A novel computational model showed that ephaptic coupling increases propagation velocity at low gap junctional conductivity while decreasing it at higher conductivities.
A novel computationally efficient model demonstrates that cellular structure and geometry, including ephaptic coupling, have a nontrivial impact on myocardial propagation velocity.
Existing models of electrical activity in myocardial tissue are unable to easily capture the effects of ephaptic coupling. Homogenized models do not account for cellular geometry, while detailed spatial models are too complicated to simulate in three dimensions. Here we propose a unique model that accurately captures the geometric effects while being computationally efficient. We use this model to provide an initial study of the effects of changes in extracellular geometry, gap junctional coupling, and sodium ion channel distribution on propagation velocity in a single 1D strand of cells. In agreement with previous studies, we find that ephaptic coupling increases propagation velocity at low gap junctional conductivity while it decreases propagation at higher conductivities. We also find that conduction velocity is relatively insensitive to gap junctional coupling when sodium ion channels are located entirely on the cell ends and cleft space is small. The numerical efficiency of this model, verified by comparison with more detailed simulations, allows a thorough study in parameter variation and shows that cellular structure and geometry has a nontrivial impact on propagation velocity. This model can be relatively easily extended to higher dimensions while maintaining numerical efficiency and incorporating ephaptic effects through modeling of complex, irregular cellular geometry.
Lin et al. (Mon,) conducted a other in Myocardial electrical activity. Computational model incorporating geometric effects and ephaptic coupling vs. Existing homogenized or detailed spatial models was evaluated on Propagation velocity in a single 1D strand of cells. A novel computational model showed that ephaptic coupling increases propagation velocity at low gap junctional conductivity while decreasing it at higher conductivities.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: