title: Variability of Ventricular Repolarization Dispersion Quantified by Time-Warping the Morphology of the T-Waves.
abstract: We propose two electrocardiogram (ECG)-derived markers of T-wave morphological variability in the temporal, dw, and amplitude, da, domains. Two additional markers, dwNLand daNL, restricted to measure the nonlinear information present within dwand daare also proposed.
  
  
  
  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.
  
  
  
  The metrics dw, da, dwNL, and daNLfollowed T-wave time- and amplitude-induced variations under different levels of noise, were strongly associated with changes in the spatio-temporal dispersion of repolarization, and showed to provide additional information to differences in the heart rate, QT and Tpeintervals, and in the T-wave width and amplitude.
  
  
  
  The proposed ECG-derived markers robustly quantify T-wave morphological variability, being strongly associated with changes in the dispersion of repolarization.
  
  
  
  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.
authors.forename: Julia
authors.initials: J
authors.lastname: Ramirez
authors.forename: Michele
authors.initials: M
authors.lastname: Orini
authors.forename: J Derek
authors.initials: JD
authors.lastname: Tucker
authors.forename: Esther
authors.initials: E
authors.lastname: Pueyo
authors.forename: Pablo
authors.initials: P
authors.lastname: Laguna
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D004562:Electrocardiography / Q000379:methods*; D006329:Heart Conduction System / Q000502:physiology*; D006801:Humans; D008955:Models, Cardiovascular; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D016276:Ventricular Function / Q000502:physiology*