INTRODUCTION: Repolarization heterogeneity (RH) is functionally linked to dispersion in refractoriness and to arrhythmogenicity. In the current study, we validate several proposed electrocardiogram (ECG) indices for RH: T-wave amplitude, -area, -complexity, and -symmetry ratio, QT dispersion, and the Tapex-end interval (the latter being an index of transmural dispersion of the repolarization (TDR)). METHODS AND RESULTS: We used ECGSIM, a mathematical simulation model of ECG genesis in a human thorax, and varied global RH by increasing the standard deviation (SD) of the repolarization instants from 20 (default) to 70 msec in steps of 10 msec. T-wave amplitude, -area, -symmetry, and Tapex-end depended linearly on SD. T-wave amplitude increased from 275 +/- 173 to 881 +/- 456 muV, T-wave area from 34 x 10(3)+/- 21 x 10(3) to 141 x 10(3)+/- 58 x 10(3)muV msec, T-wave symmetry decreased from 1.55 +/- 0.11 to 1.06 +/- 0.23, and Tapex-end increased from 84 +/- 17 to 171 +/- 52 msec. T-wave complexity increased initially but saturated at SD = 50 msec. QT dispersion increased modestly until SD = 40 msec and more rapidly for higher values of SD. TDR increased linearly with SD. Tapex-end increased linearly with TDR, but overestimated it. CONCLUSION: T-wave complexity did not discriminate between differences in larger RH values. QT dispersion had low sensitivity in the transitional zone between normal and abnormal RH. In conclusion, T-wave amplitude, -area, -symmetry, and, with some limitations, Tapex-end and T-wave complexity reliably reflect changes in RH.
INTRODUCTION: Repolarization heterogeneity (RH) is functionally linked to dispersion in refractoriness and to arrhythmogenicity. In the current study, we validate several proposed electrocardiogram (ECG) indices for RH: T-wave amplitude, -area, -complexity, and -symmetry ratio, QT dispersion, and the Tapex-end interval (the latter being an index of transmural dispersion of the repolarization (TDR)). METHODS AND RESULTS: We used ECGSIM, a mathematical simulation model of ECG genesis in a human thorax, and varied global RH by increasing the standard deviation (SD) of the repolarization instants from 20 (default) to 70 msec in steps of 10 msec. T-wave amplitude, -area, -symmetry, and Tapex-end depended linearly on SD. T-wave amplitude increased from 275 +/- 173 to 881 +/- 456 muV, T-wave area from 34 x 10(3)+/- 21 x 10(3) to 141 x 10(3)+/- 58 x 10(3)muV msec, T-wave symmetry decreased from 1.55 +/- 0.11 to 1.06 +/- 0.23, and Tapex-end increased from 84 +/- 17 to 171 +/- 52 msec. T-wave complexity increased initially but saturated at SD = 50 msec. QT dispersion increased modestly until SD = 40 msec and more rapidly for higher values of SD. TDR increased linearly with SD. Tapex-end increased linearly with TDR, but overestimated it. CONCLUSION: T-wave complexity did not discriminate between differences in larger RH values. QT dispersion had low sensitivity in the transitional zone between normal and abnormal RH. In conclusion, T-wave amplitude, -area, -symmetry, and, with some limitations, Tapex-end and T-wave complexity reliably reflect changes in RH.
Authors: Farzad Vahedi; Michael F Haney; Steen M Jensen; Ulf Näslund; Lennart Bergfeldt Journal: Ann Noninvasive Electrocardiol Date: 2011-07 Impact factor: 1.468
Authors: Marianna Meo; Pietro Bonizzi; Laura R Bear; Matthijs Cluitmans; Emma Abell; Michel Haïssaguerre; Olivier Bernus; Rémi Dubois Journal: Front Physiol Date: 2020-08-13 Impact factor: 4.566