We performed a multicenter, double-blind, randomized study to evaluate the effect of
diltiazem on reinfarction after a non-Q-wave
myocardial infarction. Nine centers enrolled 576 patients: 287 received
diltiazem (90 mg every six hours) and 289 received placebo. Treatment was initiated 24 to 72 hours after the onset of
infarction and continued for up to 14 days. The primary end point, reinfarction, was defined as an abnormal reelevation of
MB creatine kinase in plasma within 14 days. Reinfarction occurred in 27 patients in the placebo group (9.3 percent) and in 15 in the
diltiazem group (5.2 percent)--a 51.2 percent reduction in cumulative life-table incidence (P = 0.0297; 90 percent confidence interval, 7 to 67 percent).
Diltiazem reduced the frequency of refractory postinfarction angina (a secondary end point) by 49.7 percent (P = 0.0345; 90 percent confidence interval, 6 to 73 percent). Mortality was similar in the two groups (3.1 and 3.8 percent, respectively, in the placebo and
diltiazem groups), but
adverse drug reactions (most of which were mild) were more common in the
diltiazem group. Nevertheless, the
drug was well tolerated, despite concurrent treatment with beta-blockers in 61 percent of the patients. We conclude that
diltiazem was effective in preventing early reinfarction and severe angina after non-Q-wave
infarction and that it was also safe and generally well tolerated.