Prevention of ventricular fibrillation in experimental myocardial infarction.

The fall in the ventricular fibrillation threshold during the first half an hour following ligation of the descending branch of the left coronary artery in dog was not influenced by the i.v. injection of trimecain (Mesokain Spofa). On the other hand, an i.v. injection of methypranol (Trimepranol Spofa) given prior to ligation increased the level of ventricular fibrillation threshold 3 to 4 times compared to control value before occlusion in all 10 studied dogs. Depression of the beta-blocking adrenergic activity may thus prevent the occurrence of ventricular fibrillation in acute myocardial ischaemia.