The circumflex coronary artery occlusion canine model of sudden death: Methodology and electrocardiographic observations

Abstract

This study deals with a left circumflex coronary artery occlusion-reperfusion canine model of sudden death using multiple electrocardiographic leads to define a subgroup of animals at high risk of ventricular fibrillation. Occlusion was followed by ventricular fibrillation in 15 of 30 animals (50%). In the 15 dogs surviving 60 min postocclusion, reperfusion gave rise to ten cases of ventricular fibrillation (66.7%). Thus, the total incidence of occlusion-reperfusion ventricular fibrillation was 25 of 30 (83.3%). Electrocardiographic delta R% changes greater than or equal to 25% in leads 2 and 3 at both 3 and 5 min postocclusion predicted the occurrence of postocclusion ventricular fibrillation with 80% specificity and 56% sensitivity. However, ST segment elevation greater than or equal to 0.5 mV in the same leads at the same times predicted postocclusion ventricular fibrillation with 67% specificity and 100% sensitivity. When only dogs with ST segment elevation greater than or equal to 0.5 mV in leads 2 and 3 at both 3 and 5 min postocclusion were considered, ventricular fibrillation postocclusion was seen in 15 of 20 dogs (75%) and ventricular fibrillation after reperfusion occurred in four of the remaining five animals (80%). Thus, in the subgroup of animals presenting with ST segment elevation greater than or equal to 0.5 mV in leads 2 and 3 at both 3 and 5 min postocclusion, the overall incidence of occlusion-reperfusion ventricular fibrillation was 19 of 20 (95%). These data may be useful in studies aimed at testing the effectiveness of drugs or other interventions in a canine model of sudden death.