The hemodynamic effects of amrinone, a phosphodiesterase III inhibitor, were studied early after cardiac surgery in 10 patients. CI, SVI and SWI increased significantly. SAP, mPCWP, TSVR and PVR decreased significantly. DO2 and VO2 increased significantly. HR and DP were not affected. These data demonstrate that amrinone is a valuable inotropic agent with vasodilating effect for the early post-operative management of cardiac surgical patients, since it augments left ventricular performance without increase of myocardial oxygen consumption and induction of arrhythmia.