Heart rate and muscle sympathetic nerve variability during reflex changes of autonomic activity

1990 ◽  
Vol 258 (3) ◽  
pp. H713-H721 ◽  
Author(s):  
J. P. Saul ◽  
R. F. Rea ◽  
D. L. Eckberg ◽  
R. D. Berger ◽  
R. J. Cohen
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Sympathetic Activity ◽  
Spectral Power ◽  
Low Frequency ◽  
Plasma Norepinephrine ◽  
Vagal Activity ◽  
Sympathetic Outflow ◽  
Low Frequencies ◽  
Heart Rate Fluctuations

Low-frequency (less than 0.15 Hz) fluctuations of heart rate are increased by maneuvers, such as standing or hemorrhage, that increase sympathetic outflow to the heart and vasculature. To test the hypothesis that low-frequency heart rate fluctuations provide an index of sympathetic efferent activity, we compared power spectral measures of heart rate variability with two measures of sympathetic outflow, peroneal nerve sympathetic activity and antecubital vein plasma norepinephrine concentrations. Autonomic outflow was varied with graded stepwise infusions of nitroprusside and phenylephrine, which lowered or raised average diastolic pressures by approximately 15 mmHg. Before vasoactive drug infusions, no spectral measure of heart rate variability correlated significantly with muscle sympathetic activity, plasma norepinephrine concentration, average heart rate, or arterial pressure. During increases of muscle sympathetic activity and probable reductions of cardiac vagal activity induced by nitroprusside, the fraction of heart rate spectral power at low frequencies, but not the absolute value, correlated significantly with muscle sympathetic activity and plasma norepinephrine. However, during reductions of muscle sympathetic activity and probable elevations of cardiac vagal activity induced by phenylephrine, no measure of heart rate variability correlated significantly with muscle sympathetic activity. These findings can be explained by a model of heart rate control in which low-frequency heart rate fluctuations result from changing levels of both the sympathetic and parasympathetic inputs to the sinoatrial node.

Characteristics of heart rate variability in patients with acute coronary syndrome without ST segment elevation in comparison with clinical and biochemical parameters

2021 ◽  
Vol 29 (3) ◽  
pp. 369-378
Author(s):  
Aleksej A. Nizov ◽  
Aleksej I. Girivenko ◽  
Mihail M. Lapkin ◽  
Aleksej V. Borozdin ◽  
Yana A. Belenikina ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Acute Coronary Syndrome ◽  
Creatine Phosphokinase ◽  
Spectral Power ◽  
Low Frequency ◽  
Heart Rhythm ◽  
St Segment Elevation ◽  
Coronary Syndrome ◽  
St Segment

