Early Versus Delayed Angiotensin-Converting Enzyme Inhibition Therapy in Acute Myocardial Infarction

Abstract

Background Although ACE inhibitor therapy has been shown to reduce mortality in patients with acute myocardial infarction (MI), the optimal dose and the timing of its initiation have not been determined. Methods and Results In a double-blind trial of 352 patients with anterior MI, we compared the safety and effectiveness of early (day 1) versus delayed (day 14) initiation of the ACE inhibitor ramipril (10 mg) on echocardiographic measures of left ventricular (LV) area and ejection fraction (EF). An early, low-dose ramipril (0.625 mg) arm was also evaluated. Clinical events did not differ. During the first 14 days, the risk of manifesting a systolic arterial pressure of ≤90 mm Hg was increased in both ramipril groups. LVEF increased in all groups during this period, but the early, full-dose ramipril group had the greatest improvement in EF (increase: full, 4.9±10.0; low, 3.9±8.2%; delayed, 2.4±8.8%; P for trend <.05) and was the only group that did not demonstrate a significant increase in LV diastolic area. Conclusions The results of the present study demonstrated that in patients with anterior MI, the early use of ramipril (titrated to 10 mg) attenuated LV remodeling and was associated with a prompter recovery of LVEF. The use of low-dose regimen did not prevent hypotension and had only intermediate benefits on LV size and function. The more favorable effects on LV topography of the early use of full-dose ramipril support the results of the major clinical trials, which have demonstrated an early survival benefit of ACE inhibition.