WorldWideScience
1

[The resting heart rate].  

Science.gov (United States)

Assessment of resting heart rate is frequently performed and is easy, reliable and inexpensive. Heart rate is used in many algorithms to assess the prognosis of acutely ill patients. Elevated resting heart rate is independently related to the development of type 2 diabetes, cardiovascular disease and premature all-cause mortality. Adding heart rate to cardiovascular prediction models does not lead to improved prediction of vascular events or mortality. Beta blockers and non-dihydropyridine calcium channel blockers decrease heart rate (and blood pressure) and lower the risk of premature mortality in patients with heart failure or recent myocardial infarction. In two recent randomised trials, ivabradine specifically decreased heart rate (but not blood pressure) and the risk of cardiovascular events in patients with heart failure or coronary artery disease, decreased left ventricular function and resting heart rate of ? 70 beats/minute. Selective heart rate reduction is a potential treatment option to decrease cardiovascular risk. PMID:24666528

Bemelmans, Remy H H; Visseren, Frank L J

2014-01-01

2

Target Heart Rates  

Science.gov (United States)

... enough? There’s a simple way to know: Your target heart rate helps you hit the bull’s eye. “We don’ ... your maximum heart rate. This range is your target heart rate. Know Your Numbers This table shows estimated target ...

3

All about Heart Rate (Pulse)  

Science.gov (United States)

... health.” Learn more: Blood Pressure Vs. Heart Rate Target Heart Rate Arrhythmias (abnormal heart rhythms) Cardiovascular Conditions • Conditions Home • ... Popular Articles 1 Understanding Blood Pressure Readings 2 Target Heart Rates 3 Heart Attack Symptoms in Women 4 What ...

4

Target Heart Rate  

Science.gov (United States)

Students will practice how to calculate their Target Heart Rate to use during exercise routines. This will help students monitor the intensity of their workouts, and ultimately help them achieve results from their workout. Standard 2: Objective 2: a,b,c Before we discuss what the Target Heart Range is and how we can us it, we must first have some basic knowledge of the heart and it's functions. Click the "habits of the heart" to learn the basics of the heart and how it circulates blood throughout the body. Habits of the Heart The hearts ...

Peterson, Mr.

2011-09-18

5

Tachycardia | Fast Heart Rate  

Science.gov (United States)

... amounts of coffee People who drink alcohol heavily People who smoke heavily Atrial tachycardia occurs less commonly with: Heart ... amounts of coffee People who drink alcohol heavily People who smoke heavily Atrial tachycardia occurs less commonly with: Heart ...

6

Regulation of Human Heart Rate  

Science.gov (United States)

Students learn how to measure heart rate accurately. Then students design and carry out an experiment to test the effects of an activity or stimulus on heart rate, analyze and interpret the data, and present their experiments in a poster session. In this activity students learn about both cardiac physiology and experimental method.

Waldron, Ingrid

7

Conclusion  

International Nuclear Information System (INIS)

In this chapter authors made conclusion that synthetic possibilities and using areas of heterocyclic compounds are practically unlimited. Annually scientists discover the new methods of synthesis, they modify receiving methods that they have, every day replenish the assortment of products with ascertained effective properties, which are conducive satisfaction requirements of society

8

HCN Channels and Heart Rate  

Directory of Open Access Journals (Sweden)

Full Text Available Hyperpolarization and Cyclic Nucleotide (HCN -gated channels represent the molecular correlates of the “funny” pacemaker current (If, a current activated by hyperpolarization and considered able to influence the sinus node function in generating cardiac impulses. HCN channels are a family of six transmembrane domain, single pore-loop, hyperpolarization activated, non-selective cation channels. This channel family comprises four members: HCN1-4, but there is a general agreement to consider HCN4 as the main isoform able to control heart rate. This review aims to summarize advanced insights into the structure, function and cellular regulation of HCN channels in order to better understand the role of such channels in regulating heart rate and heart function in normal and pathological conditions. Therefore, we evaluated the possible therapeutic application of the selective HCN channels blockers in heart rate control.

Ilaria Dentamaro

2012-04-01

9

HEART RATE VARIABILITY AND 24-HOUR MINIMUM HEART RATE  

Science.gov (United States)

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...

10

Interaction between heart rate and heart rate variability.  

Science.gov (United States)

Heart rate variability (HRV) is significantly associated with average heart rate (HR), therefore, HRV actually provides information on two quantities, that is, on HR and its variability. It is difficult to conclude which of these two plays a principal role in the HRV clinical value, or in other words, what is the HR contribution to the clinical significance of HRV. Moreover, the association between HRV and HR is both a physiological phenomenon and a mathematical one. The physiological HRV dependence on HR is determined by the autonomic nervous system activity, but the mathematical one is caused by the nonlinear relationship between RR interval and HR. By employing modification methods of the HRV and HR relationship, it is possible to investigate the HR contribution to the HRV clinical value. Recent studies have shown that the removal of the HR impact on HRV makes HRV more predictive for noncardiac death, however, the enhancement of this impact causes HRV to be a better predictor of cardiovascular mortality. Thus, HR seems to constitute a cardiovascular factor of the HRV predictive ability. HR also influences the reproducibility of HRV, therefore, HR changes should be considered when one compares HRV measurements in a given patient. This review summarizes methodological aspects of investigations of the HRV and HR interaction as well as latest observations concerning its clinical utility. The issues discussed in this article should also refer to any other heart rate dynamics analysis which indices are significantly associated with HR. PMID:24602150

Sacha, Jerzy

2014-05-01

11

Investigating foetal heart rate asymmetry.  

Science.gov (United States)

In this study, we have investigated how the asymmetry of beat-to-beat foetal heart rate variability (fHRV) changes during development after 35 weeks and before 32 weeks of gestation. Noninvasive foetal electrocardiogram (fECG) signals from 78 pregnant women at the gestational age from 16 to 41 weeks with normal single pregnancies were analysed. Heart rate asymmetry (HRA) index that measures time asymmetry of RR interval time-series signal was used to understand the dynamics of fHRV. Results indicate that foetal HRA measured by Guzik's Index (GI) and Porta's Index (PI) changes after 35 weeks gestation compared to foetus before 32 weeks of gestation. It might be due to significant amount of maturation of the autonomic nervous system done after 35 and could potentially help identify the pathological autonomic nervous system development. PMID:25570438

Karmakar, Chandan; Khandoker, Ahsan; Kimura, Yoshitaka; Palaniswami, Marimuthu

2014-08-01

12

Influence of heart failure severity on heart rate variability  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction. Autonomic regulation of cardiovascular functions in congestive heart failure is characterised by enhanced sympathetic and diminished parasympathetic activity. The long term predominance of sympathetic tone is a significant factor in arrhythmogenesis, sudden cardiac death, and progressive pump failure. Heart rate variability (HRV is a noninvasive method for estimating the sympatho vagal balance in cardiovascular control. Aim. The aim of this study was to analyse the influence of heart failure severity on HRV. Method. HRV was estimated through the spectral analysis of short term ECG (Cardiovit AT 60, Schiller, CH in 63 patients (78% male, mean age 56.9±10.9 years and 14 healthy volunteers (57.1% male, mean age 53.1±8.2 years. The following spectral components were measured: VLF (very low frequency, LF (low frequency, HF (high frequency, and total power (Tot Power. Results. All spectral components were statistically, significantly lower in patients with heart failure in comparison to healthy controls (VLF: 159.89±147.02 vs. 285.50±202.77 ms2; p=0.023, LF: 161.48±204.01 vs. 474.57±362.93 ms2; p<0.001, HF: 88.58±102.47 vs. 362.71±318.28 ms2; p<0.001, as well as total power (Tot Power: 723.39±644.52 vs. 1807.29±1204.74 ms2; p<0.001. A significant, negative correlation between HRV parameters and NYHA class was detected in heart failure patients (VLF: r=-0.391; p=0.002, LF: r=-0.401; p=0.001, and Tot Power r=-0.372; p=0.003. Ejection fraction proved to be in significant, positive correlation to VLF (r=0.541; p=0.002, LF (r=0.531; p=0.003, HF (r=0.418; p=0.020, and Tot Power (r=0.457; p=0.013. Conclusion. Significant HRV reduction is a precursor to incipient heart failure (NYHA I. In heart failure progression, total power as well as the power of all spectral components is progressively reduced. LF and Tot Power are the most prominent parameters for discriminating between the different stages of heart failure. These results could promote HRV as an important decision-making tool in heart failure treatment as well as in monitoring the results of that treatment.

Zamaklar-Trifunovi? Danijela

2005-01-01

13

Increased heteroscedasticity of heart rate in fatal heart failure  

Science.gov (United States)

Healthy human heart rate is known to fluctuate in a highly complex manner, displaying complexity characteristics such as those shared by physical systems at a critical state. It is, however, widely believed that chronic heart failure reduces this complexity and that heart rate data from chronic-heart-failure patients can be used for the validation of complexity measures and paradigms applicable both to heart rate and more generally to assess any system's complexity. Here, we counter the above belief, showing an increase in fluctuations and in complexity of heart rate in chronic-heart-failure patients, in particular those at risk of death. This is supported by evidence of increased non-Gaussianity and heteroscedasticity resulting from the emergence of a characteristic correlation scale in the magnitude correlation landscape.

Struzik, Z. R.; Kiyono, K.; Hayano, J.; Watanabe, E.; Yamamoto, Y.

2008-04-01

14

Heart Rate Variability – A Historical Perspective  

OpenAIRE

Heart rate variability (HRV), the beat-to-beat variation in either heart rate or the duration of the R-R interval – the heart period, has become a popular clinical and investigational tool. The temporal fluctuations in heart rate exhibit a marked synchrony with respiration (increasing during inspiration and decreasing during expiration – the so called respiratory sinus arrhythmia, RSA) and are widely believed to reflect changes in cardiac autonomic regulation. Although the exact contrib...

GeorgeEBillman

2011-01-01

15

Fetal heart rate monitoring: is it salvageable?  

Science.gov (United States)

Fetal heart rate monitoring was introduced in the 1960s. After a number of randomized controlled trials in the mid 1980s, doubt arose regarding the efficacy of fetal heart rate monitoring in improving fetal outcome. The potential reasons why fetal heart rate monitoring has not been shown to be efficacious are (1) use of an outcome measure that is not related to variant fetal heart rate monitoring patterns, (2) lack of standardized interpretation of fetal heart rate patterns, (3) disagreement regarding algorithms for intervention of specific fetal heart rate patterns, and (4) the inability to demonstrate the reliability, validity, and ability of fetal heart rate monitoring to allow timely intervention. A recent National Institutes of Health committee proposed detailed, quantitative, standardized definitions of fetal heart rate patterns, which can serve as a basis for determining whether fetal heart rate monitoring is reliable and valid. In this article we examine reasons why fetal heart rate monitoring did not live up to its original expectations and why the randomized controlled trials did not demonstrate efficacy, and we make suggestions for determining whether electronic fetal heart rate monitoring should be abandoned. PMID:10764485

Parer, J T; King, T

2000-04-01

16

Reduced intrinsic heart rate is associated with reduced arrhythmic susceptibility in guinea-pig heart.  

Science.gov (United States)

Abstract Objectives. In the clinical setting, patients with slower resting heart rate are less prone to cardiovascular death compared with those with elevated heart rate. However, electrophysiological adaptations associated with reduced cardiac rhythm have not been thoroughly explored. In this study, relationships between intrinsic heart rate and arrhythmic susceptibility were examined by assessments of action potential duration (APD) rate adaptation and inducibility of repolarization alternans in sinoatrial node (SAN)-driven and atrioventricular (AV)-blocked guinea-pig hearts perfused with Langendorff apparatus. Design. Electrocardiograms, epicardial monophasic action potentials, and effective refractory periods (ERP) were assessed in normokalemic and hypokalemic conditions. Results. Slower basal heart rate in AV-blocked hearts was associated with prolonged ventricular repolarization during spontaneous beating, and with attenuated APD shortening at increased cardiac activation rates during dynamic pacing, when compared with SAN-driven hearts. During hypokalemic perfusion, the inducibility of repolarization alternans and tachyarrhythmia by rapid pacing was found to be lower in AV-blocked hearts. This difference was ascribed to prolonged ERP in the setting of reduced basal heart rate, which prevented ventricular capture at critically short pacing intervals required to induce arrhythmia. Conclusions. Reduced basal heart rate is associated with electrophysiological changes that prevent electrical instability upon an abrupt cardiac acceleration. PMID:25334079

Osadchii, Oleg E

2014-12-01

17

Periodic heart rate decelerations in premature infants  

OpenAIRE

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 abou...

Flower, Abigail A.; Moorman, J. Randall; Lake, Douglas E.; Delos, John B.

2010-01-01

18

Scale Invariant Properties in Heart Rate Signals  

Science.gov (United States)

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.

Makowiec, D.; Dudkowska, A.; Zwierz, M.; Galaska, R.; Rynkiewicz, A.

2006-05-01

19

Phase asymmetry of heart rate variability signal.  

Science.gov (United States)

Heart rate asymmetry (HRA) is considered as a physiological phenomenon in healthy subjects. In this article, we propose a novel HRA index, Slope Index (SI), to quantify phase asymmetry of heart rate variability (HRV) system. We assessed the performance of proposed index in comparison with conventional (Guzik's Index (GI) and Porta's Index (PI)) HRA indices. As illustrative examples, we used two case studies: (i) differentiate physiologic RR series from synthetic RR series; and (ii) discriminate arrhythmia subjects from Healthy using beat-to-beat heart rate time series. The results showed that SI is a superior parameter than GI and PI for both case studies with maximum ROC area of 0.84 and 0.82 respectively. In contrast, GI and PI had ROC areas {0.78, 0.61} and {0.50, 0.56} in two case studies respectively. We also performed surrogate analysis to show that phase asymmetry is caused by a physiologic phenomena rather than a random nature of the signal. In conclusion, quantification of phase asymmetry of HRV provides additional information on HRA, which might have a potential clinical use to discriminate pathological HRV in future. PMID:25585603

Karmakar, C K; Khandoker, Ah; Palaniswami, M

2015-02-01

20

Heart rate monitors: state of the art.  

Science.gov (United States)

Heart rate is a useful indicator of physiological adaptation and intensity of effort. Therefore, heart rate monitoring is an important component of cardiovascular fitness assessment and training programmes. The electrocardiogram (ECG) and Holter monitoring devices are accurate, but they are not appropriate for use in field settings due to cost, size and complexity of operation. Lightweight telemetric heart rate monitors equipped with conventional electrodes have been available since 1983 and have been shown to be accurate and valid tools for heart rate monitoring and registering in the field. Polar Electro Oy has been at the forefront of ambulatory heart rate monitor technology for 15 years. This paper reviews the development of Polar heart rate monitors and their measurement accuracy compared to Holter ECG devices at rest and during exercise, both in adults and in children. PMID:22587712

Laukkanen, R M; Virtanen, P K

1998-01-01

21

Heart rate reduction and longevity in mice.  

Science.gov (United States)

Heart rate correlates inversely with life span across all species, including humans. In patients with cardiovascular disease, higher heart rate is associated with increased mortality, and such patients benefit from pharmacological heart rate reduction. However, cause-and-effect relationships between heart rate and longevity, notably in healthy individuals, are not established. We therefore prospectively studied the effects of a life-long pharmacological heart rate reduction on longevity in mice. We hypothesized, that the total number of cardiac cycles is constant, and that a 15 % heart rate reduction might translate into a 15 % increase in life span. C57BL6/J mice received either placebo or ivabradine at a dose of 50 mg/kg/day in drinking water from 12 weeks to death. Heart rate and body weight were monitored. Autopsy was performed on all non-autolytic cadavers, and parenchymal organs were evaluated macroscopically. Ivabradine reduced heart rate by 14 % (median, interquartile range 12-15 %) throughout life, and median life span was increased by 6.2 % (p = 0.01). Body weight and macroscopic findings were not different between placebo and ivabradine. Life span was not increased to the same extent as heart rate was reduced, but nevertheless significantly prolonged by 6.2 %. PMID:25589054

Gent, Sabine; Kleinbongard, Petra; Dammann, Philip; Neuhäuser, Markus; Heusch, Gerd

2015-03-01

22

Heart rate variability in athletes.  

Science.gov (United States)

This review examines the influence on heart rate variability (HRV) indices in athletes from training status, different types of exercise training, sex and ageing, presented from both cross-sectional and longitudinal studies. The predictability of HRV in over-training, athletic condition and athletic performance is also included. Finally, some recommendations concerning the application of HRV methods in athletes are made.The cardiovascular system is mostly controlled by autonomic regulation through the activity of sympathetic and parasympathetic pathways of the autonomic nervous system. Analysis of HRV permits insight in this control mechanism. It can easily be determined from ECG recordings, resulting in time series (RR-intervals) that are usually analysed in time and frequency domains. As a first approach, it can be assumed that power in different frequency bands corresponds to activity of sympathetic (0.04-0.15 Hz) and parasympathetic (0.15-0.4 Hz) nerves. However, other mechanisms (and feedback loops) are also at work, especially in the low frequency band. During dynamic exercise, it is generally assumed that heart rate increases due to both a parasympathetic withdrawal and an augmented sympathetic activity. However, because some authors disagree with the former statement and the fact that during exercise there is also a technical problem related to the non-stationary signals, a critical look at interpretation of results is needed. It is strongly suggested that, when presenting reports on HRV studies related to exercise physiology in general or concerned with athletes, a detailed description should be provided on analysis methods, as well as concerning population, and training schedule, intensity and duration. Most studies concern relatively small numbers of study participants, diminishing the power of statistics. Therefore, multicentre studies would be preferable. In order to further develop this fascinating research field, we advocate prospective, randomised, controlled, long-term studies using validated measurement methods. Finally, there is a strong need for basic research on the nature of the control and regulating mechanism exerted by the autonomic nervous system on cardiovascular function in athletes, preferably with a multidisciplinary approach between cardiologists, exercise physiologists, pulmonary physiologists, coaches and biomedical engineers. PMID:12974657

Aubert, André E; Seps, Bert; Beckers, Frank

2003-01-01

23

Effect of Yoga Therapy on Heart Rate, Blood Pressure and Cardiac Autonomic Function in Heart Failure  

Science.gov (United States)

Background and Objective: It is well known that a hall mark of heart failure is adverse changes in autonomic function. Elevated blood pressure is a powerful predictor of congestive heart failure and other Cardiovascular Disease (CVD) outcomes. In this study, we planned to examine the effects of a 12 week yoga therapy on blood pressure, heart rate, heart rate variability, and rate pressure product (RPP). Methods: Out of 130 heart failure patients recruited for the study, 65 patients were randomly selected to receive 12 week yoga therapy along with standard medical therapy (yoga group). Other patients (n=65) received only standard medical therapy (control group). Heart rate, blood pressure, cardiac autonomic function (by short-term heart-rate variability analysis) and myocardial oxygen consumption (by RPP) were assessed before and after 12 weeks. In the yoga group, 44 patients and in the control group, 48 patients completed the study. Results: There was a significant decrease in heart rate, blood pressure and RPP in yoga group compared to control group. Also, LFnu and LF-HF ratio decreased significantly and HFnu increased significantly in yoga group compared to control group. Conclusion: Twelve-week yoga therapy significantly improved the parasympathetic activity and decreased the sympathetic activity in heart failure patients (NYHA I&II) PMID:24596712

Krishna, Bandi Hari; Pal, Pravati; G.K., Pal; J., Balachander; E., Jayasettiaseelon; Y, Sreekanth; M.G., Sridhar; G.S., Gaur

2014-01-01

24

Heart Rates of Elite Synchronized Swimmers.  

Science.gov (United States)

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)

Gemma, Karen Erickson; Wells, Christine L.

1987-01-01

25

A stochastic model for heart rate fluctuations  

CERN Document Server

Normal human heart rate shows complex fluctuations in time, which is natural, since heart rate is controlled by a large number of different feedback control loops. These unpredictable fluctuations have been shown to display fractal dynamics, long-term correlations, and 1/f noise. These characterizations are statistical and they have been widely studied and used, but much less is known about the detailed time evolution (dynamics) of the heart rate control mechanism. Here we show that a simple one-dimensional Langevin-type stochastic difference equation can accurately model the heart rate fluctuations in a time scale from minutes to hours. The model consists of a deterministic nonlinear part and a stochastic part typical to Gaussian noise, and both parts can be directly determined from the measured heart rate data. Studies of 27 healthy subjects reveal that in most cases the deterministic part has a form typically seen in bistable systems: there are two stable fixed points and one unstable one.

Kuusela, T A; Hietarinta, Jarmo; Kuusela, Tom A.; Shepherd, Tony; Hietarinta, Jarmo

2003-01-01

26

Blood Pressure vs. Heart Rate  

Science.gov (United States)

... learn about conditions, treatments and procedures related to heart disease and stroke. Start exploring today ! Related Tools HBP Risk Calculator HBP Trackers Videos Quizzes Animations Resources in Print Follow us on ...

27

Heart Rate Variability in Obstructive Sleep Apnea.  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: Obstructive Sleep Apnea (OSA is characterized by repeated episodes of upper airway obstruction leading to increased airway resistance and respiratory effort, producing oxygen desaturation, hypercapnia and central nervous system arousal. The intermittent hypoxemia and carbon-dioxide retention is responsible for the changes in autonomic and hemodynamic responses to sleep. Heart rate variability (HRV is a marker of autonomic activity and can be analyzed using time-domain and frequency-domain methods. This study was undertaken to compare the HRV in patients with Obstructed Sleep Apnoea Syndrome (OSAS and normal subjects. Methods: Heart rate variability in 30 controls (Group I and 30 patients with Obstructive Sleep Apnea Syndrome (Group II aged 35-45 yrs was studied by using electrocardiographic data obtained during Polysomnography. Low frequency (LF power, High frequency (HF power and Low frequency/ High frequency ratio (LF/HF were analyzed using frequency-domain analysis. Results: There was a significant difference (p Conclusion: In our study, there was evidence of increased Sympathetic activity and a Parasympathetic attenuation in patients with Obstructive Sleep Apnea. Further studies can evaluate the usefulness of HRV indices for the non-invasive screening of asymptomatic patients suspected to have OSAS.

Selvakumar Jagannathan

2013-07-01

28

Atrioventricular block during fetal heart rate decelerations.  

OpenAIRE

Electrocardiograms (ECG) was examined in 15 fetuses during fetal heart rate decelerations in labour. Sinus bradycardia was demonstrated in six cases and in two cases inversion of the P wave was seen. In seven cases there was complete dissociation of the P wave from the QRS complex, indicating complete atrioventricular heart block. Many decelerations are vagally mediated, but such cases associated with complete atrioventricular heart block may be due to the effect of hypoxia on the bundle of His.

Mohajer, M. P.; Sahota, D. S.; Reed, N. N.; James, D. K.

1995-01-01

29

Metaiodobenzylguanidine and heart rate variability in heart failure  

Energy Technology Data Exchange (ETDEWEB)

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

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

1998-10-01

30

Erythrocyte sedimentation rate as a marker for coronary heart disease  

Directory of Open Access Journals (Sweden)

Full Text Available Josef YayanDepartment of Internal Medicine, Vinzentius Hospital, Landau, GermanyBackground: Patients with angina pectoris or myocardial infarction frequently present without evidence of cardiac-specific heart enzymes by laboratory analysis or specific pathologic electrocardiogram findings. The current study analyzed the efficacy of the erythrocyte sedimentation rate as an additional potential indicator for coronary heart disease, the aim being to enable quicker identification of patients with angina pectoris or myocardial infarction so that they can be more rapidly treated.Methods: Patients with angina pectoris or myocardial infarction who had undergone a heart catheter examination were included in the study. The diagnosis of acute coronary heart disease was made by the physician who performed coronary angiography. Patients without coronary heart disease were used as a control group. The erythrocyte sedimentation rate was measured in all patients. Patients with angina pectoris or myocardial infarction and an inflammatory or tumor disease were excluded.Results: The erythrocyte sedimentation rate was prolonged in 79 (58.09% of 136 patients; 69 (50.74% patients (95% confidence interval ±8.4%, 42.34%–59.14% had coronary heart disease and a prolonged erythrocyte sedimentation rate. The erythrocyte sedimentation rate was prolonged in ten (7.35% patients (95% confidence interval ±4.39%, 2.96%–11.74% without coronary heart disease by coronary angiography. The specificity of the erythrocyte sedimentation rate for coronary heart disease was 70.59% and the sensitivity was 67.65%.Conclusion: Erythrocyte sedimentation rate may be a useful additional diagnostic criterion for coronary heart disease.Keywords: erythrocyte sedimentation rate, coronary heart disease, myocardial infarction, coronary angiography

Yayan J

2012-04-01

31

Heart rate recovery after exercise: relations to heart rate variability and complexity  

OpenAIRE

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. He...

Javorka M.; Zila I.; Balhárek T.; Javorka K

2002-01-01

32

Interdependence of parameters of varia-tional pulsometry, entropy of heart rate, temporal and spectral analyses of heart rate variability in normal state and in ischemic heart disease  

Directory of Open Access Journals (Sweden)

Full Text Available The research goal is to study the correlation between indices of variational pulsometry, entropy of heart rate, temporal and spectral analyses and heart rate variability in healthy patients and patients with coronary heart disease. Materials. Of the study are indicators of variational pulsometry and temporal and spectral analyses from 111 patients with coronary heart disease and in 61 healthy individuals. Results. Most parameters of HRV correlated with each other. In healthy patients the greatest independence was characterized by Mo and LF/HF, in patients with coronary artery disease — only by LF/HF Significant correlation with SDNN RMSSD, TP, LF, HF was determined. Conclusion. The variational pulsometry, temporal and spectral analyses of HRV and entropy of heart rate provide HRV assessment. The indices are interdependent and indicate interchangeability of methods

Durnova N.Yu.

2011-09-01

33

The relationship between phase and heart rate  

International Nuclear Information System (INIS)

The Fourier phase image is used in rest and stress radionuclide angiocardiography to assess the timing of ventricular wall motion in a regional fashion, and areas of high phase are taken to reprensent areas of delayed contraction. However, phase increases with heart rate and this can make interpretation difficult. This study investigates the relationship between phase and heart rate. A heterogenous group of 43 subjects was studied by ECG-gated equilibrium radionuclide angiocardiography, all of the subjects having normal extent of left ventricular wall motion as judged by normal ejection fraction and normal amplitude image. Mean left ventricular phase correlated well with mean time of end systole (r=0.92), but there was no correlation with time of end diastole.Thus phase reflects the time of end systole as a proportion of cycle length and should be linearly related to heart rate provided the duration of systole is unchanged. In 28 normal subjects mean left ventricular phase correlated linearly with resting rate (r=0.91), and when exercised the relationship was maintained up to 90 beats per minute. Above this rate the increases were less marked as the duration of systole shortened. The same was true in 4 subjects paced at different rates. Mean resting heart rate in the normal subjects was 70 beats per minute and correcting phase linearly to rate 70 did not change mean left ventricular phase but did decrease the standard deviation from 18 degree to 12 degree. It is concln from 18 degree to 12 degree. It is concluded that correcting phase for heart rate below 90 beats per minute will increase the sensitivity of the phase image to abnormalities of the timing of ventricular contraction. This correction should be appropriate in resting, isometric exercise, and cold pressor studies but because of the higher heart rates involved will not be appropriate for bicycle exercise. (Author)

34

Heart Rate Variability - A Historical Perspective  

Directory of Open Access Journals (Sweden)

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

GeorgeEBillman

2011-11-01

35

Heart rate variability in assessment of clinical status, functional conditions and prognosis in heart failure  

OpenAIRE

Data about heart rate variability analysis in healthy people and patients with chronic heart failure are reviewed. Prognostic value of time-domain and spectral measures is mentioned. Influence of standard therapy on heart rate variability is described.

Vasyuk, Y. A.; Shupenina, E. Y.; Yuschuk, ?. N.; Serova, ?. ?.

2006-01-01

36

Heart Rate Variability Analysis in General Medicine  

Directory of Open Access Journals (Sweden)

Full Text Available Autonomic nervous system plays an integral role in homeostasis. Autonomic modulation can frequently be altered in patients with cardiac disorders as well as in patients with other critical illnesses or injuries. Assessment of heart rate variability is based on analysis of consecutive normal R-R intervals and may provide quantitative information on the modulation of cardiac vagal and sympathetic nerve input. The hypothesis that depressed heart rate variability may occur over a broad range of illness and injury, and may inversely correlated with disease severity and outcome has been tested in various clinical settings over the last decade. This article reviews recent literature concerning the potential clinical implications and limitations of heart rate variability assessment in general medicine.

Yi Gang

2003-01-01

37

Heart rate dynamics during a treadmill cardiopulmonary exercise test in optimized beta-blocked heart failure patients  

Directory of Open Access Journals (Sweden)

Full Text Available BACKGROUND: Calculating the maximum heart rate for age is one method to characterize the maximum effort of an individual. Although this method is commonly used, little is known about heart rate dynamics in optimized beta-blocked heart failure patients. AIM: The aim of this study was to evaluate heart rate dynamics (basal, peak and % heart rate increase in optimized beta-blocked heart failure patients compared to sedentary, normal individuals (controls during a treadmill cardiopulmonary exercise test. METHODS: Twenty-five heart failure patients (49±11 years, 76% male, with an average LVEF of 30±7%, and fourteen controls were included in the study. Patients with atrial fibrillation, a pacemaker or noncardiovascular functional limitations or whose drug therapy was not optimized were excluded. Optimization was considered to be 50 mg/day or more of carvedilol, with a basal heart rate between 50 to 60 bpm that was maintained for 3 months. RESULTS: Basal heart rate was lower in heart failure patients (57±3 bpm compared to controls (89±14 bpm; p<0.0001. Similarly, the peak heart rate (% maximum predicted for age was lower in HF patients (65.4±11.1% compared to controls (98.6±2.2; p<0.0001. Maximum respiratory exchange ratio did not differ between the groups (1.2±0.5 for controls and 1.15±1 for heart failure patients; p=0.42. All controls reached the maximum heart rate for their age, while no patients in the heart failure group reached the maximum. Moreover, the % increase of heart rate from rest to peak exercise between heart failure (48±9% and control (53±8% was not different (p=0.157. CONCLUSION: No patient in the heart failure group reached the maximum heart rate for their age during a treadmill cardiopulmonary exercise test, despite the fact that the percentage increase of heart rate was similar to sedentary normal subjects. A heart rate increase in optimized beta-blocked heart failure patients during cardiopulmonary exercise test over 65% of the maximum age-adjusted value should be considered an effort near the maximum. This information may be useful in rehabilitation programs and ischemic tests, although further studies are required.

Vitor Oliveira Carvalho

2008-01-01

38

Heart rate variability and its relation to ventricular arrhythmias in congestive heart failure.  

OpenAIRE

BACKGROUND--It has been shown that heart rate variability is decreased in patients with congestive heart failure and that depressed heart rate variability is associated with a propensity to ventricular arrhythmias. Little is known, however, about heart rate variability in patients with both congestive heart failure and ventricular arrhythmias. METHODS--Spectral heart rate variability was analysed from 24 hour ambulatory electrocardiograms in 15 controls, 15 patients with non-sustained ventric...

Fei, L.; Keeling, P. J.; Gill, J. S.; Bashir, Y.; Statters, D. J.; Poloniecki, J.; Mckenna, W. J.; Camm, A. J.

1994-01-01

39

Music determines heart rate variability of singers  

OpenAIRE

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 bel...

RebeckaJörnsten; BjörnVickhoff; HelgeMalmgren; RickardÅström; GunnarNyberg; MathiasEngvall; JohanSnygg; MichaelNilsson

2013-01-01

40

Lessons from the Heart: Individualizing Physical Education with Heart Rate Monitors.  

Science.gov (United States)

Learning about the relationship between heart rate and physical activity is an important aspect of fitness education. Use of a heart rate monitor (HRM) helps a student to understand how stretching and large muscle movements gradually increase the heart rate and blood flow, and enables students to measure their exercise heart rates and set goals…

Kirkpatrick, Beth; Birnbaum, Burton H.

41

A Novel Thermal Measurement for Heart Rate  

Directory of Open Access Journals (Sweden)

Full Text Available Heart rate is an important indicator for the mental and physical state, but it is usually measured through physical contact. In this paper, a novel non-contact method of heart rate measurement has been proposed from the infrared sequence images. First, a square region of interest (ROI was manually selected to cover the temple on the first frame. Then a head movement detection algorithm based on the centroid coordinate change of the extracted skin area was applied to the infrared sequence images, and according to the movement result, the ROI location in subsequent frames could be identified. After that, the distance between the gravity center and the top-left corner in every ROI is computed to get a time-lapse signal. Finally, the discrete wavelet transform and an autoregressive model were used respectively to recognize the heart rate. Fourteen healthy subjects (24-29 years of age, 4 females and 10 males participated in the experiment. Compared with the concomitant ECG, mean accuracy rate of 94.5% was acquired. The results show the potential of our method for non-contact heart rate measurement.

Bin Jing

2013-09-01

42

Wireless monitoring of Heart Rate using Microcontroller  

Directory of Open Access Journals (Sweden)

Full Text Available This paper describes the development of wireless monitoring of a heart rate based on a microcontroller. We can record the ECG signals and Heart beats of all patients in a single computer. These biomedical signals are acquired and then processed with a microcontroller. After processing, all data are sent to a communication interface that can send this information to a personal computer. For the patient suffering from the cardiac disease it is very necessary to perform accurate and quick diagnosis. For this purpose a continuous monitoring of the ECG signal, patient’s current heart rate and BP are essential. We can monitor the patient’s ECG signal by using Bluetooth transmission and reception in the central place in any hospital. The MATLAB software is used to simulate the ECG waveform.

J.S. Prasath

2013-02-01

43

Fetal Heart Rate Monitoring during Labor  

Science.gov (United States)

... the baby’s heartbeat (called the fetal heart rate tracing) at set times. The tracing may be reviewed more frequently if problems arise. ... canal during delivery. If you have further questions, contact your obstetrician–gynecologist. FAQ015: Designed as an aid ...

44

Music determines heart rate variability of singers  

Directory of Open Access Journals (Sweden)

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.

RebeckaJörnsten

2013-07-01

45

Effect of endotoxemia on heart rate dynamics in rat isolated perfused hearts  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: Beat-to-beat variation in heart rate shows a complex dynamics, and this complexity is changed during systemic inflammatory response syndrome (e.g. sepsis. It is not known whether or not cardiac pacemaker dynamical rhythm is affected by sepsis. The aim of this study was to investigate heart rate dynamics of isolated heart as well as expression of pacemaker channels (HCN in a rat model of sepsis (endotoxemia compared with normal rats. Methods: Male rats weighing 250-300 g were used in this study. Bacterial lipopolysaccharide was injected intraperitoneally (1mg/kg in the endotoxemia group, and sterile saline in the control group. Three hours after injection, cardiac tissues were isolated and studied using Langendorff apparatus. Heart rate dynamics was assessed by calculating the standard deviation of inter-beat intervals as well as detrended fluctuation analysis (DFA. Quantitative RT-PCR was used to assess HCN expression in atria. Results: Hypoxia had a significantly different effect on heart rate variability in endotoxemic rats compared with controls (P<0.05. DFA analysis showed a linear relationship between logarithm of variance and the logarithm of scale in both endotoxemic and control rats. Atrial expression of HCN1 and HCN2 at mRNA level were significantly higher in endotoxemic rats in comparison with controls (P<0.05. Conclusion: Spontaneous beatings of isolated hearts exhibit a fractal-like dynamics which did not change after global hypoxia and/or endotoxemia. Endotoxemia was associated with altered heart rate variability and increased expression of pacemaker channels that might play a role in pathophysiology of cardiac complications of sepsis.

Mohammad Karim Azadbakht

2013-03-01

46

Streaming updates for heart rate variability algorithms.  

Science.gov (United States)

Heart rate variability (HRV) quantifies the fluctuations of the lengths of consecutive heart beat intervals, and is a reliable descriptor of many physiological factors modulating the normal rhythm of the heart. As the heart rate signal is nonstationary, indicators deduced from it may be present at all times, but may also occur episodically at nonpredetermined time instances. The potential for real-time feedback long-term ambulatory recordings is thus apparent. Numerous methods for measuring HRV have been standardized and are in active use, but are typically not designed to operate at real time. In this paper, we study the most popular HRV quantification methods and propose streaming algorithms that maximally utilize previously computed information without altering the output of the methods. We demonstrate speedups of more than two orders of magnitude for typical use-case scenarios. Using our algorithms on embedded systems that compute HRV leads to dramatic decreases in power consumption and in some cases allows for computation of metrics that were not previously possible at real time. PMID:24956611

Stergiou, Stergios; Balakrishnan, Rajalakshmi

2014-07-01

47

Effects of aerobic training on heart rate  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Regular physical exercise is an important factor to reduce the indexes of cardiovascular and all causes morbimortality. However, there is, apparently, additional and independent benefits of the regular practice of physical exercise and the improvement of the level of aerobic condition. Heart rate (H [...] R) is mediated primarily by the direct activity of the autonomic nervous system (ANS), specifically through the sympathetic and parasympathetic branches activities over the sinus node autorhythmicity, with predominance of the vagal activity (parasympathetic) at rest, that is progressively inhibited since the onset of the exercise. The HR behavior has been widely studied during different conditions and protocols associated to the exercise. A reduction of the cardiac vagal tone (parasympathetic function) and consequently a diminished HR variability in rest, independently of the protocol of measurement used, is related to an autonomic dysfunction, chronic-degenerative diseases and increased mortality risk. Individuals with high levels of aerobic condition have a lower resting HR, along with a larger parasympathetic activity or smaller sympathetic activity, but it is not necessarily a direct consequence of the exercise training, as long as other inherent adaptations to the aerobic conditioning can influence the resting HR. The HR response in the onset of the exercise represents the integrity of the vagus nerve, and the HR recovery on the post-exercise transient also denotes important prognostic information; by the way, individuals that have a slow HR recovery in the first minute post-exercise have increased mortality risk. In conclusion, the physiological mechanisms modulating HR during or after an exercise program are not totally clear, and further studies are needed.

Marcos B., Almeida; Claudio Gil S., Araújo.

2003-04-01

48

Fetal heart rate classification using generative models.  

Science.gov (United States)

This paper presents novel methods for classification of fetal heart rate (FHR) signals into categories that are meaningful for clinical implementation. They are based on generative models (GMs) and Bayesian theory. Instead of using scalar features that summarize information obtained from long-duration data, the models allow for explicit use of feature sequences derived from local patterns of FHR evolution. We compare our methods with a deterministic expert system for classification and with a support vector machine approach that relies on system-identification and heart rate variability features. We tested the classifiers on 83 retrospectively collected FHR records, with the gold-standard true diagnosis defined using umbilical cord pH values. We found that our methods consistently performed as well as or better than these, suggesting that the use of GMs and the Bayesian paradigm can bring significant improvement to automatic FHR classification approaches. PMID:24951678

Dash, Shishir; Quirk, J Gerald; Djuri?, Petar M

2014-11-01

49

Highly comparative fetal heart rate analysis  

OpenAIRE

A database of fetal heart rate (FHR) time series measured from 7221 patients during labor is analyzed with the aim of learning the types of features of these recordings that are informative of low cord pH. Our 'highly comparative' analysis involves extracting over 9000 time-series analysis features from each FHR time series, including measures of autocorrelation, entropy, distribution, and various model fits. This diverse collection of features was developed in previous work...

Fulcher, B. D.; Georgieva, A. E.; Redman, C. W. G.; Jones, Nick S.

2014-01-01

50

Validity of computerized fetal heart rate monitoring  

OpenAIRE

This work is focused on the validity of computerized fetal heart rate monitoring. Therefor, subpartual cardiotocograms (CTGs) were retrospectively analysed by the classification program „Trium CTG Online“ and these results, basing on the FIGO Score, were compared to the temporal corresponding fetal pH values. Short term variation (STV) and every single component of the FIGO Score was also correlated with the fetal pH values. The collektive consists of 263 births in the Frauenklinik Rechts...

Thieme, Andrea

2008-01-01

51

Heart rate and heart rate variability in dogs with different degrees of myxomatous mitral valve disease  

DEFF Research Database (Denmark)

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 electrocardiography is seen in dogs with heart failure (HF) secondary to myxomatous mitral valve disease (MMVD). However, HRV is suggested to increase with disease severity at early stages of MMVD. The aims of this study were 1) to associate HR and HRV with severity of MMVD in Cavalier King Charles Spaniels (CKCS) and 2) to compare HR and HRV between CKCS and other dog breeds in a group of dogs in HF secondary toMMVD. One-hundred dogs were examined by echocardiography and 24-hour electrocardiography. The dogs were divided into five groups: 1) CKCS with no/minimal mitral regurgitation (MR) (MR jet=15% of the left atrial area using color Doppler mapping) and no murmur, 2) CKCS with mild MR (20%50%) and no clinical signs of HF, 4) CKCS in HF (HF defined as left atrium to aortic root ratio (LA/Ao) >1.5, clinical signs of HF and furosemide responsiveness) and 5) non-CKCS in HF. Dogs in HF were allowed HF therapy. Both HR and HRV were analysed over a 24-hour period, while HRV were also analysed over a 6-hour nightly period. Analyses of variance were performed with HR or HRV as response variables and the explanatory variables dog group and echocardiographic indices of MMVD were included separately. All P-values were Bonferroni corrected. Minimum- and mean HR were significantly higher in CKCS with moderate/severe MR and in HF compared to CKCS with no/minimal and mild MR (all P<0.001). Seven out of 26 HRV variables were significantly decreased in CKCS with 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 HR and the HRV variables (7 and 10) differing between dog groups, also consistently decreased with increasing MR, LA/Ao and the proximal isovelocity surface area in CKCS. Non-CKCS in HF had a lower minimum HR compared to CKCS in HF (P=0.03) and a higher triangular index measured in both periods (all P<0.04). In conclusion, HR increased and most HRV variables decreased with increasing severity of MMVD in CKCS, even prior to the development of HF. Other breeds in HF secondary to MMVD had lower minimum HR, but higher triangular index compared to CKCS in HF.

Rasmussen, Caroline Elisabeth; Falk, Bo Torkel

2011-01-01

52

Doppler Radar for Heartbeat Rate and Heart Rate Variability Extraction  

OpenAIRE

This paper presents a Doppler radar system used to detect the heartbeat signal from a d?istance of one meter. The proposed system is based on using a vector network analyzer and two antennas. Measurements are performed at 16 GHz for different power levels between 0 and -25 dBm. Both heartbeat rate and heart rate variability are extracted and compared to a simultaneous ECG signal.

Obeid, Dany; Sadek, Sawsan; Zaharia, Gheorghe; El Zein, Ghai?s

2011-01-01

53

Time Domain Measures Of Heart Rate Variability In Heavy Workers  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Physical inactivity and low resting heart rate variability (HRV are associated with increased incidence of coronary heart disease. Heavy physical activity is associated with higher heart rate variability and reduces the risk of coronary heart diseaseObjective: To assess some time domain measures of HRV in order to compare Cardiac Autonomic Function between sedentary and heavy workers.Methods: This cross sectional study was carried out in the Department of Physiology, Bangabandhu Sheikh Mujib Medical University between 1st July 2008 to 30th June 2009 on 30 apparently healthy heavy workers aged 28-50 years from low socioeconomic condition (study group. For comparison 30 age, sex, BMI and socioeconomic status matched apparently healthy sedentary subjects (group A were also studied. The study subjects were selected among rickshaw-pullers living in the slum areas nearby BSMMU, Dhaka and the controls were from fourth class employee of BSMMU, Dhaka. Heart Rate Variability were assessed by a Polygraph. Several time domain measures of HRV such as mean R-R interval, mean HR, SDNN, RMSSD were analyzed. For statistical analysis, Independent-Samples t-test, and Pearson’s correlation coefficient tests were done as applicable.Results: Resting mean heart rate (P<0.01, SDNN (P<0.01 and RMSSD (P<0.001 were significantly lower but mean R-R interval (P<0.001 was significantly higher in heavy workers than those of sedentary control. The mean R-R interval (P<0.05 showed significant positive correlation in heavy workers but significant negative correlation in sedentary workers with BMI.Conclusion: Cardiac autonomic nerve function status may be higher with parasympathetic dominance by increased physical activity.

Taskina Ali

2011-12-01

54

Intermittency in Human Heart Rate Variability  

International Nuclear Information System (INIS)

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)

55

The influence of respiratory pattern on heart rate variability analysis in heart failure  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction. Autonomic dysfunction is present early in the course of heart failure, and has a direct role on deterioration of cardiac function and prognosis. Heart rate variability (HRV estimates sympathovagal control of heart frequency. The influence of respiratory pattern on HRV is clinically important. Breathing disorders are common in heart failure and highly affect HRV and autonomic evaluation. It was previously shown that slow and deep breathing increased parasympathetic tone, but effects of this respiratory pattern on HRV were not evaluated. Objective. The aim of the study was to estimate effects of slow and deep breathing (SDB on HRV in heart failure patients. Method. In 55 patients with heart failure (78% male, mean age 57.18±10.8 yrs, mean EF=34.12±10.01% and 14 healthy controls (57.1% male, mean age 53.1±8.2 yrs, short term HRV spectral analysis was performed (Cardiovit AT 60, Schiller. VLF, LF, HF and LF/HF were determined during spontaneous and deep and slow breathing at 0.1 Hz (SDB. Results. LF, HF and LF/HF significantly increased during SDB compared with spontaneous breathing both in controls (LF 50.71±61.55 vs. 551.14±698.01 ms2, p<0.001; HF 31.42±29.98 vs.188.78±142.74 ms2, p<0.001 and LF/HF 1.46±0.61 vs. 4.21±3.23, p=0.025 and heart failure patients (LF 27.37±36.04 vs. 94.50±96.13 ms2, p<0.001; HF 12.13±19.75 vs. 41.58±64.02 ms2, p<0.001 and LF/HF 3.77±3.79 vs. 6.38±5.98, p=0.031. Increments of LF and HF induced by SDB were significantly lower in patients than healthy controls. Heart failure patients had lower HRV compared to healthy controls both during spontaneous breathing and SDB. During spontaneous breathing, only HF was significantly lower between healthy controls and patients (p=0.002. During SDB VLF (p=0.022, LF (p<0.001 and HF (p<0.001 were significantly lower in heart failure patients compared to controls. Conclusion. These data suggest that SDB increases HRV both in healthy and heart failure patients; the highest increment is in LF range. Differences in spectral profile of HRV between healthy controls and heart failure patients become more profound during SDB. Controlled respiration during HRV analysis might increase sensitivity and reliability in detection of autonomic dysfunction in heart failure patients. .

Zamaklar-Trifunovi? Danijela

2007-01-01

56

Heart Rate Responses During Singles and Doubles Tennis Competition.  

Science.gov (United States)

Monitoring of heart rates of 17 adult male tennis players during singles and doubles competition revealed that subjects playing singles games reached an average of 61 percent of their maximal heart rate, while, in doubles competition, they reached only 33 percent of maximal heart rate. (Author/CB)

Morgans, Leland F.; And Others

1987-01-01

57

Impaired heart rate recovery indices in psoriasis patients  

Science.gov (United States)

Background Psoriasis is a systemic inflammatory disease associated with increased risk of cardiovascular diseases. The heart rate recovery index (HRRI) is an indicator of autonomic nervous system function and is an independent prognostic risk factor for cardiovascular diseases. The aim of this study was to evaluate the heart rate recovery indices in patients with psoriasis. Material/methods Thirty-three psoriasis patients (22 male; mean age 41±11 years) and 26 healthy individuals (15 male; mean age 39±11 years) as a control group were included in the study. Baseline electrocardiography, transthoracic echocardiographic examinations, and exercise stress tests were performed in psoriasis and control groups. The heart rate recovery of the psoriasis group at 1, 2, 3, 4, and 5 minutes after maximal exercise were calculated and compared to those of the control group. Results Baseline demographic and clinical characteristics of psoriasis and control groups including age, sex, body mass index, systolic blood pressure, and echocardiographic parameters were similar. Total cholesterol, low-density lipoprotein cholesterol, and triglyceride levels were significantly higher and high-density lipoprotein cholesterol levels were significantly lower in the psoriasis group (p<0.05). Heart rate recovery at 1, 2, 3, 4, and 5 minutes after maximal exercise were found to be significantly lower in the psoriasis group (p<0.05). Additionally, baseline heart rates before exercise were significantly higher in the psoriasis group (p<0.05). Conclusions We found that impaired HRRI in psoriasis patients, which indicates the underlying autonomic nervous system dysfunction, is a pathophysiologic mechanism for increased cardiovascular disease risk. PMID:24584215

Yuksel, Esra Pancar; Yuksel, Serkan; Yenercag, Mustafa; Soylu, Korhan; Aydin, Fatma; Senturk, Nilgun; Yucel, Huriye; Canturk, Tayyar; Turanli, Ahmet Y.

2014-01-01

58

Heart rate awareness in patients with chronic stable heart failure. A multi-center observational study.  

LENUS (Irish Health Repository)

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.

Moran, D

2014-08-23

59

Heart rate analysis in normal subjects of various age groups  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Analysis of heart rate variation (HRV has become a popular noninvasive tool for assessing the activities of the autonomic nervous system (ANS. HRV analysis is based on the concept that fast fluctuations may specifically reflect changes of sympathetic and vagal activity. It shows that the structure generating the signal is not simply linear, but also involves nonlinear contributions. Linear parameters, Power spectral indice (LF/HF is calculated with nonlinear indices Poincare plot geometry(SD1,SD2, Approximate Entropy (ApEn, Largest Lyapunov Exponent (LLE and Detrended Fluctuation Analysis(DFA. The results show that, with aging the heart rate variability decreases. In this work, the ranges of all linear and nonlinear parameters for four age group normal subjects are presented with an accuracy of more than 89%. As a pre-analysis step, the HRV data is tested for nonlinearity using surrogate data analysis and the results exhibited a significant difference in the ApEn, LLE, SD1/SD2 and DFA parameters of the actual data and the surrogate data. Methods The heart rate is analyzed using the various time domain parameters, frequency domain parameter and nonlinear parameters like Poincare geometry, ApEn, LLE and DFA. Results In this work, the different linear and nonlinear parameters evaluated show a particular range for various cardiac abnormalities. And the results of these were subjected to 't' test with more than 89% confidence interval giving excellent 'p' values in all cases. Conclusions Heart rate variability (HRV signal can be used as a reliable indicator of state of the heart. It becomes less random with the aging(less chaotic. This is evaluated by using various time domain, frequency domain and nonlinear parameters like SD1/SD2, ApEn, LLE ?s and ?l. Different ranges of non-linear parameters for various age groups are presented with 'p' value ? 0.12.

