Increasing coronary perfusion pressure on diastolic and systolic performance is less pronounced in right ventricle than in left ventricle

Abstract

Little is known as to whether an increase in coronary perfusion pressure can alter the right ventricular (RV) distensibility and the contractile function as it does in the case of the LV. In eight isolated isovolumically contracting canine hearts, RV and LV volumes and coronary perfusion were independently controlled. Effects of an increase in coronary perfusion pressure (from 73 +/- 1 to 152 +/- 6 mmHg) on the end-diastolic and end-systolic pressure-volume relations in both RV and LV were assessed. Following an increase in coronary perfusion, and at a similar volume of the ventricles, end-diastolic pressure was elevated by 2.8 +/- 0.8 mmHg in RV and 8.9 +/- 2.0 mmHg in LV (P < 0.01; RV vs LV), and the slope of RV end-systolic pressure-volume relation, Ees, increased by 11 +/- 6% (P < 0.05) and that of the LV Ees by 21 +/- 5% (P < 0.01). The percent change of RV pressure-volume area (PVA) was less than that in LV-PVA (26 +/- 9 vs 48 +/- 11%; P < 0.05). Accordingly, increases in coronary perfusion pressure and/or flow decreased the RV distensibility and enhanced the RV contractile function, the extent of which, however, was less than that in the LV.