Time course and spatial distribution of T wave alternans induced by coronary artery occlusion in pigs

T-wave alternans (TWA) has been linked to increased vulnerability of the myocardium to ventricular fibrillation in different clinical conditions. Our aim in this work was to study and characterize TWA in an animal model of myocardial ischemia and infarction. Infarction was induced in 29 pigs by a 40-minute-long balloon inflation on the left anterior descending coronary artery. The occlusion recording, as well as a previous baseline recordings were analyzed using the Laplacian Likelihood Method together with Periodic Component Analysis. TWA was found in 27 occlusion recordings and in only 4 baseline recordings. A two/three-peaked pattern was commonly found in the time-course of TWA, where the first peak of TWA was attained at 5 to 7 minutes from the onset of occlusion and the second at about 15 to 20 minutes. After 24 min of occlusion TWA had faded in most recordings. Analysis of the TWA amplitude lead distribution revealed that maximum TWA appears in leads V3 and V4, in consonance with human studies, confirming the regional nature of ischemia-induced TWA.