Fluid-Structure Coupled CFD Simulation of the Left Ventricular Flow During Filling Phase

Abstract

The fluid-structure coupled simulation of the heart, though at its developing stage, has shown great prospect in heart function investigations and clinical applications. The purpose of this paper is to verify a commercial software based fluid-structure interaction scheme for the left ventricular filling. The scheme applies the finite volume method to discretize the arbitrary Lagrangian-Eulerian formulation of the Navier-Stokes equations for the fluid while using the nonlinear finite element method to model the structure. The coupling of the fluid and structure is implemented by combining the fluid and structure equations as a unified system and solving it simultaneously at every time step. The left ventricular filling flow in a three-dimensional ellipsoidal thin-wall model geometry of the human heart is simulated, based on a prescribed time-varying Young's modulus. The coupling converges smoothly though the deformation is very large. The pressure-volume relation of the model ventricle, the spatial and temporal distributions of pressure, transient velocity vectors as well as vortex patterns are analyzed, and they agree qualitatively and quantitatively well with the existing data. This preliminary study has verified the feasibility of the scheme and shown the possibility to simulate the left ventricular flow in a more realistic way by adding a myocardial constitutive law into the model and using a more realistic heart geometry.

Image-based large-eddy simulation in a realistic left heart

“…The most natural one is to extract the heart geometry at one chosen moment in the heart cycle and to solve an electrical-fluid-structure interaction (EFSI) problem [27,28,29,30,31,32].…”

Left Ventricular Fluid Mechanics: The Long Way from Theoretical Models to Clinical Applications

“…The diastolic phase of the left heart was studied using an IBM method, the ventricular wall was described as a system of connected elastic springs and the flow was forced by imposing a pressure variation at the pulmonary veins connection to the left atrium. 59 The diastolic filling of an ellipsoidal LV was studied coupling a FV solution of the flow equation with a FE description of a ventricular hyperelastic wall, 12 and forcing the system with physiological time histories of the intraventricular pressure and of the mean velocity at the mitral orifice. These studies successfully reproduced the vortex formation process and its dynamics inside the LV chamber.…”

“…The fluid and structure dynamics were solved simultaneously using FE methods and adopting a non-linear elastic 12 or a hyperelastic 97 representation of the wall properties, while the presence of the cardiac valves was typically accounted imposing simplified boundary conditions at the orifices. In the computational framework of the FV method, the diastolic filling was studied in a model LV, with a fibrous elastic description of a thin ventricular wall based on the IBM approach and the use of an iterative procedure to solve simultaneously the whole system of equations.…”

Patient-specific modelling of whole heart anatomy, dynamics and haemodynamics from four-dimensional cardiac CT images

“…In recent years, computational fluid dynamics (CFD)-based techniques have been used with varying degrees of success for simulating blood flow in the heart [2][3][4][5][6][7]. Most of these techniques employ a moving boundary set-up, where the motion of the walls is prescribed by extracting the dynamics from the four-dimensional imaging data.…”