Quantitative assessment of cardiac pump performance.

Abstract

SUMMARY1. A means of quantitating left ventricular performance in the conscious dog is presented. Changes in heart rate, stroke volume and cardiac output during elevation of left atrial pressure by acute volume expansion were measured in the conscious dog.2. The changes in heart rate and stroke volume could be described by y = ym-(ym-yi)e-a', where yi and ym are the initial and maximum values of the variable and p is the change in mean left atrial pressure. 3. Because cardiac output is a derived variable (stroke volume x heart rate) its response is described by a multiple exponential relationship. 4. For a given initial heart rate and inotropic state, the stroke volume response is determined by the Frank-Starling mechanism and the pressurevolume characteristics of the myocardium.

Advancing knowledge of right ventricular pathophysiology in chronic pressure overload: Insights from experimental studies

“…The RV is therefore known to adapt much better to chronic volume overload than to pressure overload [18]. An increase in preload has been demonstrated to improve myocardial contraction in the left heart [19]. The Frank-Starling mechanism characterizes the increase in ventricular stroke work in response to wall stress enhancement.…”