Mechanical interaction between the ventricles during systole

Abstract

The immediate effect of abrupt alteration in the function of either ventricle on pressures in both ventricles has been examined in rabbits. Increasing left ventricular afterload, by aortic occlusion, caused a marked increase in peak left ventricular pressure (an increase of 44.0 ± 5.7 mmHg, from a mean of 79.4 ± 3.4 mmHg) and simultaneously a significant increase (an increase of 3.8 ± 0.6 mmHg, from a mean of 24.2 ± 1.4 mmHg) in right ventricular pressure. On the other hand, when similar increases in left ventricular pressure were induced by sudden changes in preload no alteration in right ventricular pressure was seen. High-frequency oscillatory infusion of saline into the left ventricle produced coincident oscillations in both ventricular pressures during systole. Left ventricular pressure generation was affected by interventions with right ventricular performance which altered afterload or preload and, although interaction was minimal at normal physiological pressures, a significant interaction was observed during induced systemic hypotension. A direct transference of pressure from right to left ventricle, comparable with that seen in vivo, was also observed when the ventricles of excised hearts in rigor mortis were inflated with saline. It is concluded that mechanical interaction occurs between the ventricles during systole and, consequently, the ventricles cannot be treated as mechanically independent pumps.