Abstract

We have studied six patients who had undergone mitral valve replacement. Estimations of cardiac output and of pulmonary vascular resistance were made, beginning two hours after the finish of the operation. Glucagon, 10 mg, was given intravenously, and cardiac output and pulmonary vascular resistance were measured 5 minutes and 30 minutes later. In all six cases there was a significant decrease in pulmonary vascular resistance and this occurred whether the resistance was slightly, moderately or greatly elevated. There was a highly significant increase in cardiac output in all cases.