scholarly journals Analysis of heart rhythm variability by linear and non-linear dynamics methods

2005 ◽  
Vol 62 (9) ◽  
pp. 621-627 ◽  
Author(s):  
Vesna Vuksanovic ◽  
Vera Gal
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Heart Rhythm ◽  
Sample Entropy ◽  
Largest Lyapunov Exponent ◽  
Scaling Exponent ◽  
High Frequency Power ◽  
Middle Aged ◽  
Heart Rhythm Variability ◽  
Frequency Power

Introduction. Spectral analysis of heart rhythm variability is a noninvasive method to study cardiovascular autonomic control. Nonlinear methods of analysis of heart rhythm variability may provide an additional information on properties of RR interval dynamics, which cannot be revealed by linear methods. The aim of this study was to investigate and to compare some parameters of deterministic chaos, tractal and spectral properties of heart rhythm variability in healthy subjects. Methods. Sixty healthy subjects, who participated in this study, were divided in four different age groups: children (< 15 years old), young (15-24 years), adults (25-39 years) and middle-aged (40-61 years). We analyzed the heart period variability extracted from a 5-minute electrocardiograms recordings in supine rest. Short-term fractal scaling exponent, sample entropy, minimum embedding dimension and the largest Lyapunov exponent along with the spectral measures (low-frequency and high-frequency power) were determined. Results. Heart frequency, short-term fractal scaling exponent, and the largest Lyapunov exponent did not differ between the tested groups (p > 0.05). Middle-aged subjects had the lower low-frequency power as compared to the children (p < 0.001) and the young (p < 0.05), and the lower high frequency power as compared to the other three groups (p < 0.001). Middle-aged also had a significantly lower power of high frequency and sample entropy as compared to the other three groups (p < 0.001). Children had lower values of minimum embedding dimension compared to the middle aged (p<0.001). Significant negative correlation between the age of the tested subjects, and the low-and, high-frequency power and sample entropy was found. Conclusion. The obtained results suggested that healthy aging was associated with significant alteration in heart rhythm dynamics reflected on a higher regularity and lower variability of heart rhythm time-series. Significant decrease in a high-frequency power with aging suggested that reduction in parasympathetic activity was the basic cause of these changes.

Elevated heart rate variability in physically active postmenopausal women: a cardioprotective effect?

1996 ◽  
Vol 271 (2) ◽  
pp. H455-H460 ◽  
Author(s):  
K. P. Davy ◽  
N. L. Miniclier ◽  
J. A. Taylor ◽  
E. T. Stevenson ◽  
D. R. Seals
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Postmenopausal Women ◽  
High Frequency ◽  
Low Frequency ◽  
Total Power ◽  
High Frequency Power ◽  
Fat Percentage ◽  
Physically Active ◽  
Frequency Power

Coronary heart disease (CHD) and cardiac sudden death (CSD) incidence accelerates after menopause, but the incidence is lower in physically active versus less active women. Low heart rate variability (HRV) is a risk factor for CHD and CSD. The purpose of the present investigation was to test the hypothesis that HRV at rest is greater in physically active compared with less active postmenopausal women. If true, we further hypothesized that the greater HRV in the physically active women would be closely associated with an elevated spontaneous cardiac baroreflex sensitivity (SBRS). HRV (both time and frequency domain measures) and SBRS (sequence method) were measured during 5-min periods of controlled frequency breathing (15 breaths/min) in the supine, sitting, and standing postures in 9 physically active postmenopausal women (age = 53 +/- 1 yr) and 11 age-matched controls (age = 56 +/- 2 yr). Body weight, body mass index, and body fat percentage were lower (P < 0.01) and maximal oxygen uptake was higher (P < 0.01) in the physically active group. The standard deviation of the R-R intervals (time domain measure) was higher in all postures in the active women (P < 0.05) as were the high-frequency, low-frequency, and total power of HRV. SBRS also was higher (P < 0.05) in the physically active women in all postures and accounted for approximately 70% of the variance in the high-frequency power of HRV (P < 0.05). The results of the present investigation indicate that physically active postmenopausal women demonstrate higher levels of HRV compared with age-matched, less active women. Furthermore, SBRS accounted for the majority of the variance in the high-frequency power of HRV, suggesting the possibility of a mechanistic link with cardiac vagal modulation of heart rate. Our findings may provide insight into a possible cardioprotective mechanism in physically active postmenopausal women.

