Quantification of T-wave Morphological Variability Using Time-warping Methods

  • Julia Ramírez
  • Michele Orini
  • Esther Pueyo
  • Pablo Laguna
Conference paper
Part of the IFMBE Proceedings book series (IFMBE, volume 65)


The aim of this study is to quantify the variation of the T-wave morphology during a 24-hour electrocardiogram (ECG) recording. Two ECG-derived markers are presented to quantify T-wave morphological variability in the temporal, \(d_w\), and amplitude, \(d_a\), domains. Two additional markers, \(d_w^{NL}\) and \(d_a^{NL}\), that only capture the non-linear component of \(d_w\) and \(d_a\) are also proposed. The proposed markers are used to quantify T-wave time and amplitude variations in 500 24-hour ECG recordings from chronic heart failure patients. Additionally, two mean warped T-waves, used in the calculation of those markers, are proposed to compensate for the rate dependence of the T-wave morphology. Statistical analysis is used to evaluate the correlation between \(d_w\), \(d_w^{NL}\), \(d_a\) and \(d_a^{NL}\) and the maximum intra-subject RR range, \(\Delta \)RR. Results show that the mean warped T-wave is able to compensate for the morphological differences due to RR dynamics. Moreover, the metrics \(d_w\) and \(d_w^{NL}\) are correlated with \(\Delta \)RR, but \(d_a\) and \(d_a^{NL}\) are not. The proposed \(d_w\) and \(d_w^{NL}\) quantify variations in the temporal domain of the T-wave that are correlated with the RR range and, thus, could possibly reflect the variations of dispersion of repolarization due to changes in heart rate.


Electrocardiogram morphological variability repolarization T-wave time-warping 


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Copyright information

© Springer Nature Singapore Pte Ltd. 2018

Authors and Affiliations

  • Julia Ramírez
    • 1
  • Michele Orini
    • 2
  • Esther Pueyo
    • 1
  • Pablo Laguna
    • 1
  1. 1.Biomedical Signal Interpretation and Computational Simulation (BSICoS) group Aragón Institute of Engineering Research (I3A)IIS Aragón University of Zaragoza Zaragoza Spain and Biomedical Research Networking Center (CIBER)ZaragozaSpain
  2. 2.Institute of Cardiovascular Science University College LondonLondonUK

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