In the present study 12 of 13 untreated pigs died of ventricular fibrillation during three 10 min episodes of left anterior descending coronary artery occlusion interrupted by 20 min of reperfusion. The selective beta-adrenoceptor antagonist bevantolol in a dose of 1.5 mg X kg-1, but not 0.5 mg X kg-1, offered nearly complete protection against this fatal arrhythmia. Evidence is also presented that bevantolol enhanced the recovery of regional myocardial function after these ischaemic events.