3D–0D closed-loop model for the simulation of cardiac biventricular electromechanics

Roberto Piersanti,Francesco Regazzoni,Matteo Salvador,Antonio F Corno,Luca Dede’,Christian Vergara,Alfio Quarteroni

doi:10.1016/j.cma.2022.114607

Abstract

Two crucial factors for accurate numerical simulations of cardiac electromechanics, which are also essential to reproduce the synchronous activity of the heart, are: (i) accounting for the interