[Experimental myocardial infarct in the pig: effect of temporary ligation and revascularization on the ST segment in the epicardial ECG and on the incidence of ventricular fibrillation].

A short period of myocardial ischemia induced by temporary ligation of 2 min duration prior to occlusion of the left anterior descending branch of the left coronary artery (LAD) in the pig does not have a beneficial effect on epicardial ST-segment alterations or on the incidence of ventricular fibrillation. One-stage ligation therefore seems to be the procedure of choice in occluding the porcine LAD. In 14 of 24 animals an isolated alternans of the ST-T segment was observed during the first few minutes of occlusion. Reperfusion after 60 min caused temporary increase of the ST-segment alterations, in contrast to the findings in the dog, where revascularization causes prompt return of the ST-segment to the pre-occlusion level. In addition, ectopic rhythms were frequently observed after removal of ligation.