Approximate solution to the bidomain equations for defibrillation problems.

The bidomain model can be used for calculating the electrical potential in the heart during defibrillation. However, this model consists of a coupled system of two partial differential equations that are, in general, difficult and time consuming to solve. In this paper, we present an approximate, iterative method of solving the bidomain equations. After working out the general method, we apply it to four problems: (i) a cylindrical strand in a uniform electric field, (ii) a nonuniform electric field applied to tissue with straight fibers, (iii) a spherical heart in a uniform electric field, and (iv) a two-dimensional sheet of cardiac tissue with curving fibers. Finally, we analyze the general case of three dimensions.