BACKGROUND: The search for rational methods of primary, secondary, and tertiary prevention of coronary heart disease. To date, there are several publications on heart rate variability in ischemic heart disease. AIM: To study the state of the regulatory systems in the organism of patients with acute coronary syndrome without ST segment elevation based on the heart rhythm, and their relationship with the clinical, biochemical and instrumental parameters of the disease. MATERIALS AND METHODS: The open comparative study included 76 patients (62 men, 14 women) of mean age, 61.0 0.9 years, who were admitted to the Emergency Cardiology Department diagnosed of acute coronary syndrome without ST segment elevation. On admission, cardiointervalometry was performed using Varicard 2.51 apparatus, and a number of clinical and biochemical parameters were evaluated RESULTS: Multiple correlations of parameters of heart rate variability and clinical, biochemical and instrumental parameters were observed. From this, a cluster analysis of cardiointervalometry was performed, thereby stratifying patients into five clusters. Two extreme variants of dysregulation of the heart rhythm correlated with instrumental and laboratory parameters. A marked increase in the activity of the subcortical nerve centers (maximal increase of the spectral power in the very low frequency range with the underlying reduction of SDNN) in cluster 1 was associated with reduction of the left ventricular ejection fraction: cluster 147.0 [40.0; 49.0], cluster 260.0 [58.0; 64.0], cluster 360.0 [52.5; 64.5] % (the data are presented in the form of median and interquartile range; Me [Q25; Q75], p 0,05). Cluster 5 showed significant reduction in SDNN (monotonous rhythm), combined with increased level of creatine phosphokinase (CPC): cluster 5446,0 [186.0; 782.0], cluster 4141.0 [98.0; 204.0] IU/l; Me [Q25; Q75], p 0.05) and MВ-fraction of creatine phosphokinase; cluster 532.0 [15.0; 45.0], 4 cluster 412.0 [9.0; 18.0] IU/l; Me [Q25; Q75], p 0.05). CONCLUSIONS: In patients with acute coronary syndrome without ST segment elevation, cluster analysis of parameters of heart rate variability identified different peculiarities of regulation of the heart rhythm. Pronounced strain of the regulatory systems of the body was found to be associated with signs of severe pathology: the predominance of VLF (spectral power of the curve enveloping a dynamic range of cardiointervals in the very low frequency range) in spectral analysis with an underlying reduced SDNN is characteristic of patients with a reduced ejection fraction, and a monotonous rhythm is characteristic of patients with an increased level of creatine phosphokinase and MB-fraction of creatine phosphokinase.

Effect of provocative maneuvers on heart rate variability in subjects with quadriplegia

1995 ◽  
Vol 268 (6) ◽  
pp. H2239-H2245 ◽  
Author(s):  
D. R. Grimm ◽  
R. E. DeMeersman ◽  
R. P. Garofano ◽  
A. M. Spungen ◽  
W. A. Bauman
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Sympathetic Activity ◽  
Spectral Component ◽  
Low Frequency ◽  
Power Spectral Analysis ◽  
Parasympathetic Activity ◽  
Power Spectral ◽  
Spectral Components ◽  
Male Subjects

This study investigated heart rate variability (HRV) in individuals with quadriplegia who have disruption of autonomic control of the heart. Seven male subjects with neurological complete quadriplegia and seven with incomplete quadriplegia were studied at rest and during provocation. HRV was measured by power spectral analysis using a fast Fourier transform. Two spectral components were generated: 1) the high-frequency (HF) peak, a reflection of parasympathetic activity, and 2) the low-frequency (LF) peak, primarily sympathetic activity with some parasympathetic input. Results of the provocative maneuvers were grouped into one composite variable. Significant differences in the LF spectral component were found between the groups with complete and incomplete lesions in the supine position and after provocation (LF supine: P = 0.01; LF provocation: P = 0.002). After provocation, significant differences were demonstrated in the HF spectral component between these groups (P = 0.005). In contrast to previous findings, a LF component in subjects with complete quadriplegia was observed; this LF component decreased after provocation, suggesting the parasympathetic component withdrew during stressful maneuvers. There also appeared to be general downregulation of parasympathetic activity to the heart in subjects with complete quadriplegia. The presence of an increased LF spectral component during provocation in those with incomplete lesions implies sympathetic stimulation of the heart and may be used as a marker of sympathetic activity in individuals with quadriplegia.

Evaluation of cardiac autonomic function using heart rate variability in children with acute carbon monoxide poisoning

2017 ◽  
Vol 27 (9) ◽  
pp. 1662-1669 ◽  
Author(s):  
Cagdas Vural ◽  
Ener Cagri Dinleyici ◽  
Pelin Kosger ◽  
Ozge Bolluk ◽  
Zubeyir Kilic ◽  
...  
Keyword(s):  
Heart Rate ◽  
Carbon Monoxide ◽  
Heart Rate Variability ◽  
High Frequency ◽  
Autonomic Function ◽  
Spectral Power ◽  
Carbon Monoxide Poisoning ◽  
Low Frequency ◽  
Qt Dispersion ◽  
Cardiac Autonomic Function