Effects of oral arsenic trioxide therapy on QT intervals in patients with acute promyelocytic leukemia: implications for long-term cardiac safety

Blood ◽  
2006 ◽  
Vol 108 (1) ◽  
pp. 103-106 ◽  
Author(s):  
Chung-Wah Siu ◽  
Wing-Yan Au ◽  
Cindy Yung ◽  
Cyrus R. Kumana ◽  
Chu-Pak Lau ◽  
...  
Keyword(s):  
Arsenic Trioxide ◽  
High Frequency ◽  
Peak Plasma ◽  
Low Frequency ◽  
Holter Monitoring ◽  
Cardiac Safety ◽  
High Frequency Power ◽  
Qt Intervals ◽  
Frequency Power

Ventricular tachyarrhythmias may occur during intravenous arsenic trioxide (As2O3). This has not happened during oral As2O3. Sixteen patients were studied by electrocardiography and 24-hour Holter monitoring at baseline, during and after oral As2O3 (As2O3-ON, As2O3-OFF). QT and corrected QT (QTc) were significantly longer during As2O3-ON than in As2O3-OFF, but QT and QTc dispersions were comparable. The patients' 24-hour heart rates were higher during As2O3-ON than in As2O3-OFF. QTc intervals at each hour were longer during As2O3-ON than in As2O3-OFF. However, QTc prolongation of more than 30 milliseconds only occurred at one time point (2 hours) after oral As2O3, resulting in QTc of more than 500 milliseconds in 3 of 16 patients, all within 4 hours of oral As2O3. Although the standard deviation of normal RR interval was lower during As2O3-ON, ratios of low frequency to high frequency power for As2O3-ON and As2O3-OFF were comparable. No ventricular proarrhythmias were observed. These observations, due to the lower peak plasma arsenic reached during oral As2O3, may explain the relative cardiac safety of oral As2O3. (Blood. 2006;108:103-106)

Cardiovascular variability after arousal from sleep: time-varying spectral analysis

2003 ◽  
Vol 95 (4) ◽  
pp. 1394-1404 ◽  
Author(s):  
Anna Blasi ◽  
Javier Jo ◽  
Edwin Valladares ◽  
Barbara J. Morgan ◽  
James B. Skatrud ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
High Frequency ◽  
Low Frequency ◽  
Sleep Time ◽  
Respiratory Pattern ◽  
Time Varying ◽  
High Frequency Power ◽  
Low Frequency Power ◽  
Frequency Power

We performed time-varying spectral analyses of heart rate variability (HRV) and blood pressure variability (BPV) recorded from 16 normal humans during acoustically induced arousals from sleep. Time-varying autoregressive modeling was employed to estimate the time courses of high-frequency HRV power, low-frequency HRV power, the ratio between low-frequency and high-frequency HRV power, and low-frequency power of systolic BPV. To delineate the influence of respiration on HRV, we also computed respiratory airflow high-frequency power, the modified ratio of low-frequency to high-frequency HRV power, and the average transfer gain between respiration and heart rate. During cortical arousal, muscle sympathetic nerve activity and heart rate increased and returned rapidly to baseline, but systolic blood pressure, the ratio between low-frequency and high-frequency HRV power, low-frequency HRV power, the modified ratio of low-frequency to high-frequency HRV power, and low-frequency power of systolic BPV displayed increases that remained above baseline up to 40 s after arousal. High-frequency HRV power and airflow high-frequency power showed concommitant decreases to levels below baseline, whereas the average transfer gain between respiration and heart rate remained unchanged. These findings suggest that 1) arousal-induced changes in parasympathetic activity are strongly coupled to respiratory pattern and 2) the sympathoexcitatory cardiovascular effects of arousal are relatively long lasting and may accumulate if repetitive arousals occur in close succession.

