Autonomic response to coronary occlusion in animals susceptible to ventricular fibrillation

1989 ◽  
Vol 257 (6) ◽  
pp. H1886-H1894 ◽  
Author(s):  
M. N. Collins ◽  
G. E. Billman
Keyword(s):  
Heart Rate ◽  
Ventricular Fibrillation ◽  
Coronary Occlusion ◽  
Rate Increase ◽  
Vagal Tone ◽  
Autonomic Response ◽  
Acute Ischemia ◽  
Heart Rate Increase ◽  
Sinus Arrhythmia ◽  
Cardiac Vagal Tone

Disturbances in autonomic control during myocardial ischemia may contribute significantly to the development of malignant cardiac arrhythmias. Therefore acute ischemia was induced in 29 mongrel dogs with healed myocardial infarctions during an exercise test. Seventeen animals developed ventricular fibrillation (susceptible, S), whereas 12 dogs did not (resistant, R). Before the exercise plus ischemia test a coronary occlusion was made at rest. The amplitude of respiratory sinus arrhythmia (0.24- to 1.04-Hz component of R-R interval fluctuation) was used as an index of cardiac vagal tone. Acute ischemia elicited a significantly larger heart rate increase in susceptible animals (S: control 115.6 +/- 0.8, occlusion 176.4 +/- 8.2 beats/min vs. R: control 114.6 +/- 8.9, occlusion 145.7 +/- 7.5 beats/min). Accompanying the heart rate increase were significantly greater reductions in the cardiac vagal tone index in the susceptible animals. (S: control 6.4 +/- 0.3, occlusion 2.2 +/- 0.6 ln ms2 vs. R: control 6.6 +/- 0.4, occlusion 5.1 +/- 0.5 ln ms2). beta-Adrenergic receptor blockade reduced the heart rate increases but exacerbated the reductions in the cardiac vagal tone index. These data suggest that coronary artery occlusion elicits a significantly greater increase in sympathetic activity coupled with a greater reduction in parasympathetic activity in animals subsequently shown to be susceptible to ventricular fibrillation.

scholarly journals Associations between Acoustic Features of Maternal Speech and Infants' Emotion Regulation following a Social Stressor

2021 ◽  
Author(s):  
Jacek Kolacz ◽  
Elizabeth B daSilva ◽  
Gregory F Lewis ◽  
Bennett I Bertenthal ◽  
Stephen W Porges
Keyword(s):  
Heart Rate ◽  
Social Engagement ◽  
Vagal Tone ◽  
Fast Fourier Transformation ◽  
Acoustic Features ◽  
Sinus Arrhythmia ◽  
Cardiac Vagal Tone ◽  
Gaze Aversion ◽  
Maternal Speech ◽  
Electrocardiogram Ecg

Caregiver voices may provide cues to mobilize or calm infants. This study examined whether maternal prosody predicted changes in infants' biobehavioral state during the Still Face, a stressor in which the mother withdraws and reinstates social engagement. Ninety-four dyads participated in the study (infant age 4-8 months). Infants' heart rate and respiratory sinus arrhythmia (measuring cardiac vagal tone) were derived from an electrocardiogram (ECG). Infants' behavioral distress was measured by negative vocalizations, facial expressions, and gaze aversion. Mothers' vocalizations were measured with spectral analysis and spectro-temporal modulation using a two-dimensional fast Fourier transformation of the audio spectrogram. High values on the maternal prosody composite were associated with decreases in infants' heart rate (β=-.26, 95% CI: [-.46, -.05]) and behavioral distress (β=- .20, 95% CI: [-.38, -.02]), and increases in cardiac vagal tone in infants whose vagal tone was low during the stressor (1 SD below mean β=.39, 95% CI: [.06, .73]). High infant heart rate predicted increases in the maternal prosody composite (β=.18, 95% CI: [.03, .33]). These results suggest specific vocal acoustic features of speech that are relevant for regulating infants' biobehavioral state and demonstrate mother-infant bi-directional dynamics.

Dynamic changes in cardiac vagal tone as measured by time-series analysis

1990 ◽  
Vol 258 (3) ◽  
pp. H896-H902 ◽  
Author(s):  
G. E. Billman ◽  
J. P. Dujardin
Keyword(s):  
Heart Rate ◽  
Time Series ◽  
Time Series Analysis ◽  
Rate Control ◽  
Vagal Tone ◽  
Heart Rate Control ◽  
Dynamic Changes ◽  
Sinus Arrhythmia ◽  
Cardiac Vagal Tone ◽  
Series Analysis

