Oxprenolol in myocardial infarction survivors: brief review of the European Infarction Study results in the light of other beta-blocker post infarction trials

Abstract

The European Infarction Study (EIS) was a multicentre, double-blind, randomized study comparing the effect on survival, cardiac mortality and non-fatal cardiac events of oxprenolol slow release 160 mg b.i.d. with placebo in 1,741 patients aged 35 to 69 years surviving acute myocardial infarction. During the one year follow-up there was a 30% difference in the cumulative mortality rate in favor of placebo. In the oxprenolol group the mortality was noted to be higher in patients who were 65-69 years of age. In general, there was a higher incidence of fatal reinfarctions and of sudden death in those, who discontinued study medication. 24-hour ECG recordings before randomization in 736 patients revealed a high prevalence of complex ventricular tachydysrhythmias. These patients had a significantly higher one-year mortality. Like other beta-blocking drugs oxprenolol had a weak suppressant effect on ventricular tachydysrhythmias in infarct survivors. The proportion of deaths was noted to be higher in the oxprenolol group to the same relative degree in patients with or without complex tachydysrhythmias. Reviewing the results of other beta-blocker post infarction trials it is concluded that a protective effect on sudden death in myocardial infarction survivors is related to beta-blockade. Beta-blocking drugs with significant intrinsic sympathomimetic activity, which partly counteracts beta-blockade, might be less effective. High dose oxprenolol treatment might be deleterious to some patients with more enhanced coronary heart disease.