Design, Development and Test of Different Cardiac Contraction Models in Atrial Fibrillation

Computational fluid dynamics represents a valuable non-invasive approach to determine and assess physically meaningful parameters in a complex fluid dynamics system represented by AF. The aim of this study was the design, development and test of different LA motion fields in AF on a patient-specific 3D anatomical model to clarify the influence of contraction models on LA hemodynamics. Since LA motion field is not available from clinical data during AF, three displacement models were designed to simulate the irregular, disorganized, very rapid and strongly reduced LA contraction, a random model, a discrete random model and a con-tinuous sinusoidal model. Blood velocity fields, kinetic energy, vortex structures and blood stasis were analyzed in both SR and AF conditions in the LA. Velocities in SR were higher than in AF, particular-ly during atrial systole. The three AF models resulted in different wash-out velocities both at the mitral valve and at the ostium of the LA appendage. Vortices were also differently distributed inside the LA showing a more organized flow in the sinusoidal model which was also characterized by the lowest blood stasis (8.6%) inside the LA appendage. Overall, different LA de-formation models in AF affect LA hemodynamics and additional studies should be performed to develop a realistic contraction model to simulate AF episodes.