Rotors Drift Toward and Stabilize in Low Power Regions in Heterogeneous Models of Atrial Fibrillation.

Abstract

Atrial fibrillation (AF) afflicts more than 33 million people worldwide. Success of therapy strategies remains poor and better understanding of the arrhythmia and how to device more effective therapies are needed. The aim of this work is to study the role of electric power distributions in rotors and AF dynamics. For this purpose, single cell and tissue simulations were performed to study the effect of ionic currents gradients and fibrosis in rotor's drifting. The root mean square of the ionic (P_ion), capacitance (P_c) and electrotonic (P_ele) power was computed over action potentials. Single cell simulations were performed for different values of I_K1 and I_CaL and number of coupled myofibroblasts. Tissue simulations were performed in presence of I_K1 and I_CaL gradients and diffused fibrosis. Single cell simulations showed that P_ion and P_c increased with I_K1, while decreased by increasing I_CaL. Increasing the number of coupled myofibroblasts reduced P_ion and P_c, whereas P_ele increased. Finally, in tissue simulations rotors drifted to regions with low power and anchored in regions with higher density of blunted ionic induced power gradients.