AbstractIntroductionCarbon monoxide poisoning may cause myocardial toxicity and cardiac autonomic dysfunction, which may contribute to the development of life-threatening arrhythmias. We investigated the potential association between acute carbon monoxide exposure and cardiac autonomic function measured by heart rate variability.MethodThe present study included 40 children aged 1–17 years who were admitted to the Pediatric Intensive Care Unit with acute carbon monoxide poisoning and 40 healthy age- and sex-matched controls. Carboxyhaemoglobin and cardiac enzymes were measured at admission. Electrocardiography was performed on admission and discharge, and 24-hour Holter electrocardiography was digitally recorded. Heart rate variability was analysed at both time points – 24-hour recordings – and frequency domains – from the first 5 minutes of intensive care unit admission.ResultsTime domain and frequency indices such as high-frequency spectral power and low-frequency spectral power were similar between patient and control groups (p>0.05). The ratio of low-frequency spectral power to high-frequency spectral power was significantly lower in the carbon monoxide poisoning group (p<0.001) and was negatively correlated with carboxyhaemoglobin levels (r=−0.351, p<0.05). The mean heart rate, QT dispersion, corrected QT dispersion, and P dispersion values were higher in the carbon monoxide poisoning group (p<0.05) on admission. The QT dispersion and corrected QT dispersion remained longer in the carbon monoxide poisoning group compared with controls on discharge (p<0.05).ConclusionThe frequency domain indices, especially the ratio of low-frequency spectral power to high-frequency spectral power, are useful for the evaluation of the cardiac autonomic function. The decreased low-frequency spectral power-to-high-frequency spectral power ratio reflects a balance of the autonomic nervous system, which shifted to parasympathetic components.

scholarly journals Improvement of Circadian Rhythm of Heart Rate Variability by Eurythmy Therapy Training

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Georg Seifert ◽  
Jenny-Lena Kanitz ◽  
Kim Pretzer ◽  
Günter Henze ◽  
Katharina Witt ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Circadian Rhythm ◽  
Negative Impact ◽  
Vagal Activity ◽  
Nonlinear Parameters ◽  
Low Frequencies ◽  
Before And After ◽  
Time Domains

Background. Impairment of circadian rhythm is associated with various clinical problems. It not only has a negative impact on quality of life but can also be associated with a significantly poorer prognosis. Eurythmy therapy (EYT) is an anthroposophic movement therapy aimed at reducing fatigue symptoms and stress levels.Objective. This analysis of healthy subjects was conducted to examine whether the improvement in fatigue symptoms was accompanied by improvements in the circadian rhythm of heart rate variability (HRV).Design. Twenty-three women performed 10 hours of EYT over six weeks. Electrocardiograms (ECGs) were recorded before and after the EYT trial. HRV was quantified by parameters of the frequency and time domains and the nonlinear parameters of symbolic dynamics.Results. The day-night contrast with predominance of vagal activity at night becomes more pronounced after the EYT training, and with decreased Ultralow and very low frequencies, the HRV shows evidence of calmer sleep. During the night, the complexity of the HRV is significantly increased indicated by nonlinear parameters.Conclusion. The analysis of the circadian patterns of cardiophysiological parameters before and after EYT shows significant improvements in HRV in terms of greater day-night contrast caused by an increase of vagal activity and calmer and more complex HRV patterns during sleep.

scholarly journals HEART RATE VARIABILITY OF STUDENTS WITH DIFFERENT PROFILES OF MOTOR DOMINATION DURING EXAM

2017 ◽  
Vol 18 (3.1) ◽  
pp. 203-209
Author(s):  
A.I. Lukina
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Nervous System ◽  
Activity Coefficient ◽  
Spectral Power ◽  
Regulatory Mechanisms ◽  
Wave Parameters ◽  
Increasing Trend ◽  
Heart Rate Fluctuations ◽  
Sympathetic Nervous

