Intracoronary adenosine and papaverine do not increase myocardial systolic thickening.

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.