Control of arrhythmias following ligation of the circumflex artery.

In experimental work, three groups of 10 dogs each were subjected to ligation of the circumflex coronary artery. One group was given prophylactic medication with procainamide and another group was allowed a 2 hour interval between thoracotomy and ligation. The effects of these measures on the incidence of ventricular arrhythmias during the 30 minutes immediately after coronary artery occlusion were then compared. The two groups of animals on which these preventive measures were tested both showed a significant reduction in incidence of arrhythmias as compared to the control group. The therapeutic use of procainamide was also assessed by administering the drug intravenously to all animals developing postligation arrhythmias in the two groups which were not prophylactically medicated. In 46 per cent of these cases, the arrhythmias were suppressed and threatened ventricular fibrillation was obviated.