The effect of enoximone and dobutamine on hemodynamic performance after open heart surgery. A clinical comparison. In a prospective, randomized study the phosphodiesterase inhibitor enoximone was compared to dobutamine after open heart surgery. In either group 25 patients were treated with enoximone and dobutamine, respectively, beginning immediately after weaning from cardiopulmonary bypass until 4 hours postoperatively. The drug was administered as a continuous infusion of 5 micrograms/min/kg body weight. Under enoximone a significant increase of cardiac output [enoximone (E): + 100%; dobutamine (D): + 38%] and a significant decrease of pulmonary vascular resistance (E: -34%, D: +65%) and of total systemic vascular resistance (E: -59%, D: -7%) was achieved. Systemic blood pressure and heart rate were not different. Side effects were not observed. Enoximone proved to be safe and superior to dobutamine in low cardiac output states after open heart surgery. 