T-Wave Peak-to-End Changes Quantified by Time-Warping Predicts Ventricular Fibrillation in a Porcine Myocardial Infarction Model

Background: The T-pe-interval time-warping-based morphology variation index, derived from a spatially transformed PCA lead, d(w,Tpe)(PCA,) has previously demonstrated utility in tracking repolarization changes induced by a 5-minute ischemia model in humans. The value of d(w,Tpe)(PCA,) as a predictor of ventricular fibrillation (VF) episodes is assessed in a 40-minutes porcine infarction model. Pre occlusion and occlusion ECG recordings from 10 pigs who suffered a late VF episode and 16 who did not were analyzed. The d(w,Tpe)(PCA,) series was measured by comparing T-pe morphologies at different stages of the occlusion relative to a baseline. During baseline, d(w,Tpe)(PCA,) remained stationary with an intra-recording median [IQR] value of 1.60 [1.33] ms.During occlusion, d(w,Tpe)(PCA,) followed a well-marked gradual increasing trend, reaching a median of 14.58 [17.72] ms . d(w,Tpe)(PCA, )averages were significantly higher in the VF group than in the Non-VF group at five time intervals taken every5 minutes after occlusion onset with median values of 12.5,18.8, 26.8, 24.0, and 31.0, vs 6.3, 7.6, 8.0, 7.8, and 7.8, and also at three consecutive 5-minute intervals prior to VF 18.6,25.0 and 28.8 vs 8.5, 7.2 and 6.0 ms, respectively. The TPCA(pe) interval was also significantly higher in the VF group at all analyzed time periods, but with a lower significance level. Pigs with maximum d(w,Tpe)(PCA,) >= 20.0ms and TPCA(pe) >= 85.4 ms in the early 5-10 minutes interval after occlusion, had significantly higher risk for VF occurring with 90.0%/75.0% and80.0%/69.0% sensitivity/ specificity, respectively. In conclusion, d(w,Tpe)(PCA,) is a stronger VF predictor than TPCA(pe) during ischemia in a porcine model.