Reduction in infarct size, arrhythmias and chest pain by early intravenous beta blockade in suspected acute myocardial infarction.

Four hundred seventy-seven patients suspected of having had acute myocardial infarction within less than 12 hours were randomized to receive i.v. atenolol followed by oral treatment for 10 days or to a control group. In patients with ECG changes indicative of infarction at entry, i.v. atenolol significantly reduced enzyme release by one-third and enhanced R-wave preservation. In patients without such ECG changes, treatment significantly …