Separate contribution of ventricular pumping and load impedance on ventricular power output

The heart is a rather special type of fluid pump in the sense that it is an organic pump. In this paper, however, it is postulated that the heart behaves like any other mechanical pump whose power output may assume, for a primary change in load, values bounded by two limits which are power output values obtained had the pump been a pressure generator and a flow generator respectively. A power output value outside the limits would imply a definite alteration in ventricular pump function concomitant with the load change. A nomogram to illustrate the proposal is included. The hypothesis may be developed into a powerful tool for assessing the pumping capability of the left ventricle, and this has significant clinical and physiological implications.