Hemodynamic effects of intravenous prenalterol in patients on long-term digoxin therapy for congestive heart failure.

Abstract

The hemodynamic effects of a new beta-1-adrenoceptor agonist, prenalterol, were studied in 12 patients with regurgitant valve disease and/or ischemic heart disease (prenalterol group). Five other patients were randomized to a control group and studied in the same way except that saline was administered instead of prenalterol. All patients were on long-term digoxin therapy. Heart rate, stroke volume, cardiac output, arteriovenous oxygen difference, pressures in the right atrium, pulmonary artery and left ventricle were determined both at rest and during recumbent exercise before and after administration of 50 μg prenalterol/kg body weight, or of saline. Prenalterol caused a significant increase in heart rate and cardiac output and a significant reduction in arteriovenous oxygen difference, in left ventricular filling pressure and in right atrial pressure both at rest and during exercise. A significant increase of stroke volume was seen only during exercise. In the placebo group, no significant hemodynamic changes were recorded. No adverse effects were observed. Thus, prenalterol seems to have beneficial hemodynamic effects, additive to those of digitalis. The drug is potentially useful in the treatment of heart failure, but further studies on the specific mechanism of action and the long-term effects are warranted.