In 19 patients with chronic heart failure in NYHA stages III and IV, hemodynamic measurements were made using a Swan-Ganz catheter before and 15 and 30 min after intravenous administration of enoximone. Group A (n = 10) received 1.0 mg of enoximone/kg of body weight and group B (n = 9) received 1.5 mg of enoximone/kg of body weight. In group A, there was a rise in the pulse rate of 13% and in the cardiac index of 13% with unchanged stroke volume index. At constant mean arterial pressure, the mean right atrial pressure fell by 28%, the mean pulmonary arterial pressure by 11%, the total peripheral resistance by 13%, and the total pulmonary resistance by 21% after 30 min. In group B, the pulse rate rose by 9.8%, the mean blood pressure by 2.7%, the cardiac index by 31.4%, and the stroke volume index by 18.4% 30 min after administration of enoximone, whereas a fall in the mean right atrial pressure by 57.4%, the mean pulmonary arterial pressure by 28.6%, the total peripheral resistance by 26.0%, and the total pulmonary resistance by 45.3% could be shown. At a low dosage of enoximone, the vasodilatory effects of this substance are most prominent, whereas an increase in the pumping performance of the heart could be clearly demonstrated in higher dose ranges.