Intravenous and oral prenalterol in congestive heart failure. Effects on systemic and coronary hemodynamics and myocardial catecholamine balance.

Systemic and coronary hemodynamic effects of prenalterol, a beta-1 receptor agonist, were determined in patients with chronic congestive heart failure, initially after intravenous administration (10 patients) and then after oral administration (eight patients). Cardiac index increased by 33 percent and 30 percent after intravenous and oral prenalterol, respectively. The increase in stroke volume index and stroke work index and decrease in pulmonary capillary wedge pressure and systemic vascular resistance were not significant. Myocardial oxygen consumption and coronary sinus blood flow increased in the majority of patients, although these changes were not statistically significant. There were no significant changes in transmyocardial norepinephrine or epinephrine balance. The systemic and coronary hemodynamic effects of both intravenous and oral prenalterol were similar. Major side effects included sudden death (two patients) and hypotension and bradycardia (three patients) during oral prenalterol treatment. It is concluded that improved left ventricular function following both intravenous and oral prenalterol may be associated with increased myocardial oxygen consumption, and serious adverse effects may occur during prenalterol therapy.