Coronary Blood Flow, Myocardial Oxygen Consumption, and Myocardial Metabolism in Normal and Hyperthyroid Human Subjects

The effects of thyroid hormone excess on myocardial hemodynamics and carbohydrate metabolism were determined in a group of subjects, and the findings compared with those obtained in a group of normal individuals. The results indicate that in thyrotoxicosis there tends to be an increase in coronary blood flow and myocardial oxygen consumption and a normal per cent extraction of oxygen by the myocardium. The metabolism of glucose, lactic acid, and pyruvic acid was virtually identical in the 2 groups. No relationship was demonstrable between the arterial levels of the carbohydrate substances and their extraction by the heart.