Optimal Contractility of the Heart in an Aspect of Oxygen Consumption

Abstract

Myocardial oxygen consumption (MVO₂) of the left ventricle ejecting a constant stroke volume against a given arterial pressure, hence producing constant external work, was assessed mathematically as a function of ventricular contractility (E_max). The calculation was based on a previously proposed empirical equation of MVO₂. MVO₂ became minimal at a contractility which is close to the previously observed physiological value. From the aspect of the efficiency of energy utilization, the contractility with such minimal MVO₂ can be considered optimal. Consequently, it was suggested that the ventricular contractility is physiologically controlled so as to reach such an optimal value.