THE RELATIVE IMPORTANCE OF THE PERFORMANCE OF WORK AND THE INITIAL FIBER LENGTH IN DETERMINING THE MAGNITUDE OF ENERGY LIBERATION IN THE HEART

Abstract

Measurement of O consumption in the tortoise ventricle shows that when the heart works nearly isometrically its energy liberation is the same as when contracting more nearly isotonically at the same diastolic fiber length. There is no evidence for the existence of the "Fenn effect" in cardiac muscle.