Sustained effectiveness of chronic prazosin therapy in severe chronic congestive heart failure.

Twelve patients with severe chronic congestive heart failure (CHF) (NYHA class III and IV) resistant to digitalis and diuretics were treated with the postsynaptic alpha-blocking agent prazosin (PZ) (3 to 20 mg/day). In 11 patients oral PZ treatment was well tolerated; the agent was discontinued in the remaining patient because of orthostatic dizziness. After 4 weeks of PZ, total systemic vascular resistance decreased from 2245 +/- 792 to 1603 +/- 355 dyn sec cm-5, mean blood pressure declined from 100 +/- 15 to 90 +/- 14 mm Hg, and pulmonary capillary wedge pressure decreased from 29 +/- 8 to 25 +/- 9 mm Hg. Cardiac index increased from 1.92 +/- 0.63 to 2.30 +/- 0.41 l/min/m2. The increase of stroke volume index correlated with the fall in peripheral vascular resistance (r = --0.79, p less than 0.01) and the decline in pulmonary capillary wedge pressure (r = --0.75, p less than 0.05). In parallel, exercise tolerance increased significantly. Four patients improved from functional class IV to II, four from class IV to III, and one from class III to II, while two patients were unchanged. In the eight patients followed for 6 months, the beneficial effects of ambulatory PZ were maintained throughout the expansive observation period. Three patients died as their disease process progressed during the study (sudden death, pneumonia, and post-PZ withdrawal pump failure). Prazosin is a valuable vasodilator for long-term treatment of otherwise refractory congestive heart failure with the agent given in sufficient individualized dosage.