Dynamics of T-peak-to-T-end Morphology Changes in an Open-chest Porcine Model, and its Relation to Arrhythmic Events

Neurys Gómez Fonseca1, Julia Ramírez2, Alena S. Tsvetkova3, Pyotr Platonov4, Jan Azarov5, Juan Pablo Martínez6, Pablo Laguna7
1Univesity of Zaragoza, 2University of Zaragoza, 3Institute of Physiology Komi Science Center Ural Branch Russian Academy of Sciences, 4Lund University, 5Department of Cardiac Physiology, Institute of Physiology, Komi Science Center, Ural Branch, Russian Academy of Sciences, 6jpmart@unizar.es, 7Zaragoza University

Abstract

Introduction: T-peak-to-T-end interval (Tpe) based indices have shown value in quantifying the increase in ventricular repolarization dispersion (VRD) that has been associated with ventricular arrhythmias (VA). A time-warping-based index, dw,Tpe, quantifying morphology changes within the T-peak-to-end interval, has previously demonstrated utility in predicting VA in a 40-min porcine infarction model. This work assesses the contribution of dw,Tpe as predictor of ventricular fibrillation (VF) episodes in a long-time open-chest porcine infarction model. Methods: Oclussion and pre-occlusion (control stage) body surface ECG recordings from 20 pigs undergoing a 40-minute open-chest coronary occlusion were analyzed. The dw,Tpe index quantifies the morphological differences between the Tpe morphology at different stages of the occlusion and at the control preoclussion recording. Results were compared with the classical Tpe interval. Results: From 20 pigs, 8 suffered a delayed (later than 7 min from oclussion) VF episode (VF-group). dw,Tpe remained stationary at control recordings, with a median [IQR] values of 0 [1.87] ms. During occlusion, the absolute value of dw,Tpe followed a gradual increasing trend as ischemia progressed. At 0-5, 5-10, 10-15 and 15-20 minutes after the occlusion onset, dw,Tpe absolute median values were significantly higher in the VF group than in the non-VF group (Kruskal-Wallis test), with values of 10.2, 11.7, 18.2 and 19.0 vs 1.8, 2.4, 3.2 and 2.4 ms, and p-values of 0.017, 0.041, 0.045 and 0.013, respectively (see Figure). The Tpe index did not present significant differences in any of the intervals between VF and non-VF groups. Conclusion: The time-warping-based morphology index, dw,Tpe, can monitor ischemia-induced changes. Larger dynamic increase of the dw,Tpe index during ischemia progression is associated with VF episodes and suggest the need further clinical studies in humans.