Low-dose captopril in chronic heart failure: acute haemodynamic effects and long-term treatment.

The acute haemodynamic effects of low doses of the oral converting-enzyme inhibitor, captopril, were studied in 18 patients with severe chronic heart failure. The effects of long-term therapy were also evaluated. Increasing doses (1 mg, 2.5 mg, 6.25 mg, 12.5 mg, and 25 mg) of captopril were given at 2 h intervals with haemodynamic monitoring. Graded haemodynamic improvement (increased stroke-volume index and reduced mean pulmonary capillary wedge pressure) was noted from 1 hand was closely associated with reduction of blood pressure. Maximal haemodynamic improvement for the group was seen at 6 h and 7 h after the 6.25 mg and 12.5 mg doses, when stroke-volume index had risen 35% and mean pulmonary capillary wedge pressure had fallen 40% from control. Captopril 12.5-50 mg every 8 h was continued long term but was withdrawn in 2 patients with symptomatic hypotension and 1 patient with altered taste. 4 patients died and 1 was noncompliant with therapy. At 3 months, 10 patients showed significant improvement in symptoms, treadmill-exercise duration, and echocardiographic indices of left-ventricular size and function. Repeat haemodynamic measurements were similar to optimum measurements obtained during the initial study.