A multiscale CFD model of blood flow in the human left heart coupled with a lumped parameter model of the cardiovascular system

56/2021

A multiscale CFD model of blood flow in the human left heart coupled with a lumped parameter model of the cardiovascular system

Tuesday 24th August 2021

Zingaro, A.; Fumagalli, I.; Dede' L.; Fedele M.; Africa P.C.; Corno A.F.; Quarteroni A.

In this paper, we present a novel computational model for the numerical simulation of blood flow in the human heart by focusing on 3D CFD of the left heart. With the aim of simulating the hemodynamics of the left heart, we employ the Navier-Stokes equations in an Arbitrary Lagrangian Eulerian formulation to account for the endocardium motion and we model both mitral and aortic valves by means of the Resistive Immersed Implicit Surface method. To enhance the physiological significance of our numerical simulations, we use a 3D cardiac electromechanical model of the left ventricle coupled to a lumped parameter closed-loop model of the circulation and the remaining cardiac chambers. To extend the left ventricle motion to the endocardium of the whole left heart, we introduce a preprocessing procedure that combines the harmonic extension of the left ventricle displacement and a volume-based motion of the left atrium. We thus obtain a coupled one-way electromechanical - fluid dynamics model. To better match the 3D CFD with blood circulation, we also couple the 3D Navier-Stokes equations - with motion driven by electromechanics - to the 0D circulation model. We obtain a multiscale coupled 3D-0D fluid dynamics model that we solve through a partitioned numerical scheme. We carry out numerical simulations on a healthy left heart and we validate our model by showing that some hemodynamic indicators are correctly reproduced. We finally show that our model is able to simulate the left heart's blood flow in the scenario of a regurgitant mitral valve.