Allowing ephaptic coupling to play a primary role in wave front propagation resolves the paradox of action potential wave speed and discordant alternans spatial scales in computer simulations.
This computational study suggests that ephaptic coupling, rather than just gap-junction coupling, plays a crucial role in normal cardiac wave propagation and the development of discordant alternans.
Previous computer simulations have suggested that existing models of action potential wave propagation in the heart are not consistent with observed wave propagation behavior. Specifically, computer models cannot simultaneously reproduce the rapid wave speeds and small spatial scales of discordant alternans patterns measured experimentally in the same simulation. The discrepancy is important, because discordant alternans can be a key precursor to the development of abnormal and dangerous rapid rhythms in the heart. In this Letter, we show that this paradox can be resolved by allowing so-called ephaptic coupling to play a primary role in wave front propagation in place of conventional gap-junction coupling. With this modification, physiological wave speeds and small discordant alternans spatial scales both occur with gap-junction resistance values that are more in line with those observed in experiments. Our theory thus also provides support to the hypothesis that ephaptic coupling plays an important role in normal wave propagation.
Otani et al. (Tue,) conducted a letter in Action potential wave propagation and discordant alternans. Ephaptic coupling model vs. Conventional gap-junction coupling model was evaluated on Simultaneous reproduction of rapid wave speeds and small spatial scales of discordant alternans. Allowing ephaptic coupling to play a primary role in wave front propagation resolves the paradox of action potential wave speed and discordant alternans spatial scales in computer simulations.