Amrinone has been shown to have a beneficial effect on left ventricular function in low output syndrome (LOS), but its use after open-heart surgery has not been extensively revised. We studied 10 patients with LOS post-cardiopulmonary bypass (CPB), who failed to respond to conventional treatment (vasoactive drugs plus intraaortic balloon pump) and were treated with amrinone, 0.75 mg.kg-1 followed by a continuous infusion of 5 to 10 micrograms.kg-1-min-1. One patient failed to respond to the treatment and subsequently died, but in the other nine patients blood pressure and cardiac index increased, left filling pressure decreased and they were successfully weaned from the CBP and survived. These results suggest that amrinone, either alone or combined with other inotropic drugs and mechanical support, is a valuable drug in the management of LOS after CPB.