It is established hat changing of parameters of student’s electrocardiogram during the exam are shown by shortening of the intervals RR, QT, PQ, and the complex QRS, thus expressiveness of reactions dominates in sample of lefthanders and ambidexters. The values of wave parameters of heart rate variability, including spectral power of heart rate fluctuations in different frequency ranges, increase in left-handers, while ambidexterity and right handed down. The values of statistical indices of HRV, including SDNN, RMSSD and mode cardio intervals in students during the exam are reduced, and also to a greater extent, and ambidexterity for lefties. These changes corresponded to increasing trend of the index and the activity coefficient Baevsky sympathetic nervous system, indicating a greater intensity of regulatory mechanisms in individuals with left profile of motor domination.

Low-frequency component of the heart rate variability spectrum: a poor marker of sympathetic activity

1999 ◽  
Vol 276 (1) ◽  
pp. H215-H223 ◽  
Author(s):  
Melanie S. Houle ◽  
George E. Billman
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Ventricular Fibrillation ◽  
Sympathetic Activity ◽  
Low Frequency ◽  
Frequency Component ◽  
Atropine Sulfate ◽  
Low Frequency Power ◽  
Heart Rate Variability Spectrum ◽  
Frequency Power

The low-frequency component of the heart rate variability spectrum (0.06–0.10 Hz) is often used as an accurate reflection of sympathetic activity. Therefore, interventions that enhance cardiac sympathetic drive, e.g., exercise and myocardial ischemia, should elicit increases in the low-frequency power. Furthermore, because an enhanced sympathetic activation has been linked to an increased propensity for malignant arrhythmias, one might also predict a greater low-frequency power in animals that are susceptible to ventricular fibrillation than in resistant animals. To test these hypotheses, a 2-min coronary occlusion was made during the last minute of exercise in 71 dogs with healed myocardial infarctions: 43 had ventricular fibrillation (susceptible) and 28 did not experience arrhythmias (resistant). Exercise or ischemia alone provoked significant heart rate increases in both groups of animals, with the largest increase in the susceptible animals. These heart rate increases were attenuated by β-adrenergic receptor blockade. Despite the sympathetically mediated increases in heart rate, the low-frequency power decreased, rather than increased, in both groups, with the largest decrease again in the susceptible animals: 4.0 ± 0.2 (susceptible) vs. 4.1 ± 0.2 ln ms2 (resistant) in preexercise control and 2.2 ± 0.2 (susceptible) vs. 2.9 ± 0.2 ln ms2 (resistant) at highest exercise level. In a similar manner the parasympathetic antagonist atropine sulfate elicited significant reductions in the low-frequency power. Although sympathetic nerve activity was not directly recorded, these data suggest that the low-frequency component of the heart rate power spectrum probably results from an interaction of the sympathetic and parasympathetic nervous systems and, as such, does not accurately reflect changes in the sympathetic activity.

Low-frequency Spectral Power of Heart Rate Variability Is Not a Specific Marker of Cardiac Sympathetic Modulation 

1995 ◽  
Vol 82 (3) ◽  
pp. 609-619 ◽  
Author(s):  
Hans-Bernd Hopf ◽  
Andreas Skyschally ◽  
Gerd Heusch ◽  
Jurgen Peters
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Epidural Anesthesia ◽  
Spectral Power ◽  
Low Frequency ◽  
Fast Fourier Transformation ◽  
Specific Marker ◽  
Sympathetic Blockade ◽  
Autonomic Tone ◽  
Sympathetic Modulation