Ping Luk

2004-07-01

60

Gender differences of heart rate variability in healthy volunteers  

International Nuclear Information System (INIS)

Objective: To identify the basic values of heart rate variability in Pakistani population and to verify our hypothesis that there are gender differences in cardiovascular autonomic modulation. Methods: The descriptive cross sectional study based on convenience probability sampling was conducted at Armed Forces Institute of Cardiology/National Institute of Heart Diseases (AFIC/NIHD) Pakistan. The duration of the study was from December 2009 to July 2010. It involved 24-hour holter monitoring of 45 healthy individuals using holter electrocardiography (ECG) recorder. Heart rate variability was analysed in time (SDNN, SDANN, SDNNi, rMSSD, pNN50) and frequency domains (power, VLF, LF, and HF). Results: The time domain indices; SDNN (male=140 +- 36 ms vs. females=122 +- 33 ms; p =0.09), SDANN (male=123 +- 34 ms vs. females=111+- 34 ms; P= 0.23), SDNNi (male=64 +-19 ms vs. females=52 +- 14 ms; P= 0.03), and pNN50 (male=14 +- 10 ms vs. females=12 +- 7 ms; P= 0.43) were decreased in female volunteers when compared with males. Comparison of frequency domain indices; Total power (male=4041 +- 3150 ms/sup 2/ vs. females=2750 +- 1439 ms/sup 2/; P= 0.07), VLF (male=291 2675 ms/sup 2/ vs. females=1843 +- 928 ms/sup 2/; P= 0.06), LF (male=788 +- 397 ms/sup 2/ vs. females=556 +- 346 ms/sup 2/; P= 0.04) and HF (male=318 +- 251 ms/sup 2/ vs. females=31 277 ms/sup 2/; P= 0.94) amongst males and females showed attenuated heart rate variability in females. Of all the observed values, SDNNifemales. Of all the observed values, SDNNi and LF were found significantly (p <0.05) decreased in women. Conclusion: In healthy population, heart rate variability is low in women than men. It reflects sympathetic dominance in women in our population. (author)

61

HEART RATE DURING SLEEP: IMPLICATIONS FOR MONITORING TRAINING STATUS  

Directory of Open Access Journals (Sweden)

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

Miriam R. Waldeck

2003-12-01

62

General anesthesia suppresses normal heart rate variability in humans  

Science.gov (United States)

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.

Matchett, Gerald; Wood, Philip

2014-06-01

63

General anesthesia suppresses normal heart rate variability in humans.  

Science.gov (United States)

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. PMID:24985443

Matchett, Gerald; Wood, Philip

2014-06-01

64

Effect of energy drink dose on exercise capacity, heart rate recovery and heart rate variability after high-intensity exercise  

Science.gov (United States)

[Purpose] The purpose of this research was to investigate the effects of exercise capacity, heart rate recovery and heart rate variability after high-intensity exercise on caffeine concentration of energy drink. [Methods] The volunteers for this study were 15 male university student. 15 subjects were taken basic physical examinations such as height, weight and BMI before the experiment. Primary tests were examined of VO2max per weight of each subjects by graded exercise test using Bruce protocol. Each of five subject was divided 3 groups (CON, ECG?, ECG?) by matched method based on weight and VO2max per weight what gained of primary test for minimize the differences of exercise capacity and ingestion of each groups. For the secondary tests, the groups of subjects were taken their materials before and after exercise as a blind test. After the ingestion, subjects were experimented on exercise test of VO2max 80% by treadmill until the all-out. Heart rate was measured by 1minute interval, and respiratory variables were analyzed VO2, VE, VT, RR and so on by automatic respiratory analyzer. And exercise exhaustion time was determined by stopwatch. Moreover, HRV was measured after exercise and recovery 3 min. [Results] Among the intake groups, ECG? was showed the longest of exercise exhaustion time more than CON group (p = .05). Result of heart rate during exercise according to intake groups, there was significant differences of each time (p .05). Result of RPE during exercise according to intake groups, there was significant differences of each time (p .05). [Conclusion] In conclusion, EDG? showed the significant increase of exercise exhaustion time more than CON group (p=.05) and not significant differences in HR, RPE, RER, HRV, HRR, blood pressure (p > .05). Therefore, 2.5 mg/kg-1 ingestion of energy drink might be positive effect to increase exercise performance capacity without side-effect in cardiovascular disease. PMID:25566437

An, Sang Min; Park, Jong Suk; Kim, Sang Ho

2014-01-01

65

Elevated resting heart rate is associated with the metabolic syndrome  

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Full Text Available Abstract Background Increased resting heart rate (RHR may be associated with increased cardiovascular morbidity. Our aim was to explore the possibility that increased RHR is associated with the prevalence of the metabolic syndrome (MetS in a sample of apparently healthy individuals and those with cardiovascular risk factors. Methods We performed a cross-sectional analysis in a large sample of apparently healthy individuals who attended a general health screening program and agreed to participate in our survey. We analyzed a sample of 7706 individuals (5106 men and 2600 women with 13.2% of men and 8.9% of the women fulfilling the criteria for the MetS. The participants were divided into quintiles of resting heart rate. Multiple adjusted odds ratio was calculated for having the MetS in each quintile compared to the first. Results The multi-adjusted odds for the presence of the MetS increased gradually from an arbitrarily defined figure of 1.0 in the lowest RHR quintile ( Conclusion Raised resting heart rate is significantly associated with the presence of MetS in a group of apparently healthy individuals and those with an atherothrombotic risk. The strength of this association supports the potential presence of one or more shared pathophysiological mechanisms for both RHR and the MetS.

Saar Nili

2009-10-01

66

POSTURAL CHANGES IN HEART RATE AND BLOOD PRESSURE WITH AGEING  

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Full Text Available Introduction: The change in arterial blood pressure and heart rate is one of the generally known physiological changes in aging of man. The present study was intended to evaluate BP and HR changes with age. Aim The objective of the study is to know the prevalence of orthostatic hypotension in healthy geriatric subjects. Materials and Methods: The subjects selected are 120 in number with age group 35 to >65 years of both sex and they are categorized into 4 groups based on their age. Group- I: The age of 35-45 years; Group-II: The age of 45-55 years; Group-III: The age of 55-65 Years; Group-IV: The age of >65 years. Blood Pressure is recorded by using manual sphygmomanometer and orthostatic test was conducted in all the subjects. Heart Rate was calculated by using R-R interval by ECG machine. Results: The examination of parameters, body mass index, Heart Rate, systolic and diastolic Blood Pressure during resting, immediate standing, after three minutes of standing i.e., postural variations were estimated for all subjects. The data was analyzed by using descriptive and inferential statistics. Discussion: The findings suggested that the mean SBP and DBP are higher in Group IV compared to Group I which is statistically highly significant. After immediate standing in all the subjects the SBP is decreased and DBP is increased and this variation is variable in different groups. The Heart Rate in all four Groups increases. And this variation is also variable in different groups. Conclusion: This study concluded that BP increases with increase in age due to stiffening of Blood vessels but the postural decrease in SBP in standing from lying down posture was more in elderly. Orthostatic Hypotension was found in only one elderly. So Orthostatic Hypotension was less prevalent in healthy elderly.

K. Pujitha

2014-11-01

67

Erythropoietin, Heart Disease and Global Rate  

OpenAIRE

In medicine, the relationship between erythropoietin and heart disease is sometimes mentioned. An attempt to demonstrate connection between erythropoietin and heart failure is very interesting. The attempt is based on the interrelationship among erythropoietin disturbance, anemia and heart disorder. However, the factors that can affect the endemic pattern must be considered

Viroj Wiwanitkit

2013-01-01

68

Heart rate variability in mental stress aloud.  

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Previous investigations on arithmetic stress with verbalization showed that spectral measures of heart rate variability (HRV) did not assess changes in autonomic modulation, although the heart rate (HR) increased. In this study non-linear measures of HRV are determined and linear measures are re-examined in order to understand this apparent discrepancy between HR and HRV changes. In 23 healthy subjects 5-min electrocardiograms (ECGs) were recorded at rest and during arithmetic stress aloud. We determined non-linear (short-term scaling exponent, sensitivity to the initial condition and signal complexity) and linear (low-frequency and high-frequency spectral powers) measures. Our results showed that averaging concealed out an opposite effect of mental stress aloud on spectral measures and that this could be the main reason why the effect was not quantified. We found that increase of HR upon mental stress aloud could be achieved through the decreased as well as increased modulation in high-frequency band (HF). We also showed that non-linear measures distinguished this opposite effect of mental stress aloud on linear measures. Decreased HF power is associated with increase in short-term scaling exponent and decrease in signal complexity, while increased HF power increased sensitivity to the initial conditions. Apart from their opposite response to the mental stress, the two groups differed in baseline in sensitivity to the initial conditions. We suggest that variety of changes in HR dynamics upon different perturbation could be due to some differences in intrinsic properties of the system. PMID:16807051

Vuksanovi?, Vesna; Gal, Vera

2007-04-01

69

Discharge heart rate and future events among Japanese patients with acute heart failure receiving beta-blocker therapy  

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Full Text Available Background: Randomized trials have demonstrated the efficacy of beta-blockers (BBs in heart failure (HF patients. We sought to assess the impact of BBs on long-term outcome; in particular, we assessed the association between outcome and BB dose and discharge heart rate. Methods and Results: Prescriptions for dispensed medication and outcomes were identified from a prospective, single-institution HF registry. Long-term prognosis was compared between users and non-users of BBs. BB users were further divided into 2 groups based on dose (full and non-full dose and discharge heart rate (70 bpm was significantly associated with impaired long-term outcome (HR = 1.872, P = 0.04. Conclusions: Optimizing heart rate, rather than maximizing BB dose, appears to be an appropriate treatment strategy for the beta-sensitive Japanese population.

Keiichi Fukuda

2013-03-01

70

Heart dimensions may influence the occurrence of the heart rate deflection point in highly trained cyclists  

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OBJECTIVES: To determine whether the heart rate (HR) response to exercise in 21 highly trained cyclists (mean (SD) age 25 (3) years) was related to their heart dimensions. METHODS: Before performing an incremental exercise test involving a ramp protocol with workload increases of 25 W/min, each subject underwent echocardiographic evaluation of the following variables: left ventricular end diastolic internal diameter (LVIDd), left ventricular posterior wall thickness at end diastole (LVPWTd), interventricular septal wall thickness at end diastole (IVSTd), left ventricular mass index (LVMI), left atrial dimension (LAD), longitudinal left atrial (LLAD) and right atrial (LRAD) dimensions, and the ratio of early to late (E/A) diastolic flow velocity. RESULTS: The HR response showed a deflection point (HRd) at about 85% VO2MAX in 66.7% of subjects (D group; n = 14) and was linear in 33.3% (NoD group; n = 7). Several echocardiographic variables (LVMI, LAD, LLAD, LRAD) indicative of heart dimensions were similar in each group. However, mean LPWTd (p<0.01) and IVSTd (p<0.05) values were significantly higher in the D group. Finally, no significant difference between groups was found with respect to the E/A. CONCLUSIONS: The HR response is curvilinear during incremental exercise in a considerable number of highly trained endurance athletes-that is, top level cyclists. The departure of HR increase from linearity may predominantly occur in athletes with thicker heart walls. ??? PMID:10597846

Lucia, A.; Carvajal, A.; Boraita, A.; Serratosa, L.; Hoyos, J.; Chicharro, J. L.

1999-01-01

71

Computerized fetal heart rate analysis in labor.  

Science.gov (United States)

Observer variation in visual analysis of fetal heart rate (FHR) records is reportedly high, but can be avoided by computerized numerical analysis. The FHRs of 394 women in labor at 37 or more weeks' gestation were recorded on-line and analyzed to examine how different patterns related to outcome, as judged by umbilical arterial base deficit or Apgar score on delivery. The range of normality and the diversity of patterns of those delivered without acidemia were great. Late decelerations were of poor prognostic value. There was an increase in FHR variation during labor averaging 40%. In this preliminary study, conventional attributes of the FHR, alone or in combination, did not predict metabolic acidemia. Epidural analgesia in 240 women was identified as a confounding variable that significantly affected FHR patterns without influencing the condition of the infant at birth. It was associated with a higher FHR, less FHR variation and fewer decelerations, primiparity, longer labors, more operative deliveries, and a threefold greater cesarean rate. The rise in basal FHR, perhaps due to a rise in maternal temperature, may partly explain the high intervention rate in those without fetal acidemia. PMID:1923162

Pello, L C; Rosevear, S K; Dawes, G S; Moulden, M; Redman, C W

1991-10-01

72

Loss of lag-response curvilinearity of indices of heart rate variability in congestive heart failure  

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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.

Smith Michael L

2006-06-01

73

A Smart Cushion for Real-Time Heart Rate Monitoring  

OpenAIRE

This paper presents a smart cushion for real time heart rate monitoring. The cushion comprises of an integrated micro-bending fiber sensor, which records the BCG (Ballistocardiogram) signal without direct skin-electrode contact, and an optical transceiver that does signal amplification, digitization, and pre-filtering. To remove the artifacts and extract heart rate from BCG signal, a computationally efficient heart rate detection algorithm is developed. The system doesn't re...

Deepu, Chacko John; Chen, Zhihao; Teo, Ju Teng; Ng, Soon Huat; Yang, Xiefeng; Lian, Yong

2014-01-01

74

Heart Rate Variability Interventions for Concussion and Rehabilitation  

OpenAIRE

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 ...

RobertLakeConder; AlannaA.Conder

2014-01-01

75

AUTONOMIC CONTROL OF HEART RATE AFTER EXERCISE IN TRAINED WRESTLERS  

OpenAIRE

The objective of this study was to establish differences in vagal reactivation, through heart rate recovery and heart rate variability post exercise, in Brazilian jiu-jitsu wrestlers (BJJW). A total of 18 male athletes were evaluated, ten highly trained (HT) and eight moderately trained (MT), who performed a maximum incremental test. At the end of the exercise, the R-R intervals were recorded during the first minute of recovery. We calculated heart rate recovery (HRR60s), and performed linear...

Henri?quez, Carlos F.; Eduardo Báez; Astrid Von Oetinger; Rodrigo Cañas; Rodrigo Ramírez

2013-01-01

76

Randomised controlled trial of intrapartum fetal heart rate monitoring.  

OpenAIRE

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 ...

Mahomed, K.; Nyoni, R.; Mulambo, T.; Kasule, J.; Jacobus, E.

1994-01-01

77

Temperature to heart rate relationship in the neonate  

OpenAIRE

In neonatal intensive care, measurement of heart rate is part of every clinical examination and it is used for monitoring hemodynamic status. However, it is influenced by some exogenous and endogenous factors, such as medication, pain, and stress. (1) Similarly, an increased heart rate is a normal physiological response to fever. Heart rate is known to increase by 10 beats per minute (bpm) per degree centigrade increase in body temperature in children. (2) In order to allow physicians to iden...

Nora Hofer; Wilhelm Müller; Bernhard Resch

2012-01-01

78

Genetic mapping of a new heart rate QTL on chromosome 8 of spontaneously hypertensive rats  

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Full Text Available Abstract Background Tachycardia is commonly observed in hypertensive patients, predominantly mediated by regulatory mechanisms integrated within the autonomic nervous system. The genetic loci and genes associated with increased heart rate in hypertension, however, have not yet been identified. Methods An F2 intercross of Spontaneously Hypertensive Rats (SHR × Brown Norway (BN linkage analysis of quantitative trait loci mapping was utilized to identify candidate genes associated with an increased heart rate in arterial hypertension. Results Basal heart rate in SHR was higher compared to that of normotensive BN rats (365 ± 3 vs. 314 ± 6 bpm, p Conclusion Our data suggest that an influential genetic region located on the rat chromosome 8 contributes to the regulation of heart rate. Candidate genes that have previously been associated with tachycardia and/or hypertension were found within this QTL, strengthening our hypothesis that these genes are, potentially, associated with the increase in heart rate in a hypertension rat model.

Krieger José E

2007-04-01

79

Heart Rate Variability Analysis in Different Age and Pathological Conditions  

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Full Text Available Problem statement: Heart Rate Variability (HRV has been used as a measure of mortality primarily with patients who had undergone cardiac surgery. The analysis of Heart Rate Variability (HRV demands specific capabilities which are not provided either by parametric or nonparametric conventional estimation methods. The Empirical Mode Decomposition (EMD adaptively estimates the Intrinsic Mode Functions (IMFs of nonlinear nonstationary signals. Approach: The intrinsic mode functions estimated from the HRV signal were based on local characteristics of the signal. The principle objective was to analyze the HRV latencies of healthy subjects in different age and pathological conditions. The method was applied to HRV signal of 17 healthy young control subjects, 17 healthy old control subjects and 20 congestive heart failure patients for half hour duration. Results: The results showed that a healthy person?s HRV rapidly rises to its maximum response much earlier than the HRV of pathological subjects. The rising slope of the time scale?s plot discriminates the healthy controls and pathological subjects with 100% sensitivity and specificity. Conclusion: This fact makes the method a promising approach to be applied in clinical practice as a screening test for specific risk-groups.

M. E.S. Chelladurai

2011-01-01

80

Heart rate turbulence and variability in patients with ventricular arrhythmias  

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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

Diego Tarricone

2009-08-01

81

The effect of exercise and heart rate on fibrinolytic activity.  

OpenAIRE

The effect of heart rate on plasma fibrinolytic activity was investigated in nine patients with dual chamber cardiac pacemakers before and after 10 min of stimulated tachycardia to 123 beats/min. The results were compared to seven volunteers who performed submaximal exercise to 90% target heart rate and to five of the seven who underwent a second period of exercise to a heart rate of 120 beats/min. During submaximal exercise (mean heart rate 152 beats/min) the median ECLT fell from 248 min (i...

Gough, Sc; Whitworth, S.; Rice, Pj; Grant, Pj

1992-01-01

82

Dissociation of heart rate variability and heart rate recovery in well-trained athletes.  

Science.gov (United States)

The purpose of this investigation was to examine the relationships between aerobic fitness, volume of physical activity (PA), heart rate variability (HRV), and heart rate recovery (HRR) in a group of well-trained endurance athletes. Nineteen endurance athletes participated in this study and had aerobic capacities that placed them above the 99th percentile based on normative values (VO(2max): 67.1 ± 2 ml kg(-1) min(-1)). HRV was obtained via an EKG collected during supine rest and reported as high-frequency (HF), low-frequency (LF), and total power (TP). Natural log (ln) transformation was applied when variables violated assumptions of normality. HRR recovery was reported as the reduction in heart rate from peak exercise to the heart rate 1 min after cessation of exercise and PA was estimated from a questionnaire. HRR was significantly correlated with PA and VO(2max) (r = 0.67, P = 0.003 and 0.51, P = 0.039, respectively), but not with any index of HRV. Age was significantly correlated with lnHF (r = -0.49, P = 0.033), lnLF/lnHF (r = 0.48, P = 0.037), and normalized units (NU) of LF (r = 0.47, P = 0.042) and HF (r = -0.47, P = 0.042). Stepwise regression revealed that the strongest predictor of HRR was PA (R (2) = 0.45) and that VO(2max) did not add significant predictive value to the model. The relationship between HRV and age is evident in well-trained endurance athletes, whereas the relationship between HRV and PA/aerobic fitness is not. The maintained relationship between HRR and PA/aerobic fitness suggests that HRR may be a better marker of fitness-related differences in autonomic control in this population. PMID:22124525

Lee, C Matthew; Mendoza, Albert

2012-07-01

83

Host and environmental determinants of heart rate and heart rate variability in four European populations  

OpenAIRE

OBJECTIVE: In a population-based sample of nuclear families recruited in the framework of the European Project on Genes in Hypertension (EPOGH), we investigated the association between heart rate (HR) and its variability (HRV), and gender, age, posture, breathing frequency, body mass index, systolic blood pressure, family history of hypertension and various lifestyle factors, such as smoking, alcohol and coffee consumption and physical activity. METHODS: RR interval and respiration were regis...

Stolarz, Katarzyna; Staessen, Jan A.; Kuznetsova, Tatiana; Tikhonoff, Vale?rie; State, Doina; Babeanu, Speranta; Casiglia, Edoardo; Fagard, Robert; Kawecka-jaszcz, Kalina; Nikitin, Yuri

2003-01-01

84

Biophysical characterization of the underappreciated and important relationship between heart rate variability and heart rate.  

Science.gov (United States)

Heart rate (HR) variability (HRV; beat-to-beat changes in the R-wave to R-wave interval) has attracted considerable attention during the past 30+ years (PubMed currently lists >17 000 publications). Clinically, a decrease in HRV is correlated to higher morbidity and mortality in diverse conditions, from heart disease to fetal distress. It is usually attributed to fluctuation in cardiac autonomic nerve activity. We calculated HRV parameters from a variety of cardiac preparations (including humans, living animals, Langendorff-perfused heart, and single sinoatrial nodal cell) in diverse species, combining this with data from previously published articles. We show that regardless of conditions, there is a universal exponential decay-like relationship between HRV and HR. Using 2 biophysical models, we develop a theory for this and confirm that HRV is primarily dependent on HR and cannot be used in any simple way to assess autonomic nerve activity to the heart. We suggest that the correlation between a change in HRV and altered morbidity and mortality is substantially attributable to the concurrent change in HR. This calls for re-evaluation of the findings from many articles that have not adjusted properly or at all for HR differences when comparing HRV in multiple circumstances. PMID:25225208

Monfredi, Oliver; Lyashkov, Alexey E; Johnsen, Anne-Berit; Inada, Shin; Schneider, Heiko; Wang, Ruoxi; Nirmalan, Mahesh; Wisloff, Ulrik; Maltsev, Victor A; Lakatta, Edward G; Zhang, Henggui; Boyett, Mark R

2014-12-01

85

Highly comparative fetal heart rate analysis.  

Science.gov (United States)

A database of fetal heart rate (FHR) time series measured from 7 221 patients during labor is analyzed with the aim of learning the types of features of these recordings that are informative of low cord pH. Our 'highly comparative' analysis involves extracting over 9 000 time-series analysis features from each FHR time series, including measures of autocorrelation, entropy, distribution, and various model fits. This diverse collection of features was developed in previous work [1]. We describe five features that most accurately classify a balanced training set of 59 'low pH' and 59 'normal pH' FHR recordings. We then describe five of the features with the strongest linear correlation to cord pH across the full dataset of FHR time series. The features identified in this work may be used as part of a system for guiding intervention during labor in future. This work successfully demonstrates the utility of comparing across a large, interdisciplinary literature on time-series analysis to automatically contribute new scientific results for specific biomedical signal processing challenges. PMID:23366590

Fulcher, B D; Georgieva, A E; Redman, C W G; Jones, N S

2012-01-01

86

Heart rate dynamics during a treadmill cardiopulmonary exercise test in optimized beta-blocked heart failure patients  

OpenAIRE

BACKGROUND: Calculating the maximum heart rate for age is one method to characterize the maximum effort of an individual. Although this method is commonly used, little is known about heart rate dynamics in optimized beta-blocked heart failure patients. AIM: The aim of this study was to evaluate heart rate dynamics (basal, peak and % heart rate increase) in optimized beta-blocked heart failure patients compared to sedentary, normal individuals (controls) during a treadmill cardiopulmonary exer...

Vitor Oliveira Carvalho; Guilherme Veiga Guimarães; Emmanuel Gomes Ciolac; Edimar Alcides Bocchi

2008-01-01

87

Using Target Heart-Rate Zones in Your Class  

Science.gov (United States)

Should teachers teach the calculation of target heart rate to students? And when is it appropriate to engage students in the attainment of these heart rates during physical education class activities? The answers to these questions are not easy. One might be tempted to state a simple yes or no and to identify a specific age to begin using training…

Gilbert, Jennie A.

2005-01-01

88

Effects of different training amplitudes on heart rate and heart rate variability in young rowers.  

Science.gov (United States)

The aim of this study was to investigate the autonomic nervous system recovery and the psychological response as a result of 3 training amplitudes on heart rate (HR), heart rate variability (HRV), and rate of perceived exertion (RPE) in rowing. Eight young rowers (16.8 ± 1.4 years) performed, in a randomized fashion, 2 sessions of high-intensity interval training, with high and low amplitude and a continuous training (CT) session, with the same exercise duration (10 minutes) and mean intensity (60% of maximal stroke test). The data of HR, HRV, and RPE were collected 5 minutes before, immediately after each session, and 24 hours later. High amplitude promoted higher impact in maximum HR (p ? 0.05) and RPE (p training sessions. Originally, we conclude that training with higher load variation between effort and recovery impacts HRV, HR, and RPE with greater intensity, but the younger rowers were ready for new training sessions 24 hours after either training method. Coaches can use the polarized training method, observing the stimulus nature and time required for recovery, because it may be an adequate strategy for the development of rower's conditioning. PMID:24736775

Vaz, Marcelo S; Picanço, Luan M; Del Vecchio, Fabrício B

2014-10-01

89

Repolarisation descriptors and heart rate variability in hemodialyzed patients.  

Science.gov (United States)

T wave morphology (TWM) descriptors derived from Holter electrocardiograms during hemodialysis (HD) are of potential value for cardiac risk assessment in HD patients. Our knowledge on autonomic regulation of TWM descriptors is limited. The purpose of this study was to investigate the association between TWM parameters and heart rate variability (HRV) during intradialytic monitoring. In each of 81 patients on maintenance HD, continuous electrocardiograms were recorded 5 times during HD on alternate weeks. TWM descriptors were calculated every 5 seconds in overlapping 10-second ECG segments and Low Frequency (LF) (0.04 Hz to 0.15 Hz), High Frequency (HF) (0.15 Hz to 0.40 Hz) powers of the spectrum of HRV were calculated every five minutes. The calculated values of TWM and HRV were averaged during the first hour of the recordings and subsequently over all recordings in each subject. Analyzable data for HRV and TWM were available in 71 HD patients (aged 61+/-15, 36 % diabetics, 32 % females). LF in normalized units correlated positively with Total Cosine R to T (r=0.374, p=0.001) and negatively with T wave morphology dispersion (r= -0.253, p=0.033) after adjusting for HR. In conclusion, a heart rate independent association between repolarization descriptors and HRV exists in HD patients. Autonomic modulation needs to be considered when using TWM characteristics for risk profiling of HD patients. PMID:25470516

Poulikakos, D; Banerjee, D; Malik, M

2014-12-01

90

Changes in heart rate variability in a premature infant with hydrocephalus.  

Science.gov (United States)

Objective?To define changes of heart rate variability in premature infant with hydrocephalus before and after drainage procedure. Study Design?The authors report a case of a premature infant with hydrocephalus with analysis of heart rate variability before and after drainage procedure. Three subsequent recordings of the electrocardiography and heart rate variability were done: the first at the age of 22 days before insertion of ventriculoperitoneal shunt, the second at the age of 36 days with functional shunt, the third at the age of 71 days (before discharge). Results?Before drainage operation, there was reduced heart rate variability in time and spectral domains, and sympathetic activity was dominant. After surgery, an increase in heart rate variability parameters was found, particularly with spectral analysis. The ratio of low-frequency/high-frequency band and relative power of the low-frequency band decreased, reflecting enhanced parasympathetic activity. Conclusion?Results of the heart rate variability analysis in a preterm infant with hydrocephalus before and after drainage procedure showed marked improvement in chronotropic cardiac regulation. Evaluation of heart rate variability in premature infants with hydrocephalus with increased intracranial pressure can be an additional method for monitoring of cardiac dysregulation and improvement of the cardiovascular control after successful drainage procedure. PMID:23946905

Uhrikova, Zuzana; Kolarovszki, Branislav; Javorka, Kamil; Javorka, Michal; Matasova, Katarina; Kolarovszka, Hana; Zibolen, Mirko

2012-11-01

91

Change of Diurnal Heart Rate Patterns During Pregnancy and Lactation in Dogs (Canis familiaris  

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Full Text Available Pregnancy and lactation involve great demands on the cardiovascular system. The purpose of this study was to investigate how the heart rate and diurnal heart rate pattern change when dogs become pregnant or lactate. Five clinically healthy female beagle dogs were mated, and delivered three to seven healthy puppies. The heart rate was investigated with 24-h ECG (Holter once during anoestrus, at 3, 5, 7 and 9 weeks of pregnancy, and at week 4 postpartum (lactation. However, at 9 weeks, the ECG could not be recorded for the fully 24 h in 4 of 5 dogs, because labour started and the dogs then appeared disturbed by the recordings. The results at this date are not included in the statistical comparison. The heart rate increased progressively during pregnancy and was still elevated at 4 weeks of lactation. During late pregnancy the difference in heart rates between daytime and nighttime became smaller, but the heart rate was significantly higher in daytime in all periods. In conclusion, the increased heart rates during pregnancy and lactation reflect increased demands on the cardiovascular system and may be important to consider in clinical practice.

Häggström J

2003-09-01

92

The Effect of Heart Rate on the Heart Rate Variability Response to Autonomic Interventions  

Directory of Open Access Journals (Sweden)

Full Text Available Heart rate variability (HRV, the beat-to-beat variation in either heart rate (HR or heart period (R-R interval, has become a popular clinical and investigational tool to quantify cardiac autonomic regulation. However, it is not widely appreciated that, due to the inverse curvilinear relationship between HR and R-R interval, HR per se can profoundly influence HRV. It is, therefore, critical to correct HRV for the prevailing HR particularly, as HR changes in response to autonomic neural activation or inhibition. The present study evaluated the effects of HR on the HRV response to autonomic interventions that either increased (submaximal exercise, n = 25 or baroreceptor reflex activation, n = 20 or reduced (pharmacological blockade: ?-adrenergic receptor, muscarinic receptor antagonists alone and in combination, n = 25, or bilateral cervical vagotomy, n = 9 autonomic neural activity in a canine model. Both total (RR interval standard deviation, RRSD and the high frequency variability (HF, 0.2 to 1.04 Hz were determined before and in response to an autonomic intervention. All interventions that reduced or abolished cardiac parasympathetic regulation provoked large reductions in HRV even after HR correction [division by mean RRsec or (mean RRsec2 for RRSD and HF, respectively] while interventions that reduced HR yielded mixed results. ?-adrenergic receptor blockade reduced HRV (RRSD but not HF while both RRSD and HF increased in response to increases in arterial blood (baroreceptor reflex activation even after HR correction. These data suggest that the physiological basis for HRV is revealed after correction for prevailing HR and, further, that cardiac parasympathetic activity is responsible for a major portion of the HRV in the dog.

GeorgeEBillman

2013-08-01

93

Effect of heart rate on hemodynamics in mitral stenosis  

International Nuclear Information System (INIS)

Objective: To assess the effect of heart rate (HR) on haemodynamic parameters in patients with Mitral Stenosis (MS). Methodology: The study was conducted at Cardiology department, Lady Reading Hospital, Peshawar from November 2010 to April 2011. Patients with MS, regardless of severity, were included. Patients with severe heart failure, other valvular or structural heart disease were excluded. Echocardiographic parameters were recorded at slow and fast HR. Patients with tachycardia were given a-blockers and patients with bradycardia were given parenteral Atropine. Results: A total of 60 patients were included, females were 57 (78%). Mean age was 31+- 9 years. Mean slow and fast HR was 77+-12 bpm and 110+-13 bpm, respectively. Peak mitral valve gradient (PMVG) slow vs. fast HR was 12.8+-4.80 and 14.93+-7.18 mm Hg (p=0.000). Mean mitral valve gradient (MMVG) at slow vs. fast HR was 6.62+-3.29 and 8.15+-4.88 mm of Hg (p=0.000). E pulse Doppler (E) at slow vs. fast HR was 168+-35 and 181+-40 cm/s (p=0.013), / while E tissue Doppler (E ) velocity was 10.47+-2.81 and 10.97+-2.38 cm/s/ (P=0.098), respectively. E/E ratio for slow and fast HR was 17+-5.63 vs.17+-5.41 (P=0.792). Right ventricular systolic pressure (RVSP) at slow vs. fast HR was 44+-16 vs.49+-17.05 mm of Hg (P=0.001). The above parameters had insignificant change with the HR when there was accompanying more than mild MR. Conclusion: Slowing HR in patients with MS significantly decreased PMVG, MMVG and RVSP. LV fcantly decreased PMVG, MMVG and RVSP. LV function did not change significantly with HR. Rate control drugs may be used in preference to improve symptoms in moderate and severe MS. (author)

94

Serum AChE Activities Predict Exercise Heart Rate Parameters of Asymptomatic Individuals  

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Full Text Available Background specific heart rate parameters notably associate with variable risks of cardiovascular disease and mortal-ity, however, to date there are no readily available blood tests associated with these parameters. Because of the estab-lished parasympathetic contributions towards cardiac regulation, we challenged the working hypothesis that serum acetylcholinesterase (AChE activity is involved. Methods A total of 403 Healthy men and women were included in the study and underwent treadmill exercise testing. Prior to exercise testing the subject’s serum AChE activity levels were assessed by measuring rates of acetylthiocholine hydrolysis. Results In male subjects AChE activity was positively cor-related to resting heart rate (r = 0.210, p = 0.001. Complementing this observation, AChE activity was negatively correlated to the exercise-induced heart rate increase (r = –0.181, p = 0.005 and to heart rate recovery at 1, 2 and 5 minutes following cessation of exercise (r = –0.150, p = 0.022; r = –0.157, p = 0.016; r = –0.176, p = 0.008 respec-tively. This indicated that lower than average AChE activities, which presumably reflect increased peripheral ACh levels, might be correlated to favorable heart rate parameters. Similar observations were made in female subjects, ex-cept for lack of correlation to their resting heart rate. Additionally, we observed that we were able to stratify subjects into two groups of significantly different AChE activity (p = 0.001 based on a cut point of heart rate recovery below 20 beats one minute after cessation of exercise. Conclusion In asymptomatic individuals lower than average AChE activity is associated with favorable indices of exercise-inducible heart rate increase as well as heart rate recovery. Future studies will be needed to evaluate the added prognostic significance gained by implementing this marker into routine practice.

Canaani Jonathan

2010-12-01

95

Getting to the Heart of the Matter: Written Disclosure, Gender, and Heart Rate  

Science.gov (United States)

Objective The present study examined gender differences in the psychologic and physical symptom changes associated with written disclosure. Methods Male (n = 48) and female (n = 46) college students were assigned to either a written disclosure condition or a control writing condition. Participants in each condition wrote on 3 consecutive days for 20 minutes each session. Heart rate was recorded during each writing session and the narratives were examined for linguistic content. Participants completed measures of psychologic and physical health at baseline and again 1 month later. Results Participants assigned to the written disclosure condition reported significantly greater psychological and physical health benefits at follow up compared with the control group participants. No significant gender differences were found among those participants assigned to the written disclosure condition. Additionally, although heart rate reactivity and changes in the use of words denoting positive emotion, negative emotion, and cognitive appraisal significantly differed between the writing conditions, no significant gender differences in these variables were found among individuals assigned to the written disclosure condition. Conclusions Written disclosure is associated with significant improvements in both psychologic and physical health for men and women. There was no support for the notion that men may derive greater benefits than women from written disclosure. Furthermore, the results of this study indicate that changes in physiological reactivity and word use associated with written disclosure do not differ between men and women. PMID:15911904

Epstein, Eva M.; Sloan, Denise M.; Marx, Brian P.

2006-01-01

96

Original paper
Heart rate variability in adult patients with congenital heart disease
 

OpenAIRE

Introduction: Heart rate variability (HRV) illustrates an autonomic nervous system influence on the sinus node. It is known that low HRV parameters indicate poor prognosis in patients with myocardial infarction, predict sudden cardiac death and death due to heart failure. Adult population with congenital heart disease (CongHD) is particularly exposed to these complications. The aim of this study was to evaluate HRV parameters in adult patients with CongHD and to analyse the impact of the spec...

Olga Trojnarska; Piotr Br?borowicz; Magdalena ?anocha; Maciej Lesiak; Wies?aw Bryl; Andrzej Cie?li?ski

2005-01-01

97

Fuzzy Logic System for Fetal Heart Rate Determination  

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Full Text Available This paper focuses on the Fuzzy Logic System for fetal heart rate determination. The clinical interpretation of fetal heart rate trace is a difficult task and this has led to the development of computerised systems. These systems are limited by their inability to represent uncertainty. This paper describes the development of a fuzzy expert system for fetal heart rate. The fuzzy logic system improved on the crisp system and has achieved the highest overall performance. With the results obtained, it is evident that the fuzzy logic system can be used to improve the efficiency of the clinician position for making accurate diagnosis.

UDO, E.U.

2015-02-01

98

Heart rate variability during sleep in detoxified alcohol-dependent males: A comparison with healthy controls  

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Context: Alcohol dependence can lead to autonomic neuropathy resulting in increased cardiac morbidity and mortality. This has previously been evaluated using heart-rate variability. Aims: We compared sleep heart-rate variability of alcohol-dependent patients with that of healthy controls in this study. Settings and Design: This study was conducted at NIMHANS, Bangalore. A case control study design was adopted. Materials and Methods: Sleep heart-rate variability of 20 male alcohol-dependent inpatients was recorded on the 5th day after detoxification. Sleep heart-rate variability was also recorded in 18 age- and gender-matched healthy controls. Statistical Analysis: The groups were compared using t-test for continuous variables and Chi-squared test for discrete variables. Results: Both time and frequency domain measures were significantly lower in the patients as compared to the controls, indicating decreased HRV in alcohol-dependent individuals. Conclusions: Decreased HRV in alcohol dependence indicates potential autonomic neuropathy. PMID:23825854

Ganesha, Suhas; Thirthalli, Jagadisha; Muralidharan, Kesavan; Benegal, Vivek; Gangadhar, Bangalore N.

2013-01-01

99

Statistical analysis of heart rate and heart rate variability monitoring through the use of smart phone cameras.  

Science.gov (United States)

Video recordings of finger tips made using a smartphone camera contain a pulsatile component caused by the cardiac pulse equivalent to that present in a photoplethysmographic signal. By performing peak detection on the pulsatile signal it is possible to extract a continuous heart rate signal. We performed direct comparisons between 5-lead electrocardiogram based heart rate variability measurements and those obtained from an iPhone 4s and Motorola Droid derived pulsatile signal to determine the accuracy of heart rate variability measurements obtained from the smart phones. Monitoring was performed in the supine and tilt positions for independent iPhone 4s (2 min recordings, n=9) and Droid (5 min recordings, n=13) experiments, and the following heart rate and heart rate variability parameters were estimated: heart rate, low frequency power, high frequency power, ratio of low to high frequency power, standard deviation of the RR intervals, and root mean square of successive RR-differences. Results demonstrate that accurate heart rate variability parameters can be obtained from smart phone based measurements. PMID:23366214

Bolkhovsky, Jeffrey B; Scully, Christopher G; Chon, Ki H

2012-01-01

100

Heart Rate Response and Lactic Acid Concentration in Squash Players.  

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It was concluded that playing squash is an activity that results in heart rate responses of sufficient intensity to elicit aerobic training effects without producing high lactic acid concentration in the blood. (MM)

Beaudin, Paula; And Others

1978-01-01

101

Heart Rate Variability Measures and Models  

CERN Document Server

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...

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

2001-01-01

102

Maternal Psychopathology Influences Infant Heart Rate Variability: Generation R Study  

OpenAIRE

Abstract OBJECTIVE: To assess the determinants of heart rate (HR) and heart rate variability (HRV) in children. The autonomic nervous system as measured by HR and HRV is considered a biological marker of psychopathology in children. METHODS: We examined the relationship of maternal psychopathology with infant HR and HRV. HR was recorded at 14 months in 528 infants. The high-frequency component of HRV was used as an indicator of cardiac vagal modulation. The presence of a lifetime mate...

Dierckx, B.; Tulen, J. H. M.; Lambregtse-van Den Berg, M. P.; Tharner, A.; Jaddoe, V. W. V.; Moll, H. A.; Hofman, A.; Verhulst, F. C.; Tiemeier, H.

2009-01-01

103

A comparison of heart rate responses in racquet games.  

OpenAIRE

The present study investigated the heart rate response to playing tennis with special reference to the skill levels and ages of the participants. Data obtained in a similar manner during earlier studies of badminton and squash players were compared with that obtained during tennis. The number of rallies, mean rally time and actual playing time in 30 minutes of play was also compared for the different skill levels and sports. Results showed that playing tennis raised the players' heart rates t...

Docherty, D.

1982-01-01

104

Heart rate variability in patients with chronic cerebral ischemia  

OpenAIRE

The purpose of the work is to estimate the status of autonomic nervous system in patients with chronic cerebral ischemia by means of the analysis of heart rate variability at various stages of disease. 120 patients with chronic cerebral ischemia aged from 45 to 65 took part in the research. The comparison group included 30 patients with an arterial hypertension and without chronic cerebral ischemia. Heart rate variability analisis included time-domain and frequency-domain methods of five-minu...

Smyshlaeva ?.?.

2010-01-01

105

Automatic recording of fish heart rate on a personal computer  

OpenAIRE

From acoustic tags operated into fish in a closed system, the heartbeat signals are sent via underwater telemetry and counted on a personal computer. The computer removes false pulses caused by noise, and calculates the heart rate for one minute based on reliable heartbeats. Up to 6 fish can be monitored in a sequence of one minute per fish. The heart rate is stored on a file, or transferred to another computer.

Floen, Svein; Totland, Bjørn; Øvredal, Jan Tore

1988-01-01

106

DETECTING CONGESTIVE HEART FAILURE USING HEART RATE SEQUENTIAL TREND ANALYSIS PLOT  

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Full Text Available Heart rate variability analysis is gaining acceptance as a potential non-invasive means of autonomic nervous system assessment in research as well as clinical domains. In this study, a nonlinear analysis method is developed to detect congestive heart failure. The data obtained from an online and widely used public database (i.e., MIT/BIH physionet database, is used for testing the performance of the method. The method developed is based on the sequential trend analysis plot of heart rate variability and correlates well with the characteristic autonomic nervous system regulations in congestive heart failure. The proposed method can be used for screening as well as diagnosing the heart failure patients. The algorithm is computationally simple and can be implemented in a real time processing hardware. This method classifies 31 out of 32 subjects and has the highest discrimination power in terms of sensitivity, specificity and accuracy.

SRINIVAS KUNTAMALLA,

2010-12-01

107

The heart field effect: Synchronization of healer-subject heart rates in energy therapy.  

Science.gov (United States)

Recent health research has focused on subtle energy and vibrational frequency as key components of health and healing. In particular, intentional direction of bioenergy is receiving increasing scientific attention. This study investigates the effect of the healer's electromagnetic (EM) heart field upon subjects during energy healing as measured by synchronization of heart rates and scores on a Subjective Units of Distress (SUD) scale and a Profile of Mood States (POMS) inventory. A nonequivalent pretest-posttest design was used based on heart rate comparisons between healer and subject and correlated with pre-and posttest SUD and POMS scores. Subjects included those who sat within the 3- to 4-foot "strong" range of the independent variable, the healer's heart field, while performing self-application of WHEE (the wholistic hybrid derived from EMDR [eye movement desensitization and reprocessing], and EFT [emotional freedom technique]), a meridian-based tapping technique (n=50); and those who performed the same process beyond the 15- to 18-foot range of the healer's EM heart field (n=41). The dependent variables were heart rate, SUD, and POMS inventory. All subjects completed these measures within 1 hour. Study results showed statistically significant heart-rate synchronization with the intervention population. In addition, SUD and POMS scores demonstrated considerably more improvement than in the control population, indicating additional benefit beyond the meridian-based therapies, such as WHEE, alone. Additional findings and future research recommendations are presented in this article. PMID:20664147

Bair, Christine Caldwell

2008-01-01

108

Heart rate variability and heat sensation during CT coronary angiography: Low-osmolar versus iso-osmolar contrast media  

International Nuclear Information System (INIS)

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. Thignificant 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

109

Heart Rate Variability in Complex Regional Pain Syndrome during Rest and Mental and Orthostatic Stress  

DEFF Research Database (Denmark)

BACKGROUND:: Complex regional pain syndrome (CRPS) is a pain condition with regional sensory and autonomic abnormalities in the affected limb. The authors studied systemic autonomic and hemodynamic function in CRPS patients during rest, and during orthostatic and mental arithmetic stress. METHODS:: Twenty patients with CRPS and 20 age-, sex-, and body mass index-matched control subjects participated. Mean values of heart rate variability, baroreceptor sensitivity, blood pressure, stroke volume, cardiac output, and total peripheral resistance were estimated during supine rest and 60° tilt-table testing. On a separate day, heart rate variability was also measured during mental arithmetic stress testing induced by a paced auditory serial addition task. RESULTS:: Heart rate was increased and heart rate variability reduced in patients with CRPS patients compared with control subjects during rest and mental and orthostatic stress, whereas baroreceptor sensitivity was unaffected. When tilted from supine to upright position, patients with CRPS were not able to preserve cardiac output in comparison with control subjects, and they exhibited an exaggerated increase in the total peripheral resistance. The hemodynamic changes correlated to pain duration but not to pain intensity. CONCLUSIONS:: The increased heart rate and decreased heart rate variability in CRPS suggest a general autonomic imbalance, which is an independent predictor for increased mortality and sudden death. The inability of the patients to protect their cardiac output during orthostatic stress was aggravated with the chronicity of the disease.

Terkelsen, Astrid J; MØlgaard, Henning

2012-01-01

110

The relationship between heart rate reserve and oxygen uptake reserve in heart failure patients on optimized and non-optimized beta-blocker therapy  

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Full Text Available BACKGROUND: The relationship between the percentage of oxygen consumption reserve and percentage of heart rate reserve in heart failure patients either on non-optimized or off beta-blocker therapy is known to be unreliable. The aim of this study was to evaluate the relationship between the percentage of oxygen consumption reserve and percentage of heart rate reserve in heart failure patients receiving optimized and non-optimized beta-blocker treatment during a treadmill cardiopulmonary exercise test. METHODS: A total of 27 sedentary heart failure patients (86% male, 50±12 years on optimized beta-blocker therapy with a left ventricle ejection fraction of 33±8% and 35 sedentary non-optimized heart failure patients (75% male, 47±10 years with a left ventricle ejection fraction of 30±10% underwent the treadmill cardiopulmonary exercise test (Naughton protocol. Resting and peak effort values of both the percentage of oxygen consumption reserve and percentage of heart rate reserve were, by definition, 0 and 100, respectively. RESULTS: The heart rate slope for the non-optimized group was derived from the points 0.949±0.088 (0 intercept and 1.055±0.128 (1 intercept, p<0.0001. The heart rate slope for the optimized group was derived from the points 1.026±0.108 (0 intercept and 1.012±0.108 (1 intercept, p=0.47. Regression linear plots for the heart rate slope for each patient in the non-optimized and optimized groups revealed a slope of 0.986 (almost perfect for the optimized group, but the regression analysis for the non-optimized group was 0.030 (far from perfect, which occurs at 1. CONCLUSION: The relationship between the percentage of oxygen consumption reserve and percentage of heart rate reserve in patients on optimized beta-blocker therapy was reliable, but this relationship was unreliable in non-optimized heart failure patients.

Vitor Oliveira Carvalho

2008-01-01

111

Central effects of synthesized dihydropyridine derivatives and nifedipine on systolic blood pressure and heart rate of rats  

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Conclusion: Novel dihydropyridine derivatives can possess more potent and stable in-hibitory effects on systolic blood pressure and heart rate, and some part of these properties at least, can be attributed to their direct inhibitory effects on brain neurons.

Azam Bakhtiarian

2014-03-01

112

Estimating Energy Expenditure from Heart Rate in Older Adults: A Case for Calibration  

Science.gov (United States)

Background Accurate measurement of free-living energy expenditure is vital to understanding changes in energy metabolism with aging. The efficacy of heart rate as a surrogate for energy expenditure is rooted in the assumption of a linear function between heart rate and energy expenditure, but its validity and reliability in older adults remains unclear. Objective To assess the validity and reliability of the linear function between heart rate and energy expenditure in older adults using different levels of calibration. Design Heart rate and energy expenditure were assessed across five levels of exertion in 290 adults participating in the Baltimore Longitudinal Study of Aging. Correlation and random effects regression analyses assessed the linearity of the relationship between heart rate and energy expenditure and cross-validation models assessed predictive performance. Results Heart rate and energy expenditure were highly correlated (r?=?0.98) and linear regardless of age or sex. Intra-person variability was low but inter-person variability was high, with substantial heterogeneity of the random intercept (s.d.?=?0.372) despite similar slopes. Cross-validation models indicated individual calibration data substantially improves accuracy predictions of energy expenditure from heart rate, reducing the potential for considerable measurement bias. Although using five calibration measures provided the greatest reduction in the standard deviation of prediction errors (1.08 kcals/min), substantial improvement was also noted with two (0.75 kcals/min). Conclusion These findings indicate standard regression equations may be used to make population-level inferences when estimating energy expenditure from heart rate in older adults but caution should be exercised when making inferences at the individual level without proper calibration. PMID:24787146

Schrack, Jennifer A.; Zipunnikov, Vadim; Goldsmith, Jeff; Bandeen-Roche, Karen; Crainiceanu, Ciprian M.; Ferrucci, Luigi

2014-01-01

113

Cuff inflation during ambulatory blood pressure monitoring and heart rate  

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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

Mia Skov-Madsen

2008-11-01

114

Influence of deep breathing exercise on spontaneous respiratory rate and heart rate variability: a randomised controlled trial in healthy subjects.  

Science.gov (United States)

Studies show that yogic type of breathing exercises reduces the spontaneous respiratory rate. However, there are no conclusive studies on the effects of breathing exercise on heart rate variability. We investigated the effects of non-yogic breathing exercise on respiratory rate and heart rate variability. Healthy subjects (21-33 years, both genders) were randomized into the intervention group (n=18), which performed daily deep breathing exercise at 6 breaths/min (0.1 Hz) for one month, and a control group (n=18) which did not perform any breathing exercise. Baseline respiratory rate and short-term heart rate variability indices were assessed in both groups. Reassessment was done after one month and the change in the parameters from baseline was computed for each group. Comparison of the absolute changes [median (inter-quartile ranges)] of the parameters between the intervention and control group showed a significant difference in the spontaneous respiratory rate [intervention group -2.50 (-4.00, -1.00), control group 0.00 (-1.00, 1.00), cycles/min, Psum of low and high frequency powers [intervention group 512.00 (-73.00, 999.00), control group 51.00 (-449.00, 324.00), ms2, Pdifferent across the groups. In conclusion, the changes produced by simple deep slow breathing exercise in the respiratory rate and cardiac autonomic modulation of the intervention group were significant, when compared to the changes in the control group. Thus practice of deep slow breathing exercise improves heart rate variability in healthy subjects, without altering their cardiac autonomic balance. These findings have implications in the use of deep breathing exercises to improve cardiac autonomic control in subjects known to have reduced heart rate variability. PMID:23029969

Tharion, Elizabeth; Samuel, Prasanna; Rajalakshmi, R; Gnanasenthil, G; Subramanian, Rajam Krishna

2012-01-01

115

Rate control in atrial fibrillation by cooling: effect of temperature on dromotropy in perfused rabbit hearts.  

Science.gov (United States)

Background. Cooling has emerged as a therapeutic option in critically ill patients (especially after cardiac resuscitation) and might also have a negative dromotropic effect in atrial fibrillation. We sought to determine the impact of cooling on electrophysiologic properties of Langendorff-perfused rabbit hearts. Methods and Results. In 20 isolated Langendorff-perfused rabbit hearts, the temperature of the tissue bath was changed between 17 and 42°C. With decreasing temperature, significant increases of the spontaneous sinus cycle length, decreases of the mean ventricular heart rate during atrial fibrillation, and relevant increases of atrial and ventricular refractory periods were observed (ANOVA P < .01). Conclusions. Cardiac hypothermia leads to a significant drop of mean ventricular heart rate during atrial fibrillation. Negative chronotropy and dromotropy induced by moderate cardiac hypothermia might be a feasible therapeutic approach in patients with hemodynamically relevant tachyarrhythmias in a CCU/ICU setting. PMID:21559254

Mischke, Karl; Zarse, Markus; Knackstedt, Christian; Schauerte, Patrick

2011-01-01

116

Effect of furosemide and torasemide on heart rate variability and ventricular rhythm disorders in patients with chronic heart failure complicating ischemic heart disease: comparative nonrandomized study  

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

H.H. Shugushev

2010-01-01

117

Autonomic heart rate control at rest and during unloading of the right ventricle in repaired tetralogy of Fallot in adolescents.  

Science.gov (United States)

Arrhythmias in patients with repaired tetralogy of Fallot (ToF) might be due in part to altered autonomic heart rate control caused by altered right ventricle hemodynamics. This study investigated autonomic heart rate control in adolescents with ToF at rest and during unloading of the right ventricle. A total of 17 patients with ToF and 56 healthy controls aged 12 to 18 years underwent orthostatic stress with lower body negative pressure of -20 mm Hg. Heart rate, blood pressure, and stroke volume were recorded noninvasively. Indices of heart rate variability were computed in time and frequency domains. All patients with ToF also underwent cardiac magnetic resonance imaging, demonstrating pulmonary regurgitation and right ventricular dilation. At rest, heart rate variability indices of vagal heart rate control were nonsignificantly lower in the patients with ToF compared with controls. During lower body negative pressure, heart rate increased more in controls than patients with ToF (p variables), suggesting vagal activation in the patients with ToF. In conclusion, adolescents after ToF repair have fairly normal heart rate control at rest despite altered right ventricular hemodynamics. During unloading of the right ventricle, however, vagal heart rate control increases in the patients with ToF and decreases in the controls. PMID:18929714

Wyller, Vegard Bruun; Saul, J Philip; Barbieri, Riccardo; de Lange, Charlotte; Hopp, Einar; Norum, Ingvild B; Thaulow, Erik

2008-10-15

118

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

Directory of Open Access Journals (Sweden)

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

Ali Metin Esen

2010-04-01

119

Concurrent validity of the Armour39 heart rate monitor strap.  

Science.gov (United States)

New technology offers potential advantages in physically demanding environments where convenience and comfort are important and accurate and reliable data collection is challenging. Nevertheless, it is important to validate the accuracy and reliability of such biological monitoring systems (BMS) before they are adopted. The purpose of this investigation was to assess the concurrent validity of a new heart rate monitor across a range of exercise intensities and with a large and diverse group of male subjects in a large cohort with diverse physical fitness characteristics. Seventy-five men (age, 23 ± 4 years; height, 181 ± 8 cm; body mass, 83 ± 12 kg; estimated V[Combining Dot Above]O2peak, 3.16 ± 0.63 [L·min]) volunteered and completed a graded cycle ergometer exercise protocol while heart rate was continuously monitored before, during, and after exercise with the new device (Armour39) and the gold standard (electrocardiogram). The 2-minute stages included sitting, standing, and cycling with 35 W increments until volitional fatigue. The coefficient of determination between mean heart rate values at each stage was R = 0.99, whereas Pearson correlations (r) at each stage were ? 0.99. Heart rates during exercise were typically within 1 beat of each other. The Armour39 BMS, therefore, is an acceptable means for the valid and reliable determination of heart rate under various bodily positions and levels of exertion, including maximal exercise intensity. PMID:23860286

Flanagan, Shawn D; Comstock, Brett A; Dupont, William H; Sterczala, Adam R; Looney, Dave P; Dombrowski, Dylan H; McDermott, Danielle M; Bryce, Alexander; Maladouangdock, Jesse; Dunn-Lewis, Courtenay; Luk, Hui-Ying; Szivak, Tunde K; Hooper, David R; Kraemer, William J

2014-03-01

120

Heart rate variability in patients with vasovagal syndrome.  

Science.gov (United States)

The aim of this study was to assess the heart rate variability in patients with vasovagal syndrome (VVS). Heart rate variability was expressed as: (1) the standard deviation (SD) of the mean RR interval; and (2) the SD as a percentage of the mean RR interval (%SD). Heart rate variability was measured in VVS patients and compared with control individuals. Eighteen patients (mean age 50 +/- 14 years) with a history of recurrent syncope and positive tilt testing were included in the study. Fifteen asymptomatic individuals (mean age 53 +/- 13 years) with no history of syncope and negative tilt testing were used as a control group. The SD and %SD (39 +/- 38 and 5 +/- 4 msec) in the VVS group were statistically higher at the tenth minute of tilt testing than in the control group (20 +/- 14 and 2.5 +/- 1.8 msec, P = 0.03 and P < 0.05, respectively). The mean RR interval (mean heart rate) was shorter after the 15th minute of tilt testing in the VVS group than in the control group (RR-VVS 687 +/- 136 msec, RR-control 801 +/- 131 msec, P < 0.05). It is concluded that heart rate variability, as expressed by the SD of the mean RR interval, and the SD as a percentage of the mean RR interval (%SD) are significantly higher in VVS patients than in control asymptomatic individuals. PMID:1279629

Theodorakis, G N; Kremastinos, D T; Avrambos, G T; Stefanakis, G S; Karavolias, G K; Toutouzas, P K

1992-11-01

121

Autonomic control of heart rate after exercise in trained wrestlers.  

Science.gov (United States)

The objective of this study was to establish differences in vagal reactivation, through heart rate recovery and heart rate variability post exercise, in Brazilian jiu-jitsu wrestlers (BJJW). A total of 18 male athletes were evaluated, ten highly trained (HT) and eight moderately trained (MT), who performed a maximum incremental test. At the end of the exercise, the R-R intervals were recorded during the first minute of recovery. We calculated heart rate recovery (HRR60s), and performed linear and non-linear (standard deviation of instantaneous beat-to-beat R-R interval variability - SD1) analysis of heart rate variability (HRV), using the tachogram of the first minute of recovery divided into four segments of 15 s each (0-15 s, 15-30 s, 30-45 s, 45-60 s). Between HT and MT individuals, there were statistically significant differences in HRR60s (p <0.05) and in the non linear analysis of HRV from SD130-45s (p <0.05) and SD145-60s (p <0.05). The results of this research suggest that heart rate kinetics during the first minute after exercise are related to training level and can be used as an index for autonomic cardiovascular control in BJJW. PMID:24744476

Henríquez, Olguín C; Báez, San Martín E; Von Oetinger, A; Cañas, Jamett R; Ramírez, Campillo R

2013-06-01

122

AUTONOMIC CONTROL OF HEART RATE AFTER EXERCISE IN TRAINED WRESTLERS  

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Full Text Available The objective of this study was to establish differences in vagal reactivation, through heart rate recovery and heart rate variability post exercise, in Brazilian jiu-jitsu wrestlers (BJJW. A total of 18 male athletes were evaluated, ten highly trained (HT and eight moderately trained (MT, who performed a maximum incremental test. At the end of the exercise, the R-R intervals were recorded during the first minute of recovery. We calculated heart rate recovery (HRR60s, and performed linear and non-linear (standard deviation of instantaneous beat-to-beat R-R interval variability – SD1 analysis of heart rate variability (HRV, using the tachogram of the first minute of recovery divided into four segments of 15 s each (0-15 s, 15-30 s, 30-45 s, 45-60 s. Between HT and MT individuals, there were statistically significant differences in HRR60s (p <0.05 and in the non linear analysis of HRV from SD130-45s (p <0.05 and SD145-60s (p <0.05. The results of this research suggest that heart rate kinetics during the first minute after exercise are related to training level and can be used as an index for autonomic cardiovascular control in BJJW.

Carlos F Henríquez

2013-04-01

123

The Use of Heart Rate Monitors in Physical Education  

Science.gov (United States)

The ever-rising rate of obesity and the need for increased physical activity for young children is well documented. Data suggests that today's youth are not participating in enough quality health-enhancing physical activity either in or outside of school. Heart rate monitors have been used by adult exercisers for many years to monitor and assess…

Nichols, Randall; Davis, Kathryn L.; McCord, Tim; Schmidt, Dave; Slezak, Alex M.

2009-01-01

124

Heart rate variability and target organ damage in hypertensive patients  

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Full Text Available Abstract Background We evaluated the association between linear standard Heart Rate Variability (HRV measures and vascular, renal and cardiac target organ damage (TOD. Methods A retrospective analysis was performed including 200 patients registered in the Regione Campania network (aged 62.4?±?12, male 64%. HRV analysis was performed by 24-h holter ECG. Renal damage was assessed by estimated glomerular filtration rate (eGFR, vascular damage by carotid intima-media thickness (IMT, and cardiac damage by left ventricular mass index. Results Significantly lower values of the ratio of low to high frequency power (LF/HF were found in the patients with moderate or severe eGFR (p-value? Conclusions Depressed HRV appeared to be associated with vascular and renal TOD, suggesting the involvement of autonomic imbalance in the TOD. However, as the mechanisms by which abnormal autonomic balance may lead to TOD, and, particularly, to renal organ damage are not clearly known, further prospective studies with longitudinal design are needed to determine the association between HRV and the development of TOD.

Melillo Paolo

2012-11-01

125

Loss of lag-response curvilinearity of indices of heart rate variability in congestive heart failure  

OpenAIRE

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 int...

Smith Michael L; Thakre Tushar P

2006-01-01

126

Discrimination power of long-term heart rate variability measures for Chronic Heart Failure detection  

OpenAIRE

The aim of this study was to investigate the discrimination power of standard long-term Heart Rate Variability (HRV) measures for the diagnosis of Chronic Heart Failure (CHF). We performed a retrospective analysis on 4 public Holter databases, analyzing the data of 72 normal subjects and 44 patients suffering from CHF. To assess the discrimination power of HRV measures, we adopted an exhaustive search of all possible combinations of HRV measures and we developed classifiers based on Classi...

Melillo, Paolo; Fusco, Roberta; Sansone, Mario; Bracale, Marcello; Pecchia, Leandro

2011-01-01

127

Heart rate variability in patients being treated for Dengue viral infection: New insights from mathematical correction of heart rate  

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Full Text Available Introduction: Severe dengue hemorrhagic fever (DHF is a viral infection that acts to increase permeability of capillaries, resulting in internal hemorrhage. Linear frequency domain Fourier spectral analysis represents the most published noninvasive tool for diagnosing and assessing health status via calculated heart rate variability (HRV. As such, HRV may be useful in assessing clinical status in DHF patients, but is prone to erroneous results and conclusions due to the influence of the average HR during the time period of HRV assessment (defined as the ’prevailing’ HR. We tested the hypothesis that alterations in HRV calculated with linear frequency analysis would be minimal when mathematically corrected for prevailing HR following dengue viral infection. Methods: Male (N=16 and female (N= 11 patients between the ages of 6 months and 15 years of age (10 ± 6 SD years were tracked through the progression of the dengue viral infection with treatment following the abatement of a fever (defervescence. Electrocardiographic recordings were collected and analyzed for HRV. Results: High frequency (HF, low frequency (LF, and LF/HF ratio were unaffected by correction for prevailing HR. Conclusion: HRV corrected for changes in HR did not alter the interpretations of our data. Therefore, we conclude that cardiac parasympathetic activity (HF frequency is responsible for the majority of the HR reduction following defervescence in patients with dengue viral infection.

ROBERTCARTER III

2014-02-01

128

Association of Metabolic Syndrome With Exercise Capacity and Heart Rate Recovery in Patients With Coronary Heart Disease in the Heart and Soul Study  

OpenAIRE

It is not known whether the metabolic syndrome is associated with poor exercise capacity among patients who have established coronary heart disease. We evaluated the association of the metabolic syndrome with treadmill exercise capacity and heart rate recovery among patients who had coronary heart disease. We measured treadmill exercise capacity (METs) and heart rate recovery (beats per minute) in 943 subjects who had known coronary heart disease. Of these, 377 (40%) had the metabolic syndrom...

Spies, Christian; Otte, Christian; Kanaya, Alka; Pipkin, Sharon S.; Schiller, Nelson B.; Whooley, Mary A.

2005-01-01

129

Heart rate changes during partial seizures: A study amongst Singaporean patients  

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Full Text Available Abstract Introduction Studies in Europe and America showed that tachycardia, less often bradycardia, frequently accompanied partial seizures in Caucasian patients. We determine frequency, magnitude and type of ictal heart rate changes during partial seizures in non-Caucasian patients in Singapore. Methods Partial seizures recorded during routine EEGs performed in a tertiary hospital between 1995 and 1999 were retrospectively reviewed. All routine EEGs had simultaneous ECG recording. Heart rate before and during seizures was determined and correlated with epileptogenic focus. Differences in heart rate before and during seizures were grouped into 4 types: (1 >10% decrease; (2 -10 to +20% change; (3 20–50% increase; (3 >50% increase. Results Of the total of 37 partial seizures, 18 were left hemisphere (LH, 13 were right hemisphere (RH and 6 were bilateral (BL in onset. 51% of all seizures showed no significant change in heart rate (type 2, 22% had moderate sinus tachycardia (type 3, 11% showed severe sinus tachycardia (type 4, while 16% had sinus bradycardia (type 1. Asystole was recorded in one seizure. Apart from having more tachycardia in bilateral onset seizures, there was no correlation between side of ictal discharge and heart rate response. Compared to Caucasian patients, sinus tachycardia was considerably less frequent. Frequency of bradycardia was similar to those recorded in the literature. Conclusions Significant heart rate changes during partial seizures were seen in half of Singaporean patients. Although sinus tachycardia was the most common heart rate change, the frequency was considerably lower compared to Caucasian patients. This might be due to methodological and ethnic differences. Rates of bradycardia are similar to those recorded in the literature.

Lim Shih-Hui

2001-09-01

130

Effects of Moxa (Artemisia Vulgaris Smoke Inhalation on Heart Rate and Its Variability  

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Full Text Available Objective: To evaluate the changes of human heart rate (HR and heart rate variability (HRV during and after moxa smoke inhalation and to investigate the effects of moxa smoke on human autonomic nervous system. Methods: 24 healthy volunteers were exposed to moxa smoke with their HRV parameters measured before, during and after the moxa smoke inhalation. Results: The healthy volunteers exposed to moxa smoke had significant reductions in HR and also significant changes in HRV parameters. Conclusions: Moxa smoke can improve the autonomic nervous system activity. The inhalation of moxa smoke will induce a depressant effect on human body.

Ping Liu

2011-06-01

131

Robust efficient estimation of heart rate pulse from video.  

Science.gov (United States)

We describe a simple but robust algorithm for estimating the heart rate pulse from video sequences containing human skin in real time. Based on a model of light interaction with human skin, we define the change of blood concentration due to arterial pulsation as a pixel quotient in log space, and successfully use the derived signal for computing the pulse heart rate. Various experiments with different cameras, different illumination condition, and different skin locations were conducted to demonstrate the effectiveness and robustness of the proposed algorithm. Examples computed with normal illumination show the algorithm is comparable with pulse oximeter devices both in accuracy and sensitivity. PMID:24761294

Xu, Shuchang; Sun, Lingyun; Rohde, Gustavo Kunde

2014-04-01

132

Relationship between anxiety, heart rate and efficiency of pistol shooting  

OpenAIRE

The purpose of this study was to investigate the relationship between anxiety, heart rate and efficiency of pistol shooting. In this study, 291 male volunteers working for the Turkish National Police within the age range of 20-23 years participated. The efficiency of pistol shooting was evaluated by the total points of the bullets which hit the target from 10 metres. The State-Trait Anxiety Inventory (STAI) was used to assess anxiety. The “Polar Team2 Pro” device for heart rate was used. ...

Gürhan Kayihan; Gülfem Ersoz; Ali Özkan; Mercan Tuna

2014-01-01

133

Office and 24-hour heart rate and target organ damage in hypertensive patients  

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Full Text Available Abstract Background We investigated the association between heart rate and its variability with the parameters that assess vascular, renal and cardiac target organ damage. Methods A cross-sectional study was performed including a consecutive sample of 360 hypertensive patients without heart rate lowering drugs (aged 56 ± 11 years, 64.2% male. Heart rate (HR and its standard deviation (HRV in clinical and 24-hour ambulatory monitoring were evaluated. Renal damage was assessed by glomerular filtration rate and albumin/creatinine ratio; vascular damage by carotid intima-media thickness and ankle/brachial index; and cardiac damage by the Cornell voltage-duration product and left ventricular mass index. Results There was a positive correlation between ambulatory, but not clinical, heart rate and its standard deviation with glomerular filtration rate, and a negative correlation with carotid intima-media thickness, and night/day ratio of systolic and diastolic blood pressure. There was no correlation with albumin/creatinine ratio, ankle/brachial index, Cornell voltage-duration product or left ventricular mass index. In the multiple linear regression analysis, after adjusting for age, the association of glomerular filtration rate and intima-media thickness with ambulatory heart rate and its standard deviation was lost. According to the logistic regression analysis, the predictors of any target organ damage were age (OR = 1.034 and 1.033 and night/day systolic blood pressure ratio (OR = 1.425 and 1.512. Neither 24 HR nor 24 HRV reached statistical significance. Conclusions High ambulatory heart rate and its variability, but not clinical HR, are associated with decreased carotid intima-media thickness and a higher glomerular filtration rate, although this is lost after adjusting for age. Trial Registration ClinicalTrials.gov: NCT01325064

García-García Ángel

2012-03-01

134

Direct observation of homoclinic orbits in human heart rate variability  

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Homoclinic trajectories of the interbeat intervals between contractions of ventricles of the human heart are identified. The interbeat intervals are extracted from 24-h Holter ECG recordings. Three such recordings are discussed in detail. Mappings of the measured consecutive interbeat intervals are constructed. In the second and in some cases in the fourth iterate of the map of interbeat intervals homoclinic trajectories associated with a hyperbolic saddle are found. The homoclinic trajectories are often persistent for many interbeat intervals, sometimes spanning many thousands of heartbeats. Several features typical for homoclinic trajectories found in other systems were identified, including a signature of the gluing bifurcation. The homoclinic trajectories are present both in recordings of heart rate variability obtained from patients with an increased number of arrhythmias and in cases in which the sinus rhythm is dominant. The results presented are a strong indication of the importance of deterministic nonlinear instabilities in human heart rate variability.

?ebrowski, J. J.; Baranowski, R.

2003-05-01

135

Interchangeability between heart rate and photoplethysmography variabilities during sympathetic stimulations  

International Nuclear Information System (INIS)

Photoplethysmography variability (PPGV) is currently considered to be a good surrogate to heart rate variability (HRV) measurements using the time between two pulse waves instead of RR intervals. Nevertheless, the interchangeability between HRV and PPGV has never been evaluated in situations with severe alterations in the autonomic nervous system (ANS). We aimed to identify the conditions for a correct utilization of PPGV in evaluating the consequences of sympathetic stimulations. Nine subjects performed three tests: active orthostatic test, slow walk and moderate and exhaustive cycling exercises in the supine position. Pulse waves at the fingertip and RR intervals were recorded at the same time. We used correlations and the Bland and Altman method to compare and evaluate interchangeability between several HRV indices. Bland and Altman analysis highlighted small discrepancies between PPGV and HRV for all HRV indices in the supine position and for LFms2, HFms2, LFpeak and RMSSD in the upright position. During the slow walk, it was impossible to detect properly PPG peaks. We observed large differences between the two methods during the cycling exercise. In conclusion, PPGV can be used instead of HRV without reserve in the supine position but only for some HRV indices in the upright position and not during slow walk and cycling exercise

136

Prognostic significance of heart rate in hospitalized patients presenting with myocardial infarction  

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Full Text Available AIM: To investigate the prognostic significance of resting heart rate in patients with acute coronary syndrome (ACS, independent of other known factors. METHODS: Patients 40 years of age or older who had been admitted with acute coronary syndrome (ACS to one of the 94 hospitals participating in the Prevalence of Peripheral Arterial Disease in Patients with Acute Coronary Syndrome (PAMISCA study were included. Patients were divided into two groups based on their resting heart rate (HR ? or < 70 bpm. Complications were recording during a follow-up period of 1 year. RESULTS: There were 1054 ACS patients analyzed (43.5% with ST segment elevation and 56.5% without elevation. Mean age was 66.6 ± 11.7 years, 70.6% were male and 29.4% of subjects were female. During follow-up, more patients in the HR ? 70 bpm group were hospitalized for heart failure and they also had a higher mortality rate. In the multivariate analysis, a heart rate of ? 70 bpm was independently related to overall mortality during the follow-up period (hazard ratio 2.5; 95% confidence interval, 1.26-4.97, P = 0.009. CONCLUSION: A resting heart rate ? 70 bpm in patients who survive an ACS is an indicator of a high risk of suffering cardiovascular events during follow-up.

Lorenzo Fácila

2012-01-01

137

Embryonic Heart Rate correlation with pregnancy outcome in women with first trimester bleeding  

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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.

Naemat Mohamed H.ELDin Shiry

2011-10-01

138

An improved method of measuring heart rate using a webcam  

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Measuring heart rate traditionally requires special equipment and physical contact with the subject. Reliable non-contact and low-cost measurements are highly desirable for convenient and comfortable physiological self-assessment. Previous work has shown that consumer-grade cameras can provide useful signals for remote heart rate measurements. In this paper a simple and robust method of measuring the heart rate using low-cost webcam is proposed. Blood volume pulse is extracted by proper Region of Interest (ROI) and color channel selection from image sequences of human faces without complex computation. Heart rate is subsequently quantified by spectrum analysis. The method is successfully applied under natural lighting conditions. Results of experiments show that it takes less time, is much simpler, and has similar accuracy to the previously published and widely used method of Independent Component Analysis (ICA). Benefitting from non-contact, convenience, and low-costs, it provides great promise for popularization of home healthcare and can further be applied to biomedical research.

Liu, Yi; Ouyang, Jianfei; Yan, Yonggang

2014-09-01

139

Simplifying cardiovascular risk estimation using resting heart rate.  

LENUS (Irish Health Repository)

Elevated resting heart rate (RHR) is a known, independent cardiovascular (CV) risk factor, but is not included in risk estimation systems, including Systematic COronary Risk Evaluation (SCORE). We aimed to derive risk estimation systems including RHR as an extra variable and assess the value of this addition.

Cooney, Marie Therese

2010-09-01

140

Heart Rate Variability Interventions for Concussion and Rehabilitation  

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

RobertLakeConder

2014-08-01

141

Match analysis and heart rate of futsal players during competition.  

Science.gov (United States)

Heart rates were monitored and time-motion analysis performed for 10 players (mean age 25.6 years, s = 2.5; body mass 73.8 kg, s = 5.7 kg; height 1.75 m, s = 0.06) during four competitive futsal matches. Mean heart rate during the match was 90% (s = 2) of maximum heart rate. Heart rate records were classified based on the percentage of time spent in three zones (>85%, 85-65%, and players spent 83%, 16%, and 0.3% in these three zones, respectively. During the second period, there was a significant reduction (P Players' movements were classified as standing, walking, jogging, medium-intensity running, high-intensity running, and sprinting (maximal speed running). Time-motion analysis indicated that the mean distance covered per minute of play was 117.3 m (s = 11.6), of which 28.5% (s = 2.2) was covered while performing medium-intensity running, 13.7% (s = 2) during high-intensity running, and 8.9% (s=3.4) while sprinting. From the results, we conclude that futsal is a multiple-sprints sport in which there are more high-intensity phases than in soccer and other intermittent sports. PMID:17899472

Barbero-Alvarez, J C; Soto, V M; Barbero-Alvarez, V; Granda-Vera, J

2008-01-01

142

Prediction of heart rate response to conclusion of the spontaneous breathing trial by fluctuation dissipation theory  

International Nuclear Information System (INIS)

The non-equilibrium fluctuation dissipation theorem is applied to predict how critically ill patients respond to treatment, based upon data currently collected by standard hospital monitoring devices. This framework is demonstrated on a common procedure in critical care: the spontaneous breathing trial. It is shown that the responses of groups of similar patients to the spontaneous breathing trial can be predicted by the non-equilibrium fluctuation dissipation approach. This mathematical framework, when fully formed and applied to other clinical interventions, may serve as part of the basis for personalized critical care. (paper)

143

A new physiological method for heart rate correction of the QT interval  

OpenAIRE

AIM—To reassess QT interval rate correction.?BACKGROUND—The QT interval is strongly and inversely related to heart rate. To compare QT intervals between different subjects with different heart rates requires the application of a QT interval rate correction formula. To date these formulae have inappropriately assumed a fixed relation between QT interval and heart rate. An alternative method of QT interval rate correction that makes no assumptions about the QT interval-heart rate relation...

Davey, P.

1999-01-01

144

Heart rate variability and target organ damage in hypertensive patients  

OpenAIRE

Abstract Background We evaluated the association between linear standard Heart Rate Variability (HRV) measures and vascular, renal and cardiac target organ damage (TOD). Methods A retrospective analysis was performed including 200 patients registered in the Regione Campania network (aged 62.4?±?12, male 64%). HRV analysis was performed by 24-h holter ECG. Renal damage was assessed by estimated glomerular filtration rate (eGFR), vascular damage by carotid in...

Melillo Paolo; Izzo Raffaele; Luca De Nicola; Pecchia Leandro

2012-01-01

145

Frequency dependent effect of selective biphasic left vagus nerve stimulation on heart rate and arterial pressure  

Directory of Open Access Journals (Sweden)

Full Text Available Activation of the parasympathetic pathway leads to negative chronotropic, dromotropic, and inotropic changes of heart function. The ability to selectively stimulate certain superficial compartments of peripheral nerves has been demonstrated previously. The aim of the present study was to find a clinically acceptable selective biphasic vagus nerve stimulation technique, which could allow gradual regulation of heart rate and systemic arterial pressure. In two patients, the left vagus nerve was stimulated with a combination of quasi-trapezoidal cathodic and rectangular anodic current pulses with different stimulation frequencies (10Hz, 20Hz, 30Hz and increasing current. The heart rate and systemic arterial pressure decreased with increasing current at all different stimulation frequencies (p<0.05. The heart rate and arterial pressure response was more gradual with 10Hz compared to 20Hz/30Hz vagus nerve stimulation (p<0.05. In conclusion, selective vagus nerve stimulation, with a combination of quasi-trapezoidal cathodic and rectangular anodic current pulses at 10Hz, offers gradual heart rate and systolic arterial pressure control.

MATEJ PODBREGAR

2012-10-01

146

Identifying genetic variants for heart rate variability in the acetylcholine pathway.  

Science.gov (United States)

Heart rate variability is an important risk factor for cardiovascular disease and all-cause mortality. The acetylcholine pathway plays a key role in explaining heart rate variability in humans. We assessed whether 443 genotyped and imputed common genetic variants in eight key genes (CHAT, SLC18A3, SLC5A7, CHRNB4, CHRNA3, CHRNA, CHRM2 and ACHE) of the acetylcholine pathway were associated with variation in an established measure of heart rate variability reflecting parasympathetic control of the heart rhythm, the root mean square of successive differences (RMSSD) of normal RR intervals. The association was studied in a two stage design in individuals of European descent. First, analyses were performed in a discovery sample of four cohorts (n?=?3429, discovery stage). Second, findings were replicated in three independent cohorts (n?=?3311, replication stage), and finally the two stages were combined in a meta-analysis (n?=?6740). RMSSD data were obtained under resting conditions. After correction for multiple testing, none of the SNPs showed an association with RMSSD. In conclusion, no common genetic variants for heart rate variability were identified in the largest and most comprehensive candidate gene study on the acetylcholine pathway to date. Future gene finding efforts for RMSSD may want to focus on hypothesis free approaches such as the genome-wide association study. PMID:25384021

Riese, Harriëtte; Muñoz, Loretto M; Hartman, Catharina A; Ding, Xiuhua; Su, Shaoyong; Oldehinkel, Albertine J; van Roon, Arie M; van der Most, Peter J; Lefrandt, Joop; Gansevoort, Ron T; van der Harst, Pim; Verweij, Niek; Licht, Carmilla M M; Boomsma, Dorret I; Hottenga, Jouke-Jan; Willemsen, Gonneke; Penninx, Brenda W J H; Nolte, Ilja M; de Geus, Eco J C; Wang, Xiaoling; Snieder, Harold

2014-01-01

147

Omega-3 Polyunsaturated Fatty Acids and Heart Rate Variability  

OpenAIRE

Omega-3 polyunsaturated fatty acids (PUFA) may modulate autonomic control of the heart because omega-3 PUFA is abundant in the brain and other nervous tissue as well as in cardiac tissue. This might partly explain why omega-3 PUFA offer some protection against sudden cardiac death (SCD). The autonomic nervous system is involved in the pathogenesis of SCD. Heart rate variability (HRV) can be used as a non-invasive marker of cardiac autonomic control and a low HRV is a predictor for SCD and arr...

JeppeHagstrupChristensen

2011-01-01

148

Pathogen-induced heart rate changes associated with cholinergic nervous system activation  

OpenAIRE

The autonomic nervous system plays a central role in regulation of host defense and in physiological responses to sepsis, including changes in heart rate and heart rate variability. The cholinergic anti-inflammatory response, whereby infection triggers vagal efferent signals that dampen production of proinflammatory cytokines, would be predicted to result in increased vagal signaling to the heart and increased heart rate variability. In fact, decreased heart rate variability is widely describ...

Fairchild, Karen D.; Srinivasan, Varadamurthy; Randall Moorman, J.; Gaykema, Ronald P. A.; Goehler, Lisa E.

2011-01-01

149

Functionality of the baroreceptor nerves in heart rate regulation  

DEFF Research Database (Denmark)

Two models describing the afferent baroreceptor firing are analyzed, a basic model predicting firing using a single nonlinear differential equation, and an extended model, coupling K nonlinear responses. Both models respond to the the rate (derivative) and the rate history of the carotid sinus arterial pressure. As a result both the rate and the relative level of the carotid sinus arterial pressure is sensed. Simulations with these models show that responses to step changes in pressure follow from the rate sensitivity as observed in experimental studies. Adaptation and asymmetric responses are a consequence of the memory encapsulated by the models, and the nonlinearity gives rise to sigmoidal response curves. The nonlinear afferent baroreceptor models are coupled with an effector model, and the coupled model has been used to predict baroreceptor feedback regulation of heart rate during postural change from sitting to standing and during head-up tilt. The efferent model couples the afferent nerve paths to the sympathetic and parasympathetic outflow, and subsequently predicts the build up of an action potential at the sinus knot of the heart. In this paper, we analyze the nonlinear afferent model and show that the coupled model is able to predict heart rate regulation using blood pressure data as an input.

Ottesen, Johnny T.; Olufsen, Mette

2011-01-01

150

Determination of Heart Rate from ECG Signal- A Simplified Approach  

Directory of Open Access Journals (Sweden)

Full Text Available Electrocardiography is a non-invasive technique of registration of the electrical activity of the heart and is widely used as a diagnostic tool by the physicians. ECG signal yields information about the conditions of the heart. Among many morphological markers of the ECG, the QRS complex and the R-peaks are the most significant ones---with the contribution of the R-peak to RR interval being a driving factor. The number of R-peaks in a specified interval leads to the determination of the heart rate in beats per minute. This calls for an efficient R-peak detection algorithm. The authors have suggested here a straight-forward algorithm, the efficacy of which has been improved by enhancing the quality of the ECG signal by EMD method. The performance has been compared with Pan-Tompkins algorithm---a benchmark method and also against the original values obtained from MIT/BIH database.

Sautami Basu*,

2014-12-01

151

Influence of transrectal and transabdominal ultrasound examination on salivary cortisol, heart rate, and heart rate variability in mares.  

Science.gov (United States)

Pregnancy diagnostics in equine reproduction are routinely performed using transrectal ultrasonography, although it is also possible to visualize the fetus by transabdominal ultrasound examinations from the 90th day of gestation onward. We hypothesized that ultrasound examinations may stress the mare and that the gestational stage status and lactation may influence the mare's stress reaction. To investigate the stress reaction, 25 thoroughbred mares of different age, pregnancy and lactational status underwent a transrectal examination. In pregnant mares, an additional transabdominal examination was performed. Salivary cortisol concentration, mean heart rate, and heart rate variability of mares were assessed to evaluate the reactions of hypothalamic-pituitary-adrenal (HPA) axis and of the autonomic nervous system. Significant differences were observed between lactating and nonlactating mares; with a lower responsiveness to stress in lactating mares. The transrectal ultrasound examination in nonlactating mares induced a significant increase in salivary cortisol (P < 0.05), and in the heart rate variability parameter, ratio of low to high frequencies (P < 0.05). This reflects an activation of the HPA axis and a shift to more sympathetic dominance. In contrast, a transabdominally performed pregnancy check did not induce an activation of the HPA axis over basal level but increased the mean heart rate and low to high frequency ratio. The results of this study indicate that checks of advanced pregnancies can be easily performed by transabdominal ultrasonography. With regard to animal welfare, this technique should be preferred during midgestation in nonlactating mares. PMID:25529317

Schönbom, Hanno; Kassens, Ana; Hopster-Iversen, Charlotte; Klewitz, Jutta; Piechotta, Marion; Martinsson, Gunilla; Kißler, Andreas; Burger, Dominik; Sieme, Harald

2015-03-01

152

Electron-beam CT coronary angiography in the patients with high heart rate arrhythmia or pacemaker  

International Nuclear Information System (INIS)

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)

153

Fetal heart rate pattern and umbilical cord nucleated RBC count  

Directory of Open Access Journals (Sweden)

Full Text Available "nBackground: Previous studies have suggested the presence of a relationship between the increase of NRBC and the duration and intensity of asphyxia. The purpose of this study was to evaluate the relationship of fetal heart rate pattern and the number of NRBC's in umbilical cord blood sample at birth. "nMethods: We enrolled 322 pregnant women with healthy, term fetuses who referred to Mirza Kouchak Khan Hospital for pregnancy termination in 2005 in a case-control study. All patients underwent continuous FHR monitoring and based on their FHR pattern, they were divided into two groups with normal FHR pattern and at least one abnormality in FHR pattern (including absence of beat to beat variability; absence of proper acceleration; and early, late, variable and prolonged deceleration. Samples of umbilical cord blood were evaluated for NRBC count and pH immediately after birth. The variables were compared in these two groups. "nResults: The mean NRBC count was significantly higher in patients with any kind of deceleration (late, variable, early or prolonged in comparison with controls (respectively 11.88±4.406, 8.32±4.64, 10.58±5.366, and 4.11±4.913 vs. 0.93±1.790 in controls. Furthermore the mean NRBC count was significantly higher in patients with absence of acceleration or beat to beat variability (10.73±5.07 and 13.73±3.58 vs. 1.47±2.50. There was a negative correlation between 5th minute Apgar score and umbilical cord blood sample with mean NRBC count of umbilical cord blood sample. "nConclusion: Any abnormality in FHR pattern is associated with a significant increase in mean NRBC count of umbilical cord blood sample. There is also a significant relationship between the 5th minute Apgar score and umbilical cord blood sample pH, and mean NRBC count in umbilical cord blood sample.

Niroumanesh Sh

2009-04-01

154

Peripheral oxygen saturation, heart rate, and blood pressure during dental treatment of children with cyanotic congenital heart disease  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english OBJECTIVES: In this observational study, we evaluated the peripheral oxygen saturation (SpO2), heart rate, and blood pressure of children with cyanotic congenital heart disease who were undergoing dental extraction. METHODS: Forty-four patients between the ages of 6 and 12 years who underwent upp [...] er primary tooth extraction were included in the study. Of these, 20 patients were in the cyanotic congenital heart disease group and 24 were in the control group. RESULTS: Peripheral oxygen saturation, heart rate, and systolic blood pressure in the cyanotic congenital heart disease group varied quite significantly during the treatment protocol (p

Rosane Menezes Faria, Dutra; Itamara Lucia Itagiba, Neves; Ricardo Simões, Neves; Edmar, Atik; Ubiratan de Paula, Santos.

155

Qigong Effects on Heart Rate Variability and Peripheral Vasomotor Responses.  

Science.gov (United States)

Population aging is occurring worldwide, and preventing cardiovascular event in older people is a unique challenge. The aim of this study was to examine the effects of a 12-week qigong (eight-form moving meditation) training program on the heart rate variability and peripheral vasomotor response of middle-aged and elderly people in the community. This was a quasi-experimental study that included the pre-test, post-test, and nonequivalent control group designs. Seventy-seven participants (experimental group = 47; control group = 30) were recruited. The experimental group performed 30 min of eight-form moving meditation 3 times per week for 12 weeks, and the control group continued their normal daily activities. After 12 weeks, the interaction effects indicated that compared with the control group, the experimental group exhibited significantly improved heart rate variability and peripheral vasomotor responses. PMID:24869492

Chang, Mei-Ying

2014-05-27

156

Low Cost Heart Rate Monitor Using Led-Led Sensor  

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Full Text Available A high sensitivity, low power and low cost sensor has been developed for photoplethysmography (PPG measurement. The PPG principle was applied to follow the dilatation and contraction of skin blood vessels during the cardiac cycle. A standard light emitting diodes (LEDs has been used as a light emitter and detector, and in order to reduce the space, cost and power, the classical analogue-to-digital converters (ADCs replaced by the pulse-based signal conversion techniques. A general purpose microcontroller has been used for the implementation of measurement protocol. The proposed approach leads to better spectral sensitivity, increased resolution, reduction in cost, dimensions and power consumption. The basic sensing configuration presented is capable of detecting the PPG signal from a finger or toe, and it is very simple to extract the heart rate and heart rate variability from such a signal.

Ahmed Mahrous Ragib

2009-01-01

157

The physiology of fetal heart rate patterns and perinatal asphyxia.  

Science.gov (United States)

The purpose of electronic fetal heart rate (FHR) monitoring is the ongoing assessment of fetal oxygenation. FHR tracings are analyzed for characteristic patterns that signify specific hypoxic or nonhypoxic events. A working knowledge of fetal physiology and the fetal response to hypoxia can aid and refine clinical interpretation of FHR patterns during labor. This article reviews the fetal response to decreased oxygenation, the physiology of subsequent FHR patterns and the clinical presentation of asphyxia in the newborn. PMID:11930377

King, T; Parer, J

2000-12-01

158

Heart rate variability in the dog: is it too variable?  

OpenAIRE

The purpose of the study was to evaluate resting heart rate variability (HRV) as a simple noninvasive screening test for early autonomic derangement, heralding the development of occult dilated cardiomyopathy (DCM). Time and frequency domain HRV parameters were evaluated in 32 healthy Doberman pinschers, as potential predictors of the development of occult DCM within the following year and correlated with plasma catecholamines, markers of sympathoexcitation. Ten Dobermans with occult DCM and ...

Minors, S. L.; O Grady, M. R.

1997-01-01

159

Monitoring of fetal heart rate and uterine activity  

OpenAIRE

In this thesis a renewed monitoring technique for fetal heart rate (FHR) and uterine activity has been investigated. Through non-invasive measurements of electrical signals as recorded from the maternal abdomen, both the fetal-electrocardiogram (fECG) and uterine electrohysterogram (EHG) can be filtered for calculation of FHR and uterine contractions, respectively. This monitoring technique has been known for over 100 years, however due to technical difficulties clinical implementation has no...

Graatsma, E. M.

2010-01-01

160

Heart rate variability biofeedback: How and why does it work?  

OpenAIRE

In recent years there has been substantial support for Heart Rate Variability Biofeedback (HRVB) as a treatment for a variety of disorders and for performance enhancement (Gevirtz, 2013). Since conditions as widely varied as asthma and depression seem to respond to this form of cardiorespiratory feedback training, the issue of possible mechanisms becomes more salient. The most supported possible mechanism is the strengthening of homeostasis in the barorecptor (Vashillo, et al, 2002; Lehrer, ...

PaulMLehrer

2014-01-01

161

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

OpenAIRE

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

Chouchou, Florian; Desseilles, Martin

2014-01-01

162

Neural networks for heart rate time series analysis  

OpenAIRE

The dissertation introduces method and algorithm development for nonstationary, nonlinear and dynamic signals. Furthermore, the dissertation concentrates on applying neural networks for time series analysis. The presented methods are especially applicable for heart rate time series analysis.Some classical methods for time series analysis are introduced, including improvements and new aspects for existing data preprocessing and modeling procedures, e.g., time series segmentation, digital filte...

Saalasti, Sami

2003-01-01

163

Heart Rate Variability in Patients With Multiple Sclerosis  

OpenAIRE

Objective: The aims of the present study were to compare heart rate variability (HRV) parameters of patients with multiple sclerosis (MS) and healthy controls and to investigate the correlations between HRV parameters and disease duration, subtype and severity.Methods: Thirty-two patients with MS [18 with relapsing-remitting MS (RRMS), 4 with primary progressive MS (PPMS) and 10 with secondary progressive MS (SPMS)] and 32 healthy, age-and sex-matched volunteers were included. HRV was evaluat...

Bektas?li, Fevzi; Yildiz, O?zlem Kay?m; Segmen, Hatice; Bolayir, Ertug?rul; Topaktas?, Suat

2009-01-01

164

Heart rate response to facial immersion and apnea in quadriplegia.  

Science.gov (United States)

Profound bradycardia is a common complication in the early posttraumatic period following cervical spinal cord damage. It is thought to be due to temporary inactivity of the sympathetic nervous system after separation from supraspinal control, coupled with unopposed parasympathetic dominance because of vagus nerve sparing. Hypoxia, underventilation, and tracheal suctioning appear to intensify the bradycardia. This study examined the effect of vagal stimulation using facial immersion and apnea on heart rate in patients with quadriplegia. Ten patients with quadriplegia (eight males and two females, mean age 25, age range 16-37) and ten healthy controls (eight males and two females, mean age 25, age range 15-37) underwent facial immersion during ECG monitoring. The patients with quadriplegia were studied at a mean of 9.4 months after injury (range, 4-26 months); cord level of injury ranged from C5 to C8; seven of the ten had had heart rates of less than 50 beats/min in the early period after injury and five of the ten had received treatment for this. No change in heart rate was seen in the quadriplegic group during facial immersion (delta = 1.5 +/- 2.7 beats/min, mean +/- SE), but a significant drop in heart rate was seen in the control group (delta = -12.2 +/- 3.7 beats/min, mean +/- SE; p less than 0.01). No significant decreases were seen in either group during apnea alone. Patients with chronic quadriplegia appear to have less sensitivity than controls to the vagal-stimulating maneuver of facial immersion and apnea. PMID:4062529

Garner, S H; Bloch, R F; Sutton, J R

1985-11-01

165

Cuff inflation during ambulatory blood pressure monitoring and heart rate  

OpenAIRE

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 populat...

Mia Skov-Madsen; My Svensson; Jeppe Hagstrup Christensen

2008-01-01

166

Comparison of heart rate variability adjusted for age and heart rate in women with rheumatoid arthritis and women without rheumatic diseases  

Directory of Open Access Journals (Sweden)

Full Text Available Aim. To compare the 24-hour indicators of heart rate variability (HRV, adjusted for age and 24-hour average heart rate (HR24 in women with rheumatoid arthritis (RA and womenof the control group.Material and methods. Women with RA (n=291 at the age of 20-60 were examined. Women without rheumatic diseases (n=125 were included into control group. The presenceof traditional cardiovascular risk factors, the results of 24-hour ECG monitoring were assessed in addition to clinical symptoms, RA activity and severity. Transformation ofthe initial HRV parameters in their logarithms, and the standardization of the logarithms of age and HR24, the calculation of the exponential of the standardized logarithm wereperformed to remove the effects of age and heart rate on HRV.Results. Time and frequency HRV indices, adjusted for age and HP24 (HRVa in women with RA were lower than these in women of control group. HRVa decline was observed in14–24% of women with RA. The maximum HRVa decrease was observed among the parameters that reflect an activity of parasympathetic autonomic nervous system (RMSSDn,pNN50n, HFn.Conclusion. The young and middle age women with RA differ from the women of the control group in significant decrease in the time and spectral HRV indices adjusted forage and HR24.

D.S. Novikova

2013-04-01

167

256-slice CT coronary angiography in atrial fibrillation: The impact of mean heart rate and heart rate variability on image quality  

International Nuclear Information System (INIS)

Objective: The aim of this study was to evaluate the image quality of 256-MDCT in atrial fibrillation and to compare the findings with those among patients in sinus rhythm. Materials: All reconstructed images were evaluated by two independent experienced readers blinded to patient information, heart rate, and ECG results to assess the diagnostic quality of images of the coronary artery segments using axial images, multi-planar reformations, maximum intensity projections, and volume rendering technique. Results: No statistical significance was detected in terms of the overall image quality between patients in sinus rhythm and with atrial fibrillation. Pearson's correlation analysis showed no significant association between image quality and mean heart rate no matter for patients in sinus rhythm or with atrial fibrillation. Similarly, there was no correlation between image quality and heart rate variability for either patients in sinus rhythm or with atrial fibrillation. Our results showed that the optimal reconstruction window depends on patient's HR, and the pattern for patients in atrial fibrillation is similar to that obtained from non-atrial fibrillation patients. Conclusion: This study shows the potential of using 256-MDCT coronary angiography in patients with atrial fibrillation. Our results suggest that when appropriate reconstruction timing window is applied, patients with atrial fibrillation do not have to be excluded from MDCT coronary angiographic examinatiofrom MDCT coronary angiographic examinations.

168

Application of empirical mode decomposition to heart rate variability analysis.  

Science.gov (United States)

The analysis of heart rate variability, involving changes in the autonomic modulation conditions, demands specific capabilities not provided by either parametric or non-parametric spectral estimation methods. Moreover, these methods produce time-averaged power estimates over the entire length of the record. Recently, empirical mode decomposition and the associated Hilbert spectra have been proposed for non-linear and non-stationary time series. The application of these techniques to real and simulated short-term heart rate variability data under stationary and non-stationary conditions is presented. The results demonstrate the ability of empirical mode decomposition to isolate the two main components of one chirp series and three signals simulated by the integral pulse frequency modulation model, and consistently to isolate at least four main components localised in the autonomic bands of 14 real signals under controlled breathing manoeuvres. In addition, within the short time-frequency range that is recognised for heart rate variability phenomena, the Hilbert amplitude component ratio and the instantaneous frequency representation are assessed for their suitability and accuracy in time-tracking changes in amplitude and frequency in the presence of non-stationary and non-linear conditions. The frequency tracking error is found to be less than 0.22% for two simulated signals and one chirp series. PMID:11523737

Echeverría, J C; Crowe, J A; Woolfson, M S; Hayes-Gill, B R

2001-07-01

169

Focus on ivabradine: a new heart rate-controlling drug.  

Science.gov (United States)

Angina pectoris is a cardiac condition characterized by an insufficient perfusion to meet myocardial metabolic demand. A high heart rate represents an important factor in the induction of myocardial ischemia and subsequent angina. beta-blocker drugs are effective at reducing angina pectoris by decreasing the heart rate and are usually preferred as initial therapy in the absence of contraindication or intolerance. Ivabradine, a new oral drug for the symptomatic treatment of chronic stable angina pectoris, decreases the resting heart rate of patients with normal sinus rhythm. In many clinical trials, ivabradine has been directly compared with placebo, beta-blocker drugs (e.g., atenolol and propranolol) and calcium channel blockers (e.g., amlodipine). These studies have demonstrated ivabradine, given in doses of 5-10 mg twice daily, to be more effective than placebo for increasing time to angina onset and noninferior to atenolol 50-100 mg daily and amlodipine 10 mg daily for increasing total exercise duration in patients with chronic stable angina. Visual symptoms, a transient, enhanced brightness in a limited area of the visual field known as luminous phenomena or phosphenes, were the most common adverse effects in clinical trials. This article aims to provide a research update regarding this new drug, based on a literature search. PMID:19210206

Riccioni, Graziano

2009-02-01

170

Experimental heart rate regulation in cycle-ergometer exercises.  

Science.gov (United States)

The heart rate can be effectively used as a measure of the exercise intensity during long duration cycle-ergometer exercises: precisely controlling the heart rate (HR) becomes crucial especially for athletes or patients with cardiovascular/obesity problems. The aim of this letter is to experimentally show how the nonlocal and nonswitching nonlinear control that has been recently proposed in the literature for the HR regulation in treadmill exercises can be effectively applied to cycle-ergometer exercises at constant cycling speed. The structure of the involved nonlinear model for the HR dynamics in cycle-ergometer exercises is mathematically inspired by the structure of a recently identified and experimentally validated nonlinear model for the HR dynamics in treadmill exercises: the role played by the treadmill speed is played here by the work load while the zero speed case for the treadmill exercise is here translated into the cycling operation under zero work load. Experimental results not only validate the aforementioned nonlinear model but also demonstrate the effectiveness--in terms of precise HR regulation--of an approach which simply generalizes to the nonlinear framework the classical proportional-integral control design. The possibility of online modifying the HR reference on the basis of the heart rate variability (HRV) is also suggested and experimentally motivated. PMID:23086500

Paradiso, Michele; Pietrosanti, Stefano; Scalzi, Stefano; Tomei, Patrizio; Verrelli, Cristiano Maria

2013-01-01

171

System analysis of heart rate control in man.  

Science.gov (United States)

The dynamic property of the heart rate response to exercise was determined and expressed in the frequency domain to establish a method of examining cardiovascular control function. The response of heart rate to a stimulus was measured at 5-s intervals in nine healthy young volunteers. The stimulus consisted of several runs of two-step exercise practiced in semirandom sequence for 19 min. The weight function of the system was estimated from autocorrelation function of the input signal and cross-correlation function between the input and output signals. The weight function was transformed into a transfer function and its Bode plot diagram was drawn. From the diagram, four dynamic parameters were determined. These parameters are as follows: K is a constant showing the theoretical steady-state increment of heart rate, and T1, T2, T3 are time constants. The values obtained in the present experiment with the healthy young males were: K 46.0 +/- 14.6 beats, T1, 2.12 +/- 0.44, T2, 1.12 +/- 0.16, and T3 0.70 +/- 0.07 min. PMID:993169

Sato, I; Hasegawa, Y; Hotta, K

1976-11-01

172

Heart Rate Variability and Nonlinear Dynamics in Risk Stratification  

Directory of Open Access Journals (Sweden)

Full Text Available The time domain measures and power spectral analysis of heart rate variability (HRV are classic conventional methods to assess the complex regulatory system between autonomic nervous system and heart rate and are most widely used. There are abundant scientific data about the prognostic significance of the conventional measurements of HRV in patients with various conditions, particularly with myocardial infarction. Some studies have suggested that some newer measures describing nonlinear dynamics of heart rate, such as fractal measures, may reaveal prognostic information beyond that obtained by the conventional measures of HRV. An ideal risk indicator could specifically predict sudden arrhythmic death as the implantable cardioverter-defibrillator (ICD therapy can prevent such events. In postinfarction patients, numerically the highest number of sudden deaths occur in patients with better preserved left ventricular function than in those with severe left ventricular dysfunction. Recent data support the concept that HRV measurements, when analyzed several weeks after acute myocardial infarction, predict life-threatening ventricular tachyarrhythmias in patients with moderately depressed left ventricular function. However, well-designed prospective randomized studies are needed to evaluate whether the ICD therapy based on the assessment of HRV alone or with other risk indicators improves the patients´ prognosis. Several issues, such as the optimal target population, optimal timing of HRV measurements, optimal methods of HRV analysis and optimal cutpoints for different HRV parameters, need clarification before the HRV analysis can be a widespread clinical tool in risk stratification.

JuhaPerkiömäki

2011-11-01

173

Local dynamics of heart rate: detection and prognostic implications.  

