Quantitative modelling of effect of transverse-axial tubular system on electrical activity of cardiac cells under low [K+]e

In this work, we explored quantitatively the effect of ion concentration changes in the restricted space of transverse-axial tubular system (TAT-system) on ventricular cell arrhythmogenesis under the conditions of low extracellular potassium concentration ([K+]e). The simulations were performed on a model that integrates the quantitative description of electrical activity of surface and tubular membrane with the quantitative description of dynamic changes of intracellular ion concentrations. The results predict that the TAT-system plays a significant protecting role in cellular arrhythmogenesis that arises from the enhancement of potassium concentration gradient between tubular and extracellular spaces at low level of [K+]e