Coronary artery reperfusion which has become one of the important therapeutic interventions is associated with development of cardiac arrhythmias. The present investigation was carried out to study the role of beta receptor blocking agents with different properties on reperfusion induced ventricular arrhythmias in intact rabbit heart. After anaesthesia the rabbit hearts were subjected to 30 minutes coronary artery ligation followed by reperfusion for one hour. Three doses of propranolol (0.3, 1 and 3 mgfkg), metoprolol (0.5, 0.75 and 1 mg/kg) and pindolol (25, 50 and 100 ug/kg) were given 5 minutes before (pretreatment group) and at the time of reperfusion (treatment group)

Propranolol exhibited 20-40% protection in pretreatment group and 33.3 to 66.6% protection in treatment group, with metoprolol, the protection was 33.3 to 66.6% (pretreatment) and 00 to 16.6% (treatment group). Pindolol offered 50 to 25% (pretreatment) and 16.6 to 33.3% (treatment group) protection. These results suggest a definite role of beta receptors in the pathophysiology of reperfusion induced arrhythmias.