Evolution of T wave width during severe ischemia generated by percutaneous transluminal coronary angioplasty

In this work we studied the evolution of ventricular repolarization dispersion (VRD) in the ECG during ischemia induced by Percutaneous Transluminal Coronary Angioplasty (PTCA). We hypothesized that at early ischemia stages the endocardium action potential duration (APD) is slightly reduced or unchanged while the epicardium one is reduced in a larger proportion and afterwards the APD at the epicardium returns to the normal values as ischemia evolves. This has been previously reported in isolated cat cardiac tissue studies. T-wave width (Tw) is measured by an automatic delineator and proposed as indicator of this repolarization dispersion increase. Results showed a significant widening of 11.5 ms of the T-wave during the first minute of occlusion at RCA occluded patients, with recovery to non-significant widening values after the second minute. No significant changes were observed for LAD or LCX patients. These results are in accordance with APD reported at cellular level on animal experiments.