Cardiac excitation: an interactive process of ion channels and gap junctions.

Theoretical simulations were performed to study the interplay between membrane ionic currents and gap-junction coupling in determining cardiac conduction. Results demonstrate that a much slower conduction velocity can be achieved with reduced gap-junction coupling than with reduced membrane excitability. Also, uniform reduction in intercellular coupling increases spatial asymmetries of excitability and, consequently, the vulnerability to unidirectional block.