Science.gov (United States)

The original observation that reduced heart rate variability (HRV) confers poor prognosis after myocardial infarction has been followed by many studies of heart rate dynamics. We tested the hypothesis that an entropy-based local dynamics measure gave prognostic information in ambulatory patients undergoing 24-h electrocardiography. In this context, entropy is the probability that short templates will find matches in the time series. We studied RR interval time series from 24-h Holter monitors of 1564 consecutive patients over age 39. We generated histograms of the count of templates as a function of the number of templates matches in short RR interval time series, and found characteristic appearance of histograms for atrial fibrillation, sinus rhythm with normal HRV, and sinus rhythm with reduced HRV and premature ventricular contractions (PVCs). We developed statistical models to detect the abnormal dynamic phenotype of reduced HRV with PVCs and fashioned a local dynamics score (LDs) that, after controlling for age, added more prognostic information than other standard risk factors and common HRV metrics, including, to our surprise, the PVC count and the HRV of normal-to-normal intervals. Addition of the LDs to a predictive model using standard risk factors significantly increased the ROC area and the net reclassification improvement was 27%. We conclude that abnormal local dynamics of heart rate confer adverse prognosis in patients undergoing 24-h ambulatory electrocardiography. PMID:25229393

Moss, Travis J; Lake, Douglas E; Moorman, J Randall

2014-10-01

174

Association between the Rating Perceived Exertion, Heart Rate and Blood Lactate in Successive Judo Fights (Randori  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: This study aims to investigate the association between the rating of perceived exertion (RPE, heart rate (HR and the blood lactate concentration ([La] in successive judo fight simulations (randori.Methods: Ten athletes participated in the study (age: 25.6±2.1 years; stature: 1.75±0.07 m; body mass: 75.6±14.9kg; %BF: 11.5±7.8%; practice: 14.5±6.2 years and completed 4 judo fight simulations (T1 to T4 with duration of 5 min separated by 5 min passive recovery periods. Before each randori, [La] and HR were collected, and after each randori, the same measures and the RPE (CR-10 scale were collected.Results: Significant correlations were observed between: (1 CR-10 and HR (T2: r =0.70; T3: r =0.64; both, P<0.05; (2 ?CR-10 and ?[La] (T1-T2: r = .71, P< 0.05; T2-T3: r =0.92, P<0.01; T3-T4: r =0.73, P<0.05. Moreover, significant differences were noted in the behavior of the HR between the 2nd (T2 and 3rd (T3 judo fight simulations (P<0.05.Conclusion: The use of CR-10 in the evaluation process, as well as in deciding the load of training in judo, should be done with caution

Braulio Henrique Magnani Branco

2013-06-01

175

Heart rate variability in patients with chronic cerebral ischemia  

Directory of Open Access Journals (Sweden)

Full Text Available The purpose of the work is to estimate the status of autonomic nervous system in patients with chronic cerebral ischemia by means of the analysis of heart rate variability at various stages of disease. 120 patients with chronic cerebral ischemia aged from 45 to 65 took part in the research. The comparison group included 30 patients with an arterial hypertension and without chronic cerebral ischemia. Heart rate variability analisis included time-domain and frequency-domain methods of five-minute sequence of the electrocardiographic intervals registered in at rest and in or-thostatic probe. The results of research have shown, that autonomic disorders with prevalence of sympathetic nervous system accompany initial implications of chronic cerebral ischemia. The second stage of disease is characterized by depression of activity of both autonomic, and central regulation. The expressed depression of autonomic maintenance of regulation of heart rhythm of both from sympathetic, and from parasympathetic nervous system was observed at the third stage of chronic cerebral ischemia

Smyshlaeva ?.?.

2010-12-01

176

BREAKDOWN OF SCALING PROPERTIES IN ABNORMAL HEART RATE VARIABILITY  

Directory of Open Access Journals (Sweden)

Full Text Available The heart rate variability (HRV of subjects with normal sinus rhythm (NSR and subjects with congestive heart failure(CHF is compared by using a structure function borrowed from turbulence studies. Firstly, it is shown that the HRV ofsubjects with NSR displays a power law scaling property, which indicates the presence of structured heartbeat controlmechanisms. Secondly, it is found that such a scaling property is partially lost for subjects with CHF. The absence ofscaling properties is associated to the presence of uncorrelated (i.e., noise-like heart rate variations. In order to gaininsights on the source of the scaling property, the HRV is analyzed from a systemic (i.e., feedback control viewpoint inthe frequency domain. It is found that the HRV of subjects with NSR is governed by a stable adaptive control mechanismpresumably located in the autonomic nervous system. In the case of subjects with CHF, the results show that thisregulation mechanism is partially or totally absent, which is interpreted as the cause of the breakdown of the scalinglaw property.

Rodríguez, E.

2006-04-01

177

Respiratory modulation and baroreflex control of heart rate in space  

Science.gov (United States)

During everyday life, gravity constantly stresses the human circulation by diminishing venous return in the upright position. This induces baroreflex-mediated cardiovascular adjustments that are aimed to prevent the blood pressure from falling. In weightlessness, gravitational pressure gradients do not arise in the circulation so that baroreflex function remains chronically unchallenged. This may contribute to the development of post spaceflight orthostatic intolerance. The purpose of this study was to evaluate respiratory modulation and baroreflex control of heart rate after a week of weightlessness in space. We tested the hypothesis that cardiovascular control in space will be similar to the baseline supine condition on Earth. We studied nine male cosmonauts during seven different space missions aboard the ISS (age 40 - 52 yrs, height 1.69 - 1.85 m, weight 67 - 90 kg). Data collection was performed between 30 and 45 days before launch in the standing and supine positions, and after 8 days in space. Cosmonauts were carefully trained to perform in-flight data collection by themselves. They were instructed to pace their breathing to a fixed rate of 12 breaths per minute (0.2 Hz) for a total duration of 3 minutes. The electrocardiogram and beat-by-beat finger arterial blood pressure were recorded at 1-kHz sample rate. Respiratory rate was evaluated using an abdominal pressure sensor. We used power spectral analysis to calculate respiratory sinus arrhythmia (RSA) as well as the low-frequency (0.04 - 0.15 Hz) powers of spontaneous oscillations in heart rate and systolic blood pressure. Baroreflex sensitivity (BRS) was estimated in the time domain using cross-correlation analysis. As expected, there was a rise in heart rate upon assuming the standing position before space- flight (59 ± 6 to 79 ± 11 beats per min; p ¡ 0.001). This was accompanied by an increase in mean arterial blood pressure (84 ± 6 to 93 ± 6 mmHg; p ¡ 0.001). Standing up further induced a marked increase in the low-frequency powers of systolic blood pressure oscillations (8 ± 7 to 17 ± 11 mmHg2; p = 0.018), whereas those in heart rate remained unchanged (445 ± 512 to 621 ± 799 ms2; p = 0.315). Alternatively, there was a reduction in RSA from 546 ± 167 ms2 to 158 ± 298 ms2 and in spontaneous BRS from 14 ± 5 ms/mmHg to 6 ± 2 ms/mmHg upon changing from supine to standing (both p ¡ 0.001). After a week of weightlessness in space, heart rate (61 ± 8 beats per min) and mean blood pressure (83 ± 6 mmHg) returned to the pre-flight supine values. This was also true for the low-frequency powers of systolic blood pressure (7 ± 4 mmHg2) and of heart rate (741 ± 716 ms2), as well as for RSA (465 ± 269 ms2) and spontaneous BRS (14 ± 4 ms/mmHg). It is concluded that cardiovascular control after one week in space corresponds to the pre-flight supine condition. This is characterized by a chronically increased vagal-cardiac outflow and suppressed sympathetic vasomotor modulation compared with the standing position on Earth. This kind of chronic baroreflex unloading is likely to contribute to post-spaceflight functional impairment of orthostatic blood pressure control.

Verheyden, Bart; Couckuyt, Kurt; Liu, Jiexin; Aubert, Andre

178

Heart rate dynamics during a treadmill cardiopulmonary exercise test in optimized beta-blocked heart failure patients  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english BACKGROUND: Calculating the maximum heart rate for age is one method to characterize the maximum effort of an individual. Although this method is commonly used, little is known about heart rate dynamics in optimized beta-blocked heart failure patients. AIM: The aim of this study was to evaluate hear [...] t rate dynamics (basal, peak and % heart rate increase) in optimized beta-blocked heart failure patients compared to sedentary, normal individuals (controls) during a treadmill cardiopulmonary exercise test. METHODS: Twenty-five heart failure patients (49±11 years, 76% male), with an average LVEF of 30±7%, and fourteen controls were included in the study. Patients with atrial fibrillation, a pacemaker or noncardiovascular functional limitations or whose drug therapy was not optimized were excluded. Optimization was considered to be 50 mg/day or more of carvedilol, with a basal heart rate between 50 to 60 bpm that was maintained for 3 months. RESULTS: Basal heart rate was lower in heart failure patients (57±3 bpm) compared to controls (89±14 bpm; p

Vitor Oliveira, Carvalho; Guilherme Veiga, Guimarães; Emmanuel Gomes, Ciolac; Edimar Alcides, Bocchi.

179

Reading multifractal spectra: Aging by multifractal analysis of heart rate  

Science.gov (United States)

The method of effective reading of multifractal properties is proposed. The method consists in the analysis of a given signal together with the analysis of an integrated signal. A practical way to separate monofractal-type signals from other signals is given. The method is applied to 24-hour ECG recordings of RR-interbeat intervals to assess the effect of aging on autonomic regulation of the heart in healthy adults. Heart rate variability is evaluated by multifractal analysis in the VLF band. A switch from mono- to multifractality is observed between diurnal and nocturnal parts of series in the group of young adults. With aging the multifractal structure of nocturnal signals declines. The observed changes can be related to the circadian alternation in the central mechanisms controlling the cardiovascular system which becomes impaired with advance in age in human. Indices for age impairment of autonomic regulation are proposed.

Makowiec, D.; Rynkiewicz, A.; Ga?aska, R.; Wdowczyk-Szulc, J.; ?arczy?ska-Buchowiecka, M.

2011-06-01

180

Analysis of heart rate variability using fuzzy measure entropy.  

Science.gov (United States)

This paper proposed a new entropy measure, Fuzzy Measure Entropy (FuzzyMEn), for the analysis of heart rate variability (HRV) signals. FuzzyMEn was calculated based on the fuzzy set theory and improved the poor statistical stability in the approximate entropy (ApEn) and sample entropy (SampEn). The simulation results also demonstrated that the FuzzyMEn had better algorithm discrimination ability when compared with the recently published fuzzy entropy (FuzzyEn), The validity of FuzzyMEn was tested for clinical HRV analysis on 120 subjects (60 heart failure and 60 healthy control subjects). It is concluded that FuzzyMEn could be considered as a valid and reliable method for a clinical HRV application. PMID:23273774

Liu, Chengyu; Li, Ke; Zhao, Lina; Liu, Feng; Zheng, Dingchang; Liu, Changchun; Liu, Shutang

2013-02-01

181

Identification of heart rate-associated loci and their effects on cardiac conduction and rhythm disorders  

DEFF Research Database (Denmark)

Elevated resting heart rate is associated with greater risk of cardiovascular disease and mortality. In a 2-stage meta-analysis of genome-wide association studies in up to 181,171 individuals, we identified 14 new loci associated with heart rate and confirmed associations with all 7 previously established loci. Experimental downregulation of gene expression in Drosophila melanogaster and Danio rerio identified 20 genes at 11 loci that are relevant for heart rate regulation and highlight a role for genes involved in signal transmission, embryonic cardiac development and the pathophysiology of dilated cardiomyopathy, congenital heart failure and/or sudden cardiac death. In addition, genetic susceptibility to increased heart rate is associated with altered cardiac conduction and reduced risk of sick sinus syndrome, and both heart rate-increasing and heart rate-decreasing variants associate with risk of atrial fibrillation. Our findings provide fresh insights into the mechanisms regulating heart rate and identifynew therapeutic targets.

den Hoed, Marcel; Eijgelsheim, Mark

2013-01-01

182

Identification of heart rate–associated loci and their effects on cardiac conduction and rhythm disorders  

Science.gov (United States)

Elevated resting heart rate is associated with greater risk of cardiovascular disease and mortality. In a 2-stage meta-analysis of genome-wide association studies in up to 181,171 individuals, we identified 14 new loci associated with heart rate and confirmed associations with all 7 previously established loci. Experimental downregulation of gene expression in Drosophila melanogaster and Danio rerio identified 20 genes at 11 loci that are relevant for heart rate regulation and highlight a role for genes involved in signal transmission, embryonic cardiac development and the pathophysiology of dilated cardiomyopathy, congenital heart failure and/or sudden cardiac death. In addition, genetic susceptibility to increased heart rate is associated with altered cardiac conduction and reduced risk of sick sinus syndrome, and both heart rate–increasing and heart rate–decreasing variants associate with risk of atrial fibrillation. Our findings provide fresh insights into the mechanisms regulating heart rate and identify new therapeutic targets. PMID:23583979

den Hoed, Marcel; Eijgelsheim, Mark; Esko, Tõnu; Brundel, Bianca J J M; Peal, David S; Evans, David M; Nolte, Ilja M; Segrè, Ayellet V; Holm, Hilma; Handsaker, Robert E; Westra, Harm-Jan; Johnson, Toby; Isaacs, Aaron; Yang, Jian; Lundby, Alicia; Zhao, Jing Hua; Kim, Young Jin; Go, Min Jin; Almgren, Peter; Bochud, Murielle; Boucher, Gabrielle; Cornelis, Marilyn C; Gudbjartsson, Daniel; Hadley, David; Van Der Harst, Pim; Hayward, Caroline; Heijer, Martin Den; Igl, Wilmar; Jackson, Anne U; Kutalik, Zoltán; Luan, Jian’an; Kemp, John P; Kristiansson, Kati; Ladenvall, Claes; Lorentzon, Mattias; Montasser, May E; Njajou, Omer T; O’Reilly, Paul F; Padmanabhan, Sandosh; Pourcain, Beate St.; Rankinen, Tuomo; Salo, Perttu; Tanaka, Toshiko; Timpson, Nicholas J; Vitart, Veronique; Waite, Lindsay; Wheeler, William; Zhang, Weihua; Draisma, Harmen H M; Feitosa, Mary F; Kerr, Kathleen F; Lind, Penelope A; Mihailov, Evelin; Onland-Moret, N Charlotte; Song, Ci; Weedon, Michael N; Xie, Weijia; Yengo, Loic; Absher, Devin; Albert, Christine M; Alonso, Alvaro; Arking, Dan E; de Bakker, Paul I W; Balkau, Beverley; Barlassina, Cristina; Benaglio, Paola; Bis, Joshua C; Bouatia-Naji, Nabila; Brage, Søren; Chanock, Stephen J; Chines, Peter S; Chung, Mina; Darbar, Dawood; Dina, Christian; Dörr, Marcus; Elliott, Paul; Felix, Stephan B; Fischer, Krista; Fuchsberger, Christian; de Geus, Eco J C; Goyette, Philippe; Gudnason, Vilmundur; Harris, Tamara B; Hartikainen, Anna-liisa; Havulinna, Aki S; Heckbert, Susan R; Hicks, Andrew A; Hofman, Albert; Holewijn, Suzanne; Hoogstra-Berends, Femke; Hottenga, Jouke-Jan; Jensen, Majken K; Johansson, Åsa; Junttila, Juhani; Kääb, Stefan; Kanon, Bart; Ketkar, Shamika; Khaw, Kay-Tee; Knowles, Joshua W; Kooner, Angrad S; Kors, Jan A; Kumari, Meena; Milani, Lili; Laiho, Päivi; Lakatta, Edward G; Langenberg, Claudia; Leusink, Maarten; Liu, Yongmei; Luben, Robert N; Lunetta, Kathryn L; Lynch, Stacey N; Markus, Marcello R P; Marques-Vidal, Pedro; Leach, Irene Mateo; McArdle, Wendy L; McCarroll, Steven A; Medland, Sarah E; Miller, Kathryn A; Montgomery, Grant W; Morrison, Alanna C; Müller-Nurasyid, Martina; Navarro, Pau; Nelis, Mari; O’Connell, Jeffrey R; O’Donnell, Christopher J; Ong, Ken K; Newman, Anne B; Peters, Annette; Polasek, Ozren; Pouta, Anneli; Pramstaller, Peter P; Psaty, Bruce M; Rao, Dabeeru C; Ring, Susan M; Rossin, Elizabeth J; Rudan, Diana; Sanna, Serena; Scott, Robert A; Sehmi, Jaban S; Sharp, Stephen; Shin, Jordan T; Singleton, Andrew B; Smith, Albert V; Soranzo, Nicole; Spector, Tim D; Stewart, Chip; Stringham, Heather M; Tarasov, Kirill V; Uitterlinden, André G; Vandenput, Liesbeth; Hwang, Shih-Jen; Whitfield, John B; Wijmenga, Cisca; Wild, Sarah H; Willemsen, Gonneke; Wilson, James F; Witteman, Jacqueline C M; Wong, Andrew; Wong, Quenna; Jamshidi, Yalda; Zitting, Paavo; Boer, Jolanda M A; Boomsma, Dorret I; Borecki, Ingrid B; Van Duijn, Cornelia M; Ekelund, Ulf; Forouhi, Nita G; Froguel, Philippe; Hingorani, Aroon; Ingelsson, Erik; Kivimaki, Mika; Kronmal, Richard A; Kuh, Diana; Lind, Lars; Martin, Nicholas G; Oostra, Ben A; Pedersen, Nancy L; Quertermous, Thomas; Rotter, Jerome I; van der Schouw, Yvonne T; Verschuren, W M Monique; Walker, Mark; Albanes, Demetrius; Arnar, David O; Assimes, Themistocles L; Bandinelli, Stefania; Boehnke, Michael; de Boer, Rudolf A; Bouchard, Claude; Caulfield, W L Mark; Chambers, John C; Curhan, Gary; Cusi, Daniele; Eriksson, Johan; Ferrucci, Luigi; van Gilst, Wiek H; Glorioso, Nicola; de Graaf, Jacqueline; Groop, Leif; Gyllensten, Ulf; Hsueh, Wen-Chi; Hu, Frank B; Huikuri, Heikki V; Hunter, David J; Iribarren, Carlos; Isomaa, Bo; Jarvelin, Marjo-Riitta; Jula, Antti; Kähönen, Mika; Kiemeney, Lambertus A; van der Klauw, Melanie M; Kooner, Jaspal S; Kraft, Peter; Iacoviello, Licia; Lehtimäki, Terho; Lokki, Marja-Liisa L; Mitchell, Braxton D; Navis, Gerjan; Nieminen, Markku S; Ohlsson, Claes; Poulter, Neil R; Qi, Lu; Raitakari, Olli T; Rimm, Eric B; Rioux, John D; Rizzi, Federica; Rudan, Igor; Salomaa, Veikko; Sever, Peter S; Shields, Denis C; Shuldiner, Alan R; Sinisalo, Juha; Stanton, Alice V; Stolk, Ronald P; Strachan, David P; Tardif, Jean-Claude; Thorsteinsdottir, Unnur; Tuomilehto, Jaako; van Veldhuisen, Dirk J; Virtamo, Jarmo; Viikari, Jorma; Vollenweider, Peter; Waeber, Gérard; Widen, Elisabeth; Cho, Yoon Shin; Olsen, Jesper V; Visscher, Peter M; Willer, Cristen; Franke, Lude; Erdmann, Jeanette; Thompson, John R; Pfeufer, Arne; Sotoodehnia, Nona

2013-01-01

183

Heart Rates of High School Physical Education Students during Team Sports, Individual Sports, and Fitness Activities  

Science.gov (United States)

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…

Laurson, Kelly R.; Brown, Dale D.; Cullen, Robert W.; Dennis, Karen K.

2008-01-01

184

Making the Most of the "Daphnia" Heart Rate Lab: Optimizing the Use of Ethanol, Nicotine & Caffeine  

Science.gov (United States)

Students commonly test the effects of chemical agents on the heart rate of the crustacean "Daphnia" magna, but the procedure has never been optimized. We determined the effects of three concentrations of ethanol, nicotine, and caffeine and of a control solution on heart rate in "Daphnia." Ethanol at 5% and 10% (v/v) reduced mean heart rate to…

Corotto, Frank; Ceballos, Darrel; Lee, Adam; Vinson, Lindsey

2010-01-01

185

Effects of altitude on exercise level and heart rate in patients with coronary artery disease and healthy controls.  

Science.gov (United States)

Background. To evaluate the safety and effects of high altitude on exercise level and heart rate in patients with coronary artery disease compared with healthy controls.Methods. Eight patients with a history of an acute myocardial infarction (ejection fraction >5%) with a low-risk score were compared with seven healthy subjects during the Dutch Heart Expedition at the Aconcagua in Argentina in March 2007. All subjects underwent a maximum exercise test with a cycle ergometer at sea level and base camp, after ten days of acclimatisation, at an altitude of 4200 m. Exercise capacity and maximum heart rate were compared between groups and within subjects.Results. There was a significant decrease in maximum heart rate at high altitude compared with sea level in both the patient and the control group (166 vs. 139 beats/min, p<0.001 and 181 vs. 150 beats/min, p<0.001). There was no significant difference in the decrease of the exercise level and maximum heart rate between patients and healthy controls (-31 vs. -30%, p=0.673).Conclusion. Both patients and healthy controls showed a similar decrease in exercise capacity and maximum heart rate at 4200 m compared with sea level, suggesting that patients with a history of coronary artery disease may tolerate stay and exercise at high altitude similarly to healthy controls. (Neth Heart J 2010;18:118-21.). PMID:20390061

de Vries, S T; Komdeur, P; Aalbersberg, S; van Enst, G C; Breeman, A; van 't Hof, A W J

2010-03-01

186

Impact of caffeine on heart rate and blood pressure at rest and during exercise  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction:Several studies have evaluated the impact of caffeine consumption on athletes performance from different aspects; however, the findings are varied. The aim of this research was to evaluate the impact of caffeine consumption on some of the cardiovascular factors including heart rate and blood pressure at rest, at the end of exercise, and during the 3rd and 5th minutes of recovery. Material and Methods:The subjects of this study included 20 female athletes, voluntarily participating in the study. Two separate tests with an interval of one week were conducted. The subjects received placebo for the first test and caffeine containing capsules (5 mg/kg for the second test. The patient heart rate and blood pressure were measured at rest, at the end of the exercise and during the 3rd and 5th minutes of recovery after submaximal test. Maximal oxygen consumption (VO2max was measured using Fax submaximal cardiorespiratory test. Paired t- test was used for data analysis. Results:Caffeine consumption had no significantly effect on VO2max, resting and end exercise heart rate, and blood pressure recorded at the end of the exercise. Caffeine consumption caused a significant increase in the heart rate during 3rd and 5th minutes of recovery, and in blood pressure at rest, and during the 3rd and the 5th minutes of recovery in the athletes. Conclusion:Due to the caffeine induced increase in blood pressure and heart rate, caffeine consumption (5 mg/kg before submaximal exercise is not recommended either for those who suffer hypertension or cardiac disease nor for those who do exercise for health or athletic purposes.

Azam Mousavi

2011-05-01

187

Omega-3 Polyunsaturated Fatty Acids and Heart Rate Variability  

Directory of Open Access Journals (Sweden)

Full Text Available Omega-3 polyunsaturated fatty acids (PUFA may modulate autonomic control of the heart because omega-3 PUFA is abundant in the brain and other nervous tissue as well as in cardiac tissue. This might partly explain why omega-3 PUFA offer some protection against sudden cardiac death (SCD. The autonomic nervous system is involved in the pathogenesis of SCD. Heart rate variability (HRV can be used as a non-invasive marker of cardiac autonomic control and a low HRV is a predictor for SCD and arrhythmic events. Studies on HRV and omega-3 PUFA have been performed in several populations such as patients with ischemic heart disease, patients with diabetes mellitus, patients with chronic renal failure, and in healthy subjects as well as in children.. The studies have demonstrated a positive association between cellular content of omega-3 PUFA and HRV and supplementation with omega-3 PUFA seems to increase HRV which could be a possible explanation for decreased risk of arrhythmic events and SCD sometimes observed after omega-3 PUFA supplementation. However, the results are not consistent and further research is needed

JeppeHagstrupChristensen

2011-11-01

188

Omega-3 Polyunsaturated Fatty Acids and Heart Rate Variability  

DEFF Research Database (Denmark)

Omega-3 polyunsaturated fatty acids (PUFA) may modulate autonomic control of the heart because omega-3 PUFA is abundant in the brain and other nervous tissue as well as in cardiac tissue. This might partly explain why omega-3 PUFA offer some protection against sudden cardiac death (SCD). The autonomic nervous system is involved in the pathogenesis of SCD. Heart rate variability (HRV) can be used as a non-invasive marker of cardiac autonomic control and a low HRV is a predictor for SCD and arrhythmic events. Studies on HRV and omega-3 PUFA have been performed in several populations such as patients with ischemic heart disease, patients with diabetes mellitus, patients with chronic renal failure, and in healthy subjects as well as in children. The studies have demonstrated a positive association between cellular content of omega-3 PUFA and HRV and supplementation with omega-3 PUFA seems to increase HRV which could be a possible explanation for decreased risk of arrhythmic events and SCD sometimes observed afteromega-3 PUFA supplementation. However, the results are not consistent and further research is needed.

Christensen, Jeppe Hagstrup

2011-01-01

189

The Development of a Microcontroller Based LowCost Heart Rate Counter for Health Care Systems  

OpenAIRE

The heart rate is one of the significant physiological parameters of the human cardiovascular system. Heart rate is the number of times the heart beats per minute. Heart rate data reflects various physiological states such as biological workload, stress at work and concentration on tasks, drowsiness and the active state of the autonomic nervous system. Human cardiac dynamics are driven by the complex nonlinear interactions of two competing forces: sympathetic regulation increases and parasymp...

Souvik Das

2013-01-01

190

Influence of left ventricular pressures and heart rate on myocardial high-energy phosphate metabolism.  

OpenAIRE

This review describes the effects of changes in left ventricular pressures and heart rate on myocardial high-energy phosphate metabolism. When cardiac workload is substantially increased, creatine kinase flux will increase markedly, phosphocreatine will show a small but detectable decrease, and ATP will not change. In this context, heart rate is a much weaker acute metabolic stimulus than left ventricular developed pressure. However, in heart failure, chronic reduction of heart rate has benef...

Neubauer, S.

1998-01-01

191

Day-to-night time differences in the relationship between cardiorespiratory coordination and heart rate variability  

International Nuclear Information System (INIS)

Heart rate variability (HRV) and cardiorespiratory coordination, i.e. the temporal interplay between oscillations of heartbeat and respiration, reflect information related to the cardiovascular and autonomic nervous system. The purpose of this study was to investigate the relationship between spectral measures of HRV and measures of cardiorespiratory coordination. In 127 subjects from a normal population a 24 h Holter ECG was recorded. Average heart rate (HR) and the following HRV parameters were calculated: very low (VLF), low (LF) and high frequency (HF) oscillations and LF/HF. Cardiorespiratory coordination was quantified using average respiratory rate (RespR), the ratio of heart rate and respiratory rate (HRR), the phase coordination ratio (PCR) and the extent of cardiorespiratory coordination (PP). Pearson's correlation coefficient r was used to quantify the relationship between each pair of the variables across all subjects. HR and HRR correlated strongest during daytime (r = 0.89). LF/HF and PP showed a negative correlation to a reasonable degree (r = ?0.69). During nighttime sleep these correlations decreased whereas the correlation between HRR and RespR (r = ?0.47) as well as between HRR and PCR (r = 0.73) increased substantially. In conclusion, HRR and PCR deliver considerably different information compared to HRV measures whereas PP is partially linked reciprocally to LF/HF

192

Effect of Wireless Network Radiation on Heart Rate Variability  

OpenAIRE

The health risk associated with the increased exposure to wireless network devices like Mobile Phones, Wi-Fi etc, had been area of concern. In this paper, the effects of wireless network radiations (WNR) on Heart Rate Variability (HRV) had been investigated. The two non-linear indices namely i) Approximate Entropy (ApEn) ii) Detrended Fluctuation Analysis (DFA) had been used for deciphering the hidden dynamics of HRV. The study comprised of 19 healthy male subjects in the age group of 23±4.3...

Barjinder Singh Saini; Anukul Pandey

2014-01-01

193

Correlated and uncorrelated heart rate fluctuations during relaxing visualization  

Science.gov (United States)

The heart rate variability (HRV) of healthy subjects practicing relaxing visualization is studied by use of three multiscale analysis techniques: the detrended fluctuation analysis (DFA), the entropy in natural time (ENT) and the average wavelet (AWC) coefficient. The scaling exponent of normal interbeat interval increments exhibits characteristics of the presence of long-range correlations. During relaxing visualization the HRV dynamics change in the sense that two new features emerge independent of each other: a respiration-induced periodicity that often dominates the HRV at short scales (REM sleep.

Papasimakis, N.; Pallikari, F.

2010-05-01

194

RUNNING DEMANDS AND HEART RATE RESPONSE IN RUGBY UNION  

OpenAIRE

Abstract: Suarez-Arrones, L, Portillo, LJ, García, JM, Calvo-Lluch, A, Roberts, SP, and Mendez-Villanueva, A. Running demands and heart rate response in rugby union referees. J Strength Cond Res 27(11): 2946?2951, 2013?The aim of this study was to examine the match physical demands and exercise intensity associated with men rugby union refereeing using global positioning system technology. Ten male rugby union referees (age, 37.1 ± 5.9 years; body mass, 83.7 ± 4.8 kg; height, 175.5 ± 6.2 ...

2013-01-01

195

Genetic locus on mouse chromosome 7 controls elevated heart rate  

OpenAIRE

Elevated heart rate (HR) is a risk factor for cardiovascular diseases. The goal of the study was to map HR trait in mice using quantitative trait locus (QTL) analysis followed by genome-wide association (GWA) analysis. The first approach provides mapping power and the second increases genome resolution. QTL analyses were performed in a C3HeB×SJL backcross. HR and systolic blood pressure (SBP) were measured by the tail-cuff plethysmography. HR was ?80 beats/min higher in SJL compared with C...

Smolock, Elaine M.; Ilyushkina, Irina A.; Ghazalpour, Anatole; Gerloff, Janice; Murashev, Arkady N.; Lusis, Aldons J.; Korshunov, Vyacheslav A.

2012-01-01

196

Circadian changes of heart rate in West syndrome.  

Science.gov (United States)

Patterns of circadian and ultradian rhythms in the heart rate (HR) are described in a full-term baby with birth asphyxia and convulsions. A 24h HR recording was carried out at the age of 1, 15, 56, 289, and 295 days; West syndrome diagnosis was made when the patient was 3 months old. The HR showed no circadian rhythm in the follow-up, whereas it is known that the circadian rhythm appears in healthy infants at the age of 1 month and remains thereafter. This observation may be an indirect indicator of the interference of West syndrome with centers of neurological maturity. PMID:10908132

Ardura, J; Andres, J; Muñoz, A; Revilla, M; Aragon, P

2000-07-01

197

Correlation between heart rate and performance during Olympic windsurfing competition  

OpenAIRE

The aim of this study was to examine the heart rate (HR) response to Olympic windsurfing competition and to check if there was any correlation between racing HR, performance, and the variables measured during laboratory maximal exercise. Ten elite windsurfers [age: 20.93 (3.46) years; height: 178.10 (6.34) cm; body mass: 66.79 (5.90) kg] performed a laboratory maximal oxygen consumption (VO2max) trial and national windsurf competitions wearing a HR monitor. One hundred and forty-three individ...

Chamari, Karim; Moussa-chamari, Imen; Galy, Olivier; Chaouachi, Mustapha; Koubaa, Donia; Ben Hassen, Chokri; Hue, Olivier

2003-01-01

198

Factors that affect the variability in heart rate during endoscopic retrograde cholangiopancreatography.  

DEFF Research Database (Denmark)

OBJECTIVE: To find out if drugs, position, and endoscopic manipulation during endoscopic retrograde cholangiopancreatography (ERCP) influence the changes in the variability of heart rate. DESIGN: Single-blind randomised trial. SUBJECTS: 10 volunteers given butyscopolamine, glucagon, or saline intravenously on three different study days, and 10 patients who had ERCP without butylscopolamine or glucagon. MAIN OUTCOME MEASURES: Holter tape analysis for ischaemia and changes in the variability of heart rate. RESULTS: 5 volunteers developed tachycardia after butylscopolamine, while 2 developed tachycardia after glucagon. During ERCP 9 patients developed tachycardia, and 2 developed myocardial ischaemia. Vagal tone decreased in the volunteers after butylscopolamine, but no changes were seen after glucagon or placebo, or in patients during ERCP. CONCLUSIONS: Butylscopolamine reduced vagal tone in volunteers. Patients who were having ERCP without butylscopolamine had a stable vagal tone. The previously observed reduced vagal tone during ERCP may therefore be primarily the result of giving butylscopolamine.

Christensen, Merete; Reinert, Rebekka

2002-01-01

199

Resting Heart Rate: Risk Indicator and Emerging Risk Factor in Cardiovascular Disease.  

Science.gov (United States)

Resting heart rate is central to cardiac output and is influenced by changes occuring in numerous diseases. It predicts longevity and cardiovascular diseases and current evidence suggests that it is also an important marker of outcome in cardiovascular disease including heart failure. Beta blockers improve outcomes in heart failure; however, they have effects outside reducing heart rate. Ivabradine has demonstrated efficacy in reducing rehospitalizations and mortality in heart failure and in improving exercise tolerance and reducing angina attacks in patients with coronary artery disease, while selective heart rate reduction may also prove to be beneficial in therapeutic areas outside those where ivabradine has already demonstrated clinical efficacy. This review provides an update on associations between heart rate and cardiovascular outcomes in various conditions, the experimental effects of heart rate reduction with ivabradine, and potential new indications in cardiovascular disease. PMID:25447617

Böhm, Michael; Reil, Jan-Christian; Deedwania, Prakash; Kim, Jae B; Borer, Jeffrey S

2014-10-15

200

Classification tree for risk assessment in patients suffering from congestive heart failure via long-term heart rate variability  

OpenAIRE

This study aims to develop an automatic classifier for risk assessment in patients suffering from congestive heart failure (CHF). The proposed classifier separates lower risk patients from higher risk ones, using standard long-term heart rate variability (HRV) measures. Patients are labeled as lower or higher risk according to the New York Heart Association classification (NYHA). A retrospective analysis on two public Holter databases was performed, analyzing the data of 12 patients suffering...

Melillo, Paolo; Luca, Nicola; Bracale, Marcello; Pecchia, Leandro

2013-01-01

201

The slope of the oxygen pulse curve does not depend on the maximal heart rate in elite soccer players  

Directory of Open Access Journals (Sweden)

Full Text Available INTRODUCTION: It is unknown whether an extremely high heart rate can affect oxygen pulse profile during progressive maximal exercise in healthy subjects. OBJECTIVE: Our aim was to compare relative oxygen pulse (adjusted for body weight curves in athletes at their maximal heart rate during treadmill cardiopulmonary exercise testing. METHODS: A total of 180 elite soccer players were categorized in quartiles according to their maximum heart rate values (n = 45. Oxygen consumption, maximum heart rate and relative oxygen pulse curves in the extreme quartiles, Q1 and Q4, were compared at intervals corresponding to 10% of the total duration of a cardiopulmonary exercise testing. RESULTS: Oxygen consumption was similar among all subjects during cardiopulmonary exercise testing; however subjects in Q1 started to exhibit lower maximum heart rate values when 20% of the test was complete. Conversely, the relative oxygen pulse was higher in this group when cardiopulmonary exercise testing was 40% complete (p<.01. Although the slopes of the lines were similar (p = .25, the regression intercepts differed (p<.01 between Q1 and Q4. During the last two minutes of testing, a flat or decreasing oxygen pulse was identified in 20% of the soccer players, and this trend was similar between subjects in Q1 and Q4. CONCLUSION: Relative oxygen pulse curve slopes, which serve as an indirect and non-invasive surrogate for stroke volume, suggest that the stroke volume is similar in young and aerobically fit subjects regardless of the maximum heart rate reached.

Raphael Rodrigues Perim

2011-01-01

202

Heart rate response to hypoxic exercise : role of dopamine D2-receptors and effect of oxygen supplementation  

DEFF Research Database (Denmark)

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 two consecutive maximal exercise tests, without and with oxygen supplementation respectively, at sea level and after 1, 3 and 5 days at altitude. On each study day, domperidone (30 mg; n=6) or no medication (n=6) was given 1 h before the first exercise session. Compared with sea level, hypoxia 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 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 of noradrenaline. However, dopamine D(2)-receptors are not involved in the hypoxia-induced decrease in the maximal heart rate. These data suggest that receptor uncoupling, and not down-regulation, of cardiac adrenoreceptors, is responsible for the early decrease in heart rate at maximal hypoxic exercise.

Lundby, C; MØller, P

2001-01-01

203

Heart rate effects of intraosseous injections using slow and fast rates of anesthetic solution deposition.  

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The authors, using a crossover design, randomly administered, in a single-blind manner, 3 primary intraosseous injections to 61 subjects using: the Wand local anesthetic system at a deposition rate of 45 seconds (fast injection); the Wand local anesthetic system at a deposition rate of 4 minutes and 45 seconds (slow injection); a conventional syringe injection at a deposition rate of 4 minutes and 45 seconds (slow injection), in 3 separate appointments spaced at least 3 weeks apart. A pulse oximeter measured heart rate (pulse). The results demonstrated the mean maximum heart rate was statistically higher with the fast intraosseous injection (average 21 to 28 beats/min increase) than either of the 2 slow intraosseous injections (average 10 to 12 beats/min increase). There was no statistically significant difference between the 2 slow injections. We concluded that an intraosseous injection of 1.4 mL of 2% lidocaine with 1 : 100,000 epinephrine with the Wand at a 45-second rate of anesthetic deposition resulted in a significantly higher heart rate when compared with a 4-minute and 45-second anesthetic solution deposition using either the Wand or traditional syringe. PMID:18327970

Susi, Louis; Reader, Al; Nusstein, John; Beck, Mike; Weaver, Joel; Drum, Melissa

2008-01-01

204

Heart rate monitoring and control in altered gravity conditions.  

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On the basis of indirect evidences it has been hypothesized that during space missions the almost complete absence of gravity might impair the baroreflex control of circulation. In the first part of this paper we report results obtained from a series of experiments carried out to directly verify this hypothesis during the 16-day STS 107 Shuttle flight. Spontaneous baroreflex sensitivity was assessed in four astronauts before flight (baseline) and at days 0-1, 6-7 and 12-13 during flight, both at rest and while performing moderate exercise. Our results indicate that at rest the baroreflex sensitivity significantly increased in the early flight phase, as compared to pre-flight values and tended to return to baseline in the mid-late phase of flight. During exercise, baroreflex sensitivity was lower than at rest, without any difference among pre-flight and in-flight values. These findings seem to exclude the hypothesis of an impairment of the baroreflex control of heart rate during exposure to microgravity, at least over a time window of 16 days. In the second part of the paper we propose a novel textile-based methodology for heart rate and other vital signs monitoring during gravity stress. The positive results obtained from its use during parachute jumps support the use of smart garments for the unobtrusive assessment of physiological parameters in extreme environments. PMID:18003559

Di Rienzo, M; Parati, G; Rizzo, F; Meriggi, P; Merati, G; Faini, A; Castiglioni, P

2007-01-01

205

High frequency chest compression effects heart rate variability.  

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High frequency chest compression (HFCC) supplies a sequence of air pulses through a jacket worn by a patient to remove excessive mucus for the treatment or prevention of lung disease patients. The air pulses produced from the pulse generator propagates over the thorax delivering the vibration and compression energy. A number of studies have demonstrated that the HFCC system increases the ability to clear mucus and improves lung function. Few studies have examined the change in instantaneous heart rate (iHR) and heart rate variability (HRV) during the HFCC therapy. The purpose of this study is to measure the change of HRV with four experimental protocols: (a) without HFCC, (b) during Inflated, (c)HFCC at 6Hz, and (d) HFCC at 21Hz. The nonlinearity and regularity of HRV was assessed by approximate entropy (ApEn), a method used to quantify the complexities and randomness. To compute the ApEn, we sectioned with a total of eight epochs and displayed the ApEn over the each epoch. Our results show significant differences in the both the iHR and HRV between the experimental protocols. The iHR was elevated at both the (c) 6Hz and (d) 21Hz condition from without HFCC (10%, 16%, respectively). We also found that the HFCC system tends to increase the HRV. Our study suggests that monitoring iHR and HRV are very important physiological indexes during HFCC therapy. PMID:18002145

Lee, Jongwon; Lee, Yong W; Warwick, Warren J

2007-01-01

206

HEART RATE AND MOTION ANALYSIS BY GPS IN BEACH SOCCER  

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Full Text Available Although beach soccer has become increasingly popular in recent years very little scientific research has been conducted into the sport. A pilot study was carried out with the aim of examining the physiological (heart rate and physical (motion analysis responses of beach soccer players during competitive matches. Ten players (age 25.5 ± 0.5 years; height 1.80 ± 0.08 m; weight 78.2 ± 5.6 kg. were studied over five beach soccer matches. The physiological demands were analysed by measuring heart rate (HR using telemetric devices, while the physical profile was evaluated by recording motion and speed by means of GPS devices. During competitive matches, players obtained a HRmean of 165.2 bpm (86.5% HRmax, with 59.3% of the time participating (TP corresponding to values above 90% of the HRmax. The distance covered per minute of participation was 97.7 m, with 9.5% of this distance corresponding to high-intensity running and 2.5% to sprint; the work:rest ratio was 1.4:1 and the maximum speed 21.7 km·h-1. These results showed that beach soccer is an intermittent physical activity of greater intensity than other team games. It requires a major contribution from the anaerobic system as emphasis is placed on players making quick bursts of high-intensity activity separated by brief rest periods

Julen Castellano

2010-03-01

207

False heart rate feedback and the perception of heart symptoms in patients with congenital heart disease and anxiety  

OpenAIRE

Background: Little is known about the mechanisms explaining an increased perception of heart symptoms in congenital heart disease (ConHD). In the present study, it was suggested that a combination of high trait anxiety and disease history increases the perception of heart symptoms. Purpose: It was tested whether false heart cues will result in an increased perception of heart symptoms in patients with ConHD and anxiety. Method: Thirty-six patients with ConHD and 44 healthy controls pe...

Karsdorp, P. A.; Kindt, M.; Rietveld, S.; Everaerd, W.; Mulder, B. J. M.

2009-01-01

208

Impact of heart rate and rhythm on radiation exposure in prospectively ECG triggered computed tomography  

International Nuclear Information System (INIS)

Purpose: To evaluate the influence of different heart rates and arrhythmias on scanner performance, image acquisition and applied radiation exposure in prospectively ECG triggered computed tomography (pCT). Materials and methods: An ECG simulator (EKG Phantom 320, Müller and Sebastiani Elektronik GmbH, Munich, Germany) was used to generate different heart rhythms and arrhythmias: sinus rhythm (SR) at 45, 60, 75, 90 and 120/min, supraventricular arrhythmias (e.g. sinus arrhythmia, atrial fibrillation) and ventricular arrhythmias (e.g. ventricular extrasystoles), pacemaker-ECGs, ST-changes and technical artifacts. The analysis of the image acquisition process was performed on a 64-row multidetector CT (Brilliance, Philips Medical Systems, Cleveland, USA). A prospectively triggered scan protocol as used for routine was applied (120 kV; 150 mA s; 0.4 s rotation and exposure time per scan; image acquisition predominantly in end-diastole at 75% R-R-interval, in arrythmias with a mean heart rate above 80/min in systole at 45% of the R-R-interval; FOV 25 cm). The mean dose length product (DLP) and its percentage increase from baseline (SR at 60/min) were determined. Result: Radiation exposure can increase significantly when the heart rhythm deviates from sinus rhythm. ECG-changes leading to a significant DLP increase (p 8 s) could be observed in bifocal pacemaker (12.8 s), pacemaker dysfunction (10.7 s), atrial fibrillation (10.3 s) and sinus arrhythmia (9.3 s). Conclusion: In prospectively ECG triggered CT, heart rate and rhythm can provoke different types of scanner performance, which can significantly alter radiation exposure and scan time. These results might have an important implication for indication, informed consent and contrast agent injection protocols

209

Impact of heart rate and rhythm on radiation exposure in prospectively ECG triggered computed tomography  

Energy Technology Data Exchange (ETDEWEB)

Purpose: To evaluate the influence of different heart rates and arrhythmias on scanner performance, image acquisition and applied radiation exposure in prospectively ECG triggered computed tomography (pCT). Materials and methods: An ECG simulator (EKG Phantom 320, Müller and Sebastiani Elektronik GmbH, Munich, Germany) was used to generate different heart rhythms and arrhythmias: sinus rhythm (SR) at 45, 60, 75, 90 and 120/min, supraventricular arrhythmias (e.g. sinus arrhythmia, atrial fibrillation) and ventricular arrhythmias (e.g. ventricular extrasystoles), pacemaker-ECGs, ST-changes and technical artifacts. The analysis of the image acquisition process was performed on a 64-row multidetector CT (Brilliance, Philips Medical Systems, Cleveland, USA). A prospectively triggered scan protocol as used for routine was applied (120 kV; 150 mA s; 0.4 s rotation and exposure time per scan; image acquisition predominantly in end-diastole at 75% R-R-interval, in arrythmias with a mean heart rate above 80/min in systole at 45% of the R-R-interval; FOV 25 cm). The mean dose length product (DLP) and its percentage increase from baseline (SR at 60/min) were determined. Result: Radiation exposure can increase significantly when the heart rhythm deviates from sinus rhythm. ECG-changes leading to a significant DLP increase (p < 0.05) were bifocal pacemaker (61%), pacemaker dysfunction (22%), SVES (20%), ventricular salvo (20%), and atrial fibrillation (14%). Significantly (p < 0.05) prolonged scan time (>8 s) could be observed in bifocal pacemaker (12.8 s), pacemaker dysfunction (10.7 s), atrial fibrillation (10.3 s) and sinus arrhythmia (9.3 s). Conclusion: In prospectively ECG triggered CT, heart rate and rhythm can provoke different types of scanner performance, which can significantly alter radiation exposure and scan time. These results might have an important implication for indication, informed consent and contrast agent injection protocols.

Luecke, Christian, E-mail: neep@gmx.de [University of Leipzig – Heart Center, Department of Diagnostic and Interventional Radiology, Strümpellstrasse 39, D-04289, Leipzig (Germany); Andres, Claudia; Foldyna, Borek [University of Leipzig – Heart Center, Department of Diagnostic and Interventional Radiology, Strümpellstrasse 39, D-04289, Leipzig (Germany); Nagel, Hans Dieter [Wissenschaft and Technik für die Radiologie, Buchhholz i.d.N (Germany); Hoffmann, Janine; Grothoff, Matthias; Nitzsche, Stefan; Gutberlet, Matthias; Lehmkuhl, Lukas [University of Leipzig – Heart Center, Department of Diagnostic and Interventional Radiology, Strümpellstrasse 39, D-04289, Leipzig (Germany)

2012-09-15

210

Heart rate monitoring on the stroke unit. What does heart beat tell about prognosis? An observational study  

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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.

Stypmann Jörg

2011-04-01

211

The Relationship between Menopausal Symptoms and Heart Rate Variability in Middle Aged Women  

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Background The study of the correlation of menopausal symptoms with heart rate variability (HRV) has not been adequate. The aim of this study was to investigate the relationship between postmenopausal symptoms measured by the menopause rating scale (MRS) and HRV. Methods We assessed postmenopausal symptoms (using MRS) with age, BMI, educational status, occupation, marital status, alcohol and caffeine consumption, smoking history, exercise, duration of sleep and amenorrhea, degree of anxiety and depression, menarcheal age, and heart rate variability. For evaluation of HRV, the record of electrocardiogram for 5 minutes in the resting state was divided into temporal categories and frequency categories, and analyzed. Results No significant differences in age, BMI, duration of amenorrhea, heart rate, systolic blood pressure, diastolic blood pressure, fasting blood sugar, triglyceride, and high-density lipoprotein were observed between two groups, which were divided according to menopausal symptoms. Low frequency/high frequency (LF/HF) ratio was significantly higher in symptomatic women, compared with asymptomatic women (P < 0.05). No significant differences of HRV index by the severity of postmenopausal symptoms were observed. LF/HF ratio of HRV parameters showed a significant increase in moderate or severe degree of "hot flashes" and "sleep problem" score (P < 0.05). Anxiety scale in symptomatic women was significantly higher than in asymptomatic women (P < 0.05). Conclusion The above data suggest that postmenopausal symptoms are associated with altered autonomic control of heart rate. In particular, hot flashes and sleep problems in moderate or severe degree are related to increase of sympathetic nerve activity. PMID:22745867

Lee, Jin Oh; Kang, Sung Goo; Kim, Se Hong; Park, Seo Jin

2011-01-01

212

Home telemonitoring of respiratory activity and heart rate variability in chronic heart failure patients: The challenge of the home or hospital in heart failure project  

OpenAIRE

Nocturnal respiratory disorders and depressed heart rate variability are known predictors of poor prognosis in chronic heart failure (CHF) patients. Intermittent monitoring of cardiorespiratory signals while the patient is at home might thus allow early identification of clinical deterioration and prompt optimization of treatment, leading to reduced hospitalizations and mortality and improved quality of life. Within the European Community multicenter trial HHH (Home or Hospital in Heart Failu...

Pinna, Gd; Maestri, R.; Gobbi, E.; La Rovere, Mt; Scanferlato, Jl; Witkowski, T.; Kus-klinowska, A.; Andrews, D.; Johnson, P.; Capomolla, S.; Mortara, A.

2003-01-01

213

Assessment of Cardiac Autonomic Nervous System Involvement in Systemic Sclerosis via Exercise Heart Rate Recovery.  

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Objective: To assess exercise heart rate recovery (HRR) indices in patients with systemic sclerosis (SSc) for an assessment of their cardiac autonomic function. Subjects and Methods: Thirty-five patients with diffuse or limited SSc and 35 healthy controls were enrolled. All subjects underwent exercise testing and transthoracic echocardiography. The HRR indices were calculated by subtracting the first- (HRR1), second- (HRR2) and third-minute (HRR3) heart rates from the maximal heart rate. Results: The SSc and control groups were similar in age (45.2 ± 11.6 vs. 43.9 ± 10.0 years), had identical gender ratios (31 female/4 male in both groups) and similar left ventricular ejection fraction (66.5 ± 5.1 vs. 67.7 ± 5.9%). The mean HRR1 (21.8 ± 4.4 vs. 27.7 ± 4.3 bpm, p = 0.001), HRR2 (43.8 ± 6.3 vs. 47.6 ± 4.4 bpm, p = 0.004) and HRR3 (58.8 ± 10.3 vs. 63.6 ± 7.3 bpm, p = 0.031) values were significantly lower in the SSc group than in the healthy controls. HRR indices were similar in the limited and diffuse SSc subgroups. Conclusions: The patients with SSc had lower HRR indices than normal subjects. Cardiac autonomic functions might be involved in SSc, even in patients without cardiac symptoms. © 2014 S. Karger AG, Basel. PMID:25428653

Karakulak, Ugur Nadir; Okutucu, Sercan; Sahiner, Levent; Maharjan, Naresh; Aladag, Elifcan; Akdogan, Ali; Kilic, Levent; Kaya, Ergun Baris; Aytemir, Kudret; Tokgozoglu, Lale

2014-11-22

214

HEART RATE AND BLOOD LACTATE RESPONSES TO CHANGQUAN AND DAOSHU FORMS OF MODERN WUSHU  

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Full Text Available The development of specific training designed to enhance physiological aspects of performance relies heavily on the availability of accurate and validity physiological data. In the combat sport of Wushu, katas are used to develop aerobic fitness. It is arguably important to assess and monitor heart rate (HR and lactate (La responses when designing effective training programs. The aim of this pilot study was to investigate heart rate and lactate responses to forms execution among Wushu combatants. Male elite modern Wushu athletes (n = 4 from a South Brazilian regional team participated in the study. Athletes were aged 22.5 ± 2.08 years old and had at least eight years of Wushu experience. Athletes carried out the Changquan and Daoshu forms in random order, HR and La were measured pre- and post-exercise. Results indicate that HR was 176 ± 3 and 176 ± 2 bpm and La was 4.38 ± 1.3 and 5.15 ± 1.07 mmol·l-1 for Changquan and Daoshu forms, respectively. There were no significantly differences in HR and La between the two forms. HR values represent 89.2 ± 1.1 and 89.1 ± 1.8% of age-predicted maximal heart rate and lactate was near of 4 mmol·l-1 point. In conclusion, training programs to Wushu combatants could target the range of physiological values cited above with no differences between two forms

Jerri Luiz Ribeiro

2006-07-01

215

Sex differences in the fetal heart rate variability indices of twins.  