A time-series analysis of heart rate variability was evaluated as a marker of cardiac vagal tone using well-characterized autonomic interventions. Heart period (R-R interval) was recorded in 14 mongrel dogs from which the amplitude of the respiratory sinus arrhythmia (0.24-1.04 Hz) was determined. Exercise elicited significant (P less than 0.01) reductions in the index of vagal tone (control 6.3 +/- 0.3 ln ms2 vs. exercise 2.4 +/- 0.4 ln ms2) that were accompanied by significant (P less than 0.01) increases in heart rate (control 123.1 +/- 5 vs. exercise 201.0 +/- 7.7 beats/min). The vagal tone index remained greater than 0 throughout exercise. After propranolol HCl pretreatment, the vagal tone index rapidly decreased toward zero (control 6.2 +/- 0.5; exercise 0.7 +/- 0.3 ln ms2), despite significantly lower increases in heart rate (control 109.3 +/- 4.2; exercise 178.0 +/- 7.6 beats/min). Atropine given during exercise evoked significantly greater increases in heart rate in the control (+48.7 +/- 7.9 beats/min) vs. propranolol (+14.2 +/- 6.7 beats/min) conditions. These data suggest that 1) high levels of cardiac vagal tone remain during exercise; 2) vagal withdrawal is largely responsible for the heart rate increase after beta-adrenergic receptor blockade; and 3) time-series analysis of the R-R interval can provide a dynamic and noninvasive index of cardiac vagal tone.

A Theoretical Appraisal of the Dependence of Respiratory Sinus Arrhythmia on Gradual Vagal Blockade

2004 ◽  
Vol 43 (01) ◽  
pp. 52-55 ◽  
Author(s):  
E. Pyetan ◽  
S. Akselrod
Keyword(s):  
Heart Rate ◽  
Respiratory Sinus Arrhythmia ◽  
Vagal Tone ◽  
Vagal Activity ◽  
Theoretical Evaluation ◽  
Sinus Arrhythmia ◽  
Cardiac Vagal Tone ◽  
Closed Set ◽  
Vagal Blockade ◽  
The Relationship

Summary Motivation: The high frequency (HF) indices of heart rate variability (HRV), which reflect the magnitude of respiratory sinus arrhythmia (RSA), have been repeatedly used as measures of cardiac vagal tone. Recent studies, however, have shown experimentally that variations in these indices do not necessarily reflect proportional changes in cardiac parasympathetic outflow. Objective: The goal of this study was to obtain a physiological-based theoretical evaluation of the relationship between RSA and cardiac vagal tone, which will help explain conflicting experimental results previously published. Methods: We derived a theoretical model for heart rate (HR) response to gradual vagal blockade. The model implements the integral-pulse-frequency-modulation (IPFM) approach to sinoatrial (SA) node physiology. The level of vagal blockade was simulated by the addition of a cardio-selective muscarinic antagonist. Results and Conclusion: The derivations of the model lead to a closed set of equations, from which the dependence of the HF indices on the level of vagal blockade is deduced. It is shown that several aspects of the physiological condition may have a substantial effect on this relationship: the level of baseline vagal activity, the relationship between vagal tone and the fluctuations in its traffic, the level of sympathetic activity, etc… Hence, changes in the HF indices of HRV provide a plausible assessment of the changes in cardiac vagal tone only under a specific range of physiological conditions.

Blood pressure, heart rate, and adrenal catecholamines prior to ventricular fibrillation

1961 ◽  
Vol 201 (1) ◽  
pp. 109-111 ◽  
Author(s):  
Noel M. Bass ◽  
Vincent V. Glaviano
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Ventricular Fibrillation ◽  
Coronary Occlusion ◽  
Marked Decrease ◽  
Mean Blood Pressure ◽  
Plasma Adrenaline ◽  
Acute Coronary Occlusion ◽  
Before And After

Heart rate, mean blood pressure, adrenal blood flow, and adrenal plasma adrenaline and noradrenaline were compared before and after ligation of the anterior descending coronary artery in dogs anesthetized with chloralose. One group of 12 dogs responded to acute coronary occlusion with a sudden and marked decrease in mean blood pressure (mean, 31%) and heart rate (mean, 18%) followed by an early onset (mean, 227 sec) of ventricular fibrillation. Another group of nine dogs responded with slight decreases in mean blood pressure (mean, 13%) and heart rate (mean, 5%), during which time ventricular fibrillation occurred late (mean, 30 min) or not at all. While the two groups were statistically different in mean blood pressure and heart rate, the minute output of adrenal catecholamines in either group was not found to be related to the early or late occurrence of ventricular fibrillation.

scholarly journals Effect of muscle mass and intensity of isometric contraction on heart rate

2000 ◽  
Vol 88 (2) ◽  
pp. 487-492 ◽  
Author(s):  
José M. Gálvez ◽  
Juan P. Alonso ◽  
Luis A. Sangrador ◽  
Gonzalo Navarro
Keyword(s):  
Heart Rate ◽  
Muscle Mass ◽  
Rate Increase ◽  
Isometric Exercise ◽  
Heart Rate Increase ◽  
Maximal Force ◽  
Wheel Turn ◽  
Obese Subjects ◽  
Energetic Expenditure ◽  
Handgrip Contractions

