What question did this study set out to answer?

This study aims to investigate the impact of submaximal exercise on heart rate variability and cardiac vagal tone in dogs with myocardial infarctions.

July 1, 1989CirculationOpen Access

Time-series analysis of heart rate variability during submaximal exercise. Evidence for reduced cardiac vagal tone in animals susceptible to ventricular fibrillation.

View Full Paper

Ask AI

Bookmark

Why the study?

Does exercise-induced reduction in cardiac vagal tone correlate with susceptibility to ventricular fibrillation in dogs with healed myocardial infarction?

Population

36 mongrel dogs with healed anterior myocardial infarctions

Comparison

Submaximal exercise test, followed by a 2-minute… vs Comparison between animals that developed…

Design

Preclinical

Authors

GBGeorge E. BillmanElectrophysiology RHRichard S. HoskinsThe Ohio State University

Discussion

Member takes

Implication

Indicates vagal withdrawal during exercise marks VF susceptibility in post-MI canines; leaves open human translation.

Key Points

This study aims to investigate the impact of submaximal exercise on heart rate variability and cardiac vagal tone in dogs with myocardial infarctions.
Measured heart rate variability in 36 mongrel dogs with healed anterior myocardial infarctions during a submaximal exercise test.
Analyzed respiratory component amplitude (0.24-1.04 Hz) as an index of cardiac vagal tone using time-series analysis techniques.
Conducted a 2-minute coronary occlusion on a subsequent day to assess vulnerability to ventricular fibrillation.
Susceptible animals showed a greater heart rate increase (227.0 +/- 5.4 beats/min) compared to resistant animals (205.4 +/- 7.1 beats/min).
Cardiac vagal tone index was significantly lower in susceptible animals (1.1 +/- 0.2 ln msec2) compared to resistant animals (2.7 +/- 0.3).
Atropine increased heart rate more in resistant dogs (54.2 +/- 7.0) than in susceptible dogs (18.7 +/- 4.4 beats/min) during exercise.

Structured PICO

Does exercise-induced reduction in cardiac vagal tone correlate with susceptibility to ventricular fibrillation in dogs with healed myocardial infarction?

Population

36 mongrel dogs with healed anterior myocardial infarctions

Intervention

Submaximal exercise test, followed by a 2-minute coronary occlusion during the last minute of exercise on a subsequent day, and atropine sulfate (50 micrograms/kg) administration during exercise

Comparator

Comparison between animals that developed ventricular fibrillation (susceptible, n=22) and those that did not (resistant, n=14)

Outcome

Heart rate and cardiac vagal tone index (amplitude of the respiratory component of heart rate variability, 0.24-1.04 Hz)surrogate

In a canine model of healed myocardial infarction, animals susceptible to ventricular fibrillation exhibited a greater reduction in cardiac vagal tone during exercise compared to resistant animals.

Cite This Study

Billman et al. (1989) studied this question.

synapsesocial.com/papers/6a12e7ddb761793c20c0c548 https://doi.org/10.1161/01.cir.80.1.146

View Full Paper

Ask AI

Bookmark

Time-series analysis of heart rate variability during submaximal exercise. Evidence for reduced cardiac vagal tone in animals susceptible to ventricular fibrillation.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Time-series analysis of heart rate variability during submaximal exercise. Evidence for reduced cardiac vagal tone in animals susceptible to ventricular fibrillation.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Also Consider

Also Consider