Abstract. The aims of this study are to investigate the relation of coronary T wave to the distribution of action potential duration (APD) around MI lesion, and the causes of change in APD under ischemic-like condition in vitro study. Transmembrane action potentials were recorded from the endocardial muscle preparations from canine heart under ischemic-like solution with or without verapamil or lysophosphatidylcholine (LPC, 0.2mM) or phospholipase C (PLC). The time courses of the APD transitions were measured. On the above results, computer simulation of antero-septal MI was reconstructed by Wei-Harumi model. The adequate distributions of APD around MI lesion by which the coronary T wave can be simulated were searched. As the results, the transient prolongation of APD compared with that of base line was noted during the reoxygenation period (rebound phenomenon). The duration of this phenomenon was lengthened after the LPC, but shortened after PLC, and no significant changes after verapamil. In conclusions, the appearance of coronary T wave will be related to the prolonged APD of reperfused myocardial cell. The long lasting T wave inversion seen in MI might be caused of abnormal ionic transportation due to fine structural change of lipid cell membrane.

Keywords: Coronary T Wave; Transmembrane Action Potential; Rebound Phenomenon; Computer Simulation