Effects of verapamil in preventing early postinfarction angina and reinfarction

Because verapamil is effective in the treatment of "preinfarction" angina, a single-blind, placebo-controlled trial was performed in 17 patients admitted to the coronary care unit with transmural acute myocardial infarction (AMI) to assess the effects of verapamil on angina and reinfarction after AMI. The study was terminated because results obtained in the initial 17 patients indicated that verapamil is not as effective in treating angina after AMI as it is in angina before AMI and does not prevent reinfarction. Continuous electrocardiographic monitoring during the first 3 days after AMI showed the presence of transient episodes of ST-segment elevation in 4 patients taking verapamil and 4 patients taking placebo. The total number and duration of transient ischemic episodes was similar in the 2 groups (46 vs 41 and 23 +/- 22 vs 17 +/- 15 minutes, respectively). The percentage of transient ischemic episodes accompanied by chest pain was similar in both groups (10%). The ischemic episodes were never preceded by important increases of heart rate. Four patients taking verapamil and 4 taking placebo had reinfarction within the first 10 days after the incident AMI. These findings suggest that the prevailing mechanisms of myocardial ischemia in the immediate post-AMI period could be different from those operating in angina before AMI.