Reduction in Infarct Size, Arrhythmias, Chest Pain and Morbidity by Early Intravenous β-Blockade in Suspected Acute Myocardial Infarction

Summary477 patients suspected of acute myocardial infarction, with onset of less than 12 hours, were randomised to a control group or a group receiving intravenous atenolol followed by oral treatment for 10 days. In patients with electrocardiographic (ECG) changes of infarction at entry, intravenous atenolol significantly reduced enzyme release by one- third and enhanced R wave preservation. In patients without ECG changes of infarction at entry, treatment significantly prevented the development of infarction in a proportion of patients.There was also a significant reduction in R- on- T ectopics, repetitive ventricular arrhythmias and supraventricular arrhythmias. Treated patients had greater pain relief and required less opiate analgesics. Fewer atenolol- treated patients died at 1 week, had non- fatal cardiac arrests, developed heart failure, or suffered reinfarction.