Heart failure, often associated with ventricular enlargement and recurrent myocardial infarction, is one of the major causes of postinfarction mortality. This observation suggests that measures used to prevent ventricular enlargement may improve postinfarction survival. The Survival and Ventricular Enlargement (SAVE) trial is a randomized, double-blind, placebo-controlled clinical trial with the purpose of evaluating the effect of angiotensin-converting enzyme (ACE) inhibition on postinfarction death and ventricular dilation. This multicenter trial had a sample size goal of 2,220 patients between 21 and 79 years of age who had recently sustained a myocardial infarction and who have an ejection fraction determined by radionuclide ventriculogram (RVG-EF) of less than or equal to 40%. In addition to conventional therapy, patients were randomly assigned to captopril or placebo therapy commencing within 3-16 days following their myocardial infarction. A second RVG-EF is performed on all surviving participants at the end of the average 3.5-year treatment and follow-up period. The study has 90% power to detect a 25% improvement in postinfarction mortality or prevention of greater than or equal to 9 unit absolute reduction in radionuclide ejection fraction. Additional end points, design features, and the administrative organization of the trial are described.