An Estimate of the Dispersion of Repolarization Times Based on a Biophysical Model of the ECG
The Dominant T-wave (DTW) offers an overall view of the venticular repolarization as it reflects the first-order derivative of the transmembrane potential of the myocytes during repolarization (TMPR). DTW can be estimated from the analysis of surface T-waves, which are modeled as a linear combination of DTW and its derivatives. Usually, the contribute of the DTW dominates but, when dispersion of the repolarization times increases (as during pathological conditions) the effects of DTW derivatives can not be neglected. Unfortunately the estimators of DTW proposed so far, do not consider these terms. In this work, an algorithm to estimate the DTW taking into account the second-order derivative of the TMPR curve is introduced. The algorithm was tested on synthetic ECG recordings. When the dispersion of the sources is varied from 10 to 50 ms, the new technique shows an average improvement in the precision of the estimate of the TMPR curve of about 18.9% over previous methods.