Reduction of exercise-induced ventricular arrhythmias in mild symptomatic heart failure by benazepril

We studied 14 patients who had exercise-induced ventricular arrhythmias after a previous Q-wave myocardial infarction. All had symptomatic mild heart failure in New York Heart Association class II and a maximal oxygen consumption between 16 and 20 ml/kg/min. They were treated with the angiotensin converting enzyme inhibitor benazepril (20 mg) and hydrochlorothiazide (50 mg) for 3 months in a double-blind randomized cross-over study. Benazepril improved the maximal oxygen uptake by 15% and exercise time by 18%. Hydrochlorothiazide slightly increased exercise time (5%) and the respiratory exchange ratio but not oxygen consumption. The arrhythmias were nonsustained and reproducible in two baseline recordings. Compared with baseline, benazepril reduced the mean number (3.5 +/- 2.5) (+/- SD) of episodes of ventricular tachycardia by 66%, and total (47.4 +/- 40.9) and paired (5.2 +/- 4.5) premature ventricular contractions by 61% and 62%, respectively. Hydrochlorothiazide did not reduce the number of arrhythmias. Thus an improved cardiac function induced by benazepril is associated with a reduction in exercise-induced ventricular arrhythmias in patients with symptomatic mild heart failure after infarction.