Relationships Among Stroke Work, Contractile Force and Fiber Length During Changes in Ventricular Function

Abstract

There is a linear relationship between ventricular contractile force and ventricular stroke work during changes in either atrial or aortic pressures and during the changes produced by l-norepinephrine. There is also a direct relationship between the contractile force or stroke work and the end diastolic length of the segment of ventricular muscle between the two points of attachment of a heart-lever system employed to measure the contractile force. There was no consistent relationship between the stroke work or contractile force and the systemic output or stroke volume. The relative merits of measurements of contractile force and stroke work in determining changes in ventricular contractility under a variety of conditions are discussed.