Hemodynamic effects of intravenous butopamine in congestive heart failure

Butopamine is chemically similar to dobutamine but, unlike dobutamine, it is not a catecholamine. Preclinical studies on dogs show that butopamine is inotropic intravenously and orally. We gave butopamine intravenously to eight patients with congestive heart failure using a progressive dose-response protocol ranging from 0.02 to 0.17 mcg/kg/min. The mean cardiac index and stroke volume index increased at doses greater than or equal to 0.06 mcg/kg/min; there was also an increase in heart rate at greater than or equal to 0.06 mcg/kg/min. At greater than or equal to 0.08 mcg/kg/min the augmented stroke volume tended to plateau so that additional increases in the cardiac index were secondary to the elevated heart rate. Improved ventricular performance, measured by systolic time intervals, left ventricular stroke work index, and the calculated mean rate of left ventricular pressure development during isovolumetric contraction (delta P/delta t/PCWP), was noted at greater than or equal to 0.06 mcg/kg/min. Systemic systolic blood pressure increased at greater than or equal to 0.04 mcg/kg/min but diastolic and mean arterial pressures and pulmonary artery and pulmonary capillary wedge pressures did not change. The progressive increase in cardiac output was accompanied by a reduction in pulmonary and systemic vascular resistances. Although mean premature ventricular contractions per minute did not change, two patients experienced a substantial increase in ventricular ectopy at 0.10 and 0.12 mcg/kg/min. Butopamine induces a positive inotropic response in patients with congestive heart failure but for equal increments in cardiac output, butopamine increases heart rate more than dobutamine.