Curvature effects on propagation in cardiac tissue

Simulations of reentry in 1D, 2D and 3D ionic models of cardiac excitable tissue have shown that the APD(DIA) curve is a major determinant of the stability of the propagation. Curvature is also an important factor in extended tissue and kinematical (KIN) models including K and rhythm dependence of Θ have been proposed. These models are incomplete since they do not include the effect of APD on the propagation. The authors´ objective was to find functions expressing the effect of K and DIA on Θ and APD, and to use these them to construct a more complete KIN model of propagation in 2D medium. The Θ(K,DIA) and APD(K,DIA) were obtained by fitting the results of simulations with a BRT ionic model, using an approximation of the 2D diffusion equation allowing a systematic exploration of K and DIA. The functions were used in a KIN model describing the propagation of period-1 solutions in a 2D ring of tissue