What question did this study set out to answer?

This study aims to explore how different patterns of cardiac sympathetic activity affect heart contractility and norepinephrine release.

September 1, 1976Circulation ResearchOpen Access

The effect of the pattern of cardiac sympathetic activity on myocardial contractile force and norepinephrine overflow in the dog heart.

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Why the study?

Does intermittent cardiac sympathetic nerve stimulation alter myocardial contractile force and norepinephrine overflow compared to steady stimulation in dogs?

Population

Open-chest, anesthetized dogs

Comparison

Intermittent stimulation of left or right… vs Steady stimulation at the same mean frequency

Design

Preclinical

Authors

MLMatthew N. LevyTechnion – Israel Institute of Technology BBBenjamin BlattbergMount Sinai Hospital

Discussion

Member takes

Implication

May blunt left sympathetic effects on contractility in dogs; hypothesis-generating for patterned neuromodulation before human translation.

Key Points

This study aims to explore how different patterns of cardiac sympathetic activity affect heart contractility and norepinephrine release.
Stimulated left or right sympathetic nerves in open-chest, anesthetized dogs at frequencies of 2 or 4 Hz.
Applied stimuli in patterns with repetition rates of 60/min or 15/min to mimic natural sympathetic activity.
Measured effects on myocardial contractile force and norepinephrine overflow into the coronary sinus.
Intermittent left sympathetic stimulation was 10-20% less effective in enhancing myocardial contractile force compared to steady stimulation.
Norepinephrine overflow into the coronary sinus was 20-40% lower with intermittent stimulation than steady stimulation.
Right-sided stimulation showed no significant difference between steady and intermittent patterns regarding heart rate.

Structured PICO

Does intermittent cardiac sympathetic nerve stimulation alter myocardial contractile force and norepinephrine overflow compared to steady stimulation in dogs?

Population

Open-chest, anesthetized dogs

Intervention

Intermittent stimulation of left or right cardiac sympathetic nerves (repetition rates of 60/min or 15/min, mean frequencies 2 or 4 Hz)

Comparator

Steady stimulation at the same mean frequency

Outcome

Myocardial contractile force and norepinephrine overflowsurrogate

Intermittent sympathetic nerve stimulation results in reduced norepinephrine release and less enhancement of myocardial contractile force compared to steady stimulation at the same mean frequency in a canine model.

Cite This Study

Levy et al. (1976) studied this question.

synapsesocial.com/papers/6a70925f5d37378ac1ddb002 https://doi.org/10.1161/01.res.39.3.341

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Implication

May blunt left sympathetic effects on contractility in dogs; hypothesis-generating for patterned neuromodulation before human translation.

The effect of the pattern of cardiac sympathetic activity on myocardial contractile force and norepinephrine overflow in the dog heart.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

The effect of the pattern of cardiac sympathetic activity on myocardial contractile force and norepinephrine overflow in the dog heart.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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