able to discriminate between the role of the individual indicators as well as their combined association with VO2max. Only HR, RR interval and pNN50 showed significant (p<0.01, p<0.01 and p=0.03 correlations with VO2max. Stepwise multiple regression indicated that, when combining all HRV indicators the most important predictor of cardio vascular fitness as represented by VO2max, is HR. HR explains 17% of the variation, while the inclusion of HF (high frequency HRV indicator added only an additional 3.1% to the coefficient of determination. Results also showed when testing the normalised indicators, HR explained of the largest percentage of the changes in VO2max (16.5%. Thus HR on its own is the most important predictor of changes in an important cardiac health metric such as VO2max. These results may indicate that during investigation of exercise ability (VO2max phenomena, quantification of HRV may not add significant value.
Mazloom, Roham; Eftekhari, Golnar; Rahimi-Balaei, Maryam; Rahimi, Maryam; Khori, Vahid; Hajizadeh, Sohrab; Dehpour, Ahmad R; Mani, Ali R
Previous reports have indicated that artificial stimulation of the vagus nerve reduces systemic inflammation in experimental models of sepsis. This phenomenon is a part of a broader cholinergic anti-inflammatory pathway which activates the vagus nerve to modulate inflammation through activation of alpha7 nicotinic acetylcholine receptors (α7nACHR). Heart rate variability represents the complex interplay between autonomic nervous system and cardiac pacemaker cells. Reduced heart rate variability and increased cardiac cycle regularity is a hallmark of clinical conditions that are associated with systemic inflammation (e.g. endotoxemia and sepsis). The present study was aimed to assess the role of α7nACHR in modulation of heart rate dynamics during systemic inflammation. Systemic inflammation was induced by injection of endotoxin (lipopolysaccharide) in rats. Electrocardiogram and body temperature were recorded in conscious animals using a telemetric system. Linear and non-linear indices of heart rate variability (e.g. sample entropy and fractal-like temporal structure) were assessed. RT-PCR and immunohistochemistry studies showed that α7nACHR is expressed in rat atrium and is mainly localized at the endothelial layer. Systemic administration of an α7nACHR antagonist (methyllycaconitine) did not show a significant effect on body temperature or heart rate dynamics in naïve rats. However, α7nACHR blockade could further reduce heart rate variability and elicit a febrile response in endotoxemic rats. Pre-treatment of endotoxemic animals with an α7nACHR agonist (PHA-543613) was unable to modulate heart rate dynamics in endotoxemic rats but could prevent the effect of endotoxin on body temperature within 24 h experiment. Neither methyllycaconitine nor PHA-543613 could affect cardiac beating variability of isolated perfused hearts taken from control or endotoxemic rats. Based on our observations we suggest a tonic role for nicotinic acetylcholine receptors in
Full Text Available Objective: To study the change of heart rate deceleration capacity ( DC and heart rate variability in patients with chronic heart failure (CHF and its relationship with left ventricular ejection fraction (LVEF. Methods: DC, LVEF, time and frequency domain parameters of HRV were measured in 66 patients with CHF and 34 healthy adults (control group by using 24h Holter recordings and Echocardiography. The standard deviation of normal R-R intervals( SDNN, squares of differences between adjacent NN intervals ( RMSSD，low frequency power( LFn and high frequency power( HFn and the changes of LVEF were compared between the two groups，the relationship between DC，LVEF and HRV were studied in patients with CHF. Results: The median value of DC in the patients with CHF was significantly lower than that in control group( 3.1 ± 2.4 ms vs 7.2 ± 1.3 ms，P <0.01．Incidence of abnormal DC in the CHF group was 57.5%，which was significantly higher than that in the control group (P <0.01．The HRV index, including SDNN、RMSSD、LFn、HFn, in the CHF group was significantly lower than that in normal control group (P < 0.01. Significant positive correlation between HRV index and LVEF were confirmed (P < 0.01. Conclusions: DC and HRV index are lower in patients with CHF and have a good correlation with the left ventricular ejection fraction.
Jensen, Magnus Thorsten; Marott, Jacob L; Allin, Kristine H; Nordestgaard, Børge G; Jensen, Gorm B
Aims: To investigate the association between resting heart rate (RHR) and markers of chronic low-grade inflammation. Also, to examine whether elevated resting heart rate is independently associated with cardiovascular and all-cause mortality in the general population, or whether elevated RHR is...... merely a marker of chronic low-grade inflammation. Methods and results: A group of 6518 healthy subjects from the the Danish general population were followed for 18 years during which 1924 deaths occurred. Subjects underwent assessment of baseline RHR, conventional cardiovascular risk factors, high......-sensitivity C-reactive protein (hsCRP), and fibrinogen. RHR was associated with hsCRP and fibrinogen in uni- and multivariate models (p <0.0001). A 10 beats per minute increase in RHR was associated with increased cardiovascular and all-cause mortality in univariate models - HR (95%CI) (1.21 (1.14-1.29) and 1...