scholarly journals Heart Rate Variability during Face Cooling in Concussed Adolescents

Neurology ◽  
2019 ◽  
Vol 93 (14 Supplement 1) ◽  
pp. S8.1-S8
Author(s):  
Mohammad Haider ◽  
Charles Wilber ◽  
Kaitlin Viera ◽  
Itai Bezherano ◽  
John Leddy
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
High Frequency ◽  
Low Frequency ◽  
High Frequency Power ◽  
Clinical Recovery ◽  
Face Cooling ◽  
Ratio Measure ◽  
Frequency Power ◽  
Mean Heart Rate

ObjectiveWe measured heart rate variability (HRV) during physiological stimuli in acutely concussed adolescents (CX) and after clinical recovery, and compared with healthy controls (HC).BackgroundConcussion is associated with autonomic dysfunction. Face Cooling (FC) triggers the trigeminal nerve to evoke transient increases in cardiac parasympathetic (PNS) activity.Design/Methods11 CX (14.8 ± 0.9 years, 6 male, 7 days since injury) and 11 HC (16.1 ± 1.1 years, 9 male) participated. We calculated mean heart rate (HR), standard deviation of root mean square (RMSSD, measure of PNS tone) and low-frequency to high-frequency power ratio (LF/HF ratio, measure of sympathetic [SNS] tone) at rest and 3-minute FC test.ResultsCX at Visit 1 and 2 had significantly lesser increase in HR (p = 0.02) and RMSSD (p = 0.038) than HC on FC.ConclusionsThese data show that acutely concussed participants have an attenuated PNS response to physiological stimuli which continues after clinical recovery.

scholarly journals Bispectral Index™ Alterations Have Associations with Autonomic Changes during Hypnosis in Trauma Center Researchers: A Formative Evaluation (Preprint)

2020 ◽  
Author(s):  
C. Michael Dunham ◽  
Amanda L. Burger ◽  
Barbara M. Hileman ◽  
Elisha A. Chance ◽  
Amy E. Hutchinson
Keyword(s):  
Respiratory Rate ◽  
Skin Conductance ◽  
High Frequency ◽  
Trauma Center ◽  
Formative Evaluation ◽  
Low Frequency ◽  
High Frequency Power ◽  
Interbeat Interval ◽  
Low Frequency Power ◽  
Frequency Power

BACKGROUND Hypnosis was induced to enhance reductions in Bispectral Index™ (BIS) values. OBJECTIVE Autonomic monitoring was used to assess physiologic relaxation and explore their associations with BIS values. METHODS Each session consisted of reading a 4-minute baseline neutral script and playing an 18-minute hypnosis tape to 3 researchers involved in the BIS neurofeedback study. In addition to BIS monitoring, autonomic monitoring was performed and included measures of electromyography, skin temperature, skin conductance, respiratory rate, expired carbon dioxide, and heart rate variability. The t-test, correlation analyses, and multivariate linear regression analyses were used in data analysis. RESULTS Hypnosis was associated with reductions in BIS (P<.001), electromyography (P<.001), respiratory rate (P<.001), skin conductance (P=.006), and very low frequency power (P=.04) and with increases in expired carbon dioxide (P<.001), skin temperature (P=.04), high frequency power (P<.001), and successive heart interbeat interval difference (P=.04) values. Decreased BIS values were associated with reduced electromyography measures (R=.76; P<.001), respiratory rate (R=.35; P=.004), skin conductance (R=.57; P<.001), and low frequency power (R=.32; P=.01) and with increased high frequency power (R=-.53; P<.001), successive heart interbeat interval difference (R=-.32; P=.009), and standard deviation of heart interbeat interval (R=-.26; P=.04) values. CONCLUSIONS Hypnosis appeared to induce mental and physical relaxation, enhance parasympathetic neural activation, and attenuate sympathetic nervous system activity, changes that were associated with BIS values. Findings of the preliminary formative evaluation suggest that the current hypnosis model may be useful for assessing autonomic physiological associations with changes in BIS values, thus motivating us to proceed with a larger investigation in trauma center nurses and physicians. CLINICALTRIAL None