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Abstract Aims: To evaluate the differences in linear and complex heart rate dynamics in twin pairs according to fetal sex combination [male-female (MF), male-male (MM), and female-female (FF)]. Methods: Fourteen twin pairs (6 MF, 3 MM, and 5 FF) were monitored between 31 and 36.4 weeks of gestation. Twenty-six fetal heart rate (FHR) recordings of both twins were simultaneously acquired and analyzed with a system for computerized analysis of cardiotocograms. Linear and nonlinear FHR indices were calculated. Results: Overall, MM twins presented higher intrapair average in linear indices than the other pairs, whereas FF twins showed higher sympathetic-vagal balance. MF twins exhibited higher intrapair average in entropy indices and MM twins presented lower entropy values than FF twins considering the (automatically selected) threshold rLu. MM twin pairs showed higher intrapair differences in linear heart rate indices than MF and FF twins, whereas FF twins exhibited lower intrapair differences in entropy indices. Conclusions: The results of this exploratory study suggest that twins have sex-specific differences in linear and nonlinear indices of FHR. MM twins expressed signs of a more active autonomic nervous system and MF twins showed the most active complexity control system. These results suggest that fetal sex combination should be taken into consideration when performing detailed evaluation of the FHR in twins. PMID:24945419

Tendais, Iva; Figueiredo, Bárbara; Gonçalves, Hernâni; Bernardes, João; Ayres-de-Campos, Diogo; Montenegro, Nuno

2014-06-19

216

Rapid Heartbeat, But Dry Palms: Reactions of Heart Rate and Skin Conductance Levels to Social Rejection  

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Full Text Available Background: Social rejection elicits negative mood, emotional distress and neural activity in networks that are associated with physical pain. However, studies assessing physiological reactions to social rejection are rare and results of these studies were found to be ambiguous. Therefore, the present study aimed to examine and specify physiological effects of social rejection.Methods: Participants (N = 50 were assigned to either a social exclusion or inclusion condition of a virtual ball-tossing game (Cyberball. Immediate and delayed physiological (skin conductance level and heart rate reactions were recorded. In addition, subjects reported levels of affect, emotional states and fundamental needs.Results: Subjects who were socially rejected showed increased heart rates. However, social rejection had no effect on subjects’ skin conductance levels. Both conditions showed heightened arousal on this measurement. Furthermore, psychological consequences of social rejection indicated the validity of the paradigm.Conclusions: Our results reveal that social rejection evokes an immediate physiological reaction. Accelerated heart rates indicate that behavior activation rather than inhibition is associated with socially threatening events. In addition, results revealed gender-specific response patterns suggesting that sample characteristics such as differences in gender may account for ambiguous findings of physiological reactions to social rejection.

BenjaminIffland

2014-08-01

217

Association between resting heart rate and N-terminal pro-brain natriuretic peptide in a community-based population study in Beijing  

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Full Text Available Ruihua Cao, Yongyi Bai, Ruyi Xu, Ping Ye Department of Geriatric Cardiology, Chinese PLA General Hospital, Beijing, People’s Republic of China Background: N-terminal pro-brain natriuretic peptide (NT-proBNP is associated with an increased risk of cardiac insufficiency, which possibly leads to heart failure. However, the relationship between resting heart rate and NT-proBNP is unclear.Objective: This study focuses on this relativity between resting heart rate and plasma NT-proBNP levels in a surveyed community-based population.Methods: We evaluated the relativity between resting heart rate and plasma levels of NT-proBNP in 1,567 participants (mean age 61.0 years, range 21–96 years from a community-based population in Beijing, People’s Republic of China.Results: In patients with high resting heart rate (?75 beats/min, NT-proBNP was higher than in those having low resting heart rate (<75 beats/min. In multiple linear stepwise regression analysis, plasma NT-proBNP was associated with resting heart rate (partial correlation coefficient, 0.82; 95% confidence interval, 0.18–1.51; P=0.011. A subsequent subgroup analysis revealed that the association between resting heart rate and plasma NT-proBNP was strengthened in subjects over 60 years old (partial correlation coefficient 1.28; 95% confidence interval, 0.49–2.36; P=0.031; while the relativity between resting heart rate and plasma NT-proBNP was not emerged in the younger subgroup (<60 years old.Conclusions: Resting heart rate was associated with plasma NT-proBNP in the elderly, which indicated a relationship between resting heart rate and cardiac function damage. Keywords: resting heart rate, N-terminal pro-brain natriuretic peptide, epidemiology, cardiac function, relationship

Cao R

2014-12-01

218

Can a first-order exponential decay model fit heart rate recovery after resistance exercise?  

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The time-constant of postexercise heart rate recovery (HRR? ) obtained by fitting heart rate decay curve by a first-order exponential fitting has being used to assess cardiac autonomic recovery after endurance exercise. The feasibility of this model was not tested after resistance exercise (RE). The aim of this study was to test the goodness of fit of the first-order exponential decay model to fit heart rate recovery (HRR) after RE. Ten healthy subjects participated in the study. The experimental sessions occurred in two separated days and consisted of performance of 1 set of 10 repetitions at 50% or 80% of the load achieved on the one-repetition maximum test [low-intensity (LI) and high-intensity (HI) sessions, respectively]. Heart rate (HR) was continuously registered before and during exercise and also for 10 min of recovery. A monoexponential equation was used to fit the HRR curve during the postexercise period using different time windows (i.e. 30, 60, 90, … 600 s). For each time window, (i) HRR? was calculated and (ii) variation of HR explained by the model (R(2) goodness of fit index) was assessed. The HRR? showed stabilization from 360 and 420 s on LI and HI, respectively. Acceptable R(2) values were observed from the 360 s on LI (R(2)  > 0·65) and at all tested time windows on HI (R(2)  > 0·75). In conclusion, this study showed that using a minimum length of monitoring (~420 s) HRR after RE can be adequately modelled by a first-order exponential fitting. PMID:24494748

Bartels-Ferreira, Rhenan; de Sousa, Elder D; Trevizani, Gabriela A; Silva, Lilian P; Nakamura, Fábio Y; Forjaz, Cláudia L M; Lima, Jorge Roberto P; Peçanha, Tiago

2014-02-01

219

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

DEFF Research Database (Denmark)

BACKGROUND: The presence of autonomic dysfunction in HIV patients is largely unknown. Early studies found autonomic dysfunction in patients with AIDS. Introduction of highly active antiretroviral combination therapy (ART) has dramatically changed the course of the disease and improved prognosis and decreased morbidity. At present it is not known whether introduction of ART also has decreased autonomic dysfunction. AIM: To evaluate whether autonomic dysfunction is present in an ART-treated HIV population. METHODS: HIV patients receiving ART for at least 3 years (n = 16) and an age-matched control group of healthy volunteers (n = 12) were included. All were non-smokers, non-diabetic and had never received medication for dyslipidaemia or hypertension. Following a 10 min resting period a 5 min ECG recording was performed. Heart rate variability (HRV) analysis was performed in accordance with current guidelines and data reported as median (interquartile range). RESULTS: The resting heart rate was higher in HIV patients compared with controls [69 (62-74) versus 57 (52-60); P<0.001]. Total HRV measured as standard deviation of normal-to-normal (SONN) was lower in the HIV group compared with the controls [36 (25-55) versus 74 (57-84) ms; P<0.01] as was parasympathetic activity measured as square root of the mean squared difference of successive normal-to-normal intervals (RMSSD) [22 (9-30) versus 35 (24-62) ms; P<0.05]. Low frequency power was lower in the HIV group compared with the control group [294 (161-602) versus 946 (711-1668) ms(2); P<0.01]. High frequency power as well as systolic and diastolic blood pressure did not differ between the groups. CONCLUSIONS: The HIV patients in ART have increased resting heart rate and decreased short-term heart rate variability indicating parasympathetic dysfunction.

Lebech, Anne-Mette; Kristoffersen, Ulrik Sloth

2007-01-01

220

Effects of umbilical venous catheters on arrhythmia and heart rate variability in premature newborns  

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Full Text Available Aim: Cardiac rhythm abnormalities associated with umbilical venous catheters in newborns are limited to anecdotal case reports. The present study intended to evaluate association between umbilical venous catheter, arrhythmic potential, and changes in heart rate variability.Material and Method: The study consisted of two groups; 26 preterm newborns with a umbilical venous catheter (group 1, and 26 control group without (group 2. The following parameters were recorded prospectively: gender, gestation at birth, birth weight, and clinical assessment scores (SNAP-II and SNAPPE-II. Holter recordings were fitted in all newborns. The heart rate variability study was performed by utilizing time-domain and frequency-domain analyses. Results: The study population consisted of group 1 (30.63±2.67 weeks of gestation and group 2 (31.60±2.45 weeks of gestation. There was no statistical difference between the two groups for gestational age, birth weight, SNAP-II and SNAPPE- II scores. When compared for arrhythmia there was no statistical difference in any parameters between the two study groups. Premature atrial contraction was noted in 11 babies (42.3% in group 1 and in 7 babies (26.9% in group 2. Premature ventricular contraction was noted in 3 babies (11.5% in group 1 and in one baby in group 2. Sinus tachycardia detected in 3 patients in only the group 1. None of the heart rate variability parameters were found to be statistically different between the two groups.Conclusions: Our study reassuringly demonstrated that umbilical venous catheter does not have any significant effect on arrhythmia or heart rate variability in preterm newborns. (Turk Arch Ped 2013; 48: 131-7

Kadir Babao?lu

2013-06-01

221

Fetal heart rate monitoring: interpretation and collaborative management.  

Science.gov (United States)

Effective intrapartum fetal heart rate (FHR) monitoring requires ongoing collaboration among health care providers. Nurses, midwives, and physicians must have a shared understanding of 1) how FHR tracings are interpreted, 2) which FHR patterns are associated with actual or impending fetal acidemia, 3) when and within what time frame the physician or the midwife should be notified of variant FHR patterns, 4) how quickly physicians and midwives should respond when notified of variant patterns, and 5) the indications for and optimal timing of interventions such as operative delivery. This article reviews the literature on FHR monitoring and includes a discussion of the advantages and limitations of different monitoring modalities. An overview of those FHR patterns are associated with presumed fetal acidemia is presented, as well as sample multidisciplinary FHR monitoring guidelines and an exercise in intrapartum FHR pattern evaluation that can be used to initiate development of local FHR monitoring patterns. PMID:11151463

Fox, M; Kilpatrick, S; King, T; Parer, J T

2000-01-01

222

Complex character analysis of heart rate variability following brain asphyxia.  

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In the present study Renyi entropy and L-Z complexity were used to characterize heart rate variability (HRV) of rats that were suffered from brain asphyxia and ischemia. Two groups of rats were studied: (a) rats (n=5) injected with NAALADase inhibitor, 2-PMPA, which has been proven neuroprotective in asphyxia injury and (b) control subjects (n=5) without medication. Renyi entropy and L-Z complexity of the R-R intervals (RRI) at different experiment stages were investigated in the two groups. The results show that both measures indicate less injury and better recovery in the drug injection group. The dynamic change of 90 min RRI signal after the asphyxia was investigated. The sudden reduction of the two parameters shows their sensitivity to the asphyxia insult. PMID:16129646

Cai, Yuanyuan; Qiu, Yihong; Wei, Lan; Zhang, Wei; Hu, Sijun; Smith, Peter R; Crabtree, Vincent P; Tong, Shanbao; Thakor, Nitish V; Zhu, Yisheng

2006-05-01

223

Wearable depression monitoring system with heart-rate variability.  

Science.gov (United States)

A wearable depression monitoring system is proposed with an application-specific system-on-chip (SoC) solution. The SoC is designed to accelerate the filtering and feature extraction of heart-rate variability (HRV) from the electrocardiogram (ECG). Thanks to the SoC solution and planar-fashionable circuit board (P-FCB), the monitoring system becomes a low-power wearable system. Its dimension is 14cm × 7cm with 5mm thickness covering the chest band for convenient usage. In addition, with 3.7V 500mAh battery, its lifetime is at least 10 hours. For user's convenience, the system is interfacing to smart phones through Bluetooth communication. With the features of the HRV and Beck depression inventory (BDI), the smart phone application trains and classifies the user's depression scale with 71% of accuracy. PMID:25570021

Roh, Taehwan; Sunjoo Hong; Hoi-Jun Yoo

2014-08-01

224

Neuro-Fuzzy Approach to Heart Rate Variability Analysis  

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Full Text Available Heart rate variability (HRV analysis attempts to assess cardiac autonomic regulation through quantification of sinus rhythm variability. The sinus rhythm times series is derived from the QRS to QRS (RR interval sequence of the electrocardiogram (ECG, by extracting only normal sinus to normal sinus (NN interbeat intervals. Relatively high frequency variations in sinus rhythm reflect parasympathetic (vagal modulation, and slower variations reflect a combination of both parasympathetic and sympathetic modulation and non-autonomic factors. The paper focuses on the Neuro-fuzzy system. It is used to recognize the HRV signals for diagnosis by extract the QRST zone of ECG signals using Discrete Cosine Transform (DCT. The result is exciting as much as we have used only one of ECG lead to records input data, while the current diagnosis approaches require the set of 12 lead ECG signals!

Hoang ChuDuc

2013-09-01

225

Should the augmentation index be normalized to heart rate?  

Science.gov (United States)

Pulse wave analysis(PWA) is widely used to investigate systemic arterial stiffness. The augmentation index(AIx), the primary outcome derived from PWA, is influenced by the mean arterial pressure(MAP), age, gender and heart rate(HR). Gender- and age-specific reference values have been devised, and it is recommended that the MAP be used as a statistical covariate. The AIx is also commonly statistically adjusted to a HR of 75 b·min(-1); however, this approach may be physiologically and statistically inappropriate. First, there appears to be an important physiological chronic interaction between HR and arterial stiffness. Second, the method used to correct to HR assumes that the relationship with AIx is uniform across populations. A more appropriate practice may be to include HR as an independent predictor or covariate; this approach is particularly recommended for longitudinal studies, in which changes in HR may help to explain changes in arterial stiffness. PMID:24257465

Stoner, Lee; Faulkner, James; Lowe, Andrew; M Lambrick, Danielle; M Young, Joanna; Love, Richard; S Rowlands, David

2014-01-01

226

Emergence of dynamical complexity related to human heart rate variability  

Science.gov (United States)

We apply the refined composite multiscale entropy (MSE) method to a one-dimensional directed small-world network composed of nodes whose states are binary and whose dynamics obey the majority rule. We find that the resulting fluctuating signal becomes dynamically complex. This dynamical complexity is caused (i) by the presence of both short-range connections and long-range shortcuts and (ii) by how well the system can adapt to the noisy environment. By tuning the adaptability of the environment and the long-range shortcuts we can increase or decrease the dynamical complexity, thereby modeling trends found in the MSE of a healthy human heart rate in different physiological states. When the shortcut and adaptability values increase, the complexity in the system dynamics becomes uncorrelated.

Chang, Mei-Chu; Peng, C.-K.; Stanley, H. Eugene

2014-12-01

227

Heart Rate Variability Analysis Using Threshold of Wavelet Package Coefficients  

CERN Document Server

In this paper, a new efficient feature extraction method based on the adaptive threshold of wavelet package coefficients is presented. This paper especially deals with the assessment of autonomic nervous system using the background variation of the signal Heart Rate Variability HRV extracted from the wavelet package coefficients. The application of a wavelet package transform allows us to obtain a time-frequency representation of the signal, which provides better insight in the frequency distribution of the signal with time. A 6 level decomposition of HRV was achieved with db4 as mother wavelet, and the above two bands LF and HF were combined in 12 specialized frequencies sub-bands obtained in wavelet package transform. Features extracted from these coefficients can efficiently represent the characteristics of the original signal. ANOVA statistical test is used for the evaluation of proposed algorithm.

Kheder, G; Massoued, M Ben; Samet, M

2009-01-01

228

Heart Rate Variability Analysis Using Threshold of Wavelet Package Coefficients  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, a new efficient feature extraction method based on the adaptive threshold of wavelet package coefficients is presented. This paper especially deals with the assessment of autonomic nervous system using the background variation of the signal Heart Rate Variability HRV extracted from the wavelet package coefficients. The application of a wavelet package transform allows us to obtain a time-frequency representation of the signal, which provides better insight in the frequency distribution of the signal with time. A 6 level decomposition of HRV was achieved with db4 as mother wavelet, and the above two bands LF and HF were combined in 12 specialized frequencies sub-bands obtained in wavelet package transform. Features extracted from these coefficients can efficiently represent the characteristics of the original signal. ANOVA statistical test is used for the evaluation of proposed algorithm.

G. Kheder

2009-11-01

229

Heart rate variability and motion sickness during forklift simulator driving.  

Science.gov (United States)

The goal of the study was to determine the effect of a 1-h hour long forklift truck virtual simulator driving on the mechanism of autonomic heart rate (HR) regulation in operators. The participants were divided into 2 subgroups: subjects with no definite inclination to motion sickness (group A) and subjects with a definite inclination to motion sickness (group B). Holter monitoring of electrocardiogram (ECG) signal was carried out in all subjects during the virtual simulator driving. For 12 consecutive epochs of ECG signal, HR variability analysis was conducted in time and frequency domains. In subjects with a definite inclination to motion sickness after ~30 min of the driving, changes in parameter values were found indicating an increase in sympathetic and parasympathetic activity with parasympathetic dominance. PMID:22152505

Zu?ewicz, Krystyna; Saulewicz, Antoni; Konarska, Maria; Kaczorowski, Zbigniew

2011-01-01

230

Automated Fetal Heart Rate Analysis in Labor: Decelerations and Overshoots  

International Nuclear Information System (INIS)

Electronic fetal heart rate (FHR) recording is a standard way of monitoring fetal health in labor. Decelerations and accelerations usually indicate fetal distress and normality respectively. But one type of acceleration may differ, namely an overshoot that may atypically reflect fetal stress. Here we describe a new method for detecting decelerations, accelerations and overshoots as part of a novel system for computerized FHR analysis (OxSyS). There was poor agreement between clinicians when identifying these FHR features visually, which precluded setting a gold standard of interpretation. We therefore introduced 'modified' Sensitivity (SE deg.) and 'modified' Positive Predictive Value (PPV deg.) as appropriate performance measures with which the algorithm was optimized. The relation between overshoots and fetal compromise in labor was studied in 15 cases and 15 controls. Overshoots showed promise as an indicator of fetal compromise. Unlike ordinary accelerations, overshoots cannot be considered to be reassuring features of fetal health.

231

Heart Rate Variability in Cavalier King Charles Spaniels with Different Degree of Myxomatous Mitral Valve Disease  

DEFF Research Database (Denmark)

Heart Rate Variability in Cavalier King Charles Spaniels with Different Degree of Myxomatous Mitral Valve Disease Rasmussen, C.E. 1, Falk, T. 1, Zois, N.E. 1, Moesgaard, S.G. 1, Häggström, J. 2, Pedersen, H.D. 3 and Olsen, L.H1. 1Department of Basic Animal and Veterinary Sciences, Faculty of Life Sciences, University of Copenhagen, Frederiksberg, Denmark, 2Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden; and 3Novo Nordic A/S, Maaloev, Denmark. Introduction: Modulation of heart rate by the autonomic nervous system can indirectly be measured by heart rate variability (HRV). Reduced HRV is seen in dogs with heart failure secondary to myxomatous mitral valve disease (MMVD). However, HRV is suggested to increase with disease progression in dogs with early stages of MMVD. Comparable results are found in people with primary mitral valve prolapse, a disease resembling canine MMVD. Aim: To associate progression of MMVD in dogs with time and frequency domain HRV, analysed from 24-hour electrocardiography. Materials and Methods: Eighty-one Cavalier King Charles Spaniels (CKCS) were examined by echocardiography and 24-hour electrocardiography. CKCS were divided into 4 groups: 1) no or minimal mitral regurgitation (MR) (MR jet=15% of the left atrial area) and no murmur, 2) mild MR (20%50%) and no clinical signs of heart failure, 4) left atrium to aortic root ratio >1.5, clinical signs of heart failure and furosemide responsiveness. Results: Ten out of 13 HRV variables decreased with increasing MMVD severity. In group 1, 10 HRV variables were increased compared to group 3 and 4 (P<0.05) and 2 HRV variables were increased compared to group 2 (P<0.04). Eight and 10 HRV variables were increased in group 2 compared to group 3 (P<0.01) and group 4 (P<0.001), respectively. Group 1 and 2 were younger than group 3 and 4 (P<0.0001). Only 2 HRV variables were influenced by age. Discussion and conclusion: Most HRV variables decreased with progression of MMVD in dogs; even prior to the development of overt congestive heart failure.

Rasmussen, Caroline Elisabeth; Falk, Bo Torkel

232

Heart Rate Variability in Patients With Multiple Sclerosis  

Directory of Open Access Journals (Sweden)

Full Text Available Objective: The aims of the present study were to compare heart rate variability (HRV parameters of patients with multiple sclerosis (MS and healthy controls and to investigate the correlations between HRV parameters and disease duration, subtype and severity.Methods: Thirty-two patients with MS [18 with relapsing-remitting MS (RRMS, 4 with primary progressive MS (PPMS and 10 with secondary progressive MS (SPMS] and 32 healthy, age-and sex-matched volunteers were included. HRV was evaluated by frequency-domain spectral analysis method; total power (TP, low frequency (LF power, high frequency (HF power, very low frequency (VLF power in absolute values and in normalized units (n.u. and the ratio of LF to HF was used.Results: The patients had lower TP, VLF, LF, HF and HF n.u. and higher LF n.u. and the ratio of LF to HF reflecting overall decreased HRV accompanied by sympathetic overactivity and parasympathetic hypoactivity. There was no association between EDSS score and HRV parameters; however, we found a positive correlation between disease duration and LF n.u. We did not find significant differences between the patients with RRMS and the patients with SPMS regarding cardiac autonomic activity. Although TP, LF power, HF power and VLF power of the patients with PPMS were lower than of the patients with RRMS and the patients with SPMS, no statistical analysis could be made for this group due to inadequate number of the patients in this group.Interpretation: Patients with MS have higher sympathetic and lower parasympathetic regulation activity of heart rate. Disease duration, rather than severity seems to be associated with increased sympathetic activity.

Fevzi BEKTA?LI

2009-09-01

233

Linear and non-linear 24 h heart rate variability in chronic heart failure.  

Science.gov (United States)

It has recently been demonstrated that SDNN of heart rate variability (HRV) is a useful independent prognostic tool in chronic heart failure (CHF). The purpose of the present study was to evaluate if spectral and non-linear analysis of 24-h HRV, considered markers of autonomic cardiac modulation, contain independent prognostic information in CHF patients. Twenty normal subjects and thirty consecutive outpatients with clinically stable CHF were studied for 2 years. Periods of 300 R-R intervals were analyzed from Holter recordings. The power spectral analysis, the slope of the linear relationship between log-power versus log-frequency (1/f), and the complexity content (using corrected conditional entropy; CCE) of the R-R series were calculated. The normalized power of the low frequency spectral component (LF) and the 1/f slope were significantly lower in patients compared to controls (respectively 30.1 +/- 3.0 vs. 48.6 +/- 3.4 and -1.27 +/- 0.04 vs. -1.08 +/- 0.05; P non-linear analysis of HRV in CHF patients has prognostic relevance independently from the time domain measures of HRV. In particular, the reduction of LF power seems the best indicator among those considered. PMID:11269916

Guzzetti, S; Mezzetti, S; Magatelli, R; Porta, A; De Angelis, G; Rovelli, G; Malliani, A

2000-12-28

234

State level correlations between high heart attack and stroke symptomology knowledge scores and CVD risk factors and mortality rates  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: In 2008, cardiovascular disease (CVD accounted for one in three deaths in the United States. Epidemiological analyses suggest that two or more risk factors are the indicator of high risk and/or poor CVD outcomes. Knowledge of heart attack and stroke symptomology has been the focus of much research based on the assumption that accurate identification of an event is critical to reducing time to treatment. There is a paucity of research showing a clear association between knowledge of heart attack and stroke symptomology, risk factors, and mortality rates. In this study, we hypothesized that high stroke and heart attack symptomology knowledge scores would correspond to lower stroke or CVD mortality rankings as well as to a lower prevalence of two or more CVD risk factors. Methods: State was the unit of analysis used to examine data from two different sources and combined into a customized database. The first source was a multiyear Behavioral Risk Factor Surveillance Survey (BRFSS heart attack and stroke symptom knowledge module database. CVD and stroke mortality data used came from the American Heart Association’s (AHA 2012 Heart Disease and Stroke Statistics Update. Spearman’s Rho was the test statistic. Results: A moderate negative correlation was found between high heart attack and stroke symptom knowledge scores and the percentage of adults with two or more CVD or stroke risk factors. Likewise, a similar correlation resulted from the two variables, high heart attack and stroke symptoms knowledge score and CVD mortality rank. Conclusions: This study demonstrated a significant relationship between high heart attack and stroke symptom knowledge and lower CVD mortality rates and lower prevalence of two or more CVD risk factors at the state level. Our findings suggest that it is important to continue education efforts regarding heart attack and stroke symptom knowledge. Pharmacists are one group of health care providers who could enhance the needed public health education efforts.

Mary Nawal Lutfiyya

2013-09-01

235

Comparison of heart rate variability and pulse rate variability detected with photoplethysmography  

Science.gov (United States)

This study compares ear photoplethysmography (PPG) and electrocardiogram (ECG) in providing accurate heart beat intervals for use in calculations of heart rate variability (HRV, from ECG) or of pulse rate variability (PRV, from PPG) respectively. Simultaneous measurements were taken from 44 healthy subjects at rest during spontaneous breathing and during forced metronomic breathing (6/min). Under both conditions, highly significant (p > 0.001) correlations (1.0 > r > 0.97) were found between all evaluated common HRV and PRV parameters. However, under both conditions the PRV parameters were higher than HRV. In addition, we calculated the limits of agreement according to Bland and Altman between both techniques and found good agreement ( 20%) agreement for other standard HRV and PRV parameters. Thus, PRV data seem to be acceptable for screening purposes but, at least at this state of knowledge, not for medical decision making. However, further studies are needed before more certain determination can be made.

Rauh, Robert; Limley, Robert; Bauer, Rainer-Dieter; Radespiel-Troger, Martin; Mueck-Weymann, Michael

2004-08-01

236

Skeletal muscle signaling and the heart rate and blood pressure response to exercise : insight from heart rate pacing during exercise with a trained and a deconditioned muscle group  

DEFF Research Database (Denmark)

Endurance training lowers heart rate and blood pressure responses to exercise, but the mechanisms and consequences remain unclear. To determine the role of skeletal muscle for the cardioventilatory response to exercise, 8 healthy young men were studied before and after 5 weeks of 1-legged knee-extensor training and 2 weeks of deconditioning of the other leg (leg cast). Hemodynamics and muscle interstitial nucleotides were determined during exercise with the (1) deconditioned leg, (2) trained leg, and (3) trained leg with atrial pacing to the heart rate obtained with the deconditioned leg. Heart rate was ˜15 bpm lower during exercise with the trained leg (P

Mortensen, Stefan Peter; Svendsen, Jesper H

2013-01-01

237

Simple and Cost-effective Heart Rate Meter Using PIC Microcontroller  

Directory of Open Access Journals (Sweden)

Full Text Available 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: sympathetic regulation increases and parasympathetic regulation decreases the heart rate. Monitoring of heart rate plays an important role in conveying the status of cardiovascular system and clinically correlated information to medical professionals. Therefore, heart rate measurement is regarded as an essential parameter in patient care monitoring system. Human heart rate can be measured either by the ECG waveform or by sensing the pulse, the rhythmic expansion and contraction of an artery as blood is forced through it by the regular contractions of the heart. The pulse can be sensed from those areas where the artery is close to the skin. This research paper highlights on the design of a microcontroller (PIC series based simple and cost-effective heart rate meter that is able to capture the pulse from human finger tip by sensing the change in blood volume. The heart rates of fifteen healthy normal subjects (students of age 21-22 yrs. both in relaxed and exercised (stressed states were measured using the designed system. The heart data, measured from the designed system showed satisfactory result while compared to a standard heart rate meter. The Also, the designed meter, being non-invasive one, can easily find its place in health care monitoring system.

Souvik Das

2014-04-01

238

Patients with uncomplicated coronary artery disease have reduced heart rate variability mainly affecting vagal tone  

OpenAIRE

AIM—To investigate whether uncomplicated chronic coronary artery disease causes changes in heart rate variability and if so, whether the heart rate variability pattern is different from that described in patients with acute myocardial infarction.?METHODS—Heart rate variability was studied in 65 patients with angina who had no previous myocardial infarcts, no other diseases, and were on no drug that could influence the sinus node. Results were compared with 33 age matched healthy subje...

Wennerblom, B.; Lurje, L.; Tygesen, H.; Vahisalo, R.; Hjalmarson, A.

2000-01-01

239

Shortened left ventricular filling time in dilated cardiomyopathy: additional effects on heart rate variability?  

OpenAIRE

OBJECTIVE--To assess possible mechanical influences underlying the reduced heart rate variability in patients with dilated cardiomyopathy. DESIGN--Comparison of standard non-spectral indices of heart rate variability with echocardiographic Doppler measures of left ventricular function in patients and normal controls. PATIENTS--20 patients with dilated cardiomyopathy and 15 normal subjects of similar ages were studied. METHODS--Standard non-spectral indices of heart rate variability were measu...

Mbaissouroum, M.; O Sullivan, C.; Brecker, S. J.; Xiao, H. B.; Gibson, D. G.

1993-01-01

240

Cognitive Performance and Heart Rate Variability: The Influence of Fitness Level  

OpenAIRE

In the present study, we investigated the relation between cognitive performance and heart rate variability as a function of fitness level. We measured the effect of three cognitive tasks (the psychomotor vigilance task, a temporal orienting task, and a duration discrimination task) on the heart rate variability of two groups of participants: a high-fit group and a low-fit group. Two major novel findings emerged from this study. First, the lowest values of heart rate variability were found du...

Luque-casado, Antonio; Zabala, Mikel; Morales Ortiz, Esther; Mateo-march, Manuel; Sanabria Lucena, Daniel

2013-01-01

241

Effect of Supervised Integrated Exercise on Deep Breathing- Heart Rate Variability in Male Hypertensive Patients  

OpenAIRE

The aim of the study was to evaluate if prolonged supervised integrated exercise in male hypertensive patients reverses the deterioration of heart rate variability. Sixty six male hypertensive patients were divided into exercise (n = 30) and non-exercise groups (n = 36). Exercise group patients underwent a supervised integrated exercise program for one-year. Time domain analysis of heart rate variability was performed from electrocardiogram during deep breathing. Heart rate variability ...

Niranjan, M.; Nagaraja, H. S.; Anupama, B. K.; Bhagyalakshmi, N.; Bhat, R.; Prabha, A.

2008-01-01

242

Influence of blood glucose on heart rate and cardiac autonomic function. The DESIR study.  

OpenAIRE

OBJECTIVES: ? To evaluate in a general population, the relationships between dysglycaemia, insulin resistance and metabolic variables, and heart rate, heart rate recovery and heart rate variability. METHODS: ? Four hundred and forty-seven participants in the Data from an Epidemiological Study on the Insulin Resistance syndrome (DESIR) study were classified according to glycaemic status over the preceding 9 years. All were free of self-reported cardiac antecedents and were not taking drugs...

Valensi, Paul; Extramiana, Fabrice; Lange, Ce?line; Cailleau, Martine; Haggui, Abdeddayem; Maison Blanche, Pierre; Tichet, Jean; Balkau, Beverley

2011-01-01

243

Office and 24-hour heart rate and target organ damage in hypertensive patients  

OpenAIRE

Abstract Background We investigated the association between heart rate and its variability with the parameters that assess vascular, renal and cardiac target organ damage. Methods A cross-sectional study was performed including a consecutive sample of 360 hypertensive patients without heart rate lowering drugs (aged 56 ± 11 years, 64.2% male). Heart rate (HR) and its standard deviation (HRV) in clinical and 24-hour ambulatory monitoring were evaluated. Renal da...

García-García Ángel; Gómez-Marcos Manuel A; Recio-Rodríguez José I; Patino-Alonso Maria C; Rodríguez-Sánchez Emiliano; Agudo-Conde Cristina; García-Ortiz Luis

2012-01-01

244

Decomposition of heart rate variability by adaptive filtering for estimation of cardiac vagal tone  

OpenAIRE

Heart rate fluctuations resulting from respiration and other influences upon the cardiovascular system are encoded into the patterns of heart rate variability (HRV). The fluctuations due to respiration are called respiratory sinus arrhythmia (RSA). Since RSA is primarily mediated through the autonomic nervous system (ANS), it is of interest to separate RSA from other influences to assess the underlying ANS function. On the other hand, the RSA may obscure heart rate responses to external manip...

Han, Kedu; Nagel, Joachim H.; Hurwitz, Barry E.; Schneiderman, Neil

1991-01-01

245

A novel technique for fetal heart rate estimation from Doppler ultrasound signal  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The currently used fetal monitoring instrumentation that is based on Doppler ultrasound technique provides the fetal heart rate (FHR signal with limited accuracy. It is particularly noticeable as significant decrease of clinically important feature - the variability of FHR signal. The aim of our work was to develop a novel efficient technique for processing of the ultrasound signal, which could estimate the cardiac cycle duration with accuracy comparable to a direct electrocardiography. Methods We have proposed a new technique which provides the true beat-to-beat values of the FHR signal through multiple measurement of a given cardiac cycle in the ultrasound signal. The method consists in three steps: the dynamic adjustment of autocorrelation window, the adaptive autocorrelation peak detection and determination of beat-to-beat intervals. The estimated fetal heart rate values and calculated indices describing variability of FHR, were compared to the reference data obtained from the direct fetal electrocardiogram, as well as to another method for FHR estimation. Results The results revealed that our method increases the accuracy in comparison to currently used fetal monitoring instrumentation, and thus enables to calculate reliable parameters describing the variability of FHR. Relating these results to the other method for FHR estimation we showed that in our approach a much lower number of measured cardiac cycles was rejected as being invalid. Conclusions The proposed method for fetal heart rate determination on a beat-to-beat basis offers a high accuracy of the heart interval measurement enabling reliable quantitative assessment of the FHR variability, at the same time reducing the number of invalid cardiac cycle measurements.

Jezewski Janusz

2011-10-01

246

Heart rate recovery – a potential marker of clinical outcomes in heart failure patients receiving beta-blocker therapy  

Science.gov (United States)

BACKGROUND: Heart rate recovery (HRR) within the first few minutes of graded exercise has been associated with impaired clinical outcomes in patients being evaluated for coronary artery disease. HRR is abnormal in patients with heart failure (HF), but has not been associated with clinical outcomes in these patients. The objective of the present study was to determine whether HRR following cardiopulmonary exercise testing (CPET) correlates with peak oxygen consumption (VO2), and whether it impacts clinical outcomes, including HF hospitalizations and total mortality, or the need for cardiac transplantation. METHODS: CPET was performed in 78 patients referred to the Montreal Heart Institute (Montreal, Quebec) with congestive HF between January 2000 and December 2002. All patients had New York Heart Association class II or III HF with a left ventricular ejection fraction of 45% or lower. Mean (± SD) age was 53±11 years and left ventricular ejection fraction was 27±9%. Forty-four per cent had ischemic cardiomyopathy, 88% received beta-blockers and 79% received angiotensin-converting enzyme inhibitors. HRR was defined as the difference from peak exercise HR to HR measured at specific time intervals. HRR was calculated 30 s, 60 s, 90 s and 120 s after exercise. RESULTS: Mean peak VO2 was 18.0±5.3 mL/kg/min, resting HR was 74±13 beats/min and peak HR was 119±22 beats/min. HRR measured was 10±9 beats/min after 30 s, 20±12 beats/min after 60 s, 25±15 beats/min after 90 s and 30±13 beats/min after 120 s. At 90 s, patients with an HRR below 24 beats/min were more likely to have an HF hospitalization at five-year follow-up (eight hospitalizations [22.2%] versus two hospitalizations [2.7%]; P=0.0134). There was a correlation between peak VO2 and HRR 90 s and 120 s after completion of the exercise test (r=0.40 after 90 s, P=0.001, and r=0.41 after 120 s, P=0.008). CONCLUSIONS: In patients with HF, blunted HRR 90 s and 120 s after CPET correlate with peak VO2 and are associated with increased risk of worsening HF. HRR is easily measured and a useful marker for morbidity in patients with HF. PMID:18060099

Sheppard, Richard; Racine, Normand; Roof, Andre; Ducharme, Anique; Blanchet, Martine; White, Michel

2007-01-01

247

Decreased Variability of the 6-Minute Walk Test by Heart Rate Correction in Patients with Neuromuscular Disease  

Science.gov (United States)

Objective The 6-minute walk test is widely used to assess functional status in neurological disorders. However, the test is subject to great inter-test variability due to fluctuating motivation, fatigue and learning effects. We investigated whether inter-test variability of the 6MWT can be reduced by heart rate correction. Methods Sixteen patients with neuromuscular diseases, including Facioscapulohumeral muscular dystrophy, Limb-girdle muscular dystrophy, Charcot-Marie-Tooths, Dystrophia Myotonica and Congenital Myopathy and 12 healthy subjects were studied. Patients were excluded if they had cardiac arrhythmias, if they received drug treatment for hypertension or any other medical conditions that could interfere with the interpretation of the heart rate and walking capability. All completed three 6-minute walk tests on three different test-days. Heart rate was measured continuously. Results Successive standard 6-minute walk tests showed considerable learning effects between Tests 1 and 2 (4.9%; P?=?0.026), and Tests 2 and 3 (4.5%; P?=?0.020) in patients. The same was seen in controls between Tests 1 and 2 (8.1%; P?=?0.039)). Heart rate correction abolished this learning effect. Conclusion A modified 6-minute walk test, by correcting walking distance with average heart rate during walking, decreases the variability among repeated 6-minute walk tests, and should be considered as an alternative outcome measure to the standard 6-minute walk test in future clinical follow-up and treatment trials. PMID:25479403

Prahm, Kira P.; Witting, Nanna; Vissing, John

2014-01-01

248

Heart rate variability analysis during central hypovolemia using wavelet transformation.  

Science.gov (United States)

Detection of hypovolemia prior to overt hemodynamic decompensation remains an elusive goal in the treatment of critically injured patients in both civilian and combat settings. Monitoring of heart rate variability has been advocated as a potential means to monitor the rapid changes in the physiological state of hemorrhaging patients, with the most popular methods involving calculation of the R-R interval signal's power spectral density (PSD) or use of fractal dimensions (FD). However, the latter method poses technical challenges, while the former is best suited to stationary signals rather than the non-stationary R-R interval. Both approaches are also limited by high inter- and intra-individual variability, a serious issue when applying these indices to the clinical setting. We propose an approach which applies the discrete wavelet transform (DWT) to the R-R interval signal to extract information at both 500 and 125 Hz sampling rates. The utility of machine learning models based on these features were tested in assessing electrocardiogram signals from volunteers subjected to lower body negative pressure induced central hypovolemia as a surrogate of hemorrhage. These machine learning models based on DWT features were compared against those based on the traditional PSD and FD, at both sampling rates and their performance was evaluated based on leave-one-subject-out fold cross-validation. Results demonstrate that the proposed DWT-based model outperforms individual PSD and FD methods as well as the combination of these two traditional methods at both sample rates of 500 Hz (p value DWT approach in monitoring the physiological changes caused by hemorrhage. The speed and relatively low computational costs in deriving these features may make it particularly suited for implementation in portable devices for remote monitoring. PMID:23371800

Ji, Soo-Yeon; Belle, Ashwin; Ward, Kevin R; Ryan, Kathy L; Rickards, Caroline A; Convertino, Victor A; Najarian, Kayvan

2013-06-01

249

Heart rate variability biofeedback improves cardiorespiratory resting function during sleep.  

Science.gov (United States)

The present study was designed to examine the effect of heart rate variability (HRV) biofeedback on the cardiorespiratory resting function during sleep in daily life. Forty-five healthy young adults were randomly assigned to one of three groups: HRV biofeedback, Autogenic Training(AT), and no-treatment control. Participants in the HRV biofeedback were instructed to use a handheld HRV biofeedback device before their habitual bedtime, those in the AT were asked to listen to an audiotaped instruction before bedtime,and those in the control were asked to engage in their habitual activity before bedtime. Pulse wave signal during sleep at their own residences was measured continuously with a wrist watch-type transdermal photoelectric sensor for three time points. Baseline data were collected on the first night of measurements, followed by two successive nights for HRV biofeedback, AT, or control. Cardiorespiratory resting function was assessed quantitatively as the amplitude of high frequency(HF) component of pulse rate variability, a surrogate measure of respiratory sinus arrhythmia. HF component increased during sleep in the HRV biofeedback group,although it remained unchanged in the AT and control groups. These results suggest that HRV biofeedback before sleep may improve cardiorespiratory resting function during sleep. PMID:23959190

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

2013-12-01

250

A comparison between computer-controlled and set work rate exercise based on target heart rate  

Science.gov (United States)

Two methods are compared for observing the heart rate (HR), metabolic equivalents, and time in target HR zone (defined as the target HR + or - 5 bpm) during 20 min of exercise at a prescribed intensity of the maximum working capacity. In one method, called set-work rate exercise, the information from a graded exercise test is used to select a target HR and to calculate a corresponding constant work rate that should induce the desired HR. In the other method, the work rate is controlled by a computer algorithm to achieve and maintain a prescribed target HR. It is shown that computer-controlled exercise is an effective alternative to the traditional set work rate exercise, particularly when tight control of cardiovascular responses is necessary.

Pratt, Wanda M.; Siconolfi, Steven F.; Webster, Laurie; Hayes, Judith C.; Mazzocca, Augustus D.; Harris, Bernard A., Jr.

1991-01-01

251

The Development of a Microcontroller Based LowCost Heart Rate Counter for Health Care Systems  

Directory of Open Access Journals (Sweden)

Full Text Available The heart rate is one of the significant physiological parameters of the human cardiovascular system. Heart rate is the number of times the heart beats per minute. Heart rate data reflects various physiological states such as biological workload, stress at work and concentration on tasks, drowsiness and the active state of the autonomic nervous system. Human cardiac dynamics are driven by the complex nonlinear interactions of two competing forces: sympathetic regulation increases and parasympathetic regulation decreases the heart rate. Thus, monitoring of heart rate plays a significant role in providing the status of cardiovascular system and clinically correlated information to medical professionals. Heart rate measurement is also regarded as an essential parameter in patient care monitoring system.Heart rate can be measured either by the ECG waveform or by sensing the pulse - the rhythmic expansion and contraction of an artery as blood is forced through it by the regular contractions of the heart. The pulse can be felt from those areas where the artery is close to the skin. This paper highlights on the design of a microcontroller (PIC series based heart rate counter that is able to capture the pulse from finger tip by sensing the change in blood volume. The heart rates of fifteen healthy normal subjects (students of age 21-22 yrs. both in relaxed and excited states were measured using the designed device and a standard heart rate measuring device. The outputs of the measured device were satisfactory. Also, the designed device, being noninvasive one, can easily find its place in health care monitoring system.

Souvik Das

2013-02-01

252

Association between resting heart rate and N-terminal pro-brain natriuretic peptide in a community-based population study in Beijing  

Science.gov (United States)

Background N-terminal pro-brain natriuretic peptide (NT-proBNP) is associated with an increased risk of cardiac insufficiency, which possibly leads to heart failure. However, the relationship between resting heart rate and NT-proBNP is unclear. Objective This study focuses on this relativity between resting heart rate and plasma NT-proBNP levels in a surveyed community-based population. Methods We evaluated the relativity between resting heart rate and plasma levels of NT-proBNP in 1,567 participants (mean age 61.0 years, range 21–96 years) from a community-based population in Beijing, People’s Republic of China. Results In patients with high resting heart rate (?75 beats/min), NT-proBNP was higher than in those having low resting heart rate (<75 beats/min). In multiple linear stepwise regression analysis, plasma NT-proBNP was associated with resting heart rate (partial correlation coefficient, 0.82; 95% confidence interval, 0.18–1.51; P=0.011). A subsequent subgroup analysis revealed that the association between resting heart rate and plasma NT-proBNP was strengthened in subjects over 60 years old (partial correlation coefficient 1.28; 95% confidence interval, 0.49–2.36; P=0.031); while the relativity between resting heart rate and plasma NT-proBNP was not emerged in the younger subgroup (<60 years old). Conclusions Resting heart rate was associated with plasma NT-proBNP in the elderly, which indicated a relationship between resting heart rate and cardiac function damage. PMID:25565787

Cao, Ruihua; Bai, Yongyi; Xu, Ruyi; Ye, Ping

2015-01-01

253

Association between resting heart rate and N-terminal pro-brain natriuretic peptide in a community-based population study in Beijing  

Science.gov (United States)

Background N-terminal pro-brain natriuretic peptide (NT-proBNP) is associated with an increased risk of cardiac insufficiency, which possibly leads to heart failure. However, the relationship between resting heart rate and NT-proBNP is unclear. Objective This study focuses on this relativity between resting heart rate and plasma NT-proBNP levels in a surveyed community-based population. Methods We evaluated the relativity between resting heart rate and plasma levels of NT-proBNP in 1,567 participants (mean age 61.0 years, range 21–96 years) from a community-based population in Beijing, People’s Republic of China. Results In patients with high resting heart rate (?75 beats/min), NT-proBNP was higher than in those having low resting heart rate (<75 beats/min). In multiple linear stepwise regression analysis, plasma NT-proBNP was associated with resting heart rate (partial correlation coefficient, 0.82; 95% confidence interval, 0.18–1.51; P=0.011). A subsequent subgroup analysis revealed that the association between resting heart rate and plasma NT-proBNP was strengthened in subjects over 60 years old (partial correlation coefficient 1.28; 95% confidence interval, 0.49–2.36; P=0.031); while the relativity between resting heart rate and plasma NT-proBNP was not emerged in the younger subgroup (<60 years old). Conclusions Resting heart rate was associated with plasma NT-proBNP in the elderly, which indicated a relationship between resting heart rate and cardiac function damage.

Cao, Ruihua; Bai, Yongyi; Xu, Ruyi; Ye, Ping

2015-01-01

254

The art equipment for measuring the horse’s heart rate  

Directory of Open Access Journals (Sweden)

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.

F. Cus

2010-07-01

255

Influence of physical exercise on serum digoxin concentration and heart rate in patients with atrial fibrillation.  

OpenAIRE

Heart rate and serum digoxin concentration in eight patients with atrial fibrillation were studied at rest and during exercise when initial serum digoxin concentrations were zero and at low and high therapeutic values. Eight patients with ischemic heart disease and in sinus rhythm were studied for comparison. Though the serum digoxin concentration decreased significantly during exercise, the absolute reduction in heart rate was the same at rest and during exercise in patients with atrial fibr...

Bøtker, H. E.; Toft, P.; Klitgaard, N. A.; Simonsen, E. E.

1991-01-01

256

Assessment of electrocardiography, echocardiography, and heart rate variability in dynamic and static type athletes  

Directory of Open Access Journals (Sweden)

Full Text Available Mehrnoush Toufan,1 Babak Kazemi,1 Fariborz Akbarzadeh,1 Amin Ataei,1 Majid Khalili21Cardiovascular Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; 2Azerbaijan National Academy of Sciences, Baku, AzerbaijanBackground: Over the last two decades, morphological cardiac changes induced by athletic conditioning have been of great interest. Therefore, several studies have been orchestrated to delineate electrocardiography (ECG, echocardiography, and heart rate variability (HRV findings in athletes.Purpose: To assess the ECG, echocardiography, and HRV in a group of dynamic and static type athletes.Methods: Fifty professional athletes (20 static and 30 dynamic exercise athletes and 50 healthy nonathletes (control group were recruited. Standard 12-lead ECG and transthoracic echocardiography was performed on all athletes and the control group. Through echocardiography, variables including left ventricular (LV end-diastolic/systolic diameter, LV mass, and left atrial volume index were measured. In addition, both the athletes and the control group underwent ECG Holter monitoring for 15 minutes and several parameters related to HRV (time and frequency domain were recorded.Results: The most common ECG abnormalities among the athletes were sinus bradycardia and incomplete right bundle branch block. LV end-diastolic diameter and left atrial volume index were significantly greater in the dynamic athletes (P < 0.001. LV end-systolic diameter was significantly lower in the static group (P < 0.001. LV mass of the dynamic and static athletes was significantly greater than that of the controls (P < 0.001. Among the ECG Holter monitoring findings, the dynamic athletes had lower systolic blood pressure than the controls (P = 0.01. Heart rate was lowest in the control group (P < 0.001.Conclusion: The most common ECG abnormalities among adolescent Iranian athletes were sinus bradycardia and incomplete right bundle branch block. Static exercise seemed to reduce LV end-systolic diameter, while dynamic exercise resulted in increased LV end-diastolic diameter and left atrial volume index. Additionally, Iranian athletes showed no differences in HRV parameters, excluding heart rate and systolic blood pressure, compared with the nonathletes.Keywords: athlete's heart, electrocardiography, echocardiography, heart rate variability

Ataei A

2012-07-01

257

Target heart rate to determine the normal value of coronary flow reserve during dobutamine stress echocardiography  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The determination of coronary flow reserve (CFR is an essential concept at the moment of decision-making in ischemic heart disease. There are several direct and indirect tests to evaluate this parameter. In this sense, dobutamine stress echocardiography is one of the pharmacological method most commonly used worldwide. It has been previously demonstrated that CFR can be determined by this technique. Despite our wide experience with dobutamine stress echocardiography, we ignored the necessary heart rate to consider sufficient the test for the analysis of CFR. For this reason, our main goal was to determine the velocity of coronary flow in each stage of dobutamine stress echocardiography and the heart rate value necessary to double the baseline values of coronary flow velocity in the territory of the left anterior descending (LAD coronary artery. Methods A total of 33 consecutive patients were analyzed. The patients included had low risk for coronary artery disease. All the participants underwent dobutamine stress echocardiography and coronary artery flow velocity was evaluated in the distal segment of LAD coronary artery using transthoracic color-Doppler echocardiography. Results The feasibility of determining CFR in the territory of the LAD during dobutamine stress echocardiography was high: 31/33 patients (94%. Mean CFR was 2.67 at de end of dobutamine test. There was an excellent concordance between delta HR (difference between baseline HR and maximum HR and the increase in the CFR (correlation coefficient 0.84. In this sense, we found that when HR increased by 50 beats, CFR was ? 2 (CI 93-99.2%. In addition, 96.4% of patients reached a CFR ? 2 (IC 91.1 - 99% at 75% of their predicted maximum heart rate. Conclusions We found that the feasibility of dobutamine stress echocardiography to determine CFR in the territory of the LAD coronary artery was high. In this study, it was necessary to achieve a difference of 50 bpm from baseline HR or at least 75% of the maximum predicted heart rate to consider sufficient the test for the analysis of CFR.

