Enalapril in patients with chronic heart failure: A placebo-controlled, randomized, double-blind study

Abstract

A number of studies have shown short-term hemodynamic and symptomatic improvement in patients with congestive heart failure treated with angiotensin converting enzyme inhibitors. The long-term efficacy of the oral long-acting converting-enzyme inhibitor enalapril remains to be established in controlled studies. We evaluated this drug in 36 patients with New York Heart Association functional class II to III heart failure who were clinically stable on digoxin and diuretic therapy. After baseline assessment of symptoms, exercise capacity, and results of echocardiographic examination and right heart catheterization, patients were randomly assigned to treatment with 5 mg enalapril twice daily (n = 18) or placebo (n = 18) in a double-blind fashion. The two groups had similar clinical, echocardiographic, and hemodynamic characteristics before treatment. After 3 months of treatment, the enalapril group showed a significant improvement as judged by subjective patient impression, functional class, and exercise duration (9.3 ± 5.7 vs 17.6 ± 5.6 min; p < .001). Diuretic dosage was reduced in six patients and increased in one patient, one patient had died and another had been withdrawn from the study. In the placebo group there was no significant changes with respect to patient impression, functional class, or exercise duration; diuretic dosage was increased in seven patients and four patients had died. Echocardiographic left ventricular dimensions were significantly reduced and left ventricular shortening fraction significantly increased in the enalapril group but were unchanged in the placebo group. Hemodynamic assessment showed a significant reduction in left ventricular filling pressure from 23 ± 8 to 13 ± 5 mm Hg (p