scholarly journals Low-Frequency Vibration Facilitates Post-Exercise Cardiovascular Autonomic Recovery

2021 ◽  
pp. 431-437
Author(s):  
Kuo-Cheng Liu ◽  
Jong-Shyan Wang ◽  
Chien-Ya Hsu ◽  
Chia-Hao Liu ◽  
Carl PC Chen ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
High Frequency ◽  
Pulse Wave ◽  
Low Frequency ◽  
Recovery Phase ◽  
High Frequency Power ◽  
Nerve Activity ◽  
Post Exercise ◽  
Frequency Power

It is important to use short breaks to accelerate post-exercise recovery in sports. Previous studies have revealed that vibration can reduce post-exercise muscle soreness. However, there is still high heterogeneity in the effects of vibration on cardiovascular autonomic activities, and most studies to date have focused on high-frequency vibration. This study aimed to investigate the effect of low-frequency lower-body vibration (LBV) on post-exercise changes in heart rate variability and peripheral arterial tone. Ten men and 9 women aged 20 to 25 were recruited for this study. Each subject visited the testing room three times with at least 2 days in between. Each time, the subject received one of the three different vibration frequencies (0, 5, and 15 Hz) in a random order in the sitting position for 10 minutes. LBV was performed immediately after a static standing (control) test and 3-min-step test. Heart rate variability and digital volume pulse wave were recorded during the vibration phase (V1: vibration 0-5 minutes; V2: 6-10 minutes) and the recovery phase (Rc1: recovery phase 11-15 minutes; Rc2: 16-20 minutes). The result of digital pulse wave analysis showed that the reflection index (RI) under 15 Hz decreased during V1. Heart rate of the 15-Hz group also decreased during Rc1 and Rc2. According to the analysis of heart rate variability, low-frequency power/high-frequency power (LF/HF) decreased and normalized high-frequency power (nHF) increased during V2, Rc1 and Rc2 under 15 Hz and, during Rc2 under 5 Hz vibration. This study confirmed that the application of low-frequency LBV after exercise can reduce peripheral vascular tone, accelerate heart rate recovery, decrease cardiac sympathetic nerve activity, and promote parasympathetic nerve activity. The effect was more pronounced at 15 Hz than at 5 Hz. The findings provide a method to accelerate cardiovascular autonomic recovery after exercise.

Autonomic nervous system dysfunction in sclerodermic and primary Raynaud's phenomenon

1999 ◽  
Vol 96 (1) ◽  
pp. 49-57
Author(s):  
Paolo PANCERA ◽  
Stefano SANSONE ◽  
Barbara PRESCIUTTINI ◽  
Luciano MONTAGNA ◽  
Silvia CERÙ ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Systemic Sclerosis ◽  
High Frequency ◽  
Raynaud’S Phenomenon ◽  
Low Frequency ◽  
Raynaud's Phenomenon ◽  
High Frequency Power ◽  
Primary Raynaud’S Phenomenon ◽  
Frequency Power

