Controlled study of long-term prazosin in refractory heart failure. Eur Heart J

Twelve patients with long-standing congestive heart failure refractory to digitalis and diuretics were alternately allocated to receive either 20 mg/day prazosin or placebo in addition to their standard regimen for six weeks. During the next six weeks, placebo was substituted for prazosin and vice versa. Heart rate, blood pressure, pulmonary arterial pressure, and cardiac output at rest and during exercise were determined at the onset of the study and at the end of the prazosin phase. Weight, signs of pulmonary congestion, peripheral edema and subjective complaints were evaluated weekly. The acute administration of 2 mg prazosin in seven patients at the end of the placebo phase produced a significant rise in cardiac output at rest and during exercise (P <&05) 45 min after the drug was taken. Following the six-week prazosin phase, cardiac output had increased from 3'2 to 4-0 l/min at rest and from 69 to 80 l/min during exercise (? <0-05, n = 12). Pulmonary arterial pressure, blood pressure, and heart rate did not change significantly. Most striking was a radiographically determined decrease in heart volume from 1440 to 1306 ml/1-73 m2 BSA (P <0~02). The hemodynamic improvement paralleled a clinical improvement of 0-5 to 1 Class according to NYHA criteria. Serious side-effects were not observed. Prazosin appears to have effects which complement those of digitalis and diuretics and represents a useful addition to drugs used in the treatment of congestive heart failure