Rousse Maria G

2011-04-01

258

Newborn seizure detection based on heart rate variability.  

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In this paper, we investigate the use of heart rate variability (HRV) for automatic newborn seizure detection. The proposed method consists of a sequence of processing steps, namely, obtaining HRV from the ECG, extracting a discriminating HRV feature set, selecting an optimal subset from the full feature set, and, finally, classifying the HRV into seizure/nonseizure using a supervised statistical classifier. Due to the fact that HRV signals are nonstationary, a set of time-frequency features from the newborn HRV is proposed and extracted. In order to achieve efficient HRV-based automatic newborn seizure detection, a two-phase wrapper-based feature selection technique is used to select the feature subset with minimum redundancy and maximum class discriminability. Tested on ECG recordings obtained from eight newborns with identified EEG seizure, the proposed HRV-based neonatal seizure detection algorithm achieved 85.7% sensitivity and 84.6% specificity. These results suggest that the HRV is sensitive to changes in the cardioregulatory system induced by the seizure, and therefore, can be used as a basis for an automatic seizure detection. PMID:19628449

Malarvili, M B; Mesbah, Mostefa

2009-11-01

259

Does Baseline Heart Rate Variability Reflect Stable Positive Emotionality?  

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Several recent studies have found significant correlations, medium in effect size, between baseline heart rate variability (HRV) and measures of positive functioning, such as extraversion, agreeableness, and trait positive affectivity. Other research, however, has suggested an optimal level of HRV and found nonlinear effects. In the present study, a diverse sample of 239 young adults completed a wide range of measures that reflect positive psychological functioning, including personality traits, an array of positive emotions (measured with the Dispositional Positive Emotions Scale), and depression, anxiety, and stress symptoms (measured with the DASS and CESD). HRV was measured with a 6-minute baseline period and quantified using many common HRV metrics (e.g., respiratory sinus arrhythmia, root mean square of successive differences, and others), and potentially confounding behavioral and lifestyle variables (e.g., BMI, caffeine and nicotine use, sleep quality) were assessed. Neither linear nor non-linear effects were found, and the effect sizes were small and near zero. The findings suggest that the cross-sectional relationship between HRV and positive experience deserves more attention and meta-analytic synthesis. PMID:25147421

Silvia, Paul J; Jackson, Bryonna A; Sopko, Rachel S

2014-11-01

260

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

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

Chouchou, Florian; Desseilles, Martin

2014-01-01

261

Entertainment Capture through Heart Rate Activity in Physical Interactive Playgrounds  

DEFF Research Database (Denmark)

An approach for capturing and modeling individual entertainment (“fun”) preferences is applied to users of the innovative Playware playground, an interactive physical playground inspired by computer games, in this study. The goal is to construct, using representative statistics computed from children’s physiological signals, an estimator of the degree to which games provided by the playground engage the players. For this purpose children’s heart rate (HR) signals, and their expressed preferences of how much “fun” particular game variants are, are obtained from experiments using games implemented on the Playware playground. A comprehensive statistical analysis shows that children’s reported entertainment preferences correlate well with specific features of the HR signal. Neuro-evolution techniques combined with feature set selection methods permit the construction of user models that predict reported entertainment preferences given HR features. These models are expressed as artificial neural networks and are demonstrated and evaluated on two Playware games and two control tasks requiring physical activity. The best network is able to correctly match expressed preferences in 64% of cases on previously unseen data (p?value 6 · 10?5). The generality of the methodology, its limitations, its usability as a real-time feedback mechanism for entertainment augmentation and as a validation tool are discussed. Udgivelsesdato: February

Yannakakis, Georgios; Hallam, John

2008-01-01

262

The relationship between working memory, reinvestment, and heart rate variability.  

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There is growing evidence illustrating the negative aspects of reinvestment on everyday life, however its underlying mechanisms remain unclear. The main aim of this study was to empirically clarify the relationship between reinvestment and working memory (WM). A secondary aim was to investigate the contribution of high-frequency heart rate variability (HF-HRV) to WM. Sixty-two participants took part in a within-subject design in which we measured their WM capacity in a low-pressure and a high-pressure condition while their HF-HRV was measured. In addition, they had to fill out scales assessing their dispositional reinvestment. Results showed that the correlation between reinvestment and WM is negative, exists only in the high-pressure condition, and is specific to the decision component of reinvestment and not the movement component. Moreover, a hierarchical regression analysis revealed that under high pressure resting HF-HRV predicted WM performance above DSRS, whereas DSRS did not predict WM performance above resting HF-HRV. PMID:25449388

Laborde, Sylvain; Furley, Philip; Schempp, Caroline

2015-02-01

263

Correlation between heart rate and performance during Olympic windsurfing competition.  

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The aim of this study was to examine the heart rate (HR) response to Olympic windsurfing competition and to check if there was any correlation between racing HR, performance, and the variables measured during laboratory maximal exercise. Ten elite windsurfers [age: 20.93 (3.46) years; height: 178.10 (6.34) cm; body mass: 66.79 (5.90) kg] performed a laboratory maximal oxygen consumption (.VO(2max)) trial and national windsurf competitions wearing a HR monitor. One hundred and forty-three individual races were examined. Racing HR was expressed as a percentage of (1) HR(max) (maximal treadmill HR) and (2) HR(reserve) (HR(max)-HR(rest)). The performance (racing classification: RC, which is inversely proportional to performance) was significantly correlated to the racing HR response in both light wind (LW): LW-RC=-0.12(%HR(reserve))+13.03; r=-0.71, r(2)=0.50, pwindsurfing performances are highly dependent on the capacity of the athlete to maintain a high HR for long periods of time. Furthermore, windsurfing is highly dependent on the athlete's physical fitness level as shown by the correlations between racing HRs and laboratory physiological variables. PMID:12682836

Chamari, Karim; Moussa-Chamari, Imen; Galy, Olivier; Chaouachi, Mustapha; Koubaa, Donia; Hassen, Chokri Ben; Hue, Olivier

2003-05-01

264

On heart rate regulation in cycle-ergometer exercise.  

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In this paper, we have focused on the issue of regulating the human heart rate (HR) to a predefined reference trajectory, especially for cycle-ergometer exercise used for training or rehabilitation. As measuring HR is relatively easy compared to exercise intensity, it has been used in the wide range of training programs. The aim of this paper is to develop a non-model-based control strategy using proportional, integral and derivative (PID) controller/relay controller to regulate the HR to track a desired trajectory. In the case of using PID controller, the controller output signal is interpreted as a voice or auditory command, referred to as biofeedback, which can be heard by the exercising subject as a part of the control-loop. Alternatively, the relay controller output signals can be converted to some special words which can be recognised by the exerciser. However, in both cases, to effectively communicate to the user a change in exercise intensity, the timing of this feedback signal relative to the positions of the pedals becomes quite critical. A feedback signal delivered when the pedals are not in a suitable position to efficiently exert force may be ineffective and may lead to a cognitive disengagement of the user form the feedback controller. In this paper we examine the need and the consequence of synchronising the delivery of the feedback signal with an optimal and user specific placement of the pedal. PMID:25570718

Argha, Ahmadreza; Su, Steven W; Lee, Sangwon; Nguyen, Hung; Celler, Branko G

2014-08-01

265

Kubios HRV--heart rate variability analysis software.  

Science.gov (United States)

Kubios HRV is an advanced and easy to use software for heart rate variability (HRV) analysis. The software supports several input data formats for electrocardiogram (ECG) data and beat-to-beat RR interval data. It includes an adaptive QRS detection algorithm and tools for artifact correction, trend removal and analysis sample selection. The software computes all the commonly used time-domain and frequency-domain HRV parameters and several nonlinear parameters. There are several adjustable analysis settings through which the analysis methods can be optimized for different data. The ECG derived respiratory frequency is also computed, which is important for reliable interpretation of the analysis results. The analysis results can be saved as an ASCII text file (easy to import into MS Excel or SPSS), Matlab MAT-file, or as a PDF report. The software is easy to use through its compact graphical user interface. The software is available free of charge for Windows and Linux operating systems at http://kubios.uef.fi. PMID:24054542

Tarvainen, Mika P; Niskanen, Juha-Pekka; Lipponen, Jukka A; Ranta-Aho, Perttu O; Karjalainen, Pasi A

2014-01-01

266

Heart rate and heart rate variability in multiparous dairy cows with unassisted calvings in the periparturient period.  

Science.gov (United States)

Behavioural changes before calving can be monitored on farms; however, predicting the onset of calving is sometimes difficult based only on clinical signs. Heart rate (HR) and heart rate variability (HRV) as non-invasive measures of autonomic nervous system (ANS) activity were investigated in Holstein-Friesian cows (N=20) with unassisted calvings in the periparturient period to predict the onset of calving and assess the stress associated with calving. R-R-intervals were analysed in 5-min time windows during the following three main periods of measurement: 1) between 0 and 96h before the onset of calving restlessness (prepartum period); 2) during four stages of calving: (I) early first stage; between the onset of calving restlessness and the first abdominal contractions; (II) late first stage (between the first abdominal contractions and the appearance of the amniotic sac); (III) early second stage (between the appearance of the amniotic sac and the appearance of the foetal hooves); (IV) late second stage (between the appearance of the foetal hooves and delivery of the calf), and 3) over 48h following calving (postpartum period). Data collected between 72 and 96h before calving restlessness was used as baseline. Besides HR, Poincaré measures [standard deviation 1 (SD1) and 2 (SD2) and SD2/SD1 ratio], the root mean square of successive differences (RMSSD) in R-R intervals, the high-frequency (HF) component of HRV and the ratio between the low-frequency (LF) and the HF components (LF/HF ratio) were calculated. Heart rate increased only following the onset of the behavioural signs, peaked before delivery of the calf, then decreased immediately after calving. Parasympathetic indices of HRV (RMSSD, HFnorm and SD1) decreased, whereas sympathovagal indices (LF/HF ratio and SD2/SD1 ratio) increased significantly from baseline between 12 and 24 before the onset of calving restlessness. The same pattern was observed between 0 and 1h before calving restlessness. Following the onset of behavioural signs, parasympathetic activity increased gradually with a parallel shift in sympathovagal balance towards parasympathetic tone, which was possibly a consequence of oxytocin release, which induces an increase in vagus nerve activity. Parasympathetic activity decreased rapidly between 0 and 0.5h following calving and was lower than measured during all other stages of the study, while sympathetic activity peaked during this stage and was higher than measured during any other stages. Between 0 and 4h after calving vagal tone was lower than baseline, whereas sympathovagal balance was higher, reflecting a prolonged physiological challenge caused by calving. Vagal activity decreased, whereas sympathovagal balance shifted towards sympathetic tone with increased live body weight of the calf during the late second stage of calving, suggesting higher levels of stress associated with the higher body weight of calves. All HRV indices, measured either at the late second stage of calving and between 12 and 24h after calving, were affected by the duration of calving. Our results indicate that ANS activity measured by HRV indices is a more immediate indicator of the onset of calving than behaviour or HR, as it changed earlier than when restlessness or elevation in HR could be observed. However, because of the possible effects of other physiological mechanisms (e.g. oxytocin release) on ANS activity it seems to be difficult to measure stress associated with calving by means of HRV between the onset of calving restlessness and delivery. Further research is needed to enable more precise interpretation of the prepartum changes in HR and HRV in dairy cattle. PMID:25449409

Kovács, L; T?zsér, J; Kézér, F L; Ruff, F; Aubin-Wodala, M; Albert, E; Choukeir, A; Szelényi, Z; Szenci, O

2015-02-01

267

Gene Expression Profile of Increased Heart Rate in Shensongyangxin-Treated Bradycardia Rabbits  

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Aims. The present study tries to investigate the gene expression profile of bradycardia rabbits' hearts after SSYX (SSYX, a traditional Chinese medicine) treatment. Methods. Eighteen adult rabbits were randomly assigned in three groups: sham, model, and SSYX treatment groups. Heart rate was recorded in rabbits and total RNA was isolated from hearts. Gene expression profiling was conducted and quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) was performed to confirm the gene expression results. Patch clamp using human induced pluripotent stem cell-derived cardiomyocytes was applied to record the calcium current in the presence of SSYX. Results. The mean RR interval reduced after six weeks due to the injury of the sinoatrial node in the model group. This effect was partially reversed by 4-week SSYX treatment. cDNA microarray demonstrated that genes related with pacemaker current, calcium ion homeostasis, and signaling were altered by SSYX treatment. Results from patch clamp demonstrated that SSYX reduced the calcium current which is consistent with gene expression results. Conclusion. The present study shows mRNA remodeling of bradycardia and demonstrates that SSYX is effective in treating bradycardia by reversing altered gene expression in bradycardia models. Reduced calcium current by SSYX also confirmed the gene expression results.

Liu, Zhouying; Huang, Jian; Huo, Youping

2014-01-01

268

The Influence of Motor Impairment on Autonomic Heart Rate Modulation among Children with Cerebral Palsy  

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The study of heart rate variability is an important tool for a noninvasive evaluation of the neurocardiac integrity. The present study aims to evaluate the autonomic heart rate modulation in supine and standing positions in 12 children diagnosed with cerebral palsy and 16 children with typical motor development (control group), as well as to…

Zamuner, Antonio Roberto; Cunha, Andrea Baraldi; da Silva, Ester; Negri, Ana Paola; Tudella, Eloisa; Moreno, Marlene Aparecida

2011-01-01

269

Value of heart rate variability parameters in prognosis of intrauterine infection of infants with cytomegalovirus  

Directory of Open Access Journals (Sweden)

Full Text Available Spectral analysis of heart rate variability (HRV in 35 infants with congenital cytomegalovirus (CMV infection and 37 non-infected infants (mean age 1.83 ± 0.09 years was conducted. Analysis of distribution of relative and range parameters characterizing heart rate density in various ranges and subranges allowed defining confident signs typical of intrauterine CMV infection.

Shoira Agzamova

2010-12-01

270

Heart Rate and Treatment Effect in Children with Disruptive Behavior Disorders  

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Objective: To examine whether children with disruptive behavior disorders (DBDs; hyperkinetic conduct disorder, conduct disorder, hyperkinetic disorder) characterized by low heart rate profit less from an intensive cognitive behavioral intervention aimed at reducing impulsive, oppositional and aggressive behavior problems. Method: Basal heart rate

Stadler, Christina; Grasmann, Dorte; Fegert, Jorg M.; Holtmann, Martin; Poustka, Fritz; Schmeck, Klaus

2008-01-01

271

Diagnostic accuracy of dual-source CT coronary angiography: The effect of average heart rate, heart rate variability, and calcium score in a clinical perspective  

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Background: Dual-source CT coronary angiography (CTCA) has been used to detect coronary artery disease; however, the factors with potential to affect its diagnostic accuracy remain to be defined. Purpose: To prospectively evaluate the accuracy of dual-source CTCA in diagnosing coronary artery stenosis according to conventional coronary angiography (CAG), and the effect of average heart rate, heart rate variability, and calcium score on the accuracy of CTCA. Material and Methods: A total of 113 patients underwent both dual-source CTCA and CAG. The results were used to evaluate the findings in dual-source CTCA to assess the accuracy in the diagnosis of =50% (significant stenosis) and >75% (severe stenosis) of coronary artery according to those by CAG. Patients were divided into subgroups according to their heart rate (HR), HR variability (HRV), and calcium score, and the accuracy of CTCA was further evaluated. The chi-square test was used to analyze the difference in sensitivity and specificity for the detection of =50% and >75% coronary stenosis among subgroups. The generalized estimation equation method was used in per-vessel analysis to adjust for within-patient correlation. Results: In all, 113 patients had 338 vessels and 1661 segments evaluated by CAG. Dual-source CTCA displayed 1527 segments (91.9%). Among them, 1468 segments (calcium score by CAG score 1, n=1018; score 2, n=270; score 3, n=180) were assessable in CTCA. On a per-patient analysis, the sensitivity and specificity of CTCA were 93.9% and 93.5% for significant stenosis and 86.9% and 98.1% for severe stenosis. On a per-vessel basis, the sensitivity and specificity were 90.2% and 97.1% for significant and 83.3% and 98.1% for severe stenosis. On a per-segment analysis, the sensitivity and specificity were 90.2% and 97.1% for significant and 83.3% and 98.1% for severe stenosis. Average HR had no effect on the sensitivity and specificity of CTCA (P>0.05); whereas HRV and calcium score had some effect on the sensitivity and specificity of CTCA (P<0.05). Conclusion: On a per-patient, per-vessel, and per-segment basis, dual-source CTCA has a high sensitivity and specificity for the diagnosis of coronary artery stenosis. Average HR has no effect on the diagnostic accuracy of CTCA, while HRV and calcium score have a statistically significant effect on the sensitivity and specificity of CTCA

Long-Jiang Zhang; Zhuo-Li Zhang; Chang-Sheng Zhou; Guang-Ming Lu (Dept. of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing Univ., Nanjing (China)), e-mail: cjr.luguangming@vip.163.com; Sheng-Yong Wu (Medical Imaging Inst. of Tianjin, Tianjin (China)); Jing Wang; Shi-Sen Jiang (Dept. of Cardiology, Jinling Hospital, Clinical School of Medical College, Nanjing Univ., Nanjing (China)); Ying Lu (Dept. of Radiology and Biomedical Imaging, Univ. of California, San Francisco, CA (United States))

2010-09-15

272

Diagnostic accuracy of dual-source CT coronary angiography: The effect of average heart rate, heart rate variability, and calcium score in a clinical perspective  

International Nuclear Information System (INIS)

Background: Dual-source CT coronary angiography (CTCA) has been used to detect coronary artery disease; however, the factors with potential to affect its diagnostic accuracy remain to be defined. Purpose: To prospectively evaluate the accuracy of dual-source CTCA in diagnosing coronary artery stenosis according to conventional coronary angiography (CAG), and the effect of average heart rate, heart rate variability, and calcium score on the accuracy of CTCA. Material and Methods: A total of 113 patients underwent both dual-source CTCA and CAG. The results were used to evaluate the findings in dual-source CTCA to assess the accuracy in the diagnosis of =50% (significant stenosis) and >75% (severe stenosis) of coronary artery according to those by CAG. Patients were divided into subgroups according to their heart rate (HR), HR variability (HRV), and calcium score, and the accuracy of CTCA was further evaluated. The chi-square test was used to analyze the difference in sensitivity and specificity for the detection of =50% and >75% coronary stenosis among subgroups. The generalized estimation equation method was used in per-vessel analysis to adjust for within-patient correlation. Results: In all, 113 patients had 338 vessels and 1661 segments evaluated by CAG. Dual-source CTCA displayed 1527 segments (91.9%). Among them, 1468 segments (calcium score by CAG score 1, n=1018; score 2, n=270; score 3, n=180) were assessable in CTCA. On a per-patient analysis, the sensitivity n a per-patient analysis, the sensitivity and specificity of CTCA were 93.9% and 93.5% for significant stenosis and 86.9% and 98.1% for severe stenosis. On a per-vessel basis, the sensitivity and specificity were 90.2% and 97.1% for significant and 83.3% and 98.1% for severe stenosis. On a per-segment analysis, the sensitivity and specificity were 90.2% and 97.1% for significant and 83.3% and 98.1% for severe stenosis. Average HR had no effect on the sensitivity and specificity of CTCA (P>0.05); whereas HRV and calcium score had some effect on the sensitivity and specificity of CTCA (P<0.05). Conclusion: On a per-patient, per-vessel, and per-segment basis, dual-source CTCA has a high sensitivity and specificity for the diagnosis of coronary artery stenosis. Average HR has no effect on the diagnostic accuracy of CTCA, while HRV and calcium score have a statistically significant effect on the sensitivity and specificity of CTCA

273

Reduction of Heart Rate by Omega-3 Fatty Acids and the Potential Underlying Mechanisms  

Directory of Open Access Journals (Sweden)

Full Text Available An elevated resting heart rate is one of the strongest predictors of cardiovascular mortality and is independently associated with sudden cardiac death (SCD. Agents capable of reducing heart rate without significant side effects are therefore of particular interest for the prevention of SCD. Recent human and animal studies have shown that omega-3 fatty acids can reduce heart rate. Our work has shown that omega-3 fatty acids significantly reduce membrane electrical excitability of the cardiac myocyte by lowering its resting membrane potential and the duration of the refractory period through inhibition of ion channels. We propose that these actions may be the underlying mechanisms for the omega-3 fatty acid-induced reduction of heart rate observed in both humans and animals. The heart rate-lowering capability of omega-3 fatty acids may contribute to their preventive effect against SCD.

JingXuanKang

2012-10-01

274

Correlation of heart rate and cardiac dysfunction in Duchenne muscular dystrophy.  

Science.gov (United States)

Sinus tachycardia is common in cases of Duchenne muscular dystrophy (DMD). The authors hypothesized that an elevated heart rate would herald cardiomyopathy onset. A retrospective case-control study was performed with 55 DMD boys and 150 age-matched control boys. The variables were age, heart rate, shortening fraction, and left ventricular end-diastolic dimension. Cardiomyopathy was defined as a shortening fraction less than 28%. The DMD boys had a higher initial heart rate with no baseline echocardiographic evidence of cardiomyopathy. The control subjects showed a statistically significant age-related decline in heart rate (p = 0.001) but not the DMD boys. Cardiomyopathy developed in 17 of the 55 DMD boys over a period of 4.6 ± 1.6 years. The DMD upper and lower heart rate groups were similar in age, follow-up time, and initial shortening fraction, yet cardiomyopathy developed in 14 (42%) of 33 upper quartile boys but only 3 (14%) of 22 lower quartile DMD boys (odds ratio, 6.5 (95% confidence interval, 1.15-18.92; p < 0.05). Compared with the control subjects, the DMD boys had a higher resting heart rate and a lack of age-related heart rate decline. The DMD boys in the upper heart rate quartile were more likely to progress to cardiomyopathy than those in the lower quartiles. This study establishes heart rate elevation as a statistically significant risk factor for cardiomyopathy. Further studies may define heart rate cutoffs for early pharmacologic intervention for incipient cardiomyopathy. PMID:22434508

Thomas, Tamara O; Morgan, Thomas M; Burnette, William B; Markham, Larry W

2012-10-01

275

Association between Frequency Domain Heart Rate Variability and Unplanned Readmission to Hospital in Geriatric Patients  

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Full Text Available Abstract Background An accurate prediction of unplanned readmission (UR after discharge from hospital can facilitate physician's decision making processes for providing better quality of care in geriatric patients. The objective of this study was to explore the association of cardiac autonomic functions as measured by frequency domain heart rate variability (HRV and 14-day UR in geriatric patients. Methods Patients admitted to the geriatric ward of a regional hospital in Chiayi county in Taiwan were followed prospectively from July 2006 to June 2007. Those with invasive tubes and those who were heavy smokers, heavy alcohol drinkers, on medications that might influence HRV, or previously admitted to the hospital within 30 days were excluded. Cardiac autonomic functions were evaluated by frequency domain indices of HRV. Multiple logistic regression was used to assess the association between UR and HRV indices adjusted for age and length of hospitalization. Results A total of 78 patients met the inclusion criteria and 15 of them were readmitted within 14 days after discharge. The risk of UR was significantly higher in patients with lower levels of total power (OR = 1.39; 95% CI = 1.04-2.00, low frequency power (LF (OR = 1.22; 95% CI = 1.03-1.49, high frequency power (HF (OR = 1.27; 95% CI = 1.02-1.64, and lower ratios of low frequency power to high frequency power (LF/HF ratio (OR = 1.96; 95% CI = 1.07-3.84. Conclusion This is the first study to evaluate the association between frequency domain heart rate variability and the risk of UR in geriatric patients. Frequency domain heart rate variability indices measured on admission were significantly associated with increased risk of UR in geriatric patients. Additional studies are required to confirm the value and feasibility of using HRV indices on admission as a non-invasive tool to assist the prediction of UR in geriatric patients.

Fu Chin-Hua

2011-02-01

276

Resting heart rate as a predictor of metabolic dysfunctions in obese children and adolescents  

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Full Text Available Abstract Background Recent studies have identified that a higher resting heart rate (RHR is associated with elevated blood pressure, independent of body fatness, age and ethnicity. However, it is still unclear whether RHR can also be applied as a screening for other risk factors, such as hyperglycemia and dyslipidemia. Thus, the purpose of the presented study was to analyze the association between RHR, lipid profile and fasting glucose in obese children and adolescents. Methods The sample was composed of 180 obese children and adolescents, aged between 7-16 years. Whole-body and segmental body composition were estimated by Dual-energy X-ray absorptiometry. Resting heart rate (RHR was measured by heart rate monitors. The fasting blood samples were analyzed for serum triglycerides, total cholesterol (TC, high-density lipoprotein cholesterol (HDL-C, low-density lipoprotein cholesterol (LDL-C, and glucose, using the colorimetric method. Results Fasting glucose, TC, triglycerides, HDL-C, LDL-C and RHR were similar in both genders. The group of obese subjects with a higher RHR presented, at a lower age, higher triglycerides and TC. There was a significant relationship between RHR, triglycerides and TC. In the multivariate model, triglycerides and TC maintained a significant relationship with RHR independent of age, gender, general and trunk adiposity. The ROC curve indicated that RHR has a high potential for screening elevated total cholesterol and triglycerides as well as dyslipidemia. Conclusion Elevated RHR has the potential to identify subjects at an increased risk of atherosclerosis development.

Freitas Júnior Ismael F

2012-01-01

277

Heart rate variability in normal and pathological sleep  

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Full Text Available Sleep is a physiological process involving different biological systems, from molecular to organ level; its integrity is essential for maintaining health and homeostasis in human beings. Although in the past sleep has been considered a state of quiet, experimental and clinical evidences suggest a noteworthy activation of different biological systems during sleep. A key role is played by the autonomic nervous system (ANS, whose modulation regulates cardiovascular functions during sleep onset and different sleep stages. Therefore, an interest on the evaluation of autonomic cardiovascular control in health and disease is growing by means of linear and non linear heart rate variability (HRV analyses. The application of classical tools for ANS analysis, such as HRV during physiological sleep, showed that the rapid eye movement (REM stage is characterized by a likely sympathetic predominance associated with a vagal withdrawal, while the opposite trend is observed during non-REM sleep. More recently, the use of non linear tools, such as entropy-derived indices, have provided new insight on the cardiac autonomic regulation, revealing for instance changes in the cardiovascular complexity during REM sleep, supporting the hypothesis of a reduced capability of the cardiovascular system to deal with stress challenges. Interestingly, different HRV tools have been applied to characterize autonomic cardiac control in different pathological conditions, from neurological sleep disorders to sleep disordered breathing (SDB. In summary, linear and non linear analysis of HRV are reliable approaches to assess changes of autonomic cardiac modulation during sleep both in health and diseases. The use of these tools could provide important information of clinical and prognostic relevance.

EleonoraTobaldini

2013-10-01

278

Heart rate variability (HRV): an indicator of stress  

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

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

2014-05-01

279

Wave reflections, arterial stiffness, heart rate variability and orthostatic hypotension.  

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Increased arterial stiffness and wave reflections are independently associated with orthostatic hypotension (OH). This study investigated whether heart rate variability (HRV) is also involved in the modulation of orthostatic blood pressure (BP) change. A total of 429 subjects (65.1±16.4 years, 77.4% men) were enrolled in this study. OH was defined as a ?20?mm?Hg decrease in brachial systolic blood pressure (SBP) or a ?10?mm?Hg diastolic blood pressure (DBP) decrease upon standing. Measurements of carotid-femoral pulse wave velocity (cf-PWV) and the amplitude of the reflected pressure wave from a decomposed carotid pressure wave (Pb) were obtained by carotid tonometry in the supine position. The power spectrum from a 5-min recording of an electrocardiogram at rest was analyzed to provide components in the high frequency (HF) and low frequency (LF) ranges. Subjects with OH (n=59, 13.8%) had significantly higher cf-PWV and Pb and significantly lower LogHF and LogLF than those without OH (n=370). The cf-PWV, Pb, LogHF and LogLF were significantly associated with postural SBP and DBP changes. Furthermore, cf-PWV but not Pb was significantly associated with LogHF and LogLF. Multivariate analysis showed that Pb (odds ratio (OR) per 1 s.d. 1.65, 95% confidence interval (CI) 1.282-2.137; P=0.003) and LogHF (OR 0.628, 95% CI 0.459-0.860, P=0.004), but not cf-PWV (OR 1.279, 95% CI 0.932-1.755, P=0.128), were significant independent determinants of OH. Increased wave reflections may predispose OH independently of arterial stiffness and HRV. In contrast, increased arterial stiffness may cause OH through the modulation of HRV. PMID:25142223

Lu, Dai-Yin; Sung, Shih-Hsien; Yu, Wen-Chung; Cheng, Hao-Min; Chuang, Shao-Yuan; Chen, Chen-Huan

2014-12-01

280

Simultaneous measurement of breathing rate and heart rate using a microbend multimode fiber optic sensor  

Science.gov (United States)

We propose and demonstrate the feasibility of using a highly sensitive microbend multimode fiber optic sensor for simultaneous measurement of breathing rate (BR) and heart rate (HR). The sensing system consists of a transceiver, microbend multimode fiber, and a computer. The transceiver is comprised of an optical transmitter, an optical receiver, and circuits for data communication with the computer via Bluetooth. Comparative experiments conducted between the sensor and predicate commercial physiologic devices showed an accuracy of ±2 bpm for both BR and HR measurement. Our preliminary study of simultaneous measurement of BR and HR in a clinical trial conducted on 11 healthy subjects during magnetic resonance imaging (MRI) also showed very good agreement with measurements obtained from conventional MR-compatible devices.

Chen, Zhihao; Lau, Doreen; Teo, Ju Teng; Ng, Soon Huat; Yang, Xiufeng; Kei, Pin Lin

2014-05-01

281

Lactic acidosis, potassium, and the heart rate deflection point in professional road cyclists  

Science.gov (United States)

Objective: To determine the influence of lactic acidosis, the Bohr effect, and exercise induced hyperkalaemia on the occurrence of the heart rate deflection point (HRDP) in elite (professional) cyclists. Methods: Sixteen professional male road cyclists (mean (SD) age 26 (1) years) performed a ramp test on a cycle ergometer (workload increases of 5 W/12 s, averaging 25 W/min). Heart rate (HR), gas exchange parameters, and blood variables (lactate, pH, P50 of the oxyhaemoglobin dissociation curve, and K+) were measured during the tests. Results: A HRDP was shown in 56% of subjects at about 88% of their maximal HR (HRDP group; n = 9) but was linear in the rest (No-HRDP group; n = 7). In the HRDP group, the slope of the HR-workload regression line above the HRDP correlated inversely with levels of K+ at the maximal power output (r = -0.67; p<0.05). Conclusions: The HRDP phenomenon is associated, at least partly, with exercise induced hyperkalaemia. PMID:11916893

Lucia, A; Hoyos, J; Santalla, A; Perez, M; Carvajal, A; Chicharro, J

2002-01-01

282

Heart rate variability of young table tennis players with the use of the multiball training  

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Full Text Available The purpose of this study was to evaluate the heart rate responses of the 2 multiball table tennis interval training protocols during the competitive period on young table tennis players. Fourteen (n=14 players, aged 12±2yrs participated in this study. participants were randomly divided into 2 training duration groups (15s vs. 30s and were trained under the 2 interval protocols for 6 weeks (3 sessions. w-1. heart rate (hr data was electronically recorded by using the Polar Team System at the completion of each exercise at the 1st and 5th set in the 1st and 6th week. the Wilcoxon signed-rank test was applied in or- der to compare the repeated measurements, whereas spear- man’s rank correlation (? analysis was employed to determine whether the testing parameters are significantly related. From the results it is shown that regarding to the hr both training protocols can simulate the match conditions. In both groups participants’ the footwork exercises with Forehand and Backhand strokes recorded the higher hr (190-210 b.min-1. additionally, significant hr differences were recorded in group a (z=-2.023, p=0.043 in Footwork Forehand Backhand (FtFB. In conclusion, both multiball protocols can generally simulate match conditions supporting the weekly training program of young table tennis players

MICHAIL KATSIKADELIS

2014-10-01

283

A study of mental stress in recruits during parachute training based on heart rate variability  

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Full Text Available Objective To investigate the characteristics and evaluate the mental stress level of recruits during parachute training based on the heart rate variability.Methods Twenty new parachutists were allowed to parachute for seven times.The electrocardiograms were recorded together with data from pilot physiological parameter recorder worn by the parachutists.The data analysis system which matched with the recorder was employed to analyze the heart rate variability of the parachutists when they left from their encampment,arriving in airport and in the plane.Results As compared with the first parachute,the indices of high frequency(HF and normalized high frequency(HFNU of the new parachutists measured when they were at their encampment were higher than that of their fourth and seventh parachute(P 0.05.The index of HFNU of the seventh parachute increased significantly compared with that of the first parachute when these recruits were in the plane(P < 0.05.In contrast,the indices of LFNU and LF/HF declined in the seventh parachute compared with that in the first parachute,and even lower than that in the fourth parachute(P < 0.05.Conclusion With an increase in frequency of parachute,mental stress level of the new parachutists declines significantly when they are at their encampment and in the plane.But no evident change in stress level has been detected when they are at the airport.

Liang-en CHEN

2011-04-01

284

Heart rate variability, structural and functional characteristics of the left ventricle in essential arterial hypertension  

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Full Text Available For the purpose of diagnostic and treatment improvement it is necessary to investigate relationship between different pathogenetic mechanisms in essential hypertension. The aim of our study was the comparative analysis of the parameters of cardiac remodeling and neurohumoral mechanisms of heart rate variability (HRV in patients with essential arterial hypertension. 100 patients with essential arterial hypertension were included in the study. All patients went through heart rate variability parameters and left ventricle characteristics evaluation. Time and frequency domains were decreased in patients with arterial hypertension. Excess sympathetic activation takes place, parasympathetic system is depressed and it shows pathogenetic basis of disadaptation. Left ventricle hypertrophy is associated with progressive decrease of HRV and its circadian fluctuations. Concentric left ventricle hypertrophy is characterized by the most significant decrease in time and frequency domains of HRV. 1/3 of hypertensive patients with normal left ventricle geometry have diastolic dysfunction and also some decrease in time and frequency domains. In conclusion, we found that cardiac remodeling in patients with essential hypertension seems to be related to the severity of impairment of cardiac autonomic control

Khromtsova ?.?.

2010-09-01

285

Heart rate variability analysis in sheep affected by transmissible spongiform encephalopathies  

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

Konold Timm

2011-12-01

286

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

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

GeoffreyGreen

2013-07-01

287

Cardiac Troponin T Levels in Umbilical Cord Blood of Neonates with Abnormal Fetal Heart Rate  

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Full Text Available Objective: Most neonatal encephalopathic disorders appear to be caused by perinatal events. Persistent myocardial ischemia leads to cellular necrosis and release of troponin from cardiac muscles. Fetal distress during labor may be detected by monitoring the fetal heart rate. However little is known about the relationship, if any, that exists between fetal heart rate abnormalities and the fetal cardiac musculature and its function. The aim of this study was to investigate the relationship, if any, of umbilical cord serum levels of cardiac troponin T with fetal bradycardia or late deceleration.Methods: In this cross sectional study, troponin T level in umbilical cord blood of 80 neonates are measured. There were 23 versus 57 fetuses with and without late deceleration or bradycardia.Findings: Level of cardiac troponin T in umbilical blood of neonates with fetal bradycardia or late deceleration was elevated in comparison to neonates without bradycardia or late deceleration. There was no relation between umbilical troponin T level and mode of delivery.Conclusion: Infants with fetal bradycardia or late deceleration during labor had significantly higher cord cardiac troponin T levels. If troponin level is normal, the probability of hypoxia will be very low.

Shiva Rafati

2013-02-01

288

Heart rate response and parasympathetic modulation during recovery from exercise in boys and men.  

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The purpose of this study was to examine the influence of postexercise parasympathetic modulation, measured by heart rate variability (HRV), on heart rate recovery (HRR) in boys (n = 13, 10.1 ± 0.8 years) and men (n = 13, 23.9 ± 1.5 years) following maximal and submaximal exercise. Subjects completed 10 min of supine rest, followed by graded exercise on a cycle ergometer to maximal effort. On a separate day, subjects exercised at an intensity equivalent to ventilatory threshold. Immediately following both exercise bouts, 1-min HRR was assessed in the supine position. HRV was analyzed under controlled breathing during the final 5 min of rest and recovery in the time and frequency domains and transformed to natural log (ln) values. Boys had a greater 1-min HRR than men following maximal (58 ± 8 vs. 47 ± 11 beats·min(-1)) and submaximal (59 ± 8 vs. 47 ± 15 beats·min(-1)) exercise (p 0.05). In conclusion, it appears that greater parasympathetic modulation accounts for greater HRR following maximal exercise in boys versus men. Although submaximal HRR was greater in boys, parasympathetic responses were similar between groups. PMID:24941106

Guilkey, Justin P; Overstreet, Matthew; Fernhall, Bo; Mahon, Anthony D

2014-08-01

289

Increase in hospital admission rates for heart failure in the Netherlands, 1980-1993  

OpenAIRE

OBJECTIVE: To study the trend in hospital admission rates for heart failure in the Netherlands from 1980 to 1993. DESIGN: All hospital admissions in the Netherlands with a principal discharge diagnosis of heart failure were analysed. In addition, individual records of heart failure patients from a subset of 7 hospitals were analysed to estimate the frequency and timing of readmissions. RESULTS: The total number of discharges for men increased from 7377 in 1980 to 13 022 in 1993, and for women...

Reitsma, J. B.; Mosterd, A.; Craen, A. J.; Koster, R. W.; Capelle, F. J.; Grobbee, D. E.; Tijssen, J. G.

1997-01-01

290

Discrimination power of short-term heart rate variability measures for CHF assessment  

OpenAIRE

In this study, we investigated the discrimination power of short-term Heart Rate Variability (HRV) for discriminating normal subjects versus Chronic Heart Failure (CHF) patients. We analyzed 1,914.40 hours of ECG of 83 patients of which 54 are normal and 29 are suffering from CHF with New York Heart Classification (NYHA) I, II, III, extracted by public databases. Following guidelines, we performed time and frequency analysis in order to measure HRV features. To assess the discrimination power...

Pecchia, Leandro; Melillo, Paolo; Bracale, Marcello

2011-01-01

291

Sternal Pulse Rate Variability Compared with Heart Rate Variability on Healthy Subjects  

DEFF Research Database (Denmark)

The heart rate variability (HRV) is a commonly used method to quantify the sympathetic and the parasympathetic modulation of the heart rate. HRV is mainly conducted on electrocardiograms (ECG). However, the use of photoplethysmography (PPG) as a marker of the autonomic tone is emerging. In this study we investigated the feasibility of deriving pulse rate variability (PRV) using PPG signals recorded by a reflectance PPG sensor attached to the chest bone (sternum) and comparing it to HRV. The recordings were conducted on 9 healthy subjects being in a relaxed supine position and under forced respiration, where the subjects were asked to breathe following a visual scale with a rate of 27 breaths/min. HRV parameters such as the mean intervals (meanNN), the standard deviation of intervals (SDNN), the root mean square of difference of successive intervals (RMSSD), and the proportion of intervals differing more than 50 ms (pNN50) were calculated from the R peak-to-R peak (R-R) and pulse-to-pulse (P-P) intervals. In the frequency domain the low and high frequency ratio of the power spectral density (LF/HF) was also computed. The Pearson correlation coefficient showed significant correlation for all the parameters (r > 0:95 with p < 0:001) and the Bland-Altmann analysis showed close agreement between the two methods for all the parameters during resting and forced respiration condition. Thus, PRV analysis using sternal PPG can be an alternative to HRV analysis on healthy subjects at rest.

Chreiteh, Shadi; Belhage, Bo

2014-01-01

292

Sternal pulse rate variability compared with heart rate variabilit on healthy subjects.  

Science.gov (United States)

The heart rate variability (HRV) is a commonly used method to quantify the sympathetic and the parasympa-thetic modulation of the heart rate. HRV is mainly conducted on electrocardiograms (ECG). However, the use of photo-plethysmography (PPG) as a marker of the autonomic tone is emerging. In this study we investigated the feasibility of deriving pulse rate variability (PRV) using PPG signals recorded by a reflectance PPG sensor attached to the chest bone (sternum) and comparing it to HRV. The recordings were conducted on 9 healthy subjects being in a relaxed supine position and under forced respiration, where the subjects were asked to breathe following a visual scale with a rate of 27 breaths/min. HRV parameters such as the mean intervals (meanNN), the standard deviation of intervals (SDNN), the root mean square of difference of successive intervals (RMSSD), and the proportion of intervals differing more than 50 ms (pNN50) were calculated from the R peak-to-R peak (R-R) and pulse-to-pulse (P-P) intervals. In the frequency domain the low and high frequency ratio of the power spectral density (LF/HF) was also computed. The Pearson correlation coefficient showed significant correlation for all the parameters (r > 0.95 with p <; 0.001) and the Bland-Altmann analysis showed close agreement between the two methods for all the parameters during resting and forced respiration condition. Thus, PRV analysis using sternal PPG can be an alternative to HRV analysis on healthy subjects at. PMID:25570719

Chreiteh, Shadi S; Belhage, Bo; Hoppe, Karsten; Branebjerg, Jens; Thomsen, Erik V

2014-08-01

293

The Relationship Between Daytime, Nighttime and 24-Hour Heart Rate with Urinary Albumin and Protein Excretion in Patients with Newly Diagnosed Type 2 Diabetes  

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Full Text Available OBJECTIVE: Autonomic nervous system dysfunction (ASD has been widely observed in patients with type 2 diabetes. 24-hour ambulatory blood pressure (ABP and heart rate measurements have been found to associate with ASD in patient with Type 2 diabetes. Since albumin excretion is also related with ASD in type 2 diabetes; in the current study, the relationships between daytime, nighttime and 24- hour heart rates with 24 hour urinary albumin excretion (UAE and 24-hour urinary protein excretion (UPE were analyzed in patients with newly diagnosed type 2 diabetes. MATERIAL and METHODS: All patients underwent following procedures: history taking, physical examination, BP measurement, 12 lead electrocardiographic evaluations, routine urine analysis, biochemical analysis, 24-hour urine collection to measure UAE, UPE and creatinine clearance. 24-hour ABP and heart rate monitoring were performed for all patients. RESULTS: In total 80 patients with newly diagnosed type 2 diabetes were included. Stepwise linear regression revealed that logarithmically converted 24-hour UAE were independently related with 24- hour ambulatory SBP, (P:0.001 and heart rate (night (P<0.0001. Stepwise linear regression revealed that logarithmically converted 24-hour UPE were independently related with age (P:0.032, with averaged fasting blood glucose (P:0.023, with 24-hour ambulatory SBP, (P:0.002 and with heart rate (night (P:0.001. CONCLUSION: Nighttime heart rate, but not daytime and 24-hour heart rate was related with both 24-hour UAE and UPE in patients with Type 2 diabetes.

Bar?? AF?AR

2012-05-01

294

Diagnostic performance of dual-source CT coronary angiography with and without heart rate control: Systematic review and meta-analysis  

International Nuclear Information System (INIS)

Aim: To investigate the diagnostic accuracy of dual-source computed tomography (DSCT) coronary angiography with and without the application of a ?-blocker. Materials and methods: An exact binomial rendition of the bivariate mixed-effects regression model was used to synthesize diagnostic test data. Results: The pooled sensitivity at the patient level was 0.98 [95% confidence intervals (CI): 0.97–0.99], and specificity 0.88 (95% CI: 0.84–0.91). The results showed that without heart rate control, the sensitivity and specificity at the patient level did not decrease (p = 0.27 and 0.56, respectively). At the artery level, no significant differences in sensitivity and specificity for studies with and without heart rate control were detected (p = 0.04 and 0.05, respectively). At the segment level, the specificity decreased without heart rate control (p = 0.03), whereas the sensitivity was not influenced (p = 0.63). The median radiation exposure was 2.6 mSv, with 1.6 mSv and 8 mSv for heart rate-controlled studies and uncontrolled studies, respectively. Conclusions: DSCT coronary angiography without heart rate control has a similar excellent diagnostic performance at the patient level as that of heart rate control groups. However, controlling for heart rate to decrease radiation and to provide effective information for selecting the therapeutic strategy and risk stratification is recommended

295

Effects of melatonin and ethanol on the heart rate of Daphnia magna  

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Full Text Available Melatonin, an endogenous hormone that may regulate circadian rhythms by modulating cholinergic activity, is increasing in popular use as a natural treatment for sleep disorders. However, the effects of melatonin on the human heart are not well characterized, and the consequences of combining alcohol with melatonin are unknown. The myogenic heart of the water flea Daphnia magna (D. magna is regulated by inhibitory cholinergic neurons that modulate cardiac function, including heart rate. D. magna is a useful model organism for cardiovascular function, due to its physical transparency and susceptibility to cardioactive drugs known to affect the human heart. In this study, the effects of immersion in 10 mg/L melatonin and 5% ethanol on the heart rate of D. magna were quantified. Two-hour exposure to melatonin caused a significant decrease in heart rate, from 228 ± 2 bpm to 167 ± 8 bpm. Six-minute immersion in ethanol also significantly depressed the heart rate to 176 ± 10 bpm. Pretreatment with melatonin prior to the addition of ethanol resulted in a greater decrease in heart rate (89 ± 7 bpm than ethanol or melatonin alone. These findings indicate that melatonin and alcohol may combine to cause a greater depressive effect on cardiac function.

Rebecca Kohn

2009-01-01

296

[Effects of n-butanol extract from Cortex Ilicis rotundae on blood pressure and heart rate in rate].  

Science.gov (United States)

It was studied that effects of n-butanol extract from Cortex Ilicis Rotundae on blood pressure and heart rate in differedt state. Results showed that the drug elicited a sgnificant depressor effect on both normal pressure and artery pressure to rise for common carotid artery blocked in rats. Of the two latter decline of percent of blood presure and active time and slowing heart rate were more significan than the former. It was same depressor effect that injected the drug into duodenum but not act to hypotensive rats. These results suggested that the drug induce significantly depressor effect and slow heart rat with the exception of hypotension. PMID:12572418

Dong, Y; Liang, Y; Luo, J

1997-08-01

297

Attenuated heart rate response in REM sleep behavior disorder and Parkinson's disease  

DEFF Research Database (Denmark)

The objective of this study was to determine whether patients with Parkinson's disease with and without rapid-eye-movement sleep behavior disorder and patients with idiopathic rapid-eye-movement sleep behavior disorder have an attenuated heart rate response to arousals or to leg movements during sleep compared with healthy controls. Fourteen and 16 Parkinson's patients with and without rapid-eye-movement sleep behavior disorder, respectively, 11 idiopathic rapid-eye-movement sleep behavior disorder patients, and 17 control subjects underwent 1 night of polysomnography. The heart rate response associated with arousal or leg movement from all sleep stages was analyzed from 10 heartbeats before the onset of the sleep event to 15 heartbeats following onset of the sleep event. The heart rate reponse to arousals was significantly lower in both parkinsonian groups compared with the control group and the idiopathic rapid-eye-movement sleep behavior disorder group. The heart rate response to leg movement was significantly lower in both Parkinson's groups and in the idiopathic rapid-eye-movement sleep behavior disorder group compared with the control group. The heart rate response for the idiopathic rapid-eye-movement sleep behavior disorder group was intermediate with respect to the control and the parkinsonian groups. The attenuated heart rate response may be a manifestation of the autonomic deficits experienced in Parkinson's disease. The idiopathic rapid-eye-movement sleep behavior disorder patients not only exhibited impaired motor symptoms but also incipient autonomic dysfunction, as revealed by the attenuated heart rate response.

Sorensen, Gertrud Laura; Kempfner, Jacob

2012-01-01

298

Altered heart rate and blood pressure variability in mice lacking the Mas protooncogene  

Directory of Open Access Journals (Sweden)

Full Text Available Heart rate variability is a relevant predictor of cardiovascular risk in humans. A significant genetic influence on heart rate variability is suggested, although the genes involved are ill-defined. The Mas-protooncogene encodes a G-protein-coupled receptor with seven transmembrane domains highly expressed in testis and brain. Since this receptor is supposed to interact with the signaling of angiotensin II, which is an important regulator of cardiovascular homeostasis, heart rate and blood pressure were analyzed in Mas-deficient mice. Using a femoral catheter the blood pressure of mice was measured for a period of 30 min and 250 data values per second were recorded. The mean values and range of heart rate and blood pressure were then calculated. Neither heart rate nor blood pressure were significantly different between knockout mice and controls. However, high resolution recording of these parameters and analysis of the data by non-linear dynamics revealed significant alterations in cardiovascular variability in Mas-deficient animals. In particular, females showed a strong reduction of heart rate variability. Furthermore, the data showed an increased sympathetic tone in knockout animals of both genders. The marked alterations detected in Mas-deficient mice of both genders suggest that the Mas-protooncogene is an important determinant of heart rate and blood pressure variability.

T. Walther

2000-01-01

299

Altered heart rate and blood pressure variability in mice lacking the Mas protooncogene  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Heart rate variability is a relevant predictor of cardiovascular risk in humans. A significant genetic influence on heart rate variability is suggested, although the genes involved are ill-defined. The Mas-protooncogene encodes a G-protein-coupled receptor with seven transmembrane domains highly exp [...] ressed in testis and brain. Since this receptor is supposed to interact with the signaling of angiotensin II, which is an important regulator of cardiovascular homeostasis, heart rate and blood pressure were analyzed in Mas-deficient mice. Using a femoral catheter the blood pressure of mice was measured for a period of 30 min and 250 data values per second were recorded. The mean values and range of heart rate and blood pressure were then calculated. Neither heart rate nor blood pressure were significantly different between knockout mice and controls. However, high resolution recording of these parameters and analysis of the data by non-linear dynamics revealed significant alterations in cardiovascular variability in Mas-deficient animals. In particular, females showed a strong reduction of heart rate variability. Furthermore, the data showed an increased sympathetic tone in knockout animals of both genders. The marked alterations detected in Mas-deficient mice of both genders suggest that the Mas-protooncogene is an important determinant of heart rate and blood pressure variability.

T., Walther; N., Wessel; N., Kang; A., Sander; C., Tschöpe; H., Malberg; M., Bader; A., Voss.