The purpose of this study was to determine the effect of muscle mass and the level of force on the contraction-induced rise in heart rate. We conducted an experimental study in a sample of 28 healthy men between 20 and 30 yr of age (power: 95%, α: 5%). Smokers, obese subjects, and those who performed regular physical activity over a certain amount of energetic expenditure were excluded from the study. The participants exerted two types of isometric contractions: handgrip and turning a 40-cm-diameter wheel. Both were sustained to exhaustion at 20 and 50% of maximal force. Twenty-five subjects finished the experiment. Heart rate increased a mean of 15.1 beats/min [95% confidence interval (CI): 5.5–24.6] from 20 to 50% handgrip contractions, and 20.7 beats/min (95% CI: 11.9–29.5) from 20 to 50% wheel-turn contractions. Heart rate also increased a mean of 13.3 beats/min (95% CI: 10.4–16.1) from handgrip to wheel-turn contractions at 20% maximal force, and 18.9 beats/min (95% CI: 9.8–28.0) from handgrip to wheel-turn contractions at 50% maximal force. We conclude that the magnitude of the heart rate increase during isometric exercise is related to the intensity of the contraction and the mass of the contracted muscle.

scholarly journals Monitoring athletic training status using the maximal rate of heart rate increase

2016 ◽  
Vol 19 (7) ◽  
pp. 590-595 ◽  
Author(s):  
Clint R. Bellenger ◽  
Rebecca L. Thomson ◽  
Peter R.C. Howe ◽  
Laura Karavirta ◽  
Jonathan D. Buckley
Keyword(s):  
Heart Rate ◽  
Athletic Training ◽  
Rate Increase ◽  
Training Status ◽  
Maximal Rate ◽  
Heart Rate Increase

scholarly journals Movement-induced heart rate changes in epileptic and non-epileptic seizures

2009 ◽  
Vol 67 (3b) ◽  
pp. 789-791 ◽  
Author(s):  
Gisele R. de Oliveira ◽  
Francisco de A.A. Gondim ◽  
Edward R. Hogan ◽  
Francisco H. Rola
Keyword(s):  
Heart Rate ◽  
Motor Activity ◽  
Rate Increase ◽  
Epileptic Seizures ◽  
Baseline Heart Rate ◽  
Heart Rate Increase ◽  
Event Duration ◽  
Rate Analysis ◽  
Heart Rate Analysis ◽  
Video Eeg

Heart rate changes are common in epileptic and non-epileptic seizures. Previous studies have not adequately assessed the contribution of motor activity on these changes nor have evaluated them during prolonged monitoring. We retrospectively evaluated 143 seizures and auras from 76 patients admitted for video EEG monitoring. The events were classified according to the degree of ictal motor activity (severe, moderate and mild/absent) in: severe epileptic (SE, N=17), severe non-epileptic (SNE, N=6), moderate epileptic (ME, N=28), moderate non-epileptic (MNE, N=11), mild epileptic (mE, N=35), mild non-epileptic (mNE, N=33) and mild aura (aura, N=13). Heart rate increased in the ictal period in severe epileptic, severe non-epileptic, moderate epileptic and mild epileptic events (p<0.05). Heart rate returned to baseline levels during the post ictal phase in severe non-epileptic seizures but not in severe epileptic patients. Aura events had a higher baseline heart rate. A cut-off of 20% heart rate increase may distinguish moderate epileptic and mild epileptic events lasting more than 30 seconds. In epileptic seizures with mild/absent motor activity, the magnitude of heart rate increase is proportional to the event duration. Heart rate analysis in seizures with different degrees of movement during the ictal phase can help to distinguish epileptic from non-epileptic events.

scholarly journals The Opposite of Stress

2020 ◽  
Vol 67 (2) ◽  
pp. 150-159
Author(s):  
Maria Meier ◽  
Eva Unternaehrer ◽  
Sabine M. Schorpp ◽  
Maya Wenzel ◽  
Annika Benz ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Divergent Thinking ◽  
Area Under The Curve ◽  
Vagal Tone ◽  
Positive Association ◽  
Control Group ◽  
Creative Potential ◽  
Sinus Arrhythmia ◽  
Healthy Female

Abstract. Cognition is affected by psychophysiological states. While the influence of stress on cognition has been investigated intensively, less studies have addressed how the opposite of stress, a state of relaxation, affects cognition. We investigated whether the extent of parasympathetic activation is positively related to divergent thinking. Sixty healthy female participants were randomly allocated to a standardized vagus nerve massage ( n = 19), a standardized soft shoulder massage ( n = 22), or a resting control group ( n = 19). Subsequently, participants completed the Alternative Uses Test (AUT), a measure of divergent thinking. Respiratory sinus arrhythmia (RSA), a vagally mediated heart rate variability component, was monitored throughout the experiment. The area under the curve with respect to the increase was calculated for RSA trajectories as an indicator of vagal tone during the relaxing intervention. Regressions tested the effect of vagal tone on AUT outcomes. We found an association between vagal tone and subsequent AUT outcomes. Yet, this association was no longer significant when controlling for the effect of the creative potential of an individual, which was strongly related to AUT outcomes. Being exploratory, we found a positive association between creative potential and vagal tone. These results imply that creative potential might be related to the capacity to relax.

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