Our aim was to investigate the sympathetic hyperactivity of systemic sclerosis that may lead to greater morbidity and mortality from cardiovascular events. We analysed the sympathetic (low-frequency) and vagal (high-frequency) components of heart rate variability, in supine and upright positions, in 10 patients with systemic sclerosis, 12 patients with primary Raynaud's phenomenon and 14 controls. We also analysed lung function in order to evaluate a possible link between heart rate variability and ventilation parameters. Heart rate variability was reduced in the supine position in subjects with systemic sclerosis both in comparison with primary Raynaud's phenomenon (total power: 1103±156 versus 3302±486 ;ms2, P< 0.004) and control subjects (3148±422 ;ms2, P< 0.002). Low-frequency power was higher in patients with systemic sclerosis than in the controls (54.5±4.5 versus 42.5±3.5 normalized units, P< 0.01). During tilt, the change in heart rate was +44% in controls, +24% in subjects with primary Raynaud's phenomenon, and only +17% in the patients with systemic sclerosis (P< 0.01 versus controls). In patients with systemic sclerosis we found a significant correlation between high-frequency power and the indices of lung function (residual volume: r2 = 0.5143, P< 0.01; total lung capacity: r2 = 0.5142, P< 0.01, vital capacity: r2 = 0.3789, P< 0.05). Heart rate variability was reduced and sympathetic output increased in patients with systemic sclerosis. Subjects with primary Raynaud's phenomenon were characterized by normal heart rate variability and by some degree of sympathetic hyperactivity. During tilting, subjects with systemic sclerosis maintained an unmodified heart rate variability, thus suggesting an impaired baroceptor modulation of the autonomic control. The negative correlation between high-frequency power and indices of respiratory insufficiency in patients with systemic sclerosis suggests that the pulmonary structure plays an important role in the modulation of heart rate variability.

Autonomic reactivity and hormonal secretion in lactate-induced panic attacks

1997 ◽  
Vol 272 (6) ◽  
pp. H2630-H2638 ◽  
Author(s):  
F. E. Seier ◽  
M. Kellner ◽  
A. Yassouridis ◽  
R. Heese ◽  
F. Strian ◽  
...  
Keyword(s):  
Heart Rate ◽  
High Frequency ◽  
Spectral Power ◽  
Plasma Concentrations ◽  
Low Frequency ◽  
Panic Attacks ◽  
High Frequency Power ◽  
Double Blind ◽  
Natriuretic Hormone ◽  
Frequency Power

To compare autonomic and neuroendocrine responses during lactate-induced panic attacks, heart rate variability and cortisol and atrial natriuretic hormone (ANH) levels were measured in patients with panic attacks and in healthy control subjects. In a randomized double-blind design, all subjects received either 10 ml/kg body weight of 0.5 M racemic sodium lactate or normal saline from 1100 to 1120. Spectral analysis of the R-R interval of analog electrocardiograms was performed, and total (0.001-0.45 Hz), low-frequency (0.01-0.05 Hz), midfrequency (0.05-0.15 Hz), and high-frequency power (0.15-0.45 Hz) were computed. Cortisol was measured 12 times in the period from 0900 to 1300, and ANH was measured at 1100, 1120, and 1200 by radioimmunoassay. In both panickers (n = 6) and nonpanickers (n = 8), an infusion of lactate resulted in an acceleration of heart rate, a reduction in total spectral power, and a decrease in the high- and low-frequency components of spectral power. Panickers showed a significant enhancement of the high-frequency power, whereas in nonpanickers, a shift from the mid- and high-frequency toward the low-frequency power emerged. ANH plasma concentrations during lactate infusion in panickers showed a significant increase (115 and 131% at 1120 and 1200, respectively, over concentrations at 1100) in contrast to nonpanickers (20 and 74%, respectively). No group or treatment effects on cortisol secretion emerged, which is in line with former reports. Our study supports preliminary observations that lactate-induced panic attacks enhance the release of ANH, a vasodilatator and inhibitor of sympathetic activity. Hence this hormone not only could inhibit the secretion of the stress hormone cortisol but, in parallel, could also attenuate the sympathetic stimulation to the heart. These inhibitory effects of ANH could explain the so-far-unresolved dissociation between psychopathological alterations and autonomic and endocrine responses of panic attacks.