2000-01-01

300

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

Science.gov (United States)

Heart period constantly changes on a beat to beat basis, due to autonomic influences on the sinoatrial node, and changes can be quantified as heart rate variability (HRV). In addition, after a premature ventricular beat, there are reproducible variations in RR interval, also due to baroreflex mediated autonomic influences on the sinoatrial node, that can be measured as heart rate turbulence (HRT). Impaired autonomic function as measured by HRV and HRT has proven to predict adverse outcomes in clinical settings. The ability of reduced HRV and HRT to predict adverse outcomes has been explained by their dependency on vagal mechanisms that could reflect an increased sympathetic and a reduced vagal modulation of sinus node, thus favoring cardiac electrical instability. Analysis of non-linear dynamics of HRV has also been utilized to describe the fractal like characteristic of the variability signal and proven effective in identify patients at risk for sudden cardiac death. Despite the clinical validity of these measures, it has also been evident that the relationship between neural input and sinus node responsiveness is extremely complex and variable in different clinical conditions. Thus, abnormal HRV or HRT on a clinical Holter recordings may reflect non-neural as well as autonomic mechanisms, and this also needs to be taken into account when interpreting any findings. However, under controlled conditions, the computation of the low and high frequency components of HRV and of their normalized powers or ratio seems capable of providing valid information on sympatho-vagal balance in normal subjects, as well as in most patients with a preserved left ventricular function. Thus, analysis of HRV does provide a unique tool to specifically assess autonomic control mechanisms in association with various perturbations. In conclusion, HRV measures are of substantial utility to identify patients with an increased cardiac mortality and to evaluate autonomic control mechanisms, but their ability to capture specific levels of autonomic control may be limited to controlled laboratory studies in relatively healthy subjects. PMID:22163222

Lombardi, Federico; Stein, Phyllis K

2011-01-01

301

Immediate effects of particulate air pollutants on heart rate and respiratory rate in hypertensive rats.  

Science.gov (United States)

Time-series studies have shown that the lag time between elevated particulate air pollution (PM) and increases in cardiovascular-related hospital admissions and death is very short 1 d or less. If PM does cause serious cardiovascular effects shortly after exposure, one would expect to see some physiological change during exposure. In this study, spontaneously hypertensive rats (SHRs) with surgically implanted blood pressure transmitters were exposed to concentrated ambient PM (CAPS) for 4 h to determine whether CAPS inhalation causes immediate effects. The rats were also exposed to sulfuric acid aerosols because acid is one of the components of PM that could potentially activate irritant receptors and cause effects during exposure. Exposure to CAPS caused a striking decrease in respiratory rate that was apparent soon after the start of exposure and stopped when exposure to CAPS ceased. The decrease in respiratory rate was accompanied by a decrease in heart rate. Exposure of the same rats to fine-particle-size sulfuric acid aerosol also caused a significant decrease in respiratory rate similar to the effects of CAPS. Ultrafine acid had the opposite effect on respiratory rate compared to CAPS. Because acids have been shown to evoke sensory irritant responses in rodents, the similarity between the effects of fine acid aerosol and CAPS suggests that CAPS activates airway-irritant receptors during exposure. PMID:12665658

Nadziejko, Chrinstine; Fang, Kaijie; Nadziejko, Elizabeth; Narciso, Sandy Pais; Zhong, Mianhua; Chen, Lung Chi

2002-01-01

302

Ivabradine, a novel heart rate slower: Is it a sword of double blades in patients with idiopathic dilated cardiomyopathy?  

Directory of Open Access Journals (Sweden)

Full Text Available Objective: To prospectively assess the safety and efficacy of ivabradine in patients with idiopathic dilated cardiomyopathy.Methods: We included 35 patients with idiopathic dilated cardiomyopathy with an ejection fraction (EF 70 beats/min despite optimal medical therapy, according to the international guidelines in this prospective, non-randomized, single-arm, open-label safety study. Ivabradine was used as an add-on therapy to the maximally tolerated b-blocker in an increasing titrated dose till a target dose of 15 mg/day or resting heart rate of 60 beats/min for 3 months. During follow-up period the safety, patient tolerance and efficacy of this drug were assessed. All patients underwent 12-lead resting electrocardiography and Holter monitoring at inclusion and after 3 months. Statistical analysis was accomplished using paired t-test and Pearson correlation analysis.Results: We found a significant reduction in the resting heart rate by a mean of 25.9±9.4%, without a significant change of blood pressure. There was no prolongation of PR, QTc or QRS durations. Ventricular ectopic activity showed significant reduction (p<0.001. There was a significant correlation between the resting heart rate, NYHA and left ventricular ejection fraction (p<0.001 for both. One patient developed photopsia and decompensation was observed in another patient. Conclusion: Ivabradine is a safe and effective drug in reducing resting heart rate, improving NYHA functional class without undesirable effects on conduction parameters or ectopic activity.

Mona Rayan

2011-08-01

303

ROC Analysis and a Realistic Model of Heart Rate Variability  

CERN Document Server

We have carried out a pilot study on a standard collection of electrocardiograms from patients who suffer from congestive heart failure, and subjects without cardiac pathology, using receiver-operating-characteristic (ROC) analysis. The scale-dependent wavelet-coefficient standard deviation superior to two commonly used measures of cardiac dysfunction when the two classes of patients cannot be completely separated. A jittered integrate-and-fire model with a fractal Gaussian-noise kernel provides a realistic simulation of heartbeat sequences for both heart-failure patients and normal subjects.

Thurner, S; Teich, M C; Thurner, Stefan; Feurstein, Markus C.; Teich, Malvin C.

1998-01-01

304

Heart rate changes during the Valsalva maneuver in patients with isolated aortic insufficiency  

Directory of Open Access Journals (Sweden)

Full Text Available To determine the possible relationship between left ventricular dilatation and heart rate changes provoked by the Valsalva maneuver (Valsalva ratio, we studied 9 patients with isolated chronic aortic insufficiency. Left ventricular systolic function was assessed by two-dimensional echocardiography and cardiac catheterization. All patients were asymptomatic (functional class I of the New York Heart Association. The left ventricular internal diameters and volumes were significantly increased in all patients. The asymptomatic patients had either normal or slightly depressed ejection fraction (EF>0.40. The Valsalva ratio of these asymptomatic patients showed no significant correlation with the left ventricular volumes or with the left ventricular ejection fraction. In other words, parasympathetic heart rate control, as expressed by the Valsalva ratio, was normal in the asymptomatic patients with left ventricular dilatation and preserved left ventricular ejection fraction. Therefore, left ventricular dilatation may not be the major mechanism responsible for the abnormal parasympathetic heart rate control of patients with acquired heart disease

Navarro A.E.

1997-01-01

305

The effects of heart rate and aiming time on performance in Turkish National Archery Team  

OpenAIRE

The purpose of this study is to investigate the effects of aiming time and heart rate on the performance. Three elite female national subject was used in this study. The shooting performance was observed only in 70 m. To evaluate heart rate, Delta Plus CP/I portable, interpreting model ECG, to determine the releasing time double channel ME 3000 micro-processor, Muscle Tester were used. The results of the study; the shooting heart rate is116,2±7,16 bpm., aiming time is 3,56±0,59 s. And the ...

?pek Ero?lu Kolayi?; Emel Mimaro?lu

2008-01-01

306

Discrete Scale Invariance in the Cascade Heart Rate Variability Of Healthy Humans  

CERN Document Server

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.

Lin, D C

2004-01-01

307

Temporary decrease in heart rate in Lyme carditis during treatment with antibiotics.  

OpenAIRE

Lyme disease is a recognised cause of atrioventricular block. In most cases the conduction disturbances are reversed by treatment with antibiotics. A 44 year old man with third degree atrioventricular block in Lyme carditis had a temporary decrease in heart rate during resolution of the heart block two days after treatment with antibiotics was started.

Dam, E. P.; Jonker, D. R.; Hoorntje, J. C.

1996-01-01

308

Spectral analysis of time series of events: effect of respiration on heart rate in neonates  

International Nuclear Information System (INIS)

Certain types of biomedical processes such as the heart rate generator can be considered as signals that are sampled by the occurring events, i.e. QRS complexes. This sampling property generates problems for the evaluation of spectral parameters of such signals. First, the irregular occurrence of heart beats creates an unevenly sampled data set which must either be pre-processed (e.g. by using trace binning or interpolation) prior to spectral analysis, or analyzed with specialized methods (e.g. Lomb's algorithm). Second, the average occurrence of events determines the Nyquist limit for the sampled time series. Here we evaluate different types of spectral analysis of recordings of neonatal heart rate. Coupling between respiration and heart rate and the detection of heart rate itself are emphasized. We examine both standard and data adaptive frequency bands of heart rate signals generated by models of coupled oscillators and recorded data sets from neonates. We find that an important spectral artifact occurs due to a mirror effect around the Nyquist limit of half the average heart rate. Further we conclude that the presence of respiratory coupling can only be detected under low noise conditions and if a data-adaptive respiratory band is used

309

Atrial fibrillation in heart failure: drug therapies for rate and rhythm control.  

Science.gov (United States)

Pharmacological treatment of atrial fibrillation in the context of heart failure poses numerous challenges. Management decisions are limited by contraindications to several drugs and the paucity of robust clinical trials that provide evidence-based guidance. This review proposes a structured action plan for managing atrial fibrillation coexisting with heart failure that considers published clinical guidelines and integrates recent data derived from substudies of randomized trials, including the atrial fibrillation and congestive heart failure (AF-CHF) trial. Areas of uncertainty, such as target heart rates in atrial fibrillation and upstream therapies, are also discussed. PMID:23690262

Tadros, Rafik; Khairy, Paul; Rouleau, Jean L; Talajic, Mario; Guerra, Peter G; Roy, Denis

2014-05-01

310

The influence of challenging objects and horse-rider matching on heart rate, heart rate variability and behavioural score in riding horses  

OpenAIRE

A good horse-rider ‘match’ is important in the context of equine welfare. To quantify the influence of repetition and horse-rider matching on the stress of horses encountering challenging objects, 16 Warmblood horses were ridden in a test-setting on three occasions. On each occasion the horse was ridden by a different rider and was challenged by three objects (A–C). Heart rate (HR), heart rate variability (HRV) of horse and rider, and behaviour score (BS) of the horse were o...

Munsters, C. C. B. M.; Visser, K. E. K.; Broek, J. Den; Sloet Oldruitenborgh-oosterbaan, M. M.

2012-01-01

311

Premature Born Infant's Reaction to the Mother's Voice in Comparison to their Reaction to Music - Effect on Heart Rate and Heart Rate Variability  

OpenAIRE

OBJECTIVE: The aim of the study was to compare stress-reduction effects of the mother’s voice and lullaby music in preterm infants and to explore whether the mother’s well-being affects her ability to calm down her preterm baby. It was hypothesized that both acoustic stimulation interventions can calm down the baby, i.e. decrease heart rate and increase heart rate variability (HRV) in preterm infants. Further it was hypothesized that the mother’s voice would have greater effect than lul...

Djordjevic, Dragana

2010-01-01

312

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

OpenAIRE

Objective. To determine the effects of the moxa smoke on human heart rate (HR) and heart rate variability (HRV). Methods. Fifty-five healthy young adults were randomly divided into experimental (n = 28) and control (n = 27) groups. Experimental subjects were exposed to moxa smoke (2.5 ± 0.5?mg/m3) twice for 25 minutes in one week. ECG monitoring was performed before, during, and after exposure. Control subjects were exposed to normal indoor air in a similar environment and similarly monito...

Yingxue Cui; Baixiao Zhao; Yuhai Huang; Zhanghuang Chen; Ping Liu,; Jian Huang; Lixing Lao

2013-01-01

313

Prospective and retrospective ECG-gating for CT coronary angiography perform similarly accurate at low heart rates  

International Nuclear Information System (INIS)

Objective: To compare, in patients with suspicion of coronary artery disease (CAD) and low heart rates, image quality, diagnostic performance, and radiation dose values of prospectively and retrospectively electrocardiography (ECG)-gated dual-source computed tomography coronary angiography (CTCA) for the diagnosis of significant coronary stenoses. Materials and methods: Two-hundred consecutive patients with heart rates ?70 bpm were retrospectively enrolled; 100 patients undergoing prospectively ECG-gated CTCA (group 1) and 100 patients undergoing retrospectively-gated CTCA (group 2). Coronary artery segments were assessed for image quality and significant luminal diameter narrowing. Sensitivity, specificity, positive predictive values (PPV), negative predictive values (NPV), and accuracy of both CTCA groups were determined using conventional catheter angiography (CCA) as reference standard. Radiation dose values were calculated. Results: Both groups were comparable regarding gender, body weight, cardiovascular risk profile, severity of CAD, mean heart rate, heart rate variability, and Agatston score (all p > 0.05). There was no significant difference in the rate of non-assessable coronary segments between group 1 (1.6%, 24/1404) and group 2 (1.4%, 19/1385; p = 0.77); non-diagnostic image quality was significantly (p 0.05). Mean effective radiation dose of prospectively ECG-gated CTCA (2.2 ± 0.4 mSv) was significantly (p < 0.0001) smaller than that of retrospectively ECG-gated CTCA (8.1 ± 0.6 mSv). Conclusion: Prospectively ECG-gated CTCA yields similar image quality, performs as accurately as retrospectively ECG-gated CTCA in patients having heart rates ?70 bpm while being associated with a lower mean effective radiation dose.

314

Prospective and retrospective ECG-gating for CT coronary angiography perform similarly accurate at low heart rates  

Energy Technology Data Exchange (ETDEWEB)

Objective: To compare, in patients with suspicion of coronary artery disease (CAD) and low heart rates, image quality, diagnostic performance, and radiation dose values of prospectively and retrospectively electrocardiography (ECG)-gated dual-source computed tomography coronary angiography (CTCA) for the diagnosis of significant coronary stenoses. Materials and methods: Two-hundred consecutive patients with heart rates {<=}70 bpm were retrospectively enrolled; 100 patients undergoing prospectively ECG-gated CTCA (group 1) and 100 patients undergoing retrospectively-gated CTCA (group 2). Coronary artery segments were assessed for image quality and significant luminal diameter narrowing. Sensitivity, specificity, positive predictive values (PPV), negative predictive values (NPV), and accuracy of both CTCA groups were determined using conventional catheter angiography (CCA) as reference standard. Radiation dose values were calculated. Results: Both groups were comparable regarding gender, body weight, cardiovascular risk profile, severity of CAD, mean heart rate, heart rate variability, and Agatston score (all p > 0.05). There was no significant difference in the rate of non-assessable coronary segments between group 1 (1.6%, 24/1404) and group 2 (1.4%, 19/1385; p = 0.77); non-diagnostic image quality was significantly (p < 0.001) more often attributed to stair step artifacts in group 1. Segment-based sensitivity, specificity, PPV, NPV, and accuracy were 98%, 98%, 88%, 100%, and 100% among group 1; 96%, 99%, 90%, 100%, and 98% among group 2, respectively. Parameters of diagnostic performance were similar (all p > 0.05). Mean effective radiation dose of prospectively ECG-gated CTCA (2.2 {+-} 0.4 mSv) was significantly (p < 0.0001) smaller than that of retrospectively ECG-gated CTCA (8.1 {+-} 0.6 mSv). Conclusion: Prospectively ECG-gated CTCA yields similar image quality, performs as accurately as retrospectively ECG-gated CTCA in patients having heart rates {<=}70 bpm while being associated with a lower mean effective radiation dose.

Stolzmann, Paul, E-mail: paul.stolzmann@usz.ch [Institute of Diagnostic Radiology, University Hospital Zurich, Raemistrasse 100, 8091 Zurich (Switzerland); Goetti, Robert; Baumueller, Stephan [Institute of Diagnostic Radiology, University Hospital Zurich, Raemistrasse 100, 8091 Zurich (Switzerland); Plass, Andre; Falk, Volkmar [Clinic for Cardiovascular Surgery, University Hospital Zurich (Switzerland); Scheffel, Hans; Feuchtner, Gudrun; Marincek, Borut [Institute of Diagnostic Radiology, University Hospital Zurich, Raemistrasse 100, 8091 Zurich (Switzerland); Alkadhi, Hatem [Institute of Diagnostic Radiology, University Hospital Zurich, Raemistrasse 100, 8091 Zurich (Switzerland); Cardiac MR PET CT Program, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Leschka, Sebastian [Institute of Diagnostic Radiology, University Hospital Zurich, Raemistrasse 100, 8091 Zurich (Switzerland)

2011-07-15

315

Sweet Conclusion  

Science.gov (United States)

Jen Harrington is the owner and pastry chef of Sweet Conclusion, a bakery in Tampa, Florida. Most of Harrington's business comes from baking wedding cakes, but she has been attempting to attract customers to her retail bakery, where she sells cupcakes, pies, ice cream, and coffee. Nearly four years she opened Sweet Conclusion, the retail part of…

Shirley, Britt M.; Wooldridge, Barbara Ross; Camp, Kerri M.

2012-01-01

316

The effect of programmed exercise on body compositions and heart rate of 11-13 years-old male students  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Different forms of physical activities can play a very important role in improving health and physical fitness. The purpose of this study was to examine the effect of the programmed exercise on students’ body compositions and heart rate at rest.Materials and Method: Two groups each consisting of 15students, aged averagely 12.6 years were the subjects of this experimental study. The experimental group in each session took part in an exercise program consisting of 20 minutes of aerobic activity (running, 10 minutes of aerobic exercise, 30 minutes of local training and 5 minutes of free exercise. The experiment last for 24 sessions. Control group didn’t do any special practice. In both groups, weight, fat mass, fat percentage, lean body mass and heart rate were measured during rest period before and after the experiment. Results: Results showed that the fat percentage, weight, fat mass and heart rate had decreased after 8 weeks of programmed exercise in the experimental group unlike the control group. However, no significant difference was observed in lean body mass.Conclusion: The exercise program used in this study may help loosing weight and make the heart stronger

Mohammad H. Dashti

2011-11-01

317

Effect of pre operative heart rate on post spinal hypotension in obsteric patients  

International Nuclear Information System (INIS)

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)

318

Nonlinear control techniques for the heart rate regulation in treadmill exercises.  

Science.gov (United States)

It has been recently shown in the literature that a robust output feedback controller for the heart rate regulation can be designed for an experimentally validated second order nonlinear model of the human heart rate response during long-duration treadmill exercises: It is based on piecewise linear approximations of the original nonlinear model and involves (local) robust linear control techniques. In this letter, we resort to recent nonlinear advanced control techniques in order to illustrate the existence of a nonlocal and nonswitching control which guarantees heart rate regulation with no exact knowledge of model parameters and nonlinearities: It simply generalizes to the nonlinear framework the classical proportional-integral control design for linear models of heart rate response during treadmill exercises. Simulation and experimental results demonstrate the effectiveness of the proposed approach in typical training exercises involving warm up/holding/cool down phases. PMID:22167561

Scalzi, Stefano; Tomei, Patrizio; Verrelli, Cristiano Maria

2012-03-01

319

Facial electromyogram and heart-rate correlates of a paradoxical attitude change to antinuclear war information  

International Nuclear Information System (INIS)

The effects of film images versus film descriptions of the effects of nuclear explosions (versus a no-film control) on corrugator muscle tension, heart rate, attitude and mood were investigated. The last 5 min. of the images were associated with more corrugator tension for that condition when compared to the last 5 min. of the description condition. The groups did not differ in heart rate but women in both groups showed an increase in heart rate whereas men in both groups showed a decrease in heart rate. Film groups did not differ in their significant increases in anxiety, hostility, and depression on the Multiple Adjective Affect Checklist. On the pretest there was no significant correlation between scores on Betts' Questionnaire Upon Mental Imagery and scores on Goldenring and Doctor's index of concern for nuclear war. The vivid-image film group showed a decrease in concern for nuclear war when compared to the descriptive film group and the no-film control

320

10 Conclusion  

SCPinfonet

10 Conclusion The role of regional trade integration in conflict prevention ...Trade is one of the principal drivers of that change. Since the General Agreement on Tariffs ...and Trade (GATT) was signed in

321

Using Complexity Metrics With R-R Intervals and BPM Heart Rate Measures  

DEFF Research Database (Denmark)

Lately, growing attention in the health sciences has been paid to the dynamics of heart rate as indicator of impending failures and for prognoses. Likewise, in social and cognitive sciences, heart rate is increasingly employed as a measure of arousal, emotional engagement and as a marker of interpersonal coordination. However, there is no consensus about which measurements and analytical tools are most appropriate in mapping the temporal dynamics of heart rate and quite different metrics are reported in the literature. As complexity metrics of heart rate variability depend critically 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-of-concept, we employ a simple rest-exercise-rest task and show that non-linear statistics – fractal (DFA) and recurrence (RQA) analyses – reveal information about heart beat activity above and beyond the simple level of heart rate. Non-linear statistics unveil sustained post-exercise effects on heart rate 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 as they retain most of the information about nonlinear aspects of heart beat dynamics.

Wallot, Sebastian; Fusaroli, Riccardo

2013-01-01

322

Anxiety induced by false heart rate feedback in patients with panic disorder.  

OpenAIRE

The psychophysiological model of panic attacks postulates a positive feedback loop between anxiety symptoms and the patient's anxious reaction to these symptoms. We tested the underlying assumption that the appraisal of bodily change can induce anxiety in this patient group. Twenty-five patients with panic disorder or agoraphobia with panic attacks (DSM-III) and 25 matched normal controls were given false feedback of an abrupt heart rate increase. Self-ratings of anxiety and excitement, heart...

Ehlers, A.; Margraf, J.; Roth, Wt; Taylor, Cb; Birbaumer, N.

1988-01-01

323

Fetal Heart Rate and Variability: Stability and Prediction to Developmental Outcomes in Early Childhood  

OpenAIRE

Stability in cardiac indicators before birth and their utility in predicting variation in postnatal development were examined. Fetal heart rate and variability were measured longitudinally from 20 through 38 weeks gestation (n = 137) and again at age 2 (n = 79). Significant within-individual stability during the prenatal period and into childhood was demonstrated. Fetal heart rate variability at or after 28 weeks gestation and steeper developmental trajectories were significantly associated w...

Dipietro, Janet A.; Bornstein, Marc H.; Hahn, Chun-shin; Costigan, Kathleen; Achy-brou, Aristide

2007-01-01

324

Dose-dependent heart rate reducing effect of nizatidine, a histamine H2-receptor antagonist.  

OpenAIRE

1. Twelve healthy subjects were treated in a randomised placebo-controlled crossover study with placebo, 150 mg, 300 mg, and 600 mg nizatidine, 100 mg pirenzepine, and 300 mg nizatidine plus 100 mg pirenzepine for 1 week each. 2. On the seventh treatment day, heart rate, blood pressure, systolic time intervals, impedance cardiographic and Doppler ultrasound variables were measured. 3. Stroke volume and blood pressure were not altered by nizatidine and/or pirenzepine. By contrast, heart rate a...

Hinrichsen, H.; Halabi, A.; Fuhrmann, G.; Kirch, W.

1993-01-01

325

Time-frequency Analysis of Heart Rate Variability for Neonatal Seizure Detection  

OpenAIRE

There are a number of automatic techniques available for detecting epileptic seizures using solely electroencephalogram (EEG), which has been the primary diagnosis tool in newborns. The electrocardiogram (ECG) has been much neglected in automatic seizure detection. Changes in heart rate and ECG rhythm were previously linked to seizure in case of adult humans and animals. However, little is known about heart rate variability (HRV) changes in human neonate during seizure. In this paper,...

Boualem Boashash; Malarvili, M. B.; Mostefa Mesbah

2006-01-01

326

Hardware Approach of R-Peak Detection for the Measurement of Fetal and Maternal Heart Rates  

OpenAIRE

Fetal heart rate (FHR) monitoring is a routine for obtaining significant information about the fetal condition duringpregnancy and labour. Fetal condition may change abruptly during the pregnancy period. Therefore, a continuousfetal electrocardiogram (FECG) monitoring will ease the fetal well-being. An algorithm has been developed to detectR-peak for the simultaneous measurement of the fetal and maternal hearts rates during pregnancy and labor for fetalmonitoring. The algorithm is based on a ...

Hasan, M. A.; Md. Mamun

2012-01-01

327

The Effects of distilled Wild Ginseng Herbal Acupuncture on the Heart Rate Variability(HRV)  

OpenAIRE

Objective : We investigated the effects of distilled Wild Ginseng Herbal Acupuncture on autonomic nervous system with the Heart Rate Variability(HRV) in adult man. as well as we tried to observe how distilled Wild Ginseng Herbal Acupuncture on the balance of the autonomic nervous system. Method : We investigated the effects of distilled Wild Ginseng Herbal Acupuncture on autonomic nervous system with the Heart Rate Variability(HRV) in adult man. as well as we tried to observe how dis...

Roh Jeong-Du; Kim Lak-Hyung; Song Beom-Yong; Yook Tae-Han

2008-01-01

328

Aberrant heart rate and brainstem BDNF signaling in a mouse model of Huntington’s disease  

OpenAIRE

Huntington’s disease (HD) is associated with profound autonomic dysfunction including dysregulation of cardiovascular control often preceding cognitive or motor symptoms. Brain-derived neurotrophic factor (BDNF) levels are decreased in HD brain, and restoring BDNF levels prevents neuronal loss and extends lifespan. We reasoned that heart rate changes in HD may be associated with altered BDNF signalling in cardiovascular control nuclei in the brainstem. Here we show that heart rate is elevat...

Griffioen, Kathleen J.; Wan, Ruiqian; Brown, Tashalee R.; Okun, Eitan; Camandola, Simonetta; Mughal, Mohamed R.; Phillips, Terry M.; Mattson, Mark P.

2012-01-01

329

Aging Affects the Response of Heart Rate Variability Autonomic Indices to Atropine and Isoproteronol  

OpenAIRE

Background: Normalized ratios of portions of the power frequency spectrum of heart rate (HR) are commonly used to gain insight into cardiac “sympathovagal balance.” Whether aging, which alters both sympathtetic and parasympathetic activities, infl uences these measures has not been well characterized.Objectives: We examined the ability of normalized ratios of the power frequency spectrum of heart rate to describe autonomic activity at the sinus node in older and younger adults during cond...

Madden, Kenneth M.; Levy, Wayne C.; Stratton, John R.

2008-01-01

330

HEART RATE AND BLOOD LACTATE RESPONSES TO CHANGQUAN AND DAOSHU FORMS OF MODERN WUSHU  

OpenAIRE

The development of specific training designed to enhance physiological aspects of performance relies heavily on the availability of accurate and validity physiological data. In the combat sport of Wushu, katas are used to develop aerobic fitness. It is arguably important to assess and monitor heart rate (HR) and lactate (La) responses when designing effective training programs. The aim of this pilot study was to investigate heart rate and lactate responses to forms execution among Wushu comba...

Jerri Luiz Ribeiro; Castro, Bruno Ogoday S. D.; Rosa, Caio S.; Baptista, Rafael R.; Oliveira, Alvaro R.

2006-01-01

331

Heart rate variability, structural and functional characteristics of the left ventricle in essential arterial hypertension  

OpenAIRE

For the purpose of diagnostic and treatment improvement it is necessary to investigate relationship between different pathogenetic mechanisms in essential hypertension. The aim of our study was the comparative analysis of the parameters of cardiac remodeling and neurohumoral mechanisms of heart rate variability (HRV) in patients with essential arterial hypertension. 100 patients with essential arterial hypertension were included in the study. All patients went through heart rate variability p...

Khromtsova ?.?.

2010-01-01

332

Cardiac Troponin T Levels in Umbilical Cord Blood of Neonates with Abnormal Fetal Heart Rate  

OpenAIRE

Objective: Most neonatal encephalopathic disorders appear to be caused by perinatal events. Persistent myocardial ischemia leads to cellular necrosis and release of troponin from cardiac muscles. Fetal distress during labor may be detected by monitoring the fetal heart rate. However little is known about the relationship, if any, that exists between fetal heart rate abnormalities and the fetal cardiac musculature and its function. The aim of this study was to investigate the relationship, if ...

Shiva Rafati; Maryam Rabi; Hajie Borna

2013-01-01

333

Dynamic cardiovagal response to motion sickness: A point-process heart rate variability study  

OpenAIRE

A visual display of stripes was used to examine cardio-vagal response to motion sickness. Heart rate variability (HRV) was investigated using dynamic methods to discern instantaneous fluctuations in reaction to stimulus and perception-based events. A novel point process adaptive recursive algorithm was applied to the R-R series to compute instantaneous heart rate, HRV, and high frequency (HF) power as a marker of vagal activity. Results show interesting dynamic trends in each of the considere...

Lacount, Lt; Napadow, V.; Kuo, B.; Park, K.; Kim, J.; Brown, En; Barbieri, R.

2009-01-01

334

Effect of decrease in heart rate variability on the diagnostic accuracy of 64-MDCT coronary angiography  

OpenAIRE

OBJECTIVE: The purpose of this study was to evaluate the effect of average heart rate and heart rate variability on the diagnostic accuracy of 64-MDCT in the assessment of coronary artery stenosis. SUBJECTS AND METHODS: CT and invasive coronary angiography were performed on 114 patients (mean age, 62 years) referred for known coronary artery disease (n = 26), atypical chest pain (n = 58), and presurgical exclusion of coronary artery disease before abdominal aortic (n = 14) or cardiac valve (n...

Leschka, S.; Scheffel, H.; Husmann, L.; Ga?mperli, O.; Marincek, B.; Kaufmann, P. A.; Alkadhi, H.

2008-01-01

335

Pancuronium, vecuronium, and heart rate during anesthesia for aortocoronary bypass operations.  

Science.gov (United States)

To determine the effects of pancuronium and vecuronium on heart rate, 90 patients scheduled for aortocoronary bypass were randomly assigned to one of three groups (30 patients each) which received vecuronium 100 micrograms[sdot]kg-1, pancuronium 100 micrograms[sdot]kg-1, or a mixture of vecuronium (50 micrograms[sdot]kg-1) and pancuronium (50 micrograms[dot]kg-1) in a double-blind fashion during induction of anesthesia. All patients were premedicated with lorazepam prior to surgery, hence avoiding the effects of scopolamine. Our results showed no significant increase in heart rate from the administration of pancuronium, following administration of this drug the heart rate increased by only four beats per minute. The heart rate was unchanged after the mixture, but decreased by twelve beats per minute after vecuronium (P < 0.05). The heart rate response differed by 16 beats per minute between pancuronium and vecuronium. All patients who received either of the neuromuscular relaxants and who were on beta blockers showed a decrease in heart rate. In this study, the administration of pancuronium after an adequate induction dose of fentanyl did not cause tachycardia. We therefore feel that pancuronium still has a role in cardiac anesthesia, especially as the newer muscle relaxants such as vecuronium, pipecuronium and doxacurium are significantly more expensive. PMID:7903545

Mangar, D; Turnage, W S; Connell, G R; Graubert, D

1993-01-01

336

The effects of heart rate and aiming time on performance in Turkish National Archery Team  

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Full Text Available The purpose of this study is to investigate the effects of aiming time and heart rate on the performance. Three elite female national subject was used in this study. The shooting performance was observed only in 70 m. To evaluate heart rate, Delta Plus CP/I portable, interpreting model ECG, to determine the releasing time double channel ME 3000 micro-processor, Muscle Tester were used. The results of the study; the shooting heart rate is116,2±7,16 bpm., aiming time is 3,56±0,59 s. And the heart rate of the time between two shooting is 113,13±9,54 bpm. According to statistical analysis, a significant difference between shooting HR and aiming time of arrows which hit the different point on the target has been observed (p<0,05.The relationships between shooting HR-performance and shooting HR-Aiming time have been observed.While shootings come close to the center of the target (through the 10 point the shooting heart rate and aiming time has decreased and there is no change in the value of the heart rate of the time between two shooting.

?pek Ero?lu Kolayi?

2008-05-01

337

Blue 405 nm laser light mediates heart rate – investigations at the acupoint Neiguan (Pe.6) in Chinese adults  

OpenAIRE

Background: In previous studies, we showed that laser needle acupuncture with red and infrared light has specific effects on bio-signals of the brain and heart. Aims: In this publication we report the effect of blue laser light on heart rate and heart rate variability (HRV) before, during and after acupuncture at the acupoint Neiguan (Pe.6) in Chinese adults. These are the first data published concerning heart rate and HRV, obtained with blue laser acupuncture equipment. Patients and Methods:...

Gerhard Litscher; Zheng Xie; Lu Wang; Ingrid Gaischek

2009-01-01

338

Effect of Exercise Testing on Short-term Heart Rate Variability in Patients with Coronary Heart Disease  

DEFF Research Database (Denmark)

Objective To study the effect of exercise testing on short term heart rate variability in patients with CHD.Methods In 12 patients with CHD and 12 age-and sex-matched healthy controls, short-term frequency domain analysis was performed at respective stage before, during and after ET.Results It showed that (1) No significant difference was detected in 5-minute frequency domain (LFnorm, HFnorm and LF/HF) of stationary supine position before exercise (P0.05) between CHD and controls. In CHD, there was no significant difference in 5-minute frequency spectral components of supine position between pre-exercise and post-exercise results (P0.05); (2) All of LFnorm, HFnorm and LF/HF were found to decrease gradually during ET and to reach the lowest levels in maximal ET and to increase during the recovery period in both CHD and controls (P0.05).Between the two groups, significant difference was shown in the second 5-minute frequency domain analysis (LFnorm, HFnorm and LF/HF) after ET(P0.05); (3) In the whole course of ET,the frequency domain analysis showed that LF and LFnorm were higher and HF,HFnorm were lower in CHD than those in controls.Conclusion It is concluded that (1) Sympathovagal nervous system remains balanced in patients with CHD in stationary supine position without myocardiac ischemia; (2) Vagal tone withdraws during the exercise time and increases during the recovery period; (3) The changes of HRV in patients with CHD present ischemia-induced reflective sympathetic activity predominance during the recovery period; (4) The autonomic nervous system in CHD is disordered during ET. This results suggest that ET is helpful in detecting the disorder of sympathovagal nervous system in patients with CHD.

Niu, Hui-Yan; Zhang, Dai-Fu

2005-01-01

339

Bradycardia in perspective-not all reductions in heart rate need immediate intervention.  

Science.gov (United States)

According to Wikipedia, the word 'bradycardia' stems from the Greek ??????, bradys, 'slow', and ??????, kardia, 'heart'. Thus, the meaning of bradycardia is slow heart rate but not necessarily too slow heart rate. If looking at top endurance athletes they may have a resting heart rate in the very low thirties without needing emergent intervention with anticholinergics, isoprenaline, epinephrine, chest compressions or the insertion of an emergency pacemaker (Figure 1). In fact, they withstand these episodes without incident, accommodating with a compensatory increase in stroke volume to preserve and maintain cardiac output. With this in mind, it is difficult for the authors to fully understand and agree with the general sentiment amongst many pediatric anesthesiologists that all isolated bradycardia portends impending doom and must be immediately treated with resuscitative measures. PMID:25410284

Mason, Keira P; Lönnqvist, Per-Arne

2015-01-01

340

Circadian rhythms of ECG T-wave, arterial pressure and heart rate in patients with ischemic heart disease.  

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Analysis of the data of 25 healthy subjects and 141 patients with IHD revealed circadian rhythms of heart rate, systolic and diastolic arterial pressure and ECG T-wave voltage both in patients and controls. On the basis of data obtained we conclude that circadian rhythms of heart rate and arterial pressure level in patients with IHD are changed as compared with the data of controls. This change is apparent in the alteration of the acrophase and amplitude in some cases and especially in the mesor alteration of the rhythm in others. Circadian rhythms of T-wave voltage in different leads in controls is characterized by the occurrence of acrophase at midday or in the evening hours. In patients with IHD the acrophase mainly occurs in the early morning hours or at night. These data acquire practical importance in prevention and pharmacological manipulation of IHD. PMID:7449578

Aslanian, N L; Adamian, K G; Grigorian, S V; Bagdassarian, R A; Assatrian, D G

1980-01-01

341

Predicting survival in heart failure case and control subjects by use of fully automated methods for deriving nonlinear and conventional indices of heart rate dynamics  

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BACKGROUND: Despite much recent interest in quantification of heart rate variability (HRV), the prognostic value of conventional measures of HRV and of newer indices based on nonlinear dynamics is not universally accepted. METHODS AND RESULTS: We have designed algorithms for analyzing ambulatory ECG recordings and measuring HRV without human intervention, using robust methods for obtaining time-domain measures (mean and SD of heart rate), frequency-domain measures (power in the bands of 0.001 to 0.01 Hz [VLF], 0.01 to 0.15 Hz [LF], and 0.15 to 0.5 Hz [HF] and total spectral power [TP] over all three of these bands), and measures based on nonlinear dynamics (approximate entropy [ApEn], a measure of complexity, and detrended fluctuation analysis [DFA], a measure of long-term correlations). The study population consisted of chronic congestive heart failure (CHF) case patients and sex- and age-matched control subjects in the Framingham Heart Study. After exclusion of technically inadequate studies and those with atrial fibrillation, we used these algorithms to study HRV in 2-hour ambulatory ECG recordings of 69 participants (mean age, 71.7+/-8.1 years). By use of separate Cox proportional-hazards models, the conventional measures SD (P.3), were not. In multivariable models, DFA was of borderline predictive significance (P=.06) after adjustment for the diagnosis of CHF and SD. CONCLUSIONS: These results demonstrate that HRV analysis of ambulatory ECG recordings based on fully automated methods can have prognostic value in a population-based study and that nonlinear HRV indices may contribute prognostic value to complement traditional HRV measures.

Ho, K. K.; Moody, G. B.; Peng, C. K.; Mietus, J. E.; Larson, M. G.; Levy, D.; Goldberger, A. L.

1997-01-01

342

Initial fractal exponent of heart-rate variability is associated with success of early resuscitation in patients with severe sepsis or septic shock: a prospective cohort study  

Science.gov (United States)

Introduction Heart-rate variability reflects autonomic nervous system tone as well as the overall health of the baroreflex system. We hypothesized that loss of complexity in heart-rate variability upon ICU admission would be associated with unsuccessful early resuscitation of sepsis. Methods We prospectively enrolled patients admitted to ICUs with severe sepsis or septic shock from 2009 to 2011. We studied 30 minutes of EKG, sampled at 500 Hz, at ICU admission and calculated heart-rate complexity via detrended fluctuation analysis. Primary outcome was vasopressor independence at 24 hours after ICU admission. Secondary outcome was 28-day mortality. Results We studied 48 patients, of whom 60% were vasopressor independent at 24 hours. Five (10%) died within 28 days. The ratio of fractal alpha parameters was associated with both vasopressor independence and 28-day mortality (p=0.04) after controlling for mean heart rate. In the optimal model, SOFA score and the long-term fractal alpha parameter were associated with vasopressor independence. Conclusions Loss of complexity in heart rate variability is associated with worse outcome early in severe sepsis and septic shock. Further work should evaluate whether complexity of heart rate variability (HRV) could guide treatment in sepsis. PMID:23958243

Brown, Samuel M.; Tate, Quinn; Jones, Jason P.; Knox, Daniel; Kuttler, Kathryn G.; Lanspa, Michael; Rondina, Matthew T.; Grissom, Colin K.; Behera, Subhasis; Mathews, V.J.; Morris, Alan

2013-01-01

343

Nested and swaddled positioning support in the prone position facilitates sleep and heart rate stability in very low birth weight infants  

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Full Text Available Hideki Kihara,1 Tomohiko Nakamura2 1Department of Rehabilitation, Nagano Children’s Hospital, Nagano, Japan; 2Division of Neonatology, Nagano Children’s Hospital, Nagano, Japan Abstract: The purpose of this study was to observe in very low birth weight infants (VLBWI the effect of nested and swaddled positioning support in the prone position on heart rate, sleep distribution, and behavior state. A total of 20 VLBWI who were born at a gestational age of 26.5 ± 4 weeks with a birth weight of 709 ± 207 g were studied at an average gestational age of 37.4 ± 0.6 weeks (range 36–39 and a weight of 1590 ± 337 g (range 1192–2372. A prospective and crossover design was used. Infants were observed in the prone position with and without positioning support. Heart rate and electroencephalography were monitored during 3-hour interfeeding epochs. Heart rate and the coefficient of variation of heart rate in prone infants with positioning support were lower than in prone infants without positioning support. The percent of quiet sleep and behavior state 1 in prone infants with positioning support were higher compared to prone infants without positioning support. In conclusion, the present study demonstrated that a prone position with nested and swaddled positioning support might facilitate sleep and heart rate stability compared to prone positioning alone in VLBWI. Keywords: positioning support, prone position, sleep, heart rate, very low birth weight infants

Kihara H

2013-03-01

344

Modest weight loss in moderately overweight postmenopausal women improves heart rate variability  

DEFF Research Database (Denmark)

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-loss programme. Accepted variables for characterization of HRV were analysed before and after the weight loss by 24-h ambulatory ECG monitoring; mean and standard deviation for the time between normal-to-normal complexes (MeanNN and SDNN, respectively), and the mean of standard deviations of normal-to-normal intervals for each 5-min period (SDNNindex). Baseline body fat mass (FM%) and changes in body composition was determined by dual X-ray absorptiometry. Before and after the weight-loss period, total abdominal fat, intra-abdominal fat (IAAT), and subcutaneous abdominal fat (SCAT) were measured by single-slice MRI at L3. Results: The weight loss of 3.9 2.0 kg was accompanied by an improvement of HRV. SDNN increasedby 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 pressure (SBP) decreased by 2.7%, total cholesterol by 5.1% and high-sensitivity C-reactive protein (hsCRP) by 15.8% (p ¼ 0.002). Improvements in SDNN and cholesterol were correlated with weight loss (r ¼ 0.329, p ¼ 0.024 and r ¼ 0.327, p ¼ 0.020, respectively) but changes in HR, SBP, and hsCRP were not. IAAT and the IAAT/SCAT-ratio were found to be negatively associated with HRV parameters but changes in body composition were not associated with changes in HRV. Conclusions: The observed improvement of HRV seems to be facilitated by weight loss. IAAT and the IAAT/SCAT ratio were found to be associated with low HRV.

Mouridsen, Mette Rauhe; Bendsen, Nathalie Tommerup

2013-01-01

345

Assessment of skeletal muscle fatigue of road maintenance workers based on heart rate monitoring and myotonometry  

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Full Text Available Abstract Objective This research work is dedicated to occupational health problems caused by ergonomic risks. The research object was road building industry, where workers have to work very intensively, have long work hours, are working in forced/constrained work postures and overstrain during the work specific parts of their bodies. The aim of this study was to evaluate the work heaviness degree and to estimate the muscle fatigue of workers after one week work cycle. The study group consisted of 10 road construction and maintenance workers and 10 pavers aged between 20 and 60 years. Methods Physical load were analyzed by measuring heart rate (HR, work postures (OWAS and perceived exertion (RPE. Assessments of the muscles strain and functional state (tone were carried out using myotonometric (MYO measurements. The reliability of the statistical processing of heart rate monitoring and myotonometry data was determined using correlating analysis. Results This study showed that that road construction and repairing works should be considered as a hard work according to average metabolic energy consumption 8.1 ± 1.5 kcal/min; paving, in its turn, was a moderately hard work according to 7.2 ± 1.1 kcal/min. Several muscle tone levels were identified allowing subdivision of workers into three conditional categories basing on muscle tone and fatigue: I – absolute muscle relaxation and ability to relax; II – a state of equilibrium, when muscles are able to adapt to the work load and are partly able to relax; and III – muscle fatigue and increased tone. It was also found out that the increase of muscle tone and fatigue mainly depend on workers physical preparedness and length of service, and less – on their age. Conclusion We have concluded that a complex ergonomic analysis consisting of heart rate monitoring, assessment of compulsive working postures and myotonometry is appropriate to assess the work heaviness degree and can provide prognosis of occupational pathology or work-related musculoskeletal disorders for the workers under different workload conditions. These results can also be used when deciding on necessary rest time and its periodicity.

Kalkis Henrijs

2006-07-01

346

Analysis of Heart Rate and Self-Injury with and without Restraint in an Individual with Autism  

Science.gov (United States)

The relation between self-injury and heart rate was analyzed for an individual who appeared anxious while engaging in self-injury. The analysis involved manipulating the presence or absence of restraint while simultaneously measuring heart rate. The following findings were obtained and replicated: (a) when some form of restraint was applied, heart

Jennett, Heather; Hagopian, Louis P.; Beaulieu, Lauren

2011-01-01

347

Initial experience of evaluation of coronary artery with 320-slice row CT system in high pre-test probability population without heart rate (rhythm) control  

International Nuclear Information System (INIS)

Objective: To investigate the accuracy of 320-slice row CT system for the detection of coronary artery disease (CAD) in high pre-test probability population without heart rate/rhythm control. Methods: Thirty patients with a high pre-test probability of CAD underwent 320-slice row CT without preceding heart rate/rhythm control. Invasive coronary angiography (ICA) served as the standard reference. Data sets were evaluated by 2 observers in consensus with respect to stenoses ?50% decreased diameter. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and Youden index were analyzed; the impact of heart rate and calcification on image quality as well as diagnostic accuracy were also analyzed by Chi-square test. Results: Mean heart rate during scanning was 73.7±15.4 beats per min(bpm), and median(QR) of Agatston score of segment was 45.6 (181). On a per-segment analysis, overall sensitivity was 96.1% (74/77, 95% CI:89.03%-99.19%), specificity was 98.3% (337/343, 95% CI:96.23%-99.36%), PPV was 92.5% (74/80, 95% CI:84.39%-97.20%), NPV of 99.1% (337/340, 95% CI: 97.44%-99.82%) and the Youden index was 0.94. In both heart-rate subgroups (242 in heart rate < 70 bpm group, 169 in heart rate ?70 bpm group), diagnostic accuracy for the assessment of coronary artery stenosis was similar (P<0.05). The accuracy and the quality score of the subgroup Agatston score ?100 were lower than that of the subgroup Agatston score <100; however, toup Agatston score <100; however, the difference of results between 320-slice row CT and ICA was not significant (P<0.05). Conclusion: 320-detector row CT can reliably detect coronary artery stenoses in a high pre-test probability population without heart rate/rhythm control. (authors)

348

Systolic reconstruction in patients with low heart rate using coronary dual-source CT angiography  

International Nuclear Information System (INIS)

Objectives: The purpose of our study was to determine the relationship between the predictive factors and systolic reconstruction (SR) as an optimal reconstruction window in patients with low heart rate (LHR; less than 65 bpm). Methods: 391 patients (262 male and 129 female, mean age; 67.1 ± 10.1 years of age) underwent coronary CTA without the additional administration of a beta-blocker. Affecting factors for SR were analyzed in age, gender, body weight (BW), diabetes mellitus (DM), coronary arterial disease (CAD), ejection fraction (EF), systolic and diastolic body pressure (BP) and heart rate variability (HRV) during coronary CTA. Results: In 29 (7.4%) of the 391 patients, SR was needed, but there was no apparent characteristic difference between the systolic and diastolic reconstruction groups in terms of gender, age, BW, DM, CAD and EF. In a multivariate analysis, the co-existence of DM [P < 0.05; OR, 0.27; 95% CI, 0.092-0.80], diastolic BP [P < 0.01; OR, 0.95; 95% CI, 0.92-0.98] and HRV [P < 0.01; OR, 0.98; 95% CI, 0.96-0.99] were found to be the factors for SR. In gender-related analysis, HRV was an important factor regardless of sex, but co-existence of DM affected especially for female and BP for male. Conclusion: Especially in the patients with LHR who had a medication of DM, high HRV or high BP, SR, in addition to DR, was needed to obtain high-quality coronary CTA images.

349

‘Fire of Life’ analysis of heart rate variability during alpine skiing in Austria  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Skiing is a very popular sport in Austria. Nevertheless, there is little information concerning online monitoring of bio-signals during alpine skiing in the mountains. Within the last years innovative scientific monitoring tools for evaluating features of neurocardial fitness have been developed. Aims: The goal of this study was to demonstrate the new ‘Fire of Life’ heart rate variability analysis for the first time during alpine skiing. Volunteers and Methods: Continuous electrocardiographic monitoring over a period of 12 hours was performed simultaneously in two healthy volunteers using the same type of equipment (medilog AR12 systems. Two healthy volunteers (female, 20 years, and male, 51 years, both hobby skiers, were monitored simultaneously and continuously during two resting periods before and after active sport and also during alpine skiing. Altogether each participant covered 9,084 meters altitude difference within a time period of 6:14 hours. Total length of the downhill skiing was 45 kilometers. Results: Data acquisition was performed without any technical problems in both subjects. Poincaré plots of sequential R-R intervals (beat to beat variability show two ellipses of different shape and magnitude. During resting periods respiratory sinus arrhythmia and blood pressure effects can be clearly seen in the young female. The same effects, however markedly reduced, are obvious in the older volunteer. Conclusions: The present investigations during alpine skiing highlight the potential value of the ‘Fire of Life’ heart rate variability monitoring even under difficult environmental conditions. The innovative kind of analysis helps to show how well the human body reacts to sport, stress and recovery.

Gerhard Litscher

2010-06-01

350

Forestry work in the Italians alps: metabolic demand assessed by heart rate  

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Full Text Available

Objective: This research aims to: a assess the energy expenditure during typical forestry activities; b assess the actual workload of forestry work; c define the eventual relationship between oxygen uptake ( and heart rate during the studied working phases.

Methods: Eleven healthy skilled forestry workers were studied. Using a portable device, oxygen uptake ( , carbon dioxide output ( , pulmonary ventilation ( and heart rate (HR were measured. The forestry work was divided into four phases: walking uphill, felling, limbing & chain-sawing and complementary activities. A work time report was kept and in each phase a weighted average (WA of all parameters was obtained.

Results:Walking uphill, felling, limbing & chain-sawing activities did not show significant statistical differences between each other and were classified as heavy activities (mean 2.17 lmin-1,mean HR 157 beatmin-1. The complementary activity was found to be less demanding and statistically differed in respect to the others ( 0.55 l min-1, HR 98 beat min-1. By theWA, the actual workload of forestry work resulted in a moderate to heavyoptimal job ( and HR being 1.51 l min-1 and 133.5 beat min-1 respectively in a typical working day. Furthermore it was possible to set up a relationship between and HR for the forestry work.

Conclusions: Forestry activity can be classified as moderate to heavy-optimal. Finally, a good and linear correlation between and HR proved to be an easy tool to evaluate the metabolic demand.

