Measurement of myocardial developed tension and its relation to oxygen consumption

Abstract

Myocardial O2 consumption was studied in a canine right heart-bypass preparation. Left ventricular developed tension, dependent on intraventricular pressure and internal radius of the ventricle, was determined at 20-msec. intervals throughout the cardiac cycle. Left ventricular end-diastolic and end-systolic volumes were measured by thermodilution and instantaneous volume was determined by the relative changes in a mercury in rubber gauge placed on the left ventricular circumference. Throughout a wide range of hemodynamic states, the best correlate with myocardial O2 consumption (ml/100 g/min.) was found to be the peak developed tension multiplied by heart rate.