Long-acting angiotensin-converting enzyme inhibition: once-daily lisinopril versus twice-daily captopril in mild-to-moderate heart failure.

Once-daily lisinopril (5-20 mg) was compared with twice-daily captopril (12.5-50 mg) in a double-blind, randomized, parallel-group study of angiotensin-converting enzyme (ACE) inhibition conducted in 31 centers for 12 weeks in patients with heart failure (New York Heart Association class II-III) who were currently receiving digitalis and/or diuretics. The drugs were compared with regard to their effects on exercise duration, measured with bicycle ergometry, and on ectopic activity, measured using Holter monitoring. Both drugs significantly increased exercise duration after both 6 and 12 weeks of randomized treatment. Neither ACE inhibitor had any significant impact on the hourly rate of either ventricular ectopic counts or couplets, nor was there any difference between treatments with regard to the proportions of patients in whom ventricular ectopic counts were reduced. Both drugs were well tolerated, with no differences observed between treatments. Potassium, urea, and creatinine levels remained stable for both treatments throughout the study.