Time-Warping Based End-of-T-Wave Shape Marker Reflects Repolarization Changes During Ischemia

This work proposes to use a warping-based T-wave morphology index, d w , estimated only in the T-wave peak-toend interval, to capture ischemia-induced dispersion of repolarization, avoiding the influence of ST segment elevation/depression. ECG recordings acquired during elective balloon percutaneous coronary intervention (PCI) were analyzed, together with their baseline recordings.A d w series was obtained by comparing the morphology of Mean Warped T wave peak-to end intervals (MWTPE) along the recordings with a reference MWTPE.A relative marker, R PCA d , normalizing the d w changes during PCI relative by the magnitude of the change during baseline recordings, was used to quantify the relative morphological variations generated by ischemia.d w changes during PCI followed a well marked gradual increasing trend as inflation time progressed reaching at the occlusion end a median R PCA d value of 9.44 ms, (range from 1.01 to 80.74).During baseline recordings d w remained stable with median R PCA d value of 1.00 ms, (range from 0.03 to 2.93 ms).Repolarization changes achieved R PCA d > 1, 2, 5, 10 during PCI in 94.1%, 85.11%, 64.4% and 48.5% of patients, respectively, being significantly higher than its corresponding control recordings.In conclusion, the d w marker is able to quantify ischemia-induced repolarization dispersion changes in a robust manner independent of the ST changes.