DOI: 10.1098/rsfs.2023.0035 ISSN: 2042-8901

Evaluating pro-arrhythmogenic effects of the T634S-hERG mutation: insights from a simulation study

Wei Hu, Wenfeng Zhang, Kevin Zhang, Ehab Al-Moubarak, Yihong Zhang, Stephen C. Harmer, Jules C. Hancox, Henggui Zhang
  • Biomedical Engineering
  • Biomaterials
  • Biochemistry
  • Bioengineering
  • Biophysics
  • Biotechnology

A mutation to serine of a conserved threonine (T634S) in the hERG K + channel S6 pore region has been identified as a variant of uncertain significance, showing a loss-of-function effect. However, its potential consequences for ventricular excitation and arrhythmogenesis have not been reported. This study evaluated possible functional effects of the T634S-hERG mutation on ventricular excitation and arrhythmogenesis by using multi-scale computer models of the human ventricle. A Markov chain model of the rapid delayed rectifier potassium current (I Kr ) was reconstructed for wild-type and T634S-hERG mutant conditions and incorporated into the ten Tusscher et al . models of human ventricles at cell and tissue (1D, 2D and 3D) levels. Possible functional impacts of the T634S-hERG mutation were evaluated by its effects on action potential durations (APDs) and their rate-dependence (APDr) at the cell level; and on the QT interval of pseudo-ECGs, tissue vulnerability to unidirectional conduction block (VW), spiral wave dynamics and repolarization dispersion at the tissue level. It was found that the T634S-hERG mutation prolonged cellular APDs, steepened APDr, prolonged the QT interval, increased VW, destablized re-entry and augmented repolarization dispersion across the ventricle. Collectively, these results imply potential pro-arrhythmic effects of the T634S-hERG mutation, consistent with LQT2.

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