Fig. 2.

(A) Cardiac tissue consists of discrete myocytes which are interconnected via gap junctions. (B) Discrete structures in the intracellular and extracellular spaces within the myocardium are homogenized to arrive at a continuum representation, the electrical properties at the discrete microscopic scale and at the continuous macroscopic scale match. Both homogenized domains are overlapped, separated by a membrane at each point in space (interpenetrating domains). (C) Discrete representation of both conductive domains, intra- and extracellular, and the membrane.