Investigation of the left atrium hemodynamics using finite elements and a novel post-processing approach for wall...

The blood rheology in the left atrium is associated with several pathologies including heart failure, atrial fibrillation, thrombus formation and stroke. Computational fluid dynamics (CFD) is an approach which can contribute to the investigation of atrial hemodynamics and the relation to the development of the diseases. However, CFD is based on several assumptions and parameters which can affect the simulation results significantly. In this work, we perform a detailed analysis of the various parameters which can influence the final outcomes. For this purpose, computed tomography (CT) heart imaging data are used for the 3-dimensional (3D) reconstruction of the left atrial geometries including the appendage. The geometries are discretized using tetrahedral elements, with an inflation of the atrial surface using 16 layers and an element size of 1 mm. The Navier-Stokes equations are employed for the blood flow simulation. We investigate the effect of the turbulence models, the viscosity models of blood and the necessity of transient simulations. The results demonstrated that the viscosity model may lead to a >30% difference especially at the proximal part of the left atrial appendage. The results of the turbulence models are not affected by the intensity of each model, but there is considerable difference between the SST and k-ε model. Finally, a steady simulation can replace a transient one if the inlet velocity is set to 1.1 times the mean velocity of the pulsatile profile.Clinical Relevance- The use of accurate simulation of left atrium hemodynamics can be used for the development of predictive models of diseases.