Reduction of exercise-induced myocardial ischemia during add-on treatment with the angiotensin-converting enzyme inhibitor enalapril in patients withnormal left ventricular function and optimal beta blockade

OBJECTIVES We sought to study the effect of angiotensin-converting enzyme i nhibition on exercise-induced myocardial ischemia. BACKGROUND Although angiotensin-converting enzyme inhibitors have been show n to reduce ischemic events after myocardial infarction, few data are avail able regarding their direct anti-ischemic effects in patients with coronary artery disease. METHODS We studied 43 patients (average age 63 +/- 8 years) with exercise-i nduced myocardial ischemia (greater than or equal to0.1 mV ST depression, d espite optimal beta blockade) and normal left ventricular function (ejectio n fraction >0.50). In a double-blind, placebo-controlled parallel design, p atients were treated with angiotensin-converting enzyme inhibitor (enalapri l 10 mg twice daily) or placebo. Assessments were made aii-er three weeks ( short-term) and 12 weeks (long-term). RESULTS At baseline, the groups were well matched for all clinical characte ristics. After three weeks, there was a slight but not significant increase in time to 0.1 mV ST depression in both groups (p = NS); rate pressure pro duct (RPP = heart rate x systolic blood pressure) was also unaffected. Afte r 12 weeks, however, time to 0.1 mV ST depression further increased in the enalapril group (5.6 +/- 1.9 min) but was unchanged in the placebo group (4 .4 +/- 1.3 min; p < 0.05 between groups). In contrast, RPP was not affected . Concentrations of both atrial and brain natriuretic peptides at peak exer cise tended to be lower by enalapril, if compared to placebo (p = NS). CONCLUSIONS Angiotensin-converting enzyme inhibition may reduce exercise-in duced myocardia! ischemia in patients with normal left ventricular function . Further studies are needed to elucidate the mechanisms involved. (C) 2001 by the American College of Cardiology.