Re-entry in the Luo-Rudy ventricular tissue model with different models of Ca2+ dynamics

Based on C.H. Luo and Y. Rudy´s (1994) equations for a single ventricular cell, we develop a family of computational models for 2D excitable media consisting of such cells - i.e. we construct virtual ventricular tissues. The models comprised virtual epicardial and endocardial tissues with either standard or buffered intra-cellular Ca ²⁺ handling. Re-entry, manifested as rotating spiral waves, was found to be stable in each model. We characterized re-entry by measuring the spatial extent of tip meander (R) and the rotation time period (T) of the spiral waves. For the standard epi- and endo-tissues, we measured T=90 ms and R=0.5 mm, and T=110 ms and R=0.7 mm, respectively. For epi- and endo-tissues with buffered Ca²⁺, we obtained T=90 ms and R=0.4 mm, and T=100 ms and R=0.5 mm, respectively. We conclude that simplified Ca²⁺ handling introduces only small differences in the simulation of re-entrant phenomena