Background Heart rate variability in the frequency domain has been proposed to reflect cardiac autonomic control. Therefore, measurement of heart rate variability may be useful to assess the effect of epidural anesthesia on cardiac autonomic tone. Accordingly, the effects of preganglionic cardiac sympathetic blockade by segmental epidural anesthesia were evaluated in humans on spectral power of heart rate variability. Specifically, the hypothesis that cardiac sympathetic blockade attenuates low-frequency spectral power, assumed to reflect cardiac sympathetic modulation, was tested. Methods Ten subjects were studied while supine and during a 15-min 40 degrees head-up tilt both before and after cardiac sympathetic blockade by segmental thoracic epidural anesthesia (sensory block: C6-T6). ECG, arterial pressure, and respiratory excursion (Whitney gauge) were recorded, and a fast-Fourier-transformation was applied to 512-s data segments of heart rate derived from the digitized ECG at the end of each intervention. Results With cardiac sympathetic blockade alone and the subjects supine, both low-frequency (LF, 0.06-0.15 Hz) and high-frequency (HF, 0.15-0.80 Hz) spectral power remained unchanged. During tilt, epidural anesthesia attenuated the evoked increase in heart rate (+11.min-1 +/- 7 SD vs. +6 +/- 7, P = 0.024). However, while during tilt cardiac sympathetic blockade significantly decreased the LF/HF ratio (3.68 +/- 2.52 vs. 2.83 +/- 2.15, P = 0.041 vs. tilt before sympathetic blockade), a presumed marker of sympathovagal interaction, absolute and fractional LF and HF power did not change. Conclusions Although preganglionic cardiac sympathetic blockade reduced the LF/HF ratio during tilt, it did not alter spectral power in the LF band during rest or tilt. Accordingly, low-frequency spectral power is unlikely to specifically reflect cardiac sympathetic modulation in humans.

scholarly journals Heart Rate Variability Assessment Using Time–Frequency Analysis in Hypotensive and Non-Hypotensive Patients in Hemodialysis

2020 ◽  
Vol 10 (17) ◽  
pp. 6074
Author(s):  
Brayans Becerra-Luna ◽  
Raúl Cartas-Rosado ◽  
Juan Carlos Sánchez-García ◽  
Raúl Martínez-Memije ◽  
Oscar Infante-Vázquez ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Spectral Power ◽  
Spectral Band ◽  
Average Power ◽  
Low Frequency ◽  
Intradialytic Hypotension ◽  
Time Frequency ◽  
The Mean ◽  
Stage Renal Disease

Intradialytic hypotension occurs in 10–30% of hemodialysis (HD) sessions. This phenomenon affects the cardiovascular system’s functions, which are reflected in the activity of the autonomic nervous system (ANS). To indirectly assess the ANS during HD, we analyzed the mean R–R intervals and the spectral power of heart rate variability (HRV) from 20 end-stage renal disease patients divided into hypotensive and non-hypotensive groups. The spectrotemporal analysis was accomplished using short-time Fourier transform with 10 min epochs of HRV overlapping by 40%. The spectral power was divided into three segments according to high frequency, low frequency, and very low frequency bandwidths and averaged to fit quadratic regression models. The analysis of the mean R–R intervals showed significant differences between the groups (p = 0.029). The power variation over time was significant in each spectral band (p ≪ 0.05). The average power, maximum power, and time when the peak was reached differed for each band and between groups, showing the ability to correctly identify the decompensation of the ANS and discriminate between hypotensive and non-hypotensive patients. Additionally, the changes in the sympathovagal ratio were not significant and very scattered for the hypotensive group (p = 0.23) compared to the non-hypotensive group, where the changes were significant (p ≪ 0.05) and much less scattered.

IDENTIFYING THE CORRELATION BETWEEN ENCEPHALOGRAPHIC SIGNAL IRREGULARITY AND HEART RATE VARIABILITY TO DIFFERENTIATE INTERNALLY AND EXTERNALLY OPERATIVE ATTENTION

2020 ◽  
Vol 32 (02) ◽  
pp. 2050014
Author(s):  
M. Kumar ◽  
D. Singh ◽  
K. K. Deepak
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Negative Correlation ◽  
Spectral Power ◽  
Low Frequency ◽  
Significant Negative Correlation ◽  
Eeg Signal ◽  
Rr Interval ◽  
Attention Tasks ◽  
Significant Difference

