Atrial anatomy influences onset and termination of atrial fibrillation: A computer model study

Abstract

Vulnerability to atrial fibrillation (AF) is increased in acutely dilated atria and is related to stretch-activated channels (SACs). To investigate the role of atrial anatomy in AF, we apply a computer model of human atrial electromechanics that includes SACs and contraction of the sarcomeres. Trabecular bundle structures are modeled by varying atrial wall thickness in a triangular mesh representing the human atria. Vulnerability to AF is investigated by application of overall stretch, while stimulating near the pulmonary veins. Due to contraction of some areas, stretch increases in other areas, leading to a variation in effective refractory period (ERP). Onset and perpetuation of AF in our model is explained by an increased dispersion in ERP, conduction slowing, and local conduction block. Atrial contraction attributes to the termination of AF through mechanoelectric feedback. We conclude that onset and termination of AF episodes under stretch are related to atrial structure and mechanoelectric feedback. © 2009 Springer Berlin Heidelberg.