Mechanical interaction between the ventricles.

We investigated ventricular interaction by the use of six excised, perfused, canine hearts. In this preparation, we could change the filling pressure of the right and left ventricles independently, thereby breaking the normal series-pump arrangement. We found that mechanical ventricular interaction exists in diastole and in systole. Namely, not only decreased diastolic ventricular compliance, but also the reduced performance in either ventricle was found, when the opposite ventricular pressure was increased. Thus, when the opposite ventricular filling pressure increases, we suspect that systolic ventricular function of either ventricle will be depressed significantly by these two factors; i.e., the Frank-Starling effect due to decreased ventricular diastolic volume following decreased diastolic ventricular compliance, and the depressed systolic ventricular function. Clinically, these findings may be important in considering the mechanism of the occurrence of simultaneous reduced performance of both ventricles in cases when only one side of the ventricle is affected hemodynamically and its filling pressure is greatly increased in various pathological states such as heart failure.