The β-Blocker Heart Attack Trial

THE NATIONAL Heart, Lung, and Blood Institute (NHLBI), Bethesda, Md, has taken the unusual step of curtailing one of its major clinical trials—the β-Blocker Heart Attack Trial (BHAT)—on the advice of its Policy and Data Monitoring Board. The step was taken after data indicated that the group of patients receiving propranolol hydrochloride experienced a 26% lower mortality from all causes than did a control group. The BHAT was a randomized, double-blind, multicenter clinical trial of propranolol vs placebo in patients enrolled five to 21 days after the onset of an acute myocardial infarction. The primary objective was to determine if long-term administration of propranolol in this population would result in a significant reduction in total mortality over the follow-up period. Thirty-one clinical centers, a coordinating center, a resting ECG reading center, a 24-hour ambulatory ECG reading center, a central laboratory, a drug distribution center, and an NHLBI program office were