P4-27:A new model of rabbit L-type calcium current and action potential predicts ventricular dynamics at rapid heart rates

Ventricular fibrillation (VF), a leading cause of sudden cardiac death, is due multiple re-entrant waves created as a result of spiral wave break-up. Dynamic wave instabilities can cause spontaneous wavebreak, leading to a fibrillation like state even in completely homogenous tissue. L-type calcium current (ICa,L) modulates two major determinants of dynamic wave stability, APD (action potential duration) restitution and calcium cycling, and hence, can serve as a potential therapeutic target. The essential aims of this study are to 1) develop a new model of rabbit ventricular myocyte ICa,Lbased on experimental data acquired under physiological conditions 2) develop a computationally tractable ventricular AP model that incorporates the new ICa,Lformulation and quantitatively reproduces the nonlinear aspects of the experimentally observed cardiac dynamics at rapid heart rates.