A bidomain model for ring stimulation of a cardiac strand

A bidomain model is developed to represent a cardiac muscle strand undergoing stimulation from a ring electrode. Expressions are derived for the distribution of the potentials in the strand as well as in the bath perfusing the tissue, under the condition of equal anisotropy ratios in the intracellular and interstitial spaces. The present derivation provides an example of an analytical solution technique that might also prove useful for other problems in theoretical electrophysiology.