An estimate of the dispersion of repolarization times based on a biophysical model of the ECG

IEEE Trans Biomed Eng. 2011 Dec;58(12):3396-405. doi: 10.1109/TBME.2011.2166263. Epub 2011 Aug 30.


Temporal heterogeneity of ventricular repolarization is a key quantity for the development of ventricular reentrant arrhythmia. In this paper, we introduce the V-index, a novel ECG-based estimator of the standard deviation of ventricular myocytes' repolarization times s(ϑ). Differently from other ECG metrics of repolarization heterogeneity, the V-index was derived from the analysis of a biophysical model of the ECG, where repolarization is described by the dominant T-wave (DTW) paradigm. The model explains the shape of T-waves in each lead as a projection of a main waveform (the DTW) and its derivatives weighted by scalars, the lead factors. A mathematical formula is derived to link the heterogeneity of ventricular repolarization s(ϑ) and the V-index. The formula was verified using synthetic 12-lead ECGs generated with a direct electrophysiological model for increasing values of s(ϑ) (in the range 20-70 ms). A linear relationship between the V-index and s(ϑ) was observed, V ≈ 0.675 s(ϑ) + 1.8 ms (R(2) = 0.9992). Finally, 68 ECGs from the E-OTH-12-0068-010 database of the Telemetric and Holter ECG Warehouse were analyzed. The V-index coherently increased after sotalol administration, a drug known to have QT-prolonging potential (p << 0.001).

MeSH terms

  • Algorithms
  • Computer Simulation
  • Electrocardiography / methods*
  • Heart Conduction System / physiology
  • Humans
  • Male
  • Membrane Potentials / physiology*
  • Models, Cardiovascular*
  • Models, Statistical*
  • Myocytes, Cardiac / physiology
  • Reproducibility of Results
  • Ventricular Function / physiology*