Shortening of Cardiac Action Potential Duration Near an Insulating Boundary
It is known, from both experiments and simulations, that cardiac action potentials are shortened near a nonconducting boundary. In the present paper, this effect is studied in a simple, two-current ionic model, with propagation restricted to a one-dimensional fiber. An asymptotic approximation for the dependence of action potential duration on distance to the boundary is derived. This estimate agrees well with simulations.