Aging of modulation of heart rate

1987 ◽  
Vol 253 (4) ◽  
pp. H874-H877 ◽  
Author(s):  
D. C. Shannon ◽  
D. W. Carley ◽  
H. Benson
Keyword(s):  
Heart Rate ◽  
Supine Position ◽  
High Frequency ◽  
Low Frequency ◽  
Standing Position ◽  
Total Power ◽  
High Frequency Power ◽  
Sinus Arrhythmia ◽  
Low Frequency Power ◽  
Frequency Power

We postulated that measurements of autonomically mediated fluctuations in heart rate might provide a quantitative probe of biological aging. We used power spectrum analysis of instantaneous heart rate while 33 male subjects matched their breathing to a metronome at 15 breaths/min. Measurements were made in supine and standing position. Total power and its two major components, high- and low-frequency power, declined with age in both positions but at different rates. High-frequency power that represents parasympathetically mediated respiratory sinus arrhythmia declined linearly in supine position only in subjects 9-28 yr with a slope of -0.796, which was significantly different from zero at P = 0.0007. The absolute value of high-frequency power in standing position was approximately 60% of that in supine, a difference that was statistically significant (P = 0.01). Low-frequency power that represents beta-adrenergically mediated heart rate fluctuations, especially in standing position, declined linearly to 62 yr of age (P = 0.0001). Mean heart rate increased 17.2 beats/min, and diastolic blood pressure increased 8 mmHg in the entire group in the standing compared with supine position. There were no significant differences in these changes above and below 30 yr of age. We conclude that the influence of the two major mechanisms that modulate heart rate decline at significantly different rates with aging.

scholarly journals Cross-Spectral Analysis of Electrocardiographic and Nostril Airflow Signals Identifies Two Respiratory Frequencies of Heart Rate Modulation

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Wan-An Lu ◽  
Jui-Feng Lin ◽  
Chen-Hsu Wang ◽  
Yung-Sheng Chen ◽  
Ying-Hua Shieh ◽  
...  
Keyword(s):  
Heart Rate ◽  
Spectral Analysis ◽  
High Frequency ◽  
Healthy Subjects ◽  
Low Frequency ◽  
High Frequency Power ◽  
Very Low Frequency ◽  
The Cross ◽  
Low Frequency Power ◽  
Frequency Power

Respiration is known to be a significant modulator of heart rate, and the high-frequency component in the power spectrum of heart rate variability (HRV) is believed to be caused mainly by respiration. To investigate the effect of respiration on heart rate, cross-spectral analysis of electrocardiographic (ECG) and nostril airflow signals was performed in healthy subjects to find the common features of ECG and respiration. Forty-two healthy subjects were included in this study. The autospectra of respective ECG and nostril airflow signals and the cross-spectra of ECG and nostril airflow signals were obtained and compared with the corresponding conventional HRV measures. We found that there were two spectral peaks at around 0.03 Hz and 0.3 Hz in the autospectrum of nostril airflow and the cross-spectrum of ECG and nostril airflow. In addition, the cross-spectral normalized high-frequency power (nHFPcs) was significantly larger than that of conventional HRV, while the cross-spectral normalized very low-frequency power (nVLFPcs), normalized low-frequency power (nLFPcs), and low-/high-frequency power ratio (LHRcs) were significantly lower than those of the conventional HRV. The cross-spectral nLFPcs and LHRcs had positive correlations with their corresponding HRV measures. We conclude that cross-spectral analysis of ECG and nostril airflow signals identifies two respiratory frequencies at around 0.03 Hz and below and around 0.3 Hz and can yield significantly enhanced nHFPcs and significantly suppressed nVLFPcs, as compared to their counterparts in conventional HRV. Both very low-frequency and high-frequency components of HRV are caused in part or mainly by respiration.

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