BACKGROUND Our study was designed to explore the hemodynamic effects of intravenous administration of ACE-inhibitor quinaprilat in comparison with standard inotropic-vasodilator therapy. Patients with poor left ventricular function following coronary artery bypass (CABG) surgery were examined. METHODS Thirty patients with poor left ventricular function (EF<30%) following CABG surgery with use of cardiopulmonaly bypass were examined. Fourty patients were control group. All patients had complete invasive hemodynamic monitoring. The ACE-inhibitor quinaprilat 0.5 mg/h was administered intravenously via infusion pump. The following parameters were analyzed: arterial blood pressure, systemic vascular resistance, pulmonary vascular resistance, heart rate, cardiac output, cardiac index, left ventricular stroke work index and the level of mixed venous oxygen saturation. RESULTS The results of our study were as follows: Cardiac output, cardiac index and left ventricular stroke work index were significantly increased in comparison to the control group. Systemic arterial systolic pressure and pulmonary vascular resistance were decreased and there was no significant difference in systemic vascular resistance, mixed venous oxygen saturation, heart rate and diastolic blood pressure in comparison to the control group. CONCLUSIONS Our results pointed at very satisfactory hemodynamic effects of quinaprilat on "stunned myocardium", after CABG surgery. The ACE inhibitors greatly reduce mortality in patients in all stages of heart failure, from asymptomatic dysfunction of the left ventricle to severe symptomatic stages. CONCLUSIONS In prevention of heart failure in patients with impaired left ventricle function (LVEF<30%), who had undergone CABG surgery with use of cardiopulmonaly bypass, we achieved the best effects on the hemodynamics with parenteral administration of quinaprilat.