Comparison of Myocardial Oxygen Consumption Indices in Man

Hemodynamic indices of myocardial oxygen consumption (MV0 2 ) were examined in 13 patients with coronary heart disease. The specific aim of this study was to investigate whether clinical results agree with experimental findings in animals. During hemodynamic and respiratory steady‐state conditions at rest, the MV0 2 (7.6–14.2 ml/min/100 g) was measured directly by myocardial blood flow (argon method) and arterio‐coronary venous oxygen content difference. MV0 2 was compared with five indirect indices of MV0 2 . A complex additive parameter consisting of five components of MV0 2 had the highest correlation with MV0 2 (r = 0.97), as was also demonstrated in a recent experimental study at maximum changes in hemodynamics and MV0 2 . More easily measurable predictors of MV0 2 such as tension‐time index (r = 0.923), product of mean systolic aortic pressure and square root of heart rate (r = 0.928), pressure‐rate product (r = 0.915), and triple product (r = 0.941) were less closely correlated with MV0 2. The lower correlations of the readily obtainable indices of MV0 2 are probably related to their failure to incorporate factors such as contractility and ventricular dimensions, which are known to exert an important influence on MV0 2 . The excellent correlation of the hemodynamic additive parametcr with MV0 2 supports the theoretical concept and the implications of the experimental study. The accurate prediction of MV0 2 is based on adequate measurement of MV0 2 for the velocity of tension development and maintenance of tension during systolic ejection period, both of which are integrated in the additive index.