Meandering of spiral waves in anisotropic cardiac tissue

The influence of anisotropy on spiral wave meandering in a sheet of cardiac tissue is studied numerically. The FitzHugh-Nagumo model represents the membrane excitability, and the bidomain model characterizes the passive electrical properties. The anisotropy ratios in the intracellular and extracellular spaces are unequal. Anisotropy influences the meander pattern. The spiral wave rotation frequency, f(1), and the meander frequency, f(2), are entrained at frequency ratios, f(1):f(2), of 3:1 and 7:1. The meander path changes strikingly for frequency ratios of 11:5, 13:3 and 19:5. For frequency ratios of 2:1 and 4.1, the meander pattern drifts. (C) 2001 Published by Elsevier Science B.V.