Angelo Rodio

2007-06-01

351

Limbic Dysregulation is Associated With Lowered Heart Rate Variability and Increased Trait Anxiety in Healthy Adults  

Science.gov (United States)

Objectives We tested whether dynamic interaction between limbic regions supports a control systems model of excitatory and inhibitory components of a negative feedback loop, and whether dysregulation of those dynamics might correlate with trait differences in anxiety and their cardiac characteristics among healthy adults. Experimental Design Sixty-five subjects received fMRI scans while passively viewing angry, fearful, happy, and neutral facial stimuli. Subjects also completed a trait anxiety inventory, and were monitored using ambulatory wake ECG. The ECG data were analyzed for heart rate variability, a measure of autonomic regulation. The fMRI data were analyzed with respect to six limbic regions (bilateral amygdala, bilateral hippocampus, Brodmann Areas 9, 45) using limbic time-series cross-correlations, maximum BOLD amplitude, and BOLD amplitude at each point in the time-series. Principal Observations Diminished coupling between limbic time-series in response to the neutral, fearful, and happy faces was associated with greater trait anxiety, greater sympathetic activation, and lowered heart rate variability. Individuals with greater levels of trait anxiety showed delayed activation of Brodmann Area 45 in response to the fearful and happy faces, and lowered Brodmann Area 45 activation with prolonged left amygdala activation in response to the neutral faces. Conclusions The dynamics support limbic regulation as a control system, in which dysregulation, as assessed by diminished coupling between limbic time-series, is associated with increased trait anxiety and excitatory autonomic outputs. Trait-anxious individuals showed delayed inhibitory activation in response to overt-affect stimuli and diminished inhibitory activation with delayed extinction of excitatory activation in response to ambiguous-affect stimuli. PMID:18041716

Mujica-Parodi, Lilianne R.; Korgaonkar, Mayuresh; Ravindranath, Bosky; Greenberg, Tsafrir; Tomasi, Dardo; Wagshul, Mark; Ardekani, Babak; Guilfoyle, David; Khan, Shilpi; Zhong, Yuru; Chon, Ki; Malaspina, Dolores

2010-01-01

352

Effects of antidepressant treatment on heart rate variability in major depression: A quantitative review  

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Full Text Available Abstract Background The literature measuring effects of antidepressant and electroconvulsive therapy (ECT for major depression on heart rate variability (HRV in medically well individuals was reviewed. Methods Fourteen studies evaluating HRV were included. Twenty three pre-post or within group comparisons were available. Treatment impact on measures of HRV was pooled over studies. We examined different classes of antidepressants, and for short and long electrocardiogram (ECG recordings separately. Results Tricyclic antidepressants (TCAs were associated with declines in most measures of HRV and significant increase in heart rate (HR in studies with short recording intervals. No significant changes were found for longer recording times. Treatment effects with selective serotonin reuptake inhibitors (SSRIs were more variable. Short-recording studies revealed a significant decrease in HR and an increase in one HRV measure. In two 24-hour recording studies no significant changes were observed. No relationship between ECT and HRV has been established in the literature. The effects of other drugs are reported. Limitations Few studies measure the effects of treatment of depression on HRV. Existing studies have generally used very small samples, employing a variety of measurements and methodologies. Conclusion We confirm that TCAs are associated with a large decrease in HRV and increase HR. However, data for SSRIs is not clear. Although the effect of SSRIs on HRV is weaker than for TCAs, evidence shows that SSRIs are associated with a small decrease in HR, and an increase in one measure of HRV. The use of TCAs in depression leads to changes in HRV that are associated with increased risk of mortality.

Hasegawa Takuya

2008-06-01

353

Beta Blockade Protection of Bone Marrow Following Injury: A Critical Link between Heart Rate and Immunomodulation  

Science.gov (United States)

Introduction Severe trauma induces a profound elevation of catecholamines that is associated with bone marrow (BM) hematopoietic progenitor cell (HPC) colony growth suppression, excessive BM HPC mobilization, and a persistent anemia. Previously, propranolol (BB) use after injury and shock has been shown to prevent this BM dysfunction and improve hemoglobin levels. This study seeks to further investigate the optimal therapeutic dose and timing of BB administration following injury and shock. Methods Male Sprague-Dawley rats were subjected to a combined lung contusion (LC), hemorrhagic shock (HS) model ± BB. In our dose response experiments, animals received BB at 1, 2.5, 5, or 10 mg/kg immediately following resuscitation. In our therapeutic window experiments, following LCHS rats were given BB immediately, 1 hour, or 3 hours following resuscitation. BM and peripheral blood (PB) were collected in all animals to measure cellularity, BM HPC growth, circulating HPCs, and plasma G-CSF levels. Results Propranolol at 5 and 10 mg/kg significantly reduced HPC mobilization, restored BM cellularity and BM HPC growth, and decreased plasma G-CSF levels. Propranolol at 5 and 10 mg/kg also significantly decreased heart rate. When BB was administered beyond 1 hour after LCHS, its protective effects on cellularity, BM HPC growth, HPC mobilization, and plasma G-CSF levels were greatly diminished. Conclusion Early Buse following injury and shock at a dose of at least 5mg/kg is required to maintain BM cellularity and HPC growth, prevent HPC mobilization, and reduce plasma G-CSF levels. This suggests that propranolol exerts its BM protective effect in a dose and time dependent fashion in a rodent model. Finally, heart rate may be a valuable clinical marker to assess effective dosing of propranolol.

Baranski, Gregg M; Pasupuleti, Latha V; Sifri, Ziad C; Cook, Kristin M; Alzate, Walter D; Rameshwar, Pranela; Livingston, David H; Mohr, Alicia M

2015-01-01

354

Systolic reconstruction in patients with low heart rate using coronary dual-source CT angiography  

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Objectives: The purpose of our study was to determine the relationship between the predictive factors and systolic reconstruction (SR) as an optimal reconstruction window in patients with low heart rate (LHR; less than 65 bpm). Methods: 391 patients (262 male and 129 female, mean age; 67.1 {+-} 10.1 years of age) underwent coronary CTA without the additional administration of a beta-blocker. Affecting factors for SR were analyzed in age, gender, body weight (BW), diabetes mellitus (DM), coronary arterial disease (CAD), ejection fraction (EF), systolic and diastolic body pressure (BP) and heart rate variability (HRV) during coronary CTA. Results: In 29 (7.4%) of the 391 patients, SR was needed, but there was no apparent characteristic difference between the systolic and diastolic reconstruction groups in terms of gender, age, BW, DM, CAD and EF. In a multivariate analysis, the co-existence of DM [P < 0.05; OR, 0.27; 95% CI, 0.092-0.80], diastolic BP [P < 0.01; OR, 0.95; 95% CI, 0.92-0.98] and HRV [P < 0.01; OR, 0.98; 95% CI, 0.96-0.99] were found to be the factors for SR. In gender-related analysis, HRV was an important factor regardless of sex, but co-existence of DM affected especially for female and BP for male. Conclusion: Especially in the patients with LHR who had a medication of DM, high HRV or high BP, SR, in addition to DR, was needed to obtain high-quality coronary CTA images.

Okada, Munemasa, E-mail: radokada@yamaguchi-u.ac.jp [Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505 (Japan); Nakashima, Yoshiteru; Shigemoto, Youko; Matsunaga, Naofumi [Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505 (Japan); Miura, Toshiro; Nao, Tomoko [Department of Cardiology, Yamaguchi University Graduate School of Medicine (Japan); Sano, Yuichi; Narazaki, Akiko [Department of Radiology, Yamaguchi University Hospital (Japan); Kido, Shoji [Computer-aided Diagnosis and Biomedical Imaging Research Biomedical Engineering, Applied Medical Engineering Science Graduate School of Medicine, Yamaguchi University (Japan)

2011-11-15

355

Assessment of the autonomic nervous injury by adriamycin using the analysis of heart rate variability  

International Nuclear Information System (INIS)

Analysis of the heart rate variability were carried out for the cases with malignant tumors of the erythropoietic organ who received adriamycin (ADR), and the effects of ADR on the autonomic nervous of these patients were studied. Seven of 35 cases were examined for the consecutive heart rate variability and 123I-metaiodobenzylguanidine (MIBG) myocardial SPECT, after the administration of ADR. TP value, LF value, LF/HF and SDANN value were 1,448 msec2, 354 msec2, 2.0 and 97 msec, respectively, indicating that these values were significantly lower than the healthy controls (the C group) (P2 to 1,058 msec2, and HF value decreased from 191 msec2 to 123 msec2, significantly (P2, sympathetic nervous injury and parasympathetic nervous was caused by such dose ADR, when examinated by the analysis of the heart rate variability and MIBG myocardial SPECT. It is possible to estimate the myocardial injury of heart autonomic nervous that precedes the injury of heart muscle by ADR, by analyzing the heart rate variability, when the cases with malignant tumors are subject to thwith malignant tumors are subject to the chemotherapy. Thus it was suggested that the death by arrhythmia and the irreversible myocardial injury might be predictable. (author)

356

Effects of pinacidil, verapamil, and heart rate on afterdepolarizations in the guinea-pig heart in vivo.  

Science.gov (United States)

Recently, ionic current simulation in the Luo-Rudy model has elucidated putative mechanisms of afterdepolarizations under various experimental conditions. The present study was aimed at gaining insight into the differential mechanism of different types of afterdepolarizations in the guinea-pig heart in vivo. The effects of pharmacological and heart rate perturbations on early (EADs) and delayed (DADs) afterdepolarizations, induced by either digoxin, CsCl, or BayK 8644 were studied, using mid-myocardial left ventricular monophasic action potential (MAP) recordings. Digoxin insignificantly shortened sinus cycle length (SCL) and CsCl and BayK 8644 differentially prolonged SCL and MAP duration. Digoxin induced phase 3-EADs and DADs and CsCl or BayK 8644 induced phase 2- and phase 3-EADs. Pinacidil shortened MAP duration, suppressed almost all the phase 2-EADs and some of the phase 3-EADs, but not the DADs. In a few cases, DADs were manifested following the abolishment of phase 2-EADs by pinacidil, but this phenomenon did not occur in the presence of hexamethonium. Verapamil prolonged SCL, did not significantly affect phase 2-EADs, but suppressed almost all of the DADs, including those which appeared after pinacidil, and all but one of the phase 3-EADs. The effects of pinacidil and verapamil were independent of the mode of afterdepolarization induction. A pacing-induced heart rate increase, which shortened MAP duration, and vagal stimulation, which prolonged MAP duration, attenuated and enhanced phase 2-EADs, respectively. The amplitude of phase 3-EADs was inversely related to the heart rate. These data, taken together, are consistent with those obtained previously by others in a computer model and recent observations on CsCl-induced EADs in the guinea-pig Purkinje fibers in vitro which have indicated that the mechanism of phase 2-EADs is different from that of DADs and that late phase 3-EADs generated under conditions of Ca2+ overload and DADs share similar properties. PMID:9248848

Xu, J; Zaim, S; Pelleg, A

1996-01-01

357

Prognostic value of ambulatory heart rate revisited in 6928 subjects from 6 populations  

DEFF Research Database (Denmark)

The evidence relating mortality and morbidity to heart rate remains inconsistent. We performed 24-hour ambulatory blood pressure monitoring in 6928 subjects (not on beta-blockers; mean age: 56.2 years; 46.5% women) enrolled in prospective population studies in Denmark, Belgium, Japan, Sweden, Uruguay, and China. We computed standardized hazard ratios for heart rate, while stratifying for cohort, and adjusting for blood pressure and other cardiovascular risk factors. Over 9.6 years (median), 850, 325, and 493 deaths accrued for total, cardiovascular, and noncardiovascular mortality, respectively. The incidence of fatal combined with nonfatal end points was 805, 363, 439, and 324 for cardiovascular, stroke, cardiac, and coronary events, respectively. Twenty-four-hour heart rate predicted total (hazard ratio: 1.15) and noncardiovascular (hazard ratio: 1.18) mortality but not cardiovascular mortality (hazard ratio: 1.11) or any of the fatal combined with nonfatal events (hazard ratio: or =1.15) but none of the fatal combined with nonfatal events (hazard ratio: or =1.15) with the exception of stroke (hazard ratio: 1.06). Sensitivity analyses, in which we stratified by risk factors or from which we excluded 1 cohort at a time or the events occurring within 2 years of enrollment, showed consistent results. In the general population, heart rate predicts total and noncardiovascular mortality. With the exception of the night:day heart rate ratio, heart rate did not add to the risk stratification for fatal combined with nonfatal cardiovascular events. Thus, heart rate adds little to the predictionof cardiovascular risk Udgivelsesdato: 2008/8

Hansen, Tine Willum; Thijs, Lutgarde

2008-01-01

358

What does the correlation dimension of the human heart rate measure?  

CERN Document Server

It is shown that for the heart rate variability, finite values of the correlation dimension D (calculated by the Grassberger-Procaccia algorithm) cannot be considered as an evidence for a deterministic chaos inside the heart. Finiteness of D is explained by finite resolving power of the recording apparatus. The correlation dimension depends both on the short-time variability of the heart rhythm, and on the resolving power of the electrocardiogram. In principle, it can be used as a certain measure of short-time variability of the signal, but its diagnostic value on test groups was negligible.

Sakki, M; Vainu, M; Laan, M

2001-01-01

359

Heart rate increment analysis is not effective for sleep-disordered breathing screening in patients with chronic heart failure.  

Science.gov (United States)

Frequency domain analysis of heart rate variation has been suggested as an effective screening tool for sleep-disordered breathing (SDB) in the general population. The aim of this study was to assess this method in patients with chronic congestive heart failure (CHF). We included prospectively 84 patients with stable CHF, left ventricular ejection fraction (LVEF) or =15 h(-1) was diagnosed in 57.4% of patients. Percent VLFI was not correlated with AHI (r = 0.12). Receiver-operating characteristic curves constructed using various AHI cut-offs (5-30 h(-1)) failed to identify a %VLFI cut-off associated with SDB. The 2.4% VLFI cut-off recommended for the general population of patients with suspected SDB had low specificity (35%) and low positive and negative predictive values (35% and 54%, respectively). Heart rate increment analysis has several limitations in CHF patients and cannot be recommended as an SDB screening tool in the CHF population. PMID:19732315

Damy, Thibaud; D'Ortho, Marie-Pia; Estrugo, Brigitte; Margarit, Laurent; Mouillet, Gauthier; Mahfoud, Mohannad; Roudot-Thoraval, Francoise; Vermes, Emmanuelle; Hittinger, Luc; Roche, Frederic; Macquin-Mavier, Isabelle

2010-03-01

360

Considerations in the assessment of heart rate variability in biobehavioral research  

OpenAIRE

Heart rate variability (HRV) refers to various methods of assessing the beat-to-beat variation in the heart over time, in order to draw inference on the outflow of the autonomic nervous system. Easy access to measuring HRV has led to a plethora of studies within emotion science and psychology assessing autonomic regulation, but significant caveats exist due to the complicated nature of HRV. Firstly, both breathing and blood pressure regulation have their own relationship to social, emotional ...

DanielSQuintana; JamesA JHeathers

2014-01-01

361

Frequency dependent effect of selective biphasic left vagus nerve stimulation on heart rate and arterial pressure  

OpenAIRE

Activation of the parasympathetic pathway leads to negative chronotropic, dromotropic, and inotropic changes of heart function. The ability to selectively stimulate certain superficial compartments of peripheral nerves has been demonstrated previously. The aim of the present study was to find a clinically acceptable selective biphasic vagus nerve stimulation technique, which could allow gradual regulation of heart rate and systemic arterial pressure. In two patients, the left vagus nerve was...

MATEJ PODBREGAR; IVAN RADAN; TOMISLAV MIRKOVIC; IVAN KNEŽEVI?; BORUT GERŠAK; JANEZ ROZMAN

2012-01-01

362

Resting Sinus Heart Rate and First Degree AV block: Modifiable Risk Predictors or Epiphenomena?  

OpenAIRE

Simple and cost-effective tools that identify patients at increased risk for adverse cardiovascular events are actively sought. High resting sinus heart rate and first degree AV block are easily recognized and commonly encountered findings in a cardiology practice. A growing body of epidemiological and clinical evidence has been shown them to be independent predictors of all-cause and cardiovascular mortality, both in the general population and in patients with structural heart disease. This ...

Rakesh Gopinathannair; Brian Olshansky

2009-01-01

363

Normal relation between heart rate and cardiac repolarisation in sudden infant death syndrome.  

OpenAIRE

OBJECTIVE--To determine whether there was a difference in the relation between heart rate and RT intervals in infants who later died of sudden infant death syndrome (SIDS) and controls. DESIGN--A blinded, computer analysis of prospectively acquired physiological data on SIDS cases and controls. SETTING--Physiological data obtained from infants at home (collaborative analysis National Heart and Lung Institute and Exeter University). PARTICIPANTS--Nine fullterm infants who subsequently died of ...

Wynn, V. T.; Southall, D. P.

1992-01-01

364

LF/(LF+HF) index in ventricular repolarization variability correlated and uncorrelated with heart rate variability.  

OpenAIRE

The purpose of this study, was to asses whether LF/(LF+HF) obtained from ventricular repolarization variability (VRV) reflects the state of sympathovagal balance. The VRV time series and heart rate variability (HRV) time series from seventy two electrocardiogram (ECG) records in four different autonomic nervous system (ANS) profiles (athletes, cardiac transplant patient, heart failure patients and normal subjects) were extracted. A dynamic linear parametric model was applied to separate the V...

Altuve, Miguel; Wong, Sara; Passariello, Gianfranco; Carrault, Guy; Herna?ndez, Alfredo

2006-01-01

365

Prolonged QT interval and reduced heart rate variability in patients with uncomplicated essential hypertension  

OpenAIRE

A prolonged QT interval is a risk factor for ischemic heart disease in hypertensive subjects. Heart rate variability (HRV) is both an index of autonomic function and an important prognostic factor in several diseases. The aim of the present study was to evaluate the relation between a prolonged QT interval and autonomic nervous system function in patients with untreated uncomplicated essential hypertension. Two hundred and fifteen untreated patients with essential hypertension underwent a Hol...

Veglio, Franco; Mulatero, Paolo

2008-01-01

366

Effects and after-effects of chewing gum on vigilance, heart rate, EEG and mood.  

Science.gov (United States)

Research has shown that chewing gum improves attention, although the mechanism for this effect remains unclear. This study investigated the effects and after-effects of chewing gum on vigilance, mood, heart rate and EEG. Participants completed a vigilance task four times; at baseline, with or without chewing gum, and twice post-chewing. EEG alpha and beta power at left frontal and temporal lobes, subjective mood and heart rate were assessed. Chewing gum shortened reaction time and increased the rate of hits, although hits fell during the second post-chewing task. Chewing gum heightened heart rate, but only during chewing. Gum also increased beta power at F7 and T3 immediately post-chewing, but not following the post-chewing tasks. The findings show that chewing gum affects several different indicators of alertness. PMID:24857722

Allen, Andrew P; Jacob, Tim J C; Smith, Andrew P

2014-06-22

367

HEART RATE RECOVERY AFTER EXERCISE AND NEURAL REGULATION OF HEART RATE VARIABILITY IN 30-40 YEAR OLD FEMALE MARATHON RUNNERS  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of the present study was to examine the effects of endurance training on heart rate (HR recovery after exercise and cardiac autonomic nervous system (ANS modulation in female marathon runners by comparing with untrained controls. Six female marathon runners (M group aged 32-40 years and eight age-matched untrained females (C group performed a maximum-effort treadmill running exercise. Maximal oxygen uptake (VO2max was measured during the exercise with a gas analyzer connected to subjects through a face mask. Heart rate, blood pressure and blood lactate were measured before and after the exercise. Rating of perceived exertion (RPE to the exercise was obtained immediately after the exercise. Holter ECG was recorded and analyzed with power spectral analysis of heart rate variability (HRV to investigate the cardiac ANS modulation. The M group had significantly higher VO2max, faster HR recovery after exercise, higher Mean RR, SDRR, HF power and lower LF/HF ratio at rest compared with the C group. The M group also presented greater percent decrease of blood pressure after exercise, although their blood pressure after exercise was higher than the C group. It is suggested that endurance training induced significant alterations in cardiac ANS modulation at rest and significant acceleration of HR recovery after exercise in female marathon runners. Faster HR recovery after exercise in the female marathon runners should result from their higher levels of HRV, higher aerobic capacity and exaggerated blood pressure response to exercise compared with untrained controls.

Toshio Matsuoka

2005-03-01

368

Ultrasound-induced heart rate decrease: role of the vagus nerve.  

Science.gov (United States)

The goal of this study is to investigate the role of the vagus nerve (VN) in the ultrasound (US)-induced negative chronotropic effect (deceased heart rate). One of the functions of the VN is to mediate lowering of the heart rate. A previous study showed a decrease of ~20% in the heart rate but the mechanism of the effect was not investigated. Sprague Dawley rats (n = 20) were exposed transthoracically to ultrasonic pulses at an approximate duty factor of 1% with sequentially 2.0, 2.5, and 3.0 MPa peak rarefactional pressure amplitudes (PRPAs). The ultrasonic exposure parameters herein were chosen to match those of the previous study to have confidence that an ultrasound-induced negative chronotropic effect would occur. For each of the three PRPA sequences, the pulse repetition frequency (PRF) started slightly greater than the rat's heart rate and then was decreased sequentially in 1-Hz steps every 10 s (i.e., 6, 5, and 4 Hz for a total duration of 30 s). The experiments were organized in a standard (2 × 2) factorial design with VN (cut versus intact) as one factor and US (on versus off) as another factor. VN (intact/cut) and US (on/off) groups were divided into four groups each consisting of 5 animals: 1) VN intact-US off, 2) VN intact-US on, 3) VN cut-US off, and 4) VN cut-US on. Two-way analysis of variance for repeated measures was used to compare heart rate, cardiac output, systolic volume, ejection fraction, end-diastolic volume, end-systolic volume, respiratory rate, and arterial pressure before and after ultrasound stimulation. In this study, the heart rate decreased ~4% for the non-vagotomy and vagotomy groups. The ultrasound effect was significant for heart rate (p = 0.02) and cardiac output (p = 0.005) at 3 min post US exposure; the vagotomy effect was not significant. For heart rate, the Bonferroni test showed no differences between the four groups. The vagotomy group showed similar ultrasound-induced cardiac effects compared with the non-vagotomy group, suggesting that the vagus nerve is not influenced by the ultrasound exposure procedures. The US application caused a negative chronotropic effect of the rat heart without affecting the hemodynamic conditions. The results at this point are suggestive for an alternative cardiac pacing capability. PMID:25643082

Coiado, Olivia; Buiochi, Elaine; O'brien, William

2015-02-01

369

Evaluation of three-dimensional navigator-gated whole heart MR coronary angiography: The importance of systolic imaging in subjects with high heart rates  

International Nuclear Information System (INIS)

Purpose: To evaluate the influence of heart rate (HR) on magnetic resonance coronary angiography (MRCA) image quality in diastolic and systolic phases. Materials and methods: Twenty-seven healthy volunteers (9 men; 33 ± 9 years, HR 53-110 bpm), were evaluated with the electrocardiography and three-dimensional navigator-gating MRCA in a 1.5-T MR scanner (Avanto, Siemens) in diastolic and systolic phases (steady-state free precession; TR/TE/flip angle = 3.2 ms/1.6 ms/90o). The timing of scanning was individually adapted to the cardiac rest periods obtained in the prescanning, by visually identifying when the movement of right coronary artery was minimized during diastole and systole. Images of two phases were side-by-side compared on a four-point scale (from 1 = poor to 4 = excellent visibility; score of 3 or 4 as diagnostic). Results: Of 13 subjects with HR ?65 bpm (low HR group, mean 59.8 ± 4.9 bpm, range 53-65), the image quality scores were significantly better than that with higher heart rates (73.9 ± 9.0 bpm, range 68-110) in diastolic MRCA. The image quality was significantly improved during systole in high HR group. Overall, 91.3% of low HR group had MRCA image of diagnostic quality acquired at diastole, while 88.3% of high HR group had diagnostic images at systole by segmental analysis (p = NS). Conclusions: MRCA at systole offered superior quality in patients with high heart rates

370

Effect of Supervised Integrated Exercise on Deep Breathing- Heart Rate Variability in Male Hypertensive Patients  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of the study was to evaluate if prolonged supervised integrated exercise in male hypertensive patients reverses the deterioration of heart rate variability. Sixty six male hypertensive patients were divided into exercise (n = 30 and non-exercise groups (n = 36. Exercise group patients underwent a supervised integrated exercise program for one-year. Time domain analysis of heart rate variability was performed from electrocardiogram during deep breathing. Heart rate variability decreased significantly (p<0.001 in hypertensive patients. HRV increased significantly after six months (p<0.001 and 12 months (p<0.01 of integrated exercise training. There was a significant decrease in blood pressure (p<0.001 in exercised hypertensive patients after 12 months compared to non-exercised group. Heart rate variability was significantly decreased (p<0.001 than normotensives after one-year in the non-exercised hypertensive patients. Long term supervised integrated exercise increased deep breathing heart rate variability and decreased blood pressure in the hypertensive patients. This suggested that integrated exercise program was able to reverse the autonomic dysregulation seen in hypertensive patients.

M. Niranjan

2008-01-01

371

Stochastic analysis of heart rate variability and its relation to echocardiography parameters in hypertrophic cardiomyopathy patients  

International Nuclear Information System (INIS)

The heart rate variability of 10 healthy males (age 26 ? 4/+ 3 y) and 49 patients with hypertrophic cardiomyopathy (HCM) (25 males, 24 females, age 29.5 ? 11.5/+ 10.5 y) was studied. We applied Kramers–Moyal expansion to extract the drift and diffusion terms of the Langevin equation for the RR interval time series. These terms may be used for a stochastic reconstruction of the time series and for description of the properties of heart rate variability. New parameters characterizing the diffusion term are proposed: the coefficients of the linear fit to the left (LCF) and right (RCF) branch of the dependence of the diffusion term on the rescaled heart rate. Relations of the new parameters to classical echocardiography parameters were studied. Using the relation between the difference LCF–RCF and the left ventricular systolic diameter, the HCM patients studied were divided into three groups. In addition, comparison of the properties of the heart rate variability in the HCM group with that obtained for the healthy young men showed that the parameter LCF–RCF may be treated as a measure of the effect of HCM on heart rate variability and may have diagnostic value

372

The relationships between exercise intensity, heart rate, and blood pressure during an incremental isometric exercise test.  

Science.gov (United States)

Currently, it is not possible to prescribe isometric exercise at an intensity that corresponds to given heart rates or systolic blood pressures. This might be useful in optimizing the effects of isometric exercise training. Therefore, the aim of this study was to explore the relationships between isometric exercise intensity and both heart rate and systolic blood pressure during repeated incremental isometric exercise tests. Fifteen participants performed seated isometric double-leg knee extension, during which maximum voluntary contraction (MVC) was assessed, using an isokinetic dynamometer. From this, a corresponding peak electromyographic activity (EMG(peak)) was determined. Subsequently, participants performed two incremental isometric exercise tests (at least 48 h apart) at 10, 15, 20, 25, and 30% EMG(peak), during which steady-state heart rate and systolic blood pressure were recorded. In all participants, there were linear relationships between %EMG(peak) and heart rate (r at least 0.91; P 0.50) or elevations (P > 0.10) for either of the relationships. Therefore, these linear relationships could be used to identify isometric exercise training intensities that correspond to precise heart rates or systolic blood pressures. Training performed in this way might provide greater insight into the underlying mechanisms for the cardiovascular adaptations that are known to occur as a result. PMID:17852666

Wiles, Jonathan D; Allum, Simon R; Coleman, Damian A; Swaine, Ian L

2008-01-15

373

Acoustic features of prairie vole (Microtus ochrogaster) ultrasonic vocalizations covary with heart rate.  

Science.gov (United States)

Vocalizations serve as a conspecific social communication system among mammals. Modulation of acoustic features embedded within vocalizations is used by several mammalian species to signal whether it is safe or dangerous to approach conspecific and heterospecific mammals. As described by the Polyvagal Theory, the phylogenetic shift in the evolution of mammals involved an adaptive neuroanatomical link between the neural circuits regulating heart rate and the muscles involved in modulating the acoustic features of vocalizations. However, few studies have investigated the covariation between heart rate and the acoustic features of vocalizations. In the current study, we document that specific features of vocalizations covary with heart rate in a highly social and vocal mammal, the prairie vole (Microtus ochrogaster). Findings with the prairie vole illustrate that higher pitch (i.e., fundamental frequency) and less variability in acoustic features of vocalizations (i.e., less vocal prosody) are associated with elevated heart rate. The study provides the first documentation that the acoustic features of prairie vole vocalizations may function as a surrogate index of heart rate. PMID:25447483

Stewart, Adam Michael; Lewis, Gregory F; Yee, Jason R; Kenkel, William M; Davila, Maria I; Sue Carter, C; Porges, Stephen W

2015-01-01

374

Field test of a paradigm: hysteresis of heart rate in thermoregulation by a free-ranging lizard (Pogona barbata).  

Science.gov (United States)

The discovery that changes in heart rate and blood flow allow some reptiles to heat faster than they cool has become a central paradigm in our understanding of reptilian thermoregulation. However, this hysteresis in heart rate has been demonstrated only in simplistic laboratory heating and cooling trials, leaving its functional significance in free-ranging animals unproven. To test the validity of this paradigm, we measured heart rate and body temperature (Tb) in undisturbed, free-ranging bearded dragons (Pogona barbata), the species in which this phenomenon was first described. Our field data confirmed the paradigm and we found that heart rate during heating usually exceeded heart rate during cooling at any Tb. Importantly, however, we discovered that heart rate was proportionally faster in cool lizards whose Tb was still well below the 'preferred Tb range' compared to lizards whose Tb was already close to it. Similarly, heart rate during cooling was proportionally slower the warmer the lizard and the greater its cooling potential compared to lizards whose Tb was already near minimum operative temperature. Further, we predicted that, if heart rate hysteresis has functional significance, a 'reverse hysteresis' pattern should be observable when lizards risked overheating. This was indeed the case and, during heating on those occasions when Tb reached very high levels (> 40 degrees C), heart rate was significantly lower than heart rate during the immediately following cooling phase. These results demonstrate that physiological control of thermoregulation in reptiles is more complex than has been previously recognized. PMID:10418165

Grigg, G C; Seebacher, F

1999-06-22

375

Power Spectral Analysis of Heart Rate Variability in Female Rheumatoid Arthritis Patients  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Association of increased cardiovascular morbidity and higher sympathetic activity in patients with Rheumatoid arthritis (RA has been recognized. Heart rate variability (HRV is a useful measure to assess sympatho-vagal balance.Objective: To assess autonomic nerve function status in patients with Rheumatoid Arthritis (RA by HRV analysis.Methods: This cross sectional study was conducted in the Department of Physiology, Bangabandhu Sheikh Mujib Medical University (BSMMU, Shahbag, Dhaka from January to December 2010. Sixty female RA patients aged 18-50 years were included in the study group. They were enrolled from the Out Patient Department of Rheumatology Wing of the Department of Medicine, BSMMU, Dhaka. For comparison age matched thirty apparently healthy females were also studied as control. The HRV parameters were recorded by a Polyrite machine. For statistical analysis independent sample t test was used.Results: Mean resting pulse rate, diastolic blood pressure and mean systolic blood pressure were higher in rheumatoid arthritis patients in comparison to those of healthy control. Mean values of LF power, LF norm and LF/ HF were significantly higher (p<0.001 & TP and HF power, HF norm were significantly lower (p<0.001 in RA patients in comparison to those of healthy control.Conclusion: This study may conclude that sympathetic activity was higher with lower parasympathetic activity along with shifting of sympathovagal balance towards sympathetic predominance in patients with rheumatoid arthritis.

Kawser Jahan

2012-06-01

376

Local scale exponents of blood pressure and heart rate variability by detrended fluctuation analysis: effects of posture, exercise, and aging.  

Science.gov (United States)

Heart rate self-affinity is often assessed by detrended fluctuations analysis, obtaining two coefficients only: a short-term (alpha(1)) exponent and a long-term (alpha(2)) exponent. Our aim is to show the limits of this approach and alternatively propose the estimation of the whole spectrum of local exponents alpha(n) for heart rate and blood pressure. To illustrate the advantages of this approach, we assess the effects of autonomic activations and age on alpha(n). We measured ECG and arterial pressure in 60 volunteers for 10 min, considering three conditions at increasing sympathetic activation: supine rest, sitting, and sitting during exercise. We computed alpha(n) of R-R intervals and systolic, mean, and diastolic blood pressures, as the slope of the detrended fluctuations function in a log-log plot. Volunteers were divided into age groups and compared. Results indicate that: 1) alpha(1) cannot be defined because short-term coefficients decrease with n, while alpha(2) cannot be defined only for blood pressure during supine rest; 2) heart rate and blood pressure scaling structures differ during supine rest but not during exercise; and 3) age effects appear mainly in supine rest, explaining discrepant results in literature. In conclusion, we recommend estimating the whole alpha(n) spectrum before possibly providing the "two-exponent" description only. PMID:19389684

Castiglioni, Paolo; Parati, Gianfranco; Civijian, Andrei; Quintin, Luc; Di Rienzo, Marco

2009-03-01

377

Effect of amlodipine and of nifedipine retard on autonomic regulation of heart rate in elderly patients with arterial hypertension  

Directory of Open Access Journals (Sweden)

Full Text Available Aim. To study the effect of the monotherapy with calcium channel blockers (amlodipine, 5 mg/d and nifedipine retard, 40 mg/d on heart rate variability (HRV in elderly hypertensive patients with different rate of biological ageing.Material and methods. 55 male hypertensive patients of 60-86 years with ischemic heart disease and chronic heart failure, class I-III (NYHA, were examined. Biological age was determined by the linear regression. HRVwas determined by cardiointervalography and variation pulsemetry at the rest and in orthostatic test. Patientswere split in to 2 groups (I - normal; II - fast ageing rate and treated with the investigated drugs for 4 weeks. At the baseline and at the end of the study HRV and clinical blood pressure (BP were determined.Results. Normal sympathetic activity and moderate overactivity was observed in patients of I group, and prominent sympathetic overactivity - in patients of II group. Monotherapywith amlodipine in patients of I and II groups improved indices of HRV (variation range, dispersion and stress index and provided target BP reduction.Monotherapywith nifedipine retard in patients of I group elevated variation range, decreased stress index and provided target BP reduction. Sympathetic activity was not changed in patients of the II group. Autonomic regulation was normalized due to amlodipine and nifedipine retard therapy in patients of the both groups.Conclusion. The sympathetic overactivity is observed in elderly hypertensive patients. Monotherapy with calcium blockers improves HRV and provides target BP reduction.

E.D. Golovanova

2008-01-01

378

HEART RATE RECOVERY AFTER EXERCISE AND NEURAL REGULATION OF HEART RATE VARIABILITY IN 30-40 YEAR OLD FEMALE MARATHON RUNNERS  

OpenAIRE

The aim of the present study was to examine the effects of endurance training on heart rate (HR) recovery after exercise and cardiac autonomic nervous system (ANS) modulation in female marathon runners by comparing with untrained controls. Six female marathon runners (M group) aged 32-40 years and eight age-matched untrained females (C group) performed a maximum-effort treadmill running exercise. Maximal oxygen uptake (VO2max) was measured during the exercise with a gas analyzer connected to ...

Toshio Matsuoka; Harumi Kawase; Ichie Matsumoto; Yoshihiro Kato; Kazuo Oguri; Siqin Bai; Na Du

2005-01-01

379

Low doses of caffeine reduce heart rate during submaximal cycle ergometry  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The purpose of this study was to examine the cardiovascular effects of two low-levels of caffeine ingestion in non habitual caffeine users at various submaximal and maximal exercise intensities. Methods Nine male subjects (19–25 yr; 83.3 ± 3.1 kg; 184 ± 2 cm, underwent three testing sessions administered in a randomized and double-blind fashion. During each session, subjects were provided 4 oz of water and a gelatin capsule containing a placebo, 1.5 mg/kg caffeine, or 3.0 mg/kg caffeine. After thirty minutes of rest, a warm-up (30 Watts for 2 min the pedal rate of 60 rpm was maintained at a steady-state output of 60 watts for five minutes; increased to 120 watts for five minutes and to 180 watts for five minutes. After a 2 min rest the workload was 180 watts for one minute and increased by 30 watts every minute until exhaustion. Heart rate (HR was measured during the last 15-seconds of each minute of submaximal exercise. Systolic blood pressure (BP was measured at rest and during each of the three sub-maximal steady state power outputs. Minute ventilation (VE, Tidal volume (VT, Breathing frequency (Bf, Rating of perceived exertion (RPE, Respiratory exchange ratio (RER, and Oxygen consumption (VO2 were measured at rest and during each minute of exercise. Results Caffeine at 1.5 and 3.0 mg/kg body weight significantly lowered (p E, VT, VO2, RPE, maximal power output or time to exhaustion. Conclusion In non habitual caffeine users it appears that consuming a caffeine pill (1.5 & 3.0 mg/kg at a dose comparable to 1–3 cups of coffee lowers heart rate during submaximal exercise but not at near maximal and maximal exercise. In addition, this caffeine dose also only appears to affect systolic blood pressure at rest but not during cycling exercise.

Wetter Thomas J

2007-10-01

380

Effect of heart rate and myocardial contractile force on coronary resistance.  

Directory of Open Access Journals (Sweden)

Full Text Available The effect of the heart rate and myocardial contractile force on the extravascular resistance to blood flow of the left anterior descending coronary artery (LAD was evaluated in 15 mongrel dogs anesthetized with sodium pentobarbital. The LAD was maximally dilated by intracoronary infusion of adenosine, which precluded the influence of vasomotor tone. Increases in the heart rate and myocardial contractile force decreased coronary blood flow in the absence of a change in coronary perfusion pressure. The changes in mean coronary resistance showed a significant linear relationship to changes in developed tension. The changes in coronary resistance caused by varying the heart rate and contractile force were so small that a normal coronary vascular tree could easily compensate for the increase in resistance. However, it is supposed that with critical stenosis of the vascular tree even a small increase in resistance might cause deleterious effects on coronary blood flow.

Saito,Daiji

1988-12-01

381

L-arginine increases nitric oxide and attenuates pressor and heart rate responses to change in posture in sickle cell anemia subjects.  

Science.gov (United States)

Pressor and heart rate changes following change in posture without or with L-arginine supplementation (1g/day for 6 weeks) were studied in 28 sickle cell anemia (SCA) and 32 non-sickle cell anemia (NSCA) subjects. Change in posture increased HR (pRPP (pRPP responses in SCAS were attenuated, the same responses were enhanced in NSCAS by change in posture after supplementation. In conclusion, study shows that oral, low dose, chronic supplementation with L-arginine increased NO availability and attenuated pressor and heart rate responses to change in posture in sickle cell anemia subjects. PMID:23955406

Ogungbemi, S I; Anigbogu, C N; Kehinde, M O; Jaja, S I

2013-01-01

382

Variability of the human heart rate as a diagnostic instrument obtained by mean of a wireless monitor  

Science.gov (United States)

Introduction: Heart rate variability (HRV) is the cyclic measurement of RR intervals between normal beats. Aim: To determine the VFC via a wireless Polar monitor. Material and methods: 100 symptomatic menopausal women were studied for measurements of HRV were I post a Polar RS400 Watch four hrs. Results: Obtained through the fast Fourier transform, the frequency domain HRV low frequency (LF) 0.04-0.15 Hz, high frequency (HF) 0.15-0.4Hz and the ratio LF / HF. Conclusion: obtaining HRV is important for cardiovascular autonomic assessment in menopausal women.

Barajas Mauricio, Sánchez; Hernández González, Martha Alicia; Figueroa Vega, Nicte; Malacara Hernández, Juan Manuel; Fraga Teodoro, Córdova

2014-11-01

383

Heart Rate Variability Classification and Feature Extraction Using Support Vector Machine and PCA: An Overview  

Directory of Open Access Journals (Sweden)

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

Rahul Pitale

2014-01-01

384

Effect of partial sports massage on blood pressure and heart rate  

OpenAIRE

With the growing popularity and demand for different types of massages (including sports) is a growing need for research on specific forms. There is also a need to study the advantages and effects on various body functions. The objective was to study the effect of partial sports massage on blood pressure and heart rate in both men and women. Material and methods. Research has been extended 80 healthy men and women are physically active (age 20-25 years). Blood pressure and heart rate were mad...

Pystupa T.D.

2013-01-01

385

Heart rate variability in athletes and nonathletes at rest and during head-up tilt  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The purpose of the present study was to determine if autonomic heart rate modulation, indicated by heart rate variability (HRV), differs during supine rest and head-up tilt (HUT) when sedentary and endurance-trained cyclists are compared. Eleven sedentary young men (S) and 10 trained cyclists (C) we [...] re studied. The volunteers were submitted to a dynamic ECG Holter to calculate HRV at rest and during a 70º HUT. The major aerobic capacity of athletes was expressed by higher values of at anaerobic threshold and peak conditions (P

F.S., Martinelli; M.P.T., Chacon-Mikahil; L.E.B., Martins; E.C., Lima-Filho; R., Golfetti; M.A., Paschoal; L., Gallo-Junior.

2005-04-01

386

Heritability and linkage study on heart rates in a Mongolian population  

OpenAIRE

Elevated heart rate has been proposed as an independent risk factor for cardiovascular diseases, but their interrelationships are not well understood. In this study, we performed a genome-wide linkage scan in 1,026 individuals (mean age 30.6 years, 54.5% women) from 73 extended families of Mongolia and determined quantitative trait loci that influence heart rate. The DNA samples were genotyped using deCODE 1,039 microsatellite markers for 3 cM density genome-wide linkage scan. Correlation ana...

Gombojav, Bayasgalan; Park, Hansoo; Kim, Jong-il; Ju, Young Seok; Sung, Joohon; Cho, Sung-il; Lee, Mi-kyeong; Ohrr, Heechoul; Radnaabazar, Janchiv; Seo, Jeong-sun

2008-01-01

387

Normal values of heart rate variability at rest in a young, healthy and active Mexican population  

OpenAIRE

This study analyzed Heart Rate Variability in a large sample of active young subjects within a narrow age range (18 to 25), using time and frequency domain methods and a Poincaré plot. Heart rate was recorded (beat to beat) for 30 minutes at rest in 200 healthy subjects divided into 4 groups: 50 sportsmen (20.54 ± 1.52 years); 50 active men (21.22 ± 1.31 years); 50 sportswomen (20.10 ± 1.87 years) and 50 active women (20.92 ± 1.87 years). Significant differences were found for most param...

Marco Antonio Garrido Salazar; Alberto Garrido Esquivel; Blanca de la Cruz Torres; Marina Medina Corrales; José Naranjo Orellana

2012-01-01

388

Correlated and Uncorrelated Regions in Heart-Rate Fluctuations during Sleep  

Science.gov (United States)

Healthy sleep consists of several stages: deep sleep, light sleep, and rapid eye movement (REM) sleep. Here we show that these sleep stages can be characterized and distinguished by correlations of heart rates separated by n beats. Using the detrended fluctuation analysis (DFA) up to fourth order we find that long-range correlations reminiscent to the wake phase are present only in the REM phase. In the non-REM phases, the heart rates are uncorrelated above the typical breathing cycle time, pointing to a random regulation of the heartbeat during non-REM sleep.

Bunde, Armin; Havlin, Shlomo; Kantelhardt, Jan W.; Penzel, Thomas; Peter, Jörg-Hermann; Voigt, Karlheinz

2000-10-01

389

Changes in heart rate variability (HRV) in field hockey players during the 2006 World Cup  

OpenAIRE

The aim of this study is to determine the changes in heart rate variability (HRV) in field hockey players during the course of a world championship. The Spanish national team took part in the study by making daily records of the R-R interval (Omegawave System) on the days when matches took place. The baseline heart rate (HR) and several parameters of HRV were measured. The evolution of the average values of the HR and the various parameters of HRV during the 7 matches was compared using a...

Rodas Font, Gil; Yanguas Leyes, Javier; Pedret, Carles; Ramos Castro, Juan Jose?; Capdevila, L.

2011-01-01

390

Monitoring the fetal heart rate variations by means of time-variant multivariate analysis.  

Science.gov (United States)

The analysis of the fetal heart rate (fHR) is important in detecting the fetal distress related with hypoxic episodes, noticed sometimes during the uterine activity, which can severely affect the fetus. Occasional synchrony between the fHR and the maternal heart rate (mHR) was reported and the mHR shows some variations during pregnancy and labor, especially when the contractions are very strong. The current study proposes a new strategy to investigate the relations between the fHR, the mHR and the uterine activity, by applying the time-variant Partial Directed Coherence (tvPDC). PMID:24110701

Ungureanu, G Mihaela; Taralunga, Dragos D; Gussi, Ilinca; Wolf, Werner; Piper, Diana; Strungaru, Rodica

2013-01-01

391

Parametric study of antennas for long range Doppler radar heart rate detection.  

Science.gov (United States)

This research presents results obtained from long range measurements of physiological motion pertaining to human cardiac and respiration activity. A pulse pressure sensor was used as reference to verify the results from radar signals. A motion detection and grading algorithm was used to detect the presence of heart rate. In addition to showing that human heart rate and respiration can be measured at distances of 21 and 69 meters respectively, the effect of antenna size, radiation pattern and gain on the range of the radar has also been studied. PMID:23366747

Baboli, Mehran; Singh, Aditya; Hafner, Noah; Lubecke, Victor

2012-01-01

392

Heart rate variability of young table tennis players with the use of the multiball training  

OpenAIRE

The purpose of this study was to evaluate the heart rate responses of the 2 multiball table tennis interval training protocols during the competitive period on young table tennis players. Fourteen (n=14) players, aged 12±2yrs participated in this study. participants were randomly divided into 2 training duration groups (15s vs. 30s) and were trained under the 2 interval protocols for 6 weeks (3 sessions. w-1). heart rate (hr) data was electronically recorded by using the Polar Team System at...

MICHAIL KATSIKADELIS; THEOPHILOS PILIANIDIS; NIKOLAOS MANTZOURANIS; IOANNIS FATOUROS; NIKOLAOS AGELOUSIS

2014-01-01

393

Evaluation of therapy for dilated cardiomyopathy with heart failure by iodine-123 metaiodobenzyl-guanidine imaging. Comparison with heart rate variability power spectral analysis  

International Nuclear Information System (INIS)

The relationship between the myocardial uptake of iodine-123 metaiodobenzylguanidine (123I-MIBG) and heart rate variability parameters has not been determined. This study determined the relationship between the change in myocardial uptake of 123I-MIBG and improvement in left ventricular function after treatment, to determine the usefulness of 123I-MIBG imaging to assess the effect of therapy on heart failure due to dilated cardiomyopathy (DCM). 123I-MIBG imaging and power spectral analysis of heart rate variability were performed before and after treatment in 17 patients with heart failure due to DCM. The following parameters were compared before and after treatment: New York Heart Association (NYHA) functional class, radiographic cardiothoracic ratio (CTR), blood pressure, echocardiographic data (left ventricular end-systolic (LVDs) and end-diastolic (LVDd) diameters, left ventricular ejection fraction (LVEF)), plasma concentrations of norepinephrine and epinephrine, heart rate variability power spectral analysis data (mean low frequency (MLF) and high frequency power (MHF)) and the myocardium to mediastinum activity ratio (MYO/M) obtained in early and late images, and washout rate calculated by anterior planar imaging of 123I-MIBG. The NYHA functional class, LVEF, LVDs, CTR, MLF and MHF improved after treatment. Early MYO/M and late MYO/M improved after treatment. The rate of increase in late MYO/M was positivelte of increase in late MYO/M was positively correlated with the rate of improvement of LVEF after treatment. Furthermore, the late MYO/M was negatively correlated with MLF. Washout rate revealed no correlation with hemodynamic parameters. These findings suggest that late MYO/M is more useful than washout rate to assess the effect of treatment on heart failure due to DCM. Furthermore, the 123I-MIBG imaging and heart rate variability parameters are useful to assess the autonomic tone in DCM with heart failure. (author)

394

Evaluation of therapy for dilated cardiomyopathy with heart failure by iodine-123 metaiodobenzyl-guanidine imaging. Comparison with heart rate variability power spectral analysis  

Energy Technology Data Exchange (ETDEWEB)

The relationship between the myocardial uptake of iodine-123 metaiodobenzylguanidine ({sup 123}I-MIBG) and heart rate variability parameters has not been determined. This study determined the relationship between the change in myocardial uptake of {sup 123}I-MIBG and improvement in left ventricular function after treatment, to determine the usefulness of {sup 123}I-MIBG imaging to assess the effect of therapy on heart failure due to dilated cardiomyopathy (DCM). {sup 123}I-MIBG imaging and power spectral analysis of heart rate variability were performed before and after treatment in 17 patients with heart failure due to DCM. The following parameters were compared before and after treatment: New York Heart Association (NYHA) functional class, radiographic cardiothoracic ratio (CTR), blood pressure, echocardiographic data (left ventricular end-systolic (LVDs) and end-diastolic (LVDd) diameters, left ventricular ejection fraction (LVEF)), plasma concentrations of norepinephrine and epinephrine, heart rate variability power spectral analysis data (mean low frequency (MLF) and high frequency power (MHF)) and the myocardium to mediastinum activity ratio (MYO/M) obtained in early and late images, and washout rate calculated by anterior planar imaging of {sup 123}I-MIBG. The NYHA functional class, LVEF, LVDs, CTR, MLF and MHF improved after treatment. Early MYO/M and late MYO/M improved after treatment. The rate of increase in late MYO/M was positively correlated with the rate of improvement of LVEF after treatment. Furthermore, the late MYO/M was negatively correlated with MLF. Washout rate revealed no correlation with hemodynamic parameters. These findings suggest that late MYO/M is more useful than washout rate to assess the effect of treatment on heart failure due to DCM. Furthermore, the {sup 123}I-MIBG imaging and heart rate variability parameters are useful to assess the autonomic tone in DCM with heart failure. (author)

Li, Shou-lin; Ikeda, Jun; Takita, Tamotsu; Sekiguchi, Yohei; Demachi, Jun; Chikama, Hisao; Goto, Atsushi; Shirato, Kunio [Tohoku Univ., Sendai (Japan). School of Medicine

1998-11-01

395

Heart rate variability in healthy subjects: effect of age and the derivation of normal ranges for tests of autonomic function.  

OpenAIRE

The diagnosis of autonomic neuropathy frequently depends on results of tests which elicit reflex changes in heart rate. Few well-documented normal ranges are available for these tests. The present study was designed to investigate the effect of age upon heart rate variability at rest and in response to a single deep breath, the Valsalva manoeuvre, and standing. A computerised method of measurement of R-R interval variation was used to study heart rate responses in 310 healthy subjects aged 18...

O Brien, I. A.; O Hare, P.; Corrall, R. J.

1986-01-01

396

Field test of a paradigm: hysteresis of heart rate in thermoregulation by a free-ranging lizard (Pogona barbata).  

OpenAIRE

The discovery that changes in heart rate and blood flow allow some reptiles to heat faster than they cool has become a central paradigm in our understanding of reptilian thermoregulation. However, this hysteresis in heart rate has been demonstrated only in simplistic laboratory heating and cooling trials, leaving its functional significance in free-ranging animals unproven. To test the validity of this paradigm, we measured heart rate and body temperature (Tb) in undisturbed, free-ranging bea...

Grigg, G. C.; Seebacher, F.

1999-01-01

397

E-bra with nanosensors, smart electronics and smart phone communication network for heart rate monitoring  

Science.gov (United States)

Heart related ailments have been a major cause for deaths in both men and women in United States. Since 1985, more women than men have died due to cardiac or cardiovascular ailments for reasons that are not well understood as yet. Lack of a deterministic understanding of this phenomenon makes continuous real time monitoring of cardiovascular health the best approach for both early detection of pathophysiological changes and events indicative of chronic cardiovascular diseases in women. This approach requires sensor systems to be seamlessly mounted on day to day clothing for women. With this application in focus, this paper describes a e-bra platform for sensors towards heart rate monitoring. The sensors, nanomaterial or textile based dry electrodes, capture the heart activity signals in form Electrocardiograph (ECG) and relay it to a compact textile mountable amplifier-wireless transmitter module for relay to a smart phone. The ECG signal, acquired on the smart phone, can be transmitted to the cyber space for post processing. As an example, the paper discusses the heart rate estimation and heart rate variability. The data flow from sensor to smart phone to server (cyber infrastructure) has been discussed. The cyber infrastructure based signal post processing offers an opportunity for automated emergency response that can be initiated from the server or the smartphone itself. Detailed protocols for both the scenarios have been presented and their relevance to the present emergency healthcare response system has been discussed.

Varadan, Vijay K.; Kumar, Prashanth S.; Oh, Sechang; Mathur, Gyanesh N.; Rai, Pratyush; Kegley, Lauren

2011-04-01