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Intracoronary adenosine and papaverine do not increase myocardial systolic thickening
R S Kiesz1, J D Gehman, J A Gascho
1Department of Medicine, Milton S Hershey Medical Center, Pennsylvania State College of Medicine, Hershey 17033.
Insights
Augmenting coronary blood flow with intracoronary vasodilators like adenosine and papaverine did not improve myocardial systolic thickening in dogs. Increased blood flow does not necessarily enhance systolic function.
Area of Science:
- Cardiovascular Physiology
- Myocardial Function
Background:
- Coronary blood flow is crucial for myocardial function.
- Vasodilators are used to increase blood flow, but their effect on systolic function is not fully understood.
Purpose of the Study:
- To investigate if increased coronary blood flow via intracoronary vasodilators enhances myocardial systolic thickening.
- To test the hypothesis that augmented myocardial blood flow improves systolic function.
Main Methods:
- Systolic thickening fraction was measured using pulsed Doppler and sonomicrometer crystals.
- Measurements were taken in anesthetized mongrel dogs before and during intracoronary infusion of adenosine and papaverine.
Main Results:
- Intracoronary adenosine increased myocardial blood flow 3-4 fold but did not alter systemic hemodynamics.
- Intracoronary papaverine slightly decreased systemic arterial pressure and increased heart rate.
- Neither vasodilator increased systolic thickening fraction.
Conclusions:
- The study does not support the hypothesis that increased myocardial blood flow from intracoronary vasodilators enhances myocardial systolic function.
- Coronary vasodilation may not directly translate to improved systolic performance.
Study Objective:
The aim was to determine if myocardial systolic thickening increases when coronary flow is augmented by infusing intracoronary vasodilators (adenosine and papaverine).
Design:
Systolic thickening fraction was measured with pulsed Doppler crystals and sonomicrometer crystals before and during the intracoronary infusion of adenosine and papaverine.
Subjects:
Sixteen anaesthetized mongrel dogs were studied.
Measurements And Main Results:
Intracoronary adenosine did not alter systemic haemodynamics, but did induce a three- to fourfold increase in myocardial blood flow. Intracoronary papaverine caused a slight decrease in systemic arterial pressure and rise in heart rate. Neither intracoronary adenosine nor intracoronary papaverine increased systolic thickening: control thickening fraction (TF%) = 20 (SEM 1)%, adenosine TF% = 18(1)%; control TF% = 22(2)%, papaverine TF% = 20(2)%.
Conclusions:
These experiments do not support the hypothesis that an increase in myocardial blood flow induced by intracoronary vasodilators causes an increase in myocardial systolic function.