Variability of Ventricular Repolarization Dispersion Quantified by Time-Warping the Morphology of the T-waves

We propose two electrocardiogram (ECG)-derived markers of T-wave morphological variability in the temporal, dw , and amplitude, da , domains. Two additional markers, d(NL)w and d(NL)a , restricted to measure the non-linear information present within dw and da are also proposed. METHODS: We evaluated the accuracy of the proposed markers in capturing T-wave time and amplitude variations in 3 situations: (1) In a simulated set up with presence of additive Laplacian noise, (2) when modifying the spatio-temporal distribution of electrical repolarization with an electro-physiological cardiac model and (3) in ECG records from healthy subjects undergoing a tilt table test. RESULTS: The metrics dw , da , d(NL)w and d(NL)a followed T-wave time and amplitude induced variations under different levels of noise, were strongly associated with changes in the spatiotemporal dispersion of repolarization, and showed to provide additional information to differences in the heart rate, QT and Tpe intervals, and in the T-wave width and amplitude. CONCLUSION: The proposed ECG-derived markers robustly quantify T-wave morphological variability, being strongly associated with changes in the dispersion of repolarization. SIGNIFICANCE: The proposed ECG-derived markers can help to quantify the variability in the dispersion of ventricular repolarization, showing a great potential to be used as arrhythmic risk predictors in clinical situations