A model study of electric field interactions between cardiac myocytes

The transmission of excitation via electric field coupling is studied in a model comprising two myocytes abutted end-to-end and placed in an unbounded volume conductor. Each myocyte was modeled as a small cylinder of membrane capped at both ends. A Beeler-Reuter model modified for the Na ⁺ current dynamics served to simulate the membrane ionic current. There was no resistive coupling between the myocytes, and the intercellular junction consisted of closely apposed pre- and post-junctional membranes, separated by a uniform cleft distance. The purpose is to examine how the field coupling is affected by the physical characteristics of the intercellular gap, namely, its size and the extend of the membrane folding, and the possible development of excitation in the post-junctional cell when an action potential reaches the junction.