This study identifies a correlation between low-frequency heart rate variability (LF-HRV) and encephalographic (EEG) complexity to differentiate internally operative attention (INT) and externally operative attention (EXT). Electrophysiological fluctuations in response to Posner’s spatial orienting paradigm were explored in 14 healthy volunteers who participated in 6 alternating sessions of attention tasks. HRV analysis was used to measure heart rate fluctuations, and approximate entropy (ApEn) was used to measure changes in the irregularity of EEG and HRV. Power spectral analysis of HRV revealed that there was found to be a significant difference between INT and EXT for HRV-low frequency (HRV-LF) and LH/HF ratio. ApEn for RR-interval time series increased for both attention tasks as compared to baseline and recovery session. The relationship between HRV-LF and EEG spectral power measured at F4 revealed significant negative correlation during ([Formula: see text], with [Formula: see text]) EXT than ([Formula: see text], with [Formula: see text]) INT. Furthermore, a significant positive correlation, yet of moderate strength was noted between HRV-LF and ApEn of EEG signal measured at POz ([Formula: see text], with [Formula: see text]) during EXT as compared to INT ([Formula: see text], with [Formula: see text]) and, a significant negative correlation was observed between ApEn of RR-interval and ApEn of EEG signal measured at POz ([Formula: see text], with [Formula: see text]) during EXT as compared to INT ([Formula: see text], with [Formula: see text]). Thus, it is evident that EXT leads to more irregularity in parietal regions of the brain than the INT. During EXT, the irregularity over the parietal region linked to increased sympathetic activity as compared to INT and corresponds to decreased heart rate. These results may benefit in designing robust human-computer interfaces and accelerated training paradigm to raise an athlete’s performance.

scholarly journals Cardiac Neural Regulation Oscillates with the Estrous Cycle in Freely Moving Female Rats: The Role of Endogenous Estrogens

Endocrinology ◽  
2010 ◽  
Vol 151 (6) ◽  
pp. 2613-2621 ◽  
Author(s):  
Terry B. J. Kuo ◽  
C. T. Lai ◽  
Fu-Chun Hsu ◽  
Yi-Jhan Tseng ◽  
Jia-Yi Li ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Estrous Cycle ◽  
Sympathetic Activity ◽  
Low Frequency ◽  
Female Rats ◽  
Tamoxifen Treatment ◽  
Freely Moving ◽  
Low Frequency Power ◽  
Frequency Power

Both estrogens levels and sleep/wakefulness states have been separately reported to affect cardiac autonomic regulation. In this study, we examined the integrated effects of the estrous and sleep cycles on cardiac autonomic activity in freely moving adult female rats. Cardiac autonomic activities were measured by analyzing the power spectrum of heart rate variability. High-frequency power (HF) and low-frequency power to HF ratio are closely correlated with cardiac parasympathetic and sympathetic activity, respectively. Ten days after electrodes were implanted, electroencephalogram, electromyogram, and electrocardiogram were recorded 6 h daily for 12 consecutive days to cover at least two estrous cycles. Estrous-cycle stages were determined using vaginal smears. Sleep cycle-related heart rate variability parameter oscillations were seen in all rats. However, the estrous cyclicity and estrous-cycle-related changes were only observed in the control rats and not in ovariectomized or the estrogen receptor antagonist, tamoxifen, treatment rats. A significantly higher HF was observed in estrous rats compared with diestrous rats or ovariectomized rats no matter whether the rats were asleep or awake. However, a significantly low-frequency power to HF ratio was only observed in quiet sleep (QS) during estrus. All these differences disappeared after treatment with tamoxifen. Our results suggest that estrous-cycle-related changes in cardiac neural regulations can be mainly attributed to endogenous estrogens, and these effects are most obviously manifest during QS. Estrous rats during QS would be equivalent to the late follicular phase of the women menstrual cycle and involve strong vagal tone but weak sympathetic activity.

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