Angiotensin-converting enzyme (ACE) inhibitors have been shown to reduce the incidence of sudden cardiac death and nonfatal subsequent infarctions following myocardial infarction (MI). These agents attenuate left ventricular dilation, resulting in less ventricular enlargement. ACE inhibitors have also been shown to decrease the likelihood of malignant ventricular arrhythmias. Domanski and colleagues reviewed the literature from 1978 to 1997 in an attempt to confirm the benefit of ACE inhibitors in reducing mortality after MI.
A MEDLINE search for all randomized trials of ACE inhibitor use in post-myocardial infarction for January 1978 through August 1997 was conducted for meta-analysis. Inclusion criteria consisted of randomized comparisons of ACE inhibitor and placebo treatment of acute MIs within 14 days after the event, studies that were conducted for a period of six weeks or longer with a blinded follow-up of six weeks or longer, and studies that reported the total, cardiovascular and sudden cardiac death mortalities.
Sudden cardiac death was defined as “sudden unexpected collapse without documentation of arrhythmia or collapse due to intractable ventricular tachycardia/fibrillation.”
Fifteen studies, with a total of 15,104 patients, met the inclusion criteria. Of the 2,054 cardiovascular deaths identified, 900 were considered sudden cardiac deaths. Meta-analysis of the data from these studies revealed that the incidence of cardiovascular or sudden cardiac death was lower in patients taking ACE inhibitors than in those taking placebo. Study duration and the use of other agents, such as aspirin, beta-adrenergic blocking agents and calcium channel blockers, were not included in the meta-analysis, since they had only a small treatment effect.
The authors conclude that ACE inhibitor therapy reduces the overall incidence of cardiovascular death following acute MI. The use of ACE inhibitors also reduces sudden cardiac deaths by 20 percent, which is a significant reduction. However, the exact mechanism for this reduction has not been definitively established.