Ventricular systolic pressure-volume area (PVA) and contractile state (Emax) determine myocardial oxygen demand.

Abstract

We have briefly reviewed the recent advances in the understanding of primary determinants of cardiac oxygen consumption (Vo2). We focused on our own experimental findings that Vo2 is a function of left ventricular systolic pressure-volume area (PVA), as a measure of total mechanical energy generated by contraction, and the left ventricular contractility index (Emax). We conclude that the cardiac oxygen demand of the ongoing contractions is equivalent to Vo2 and is a precise function of PVA and Emax whether coronary oxygen supply is normal or mildly limited in the excised, cross-circulated dog left ventricle. However, when the coronary oxygen supply is severely limited, Vo2 may not always be equivalent to the oxygen demand capability shown by the heart when its coronary oxygen supply is restored.