DATA SOURCES: MEDLINE searches identified applicable literature, including experimental trials and review articles.
STUDY SELECTION: Morbidity and mortality data evaluating the effect of postinfarction
ventricular remodeling are rare. At the time of publication, all available clinical trials studying the effects of
ACE inhibitors on postinfarction
ventricular remodeling were included, regardless of whether morbidity and mortality were assessed. Data from the Survival and Ventricular Enlargement (SAVE) and Cooperative New Scandinavian
Enalapril Survival Study II (CONSENSUS II) trials include almost 10,000 patients. Data were extracted by two independent observers. Data quality and validity were assessed based on sample size, stratification of study population, and statistical power of the studies.
DATA SYNTHESIS:
ACE inhibitors may prevent the deleterious consequences of AMI, including
ventricular remodeling and neurohumoral activation. Ventricular
hypertrophy begins acutely following
infarction, an early physiologic response to myocardial injury. Hemodynamic benefits from the initial phase of
left ventricular hypertrophy include increased ventricular working capacity, normalized systolic wall stress, and maintenance of stroke volume. Although acute dilatation may delay hemodynamic deterioration for six to eight months, it also results in reduced coronary reserve, decreased ventricular compliance, and altered myocardial contractility. With chronic dilatation, the beneficial effects reach a plateau, stroke volume decreases, contractility is reduced, and
cardiac failure may ensue. Ventricular
hypertrophy is associated with worsened prognosis following
infarction and may be the most important single determinant of late prognosis. Ventricular
hypertrophy contributes to postinfarction
heart failure, angina, and
sudden death. Clinical trials show a beneficial effect of the
ACE inhibitor captopril on the prevention of
left ventricular dysfunction. Although
captopril therapy significantly improved survival and myocardial function following AMI in the SAVE trial, these results cannot be generalized to all patient subpopulations. The CONSENSUS II trial demonstrated a decreased survival rate when
enalapril was administered within 24 hours of AMI, indicating that timing of
therapy may be an important consideration.
Captopril therapy may positively affect outcome when initiated 3-16 days following
infarction in patients with ejection fractions below 40 percent and who have no signs of
ischemia or
heart failure. Based on the CONSENSUS II results,
enalapril therapy immediately following AMI cannot be recommended.
CONCLUSIONS: Clinical trials have demonstrated that
ACE inhibitors can limit ventricular
hypertrophy following AMI, resulting in clinical benefit and improved survival. These effects may be secondary to modulation of neurohumoral activation or the antiischemic effect of
ACE inhibitors, which may also reduce the incidence of reinfarction. Early intervention with
ACE inhibitors (within 3-16 days of
infarction) can slow the progression of
cardiovascular disease and improve the survival rate.