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

Michela Colonnelli1, Alessandro Masci2, Corrado Tomasi3, Cristiana Corsi4
1DEI, University of Bologna, Campus of Cesena, 2University of Bologna, 3Department of Cardiology, Ospedale Santa Maria delle Croci, AUSL della Romagna, 4DEI- University of Bologna


Introduction. Computational fluid dynamics represents a valuable non-invasive approach to determine and assess physically meaningful parame-ters 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. Methods. A patient-specific 3D anatomical model of the LA was obtained from CT data. Non-rigid registration of the dynamic acquisitions allowed us to derive the 3D LA motion field in sinus rhythm (SR). 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 re-duced LA contraction, a random model, a discrete random model and a con-tinuous sinusoidal model. Blood velocity fields, kinetic energy, vortex struc-tures and blood stasis were analyzed in both SR and AF conditions in the LA. Results and Conclusions. 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 orga-nized flow in the sinusoidal model which was also characterized by the low-est 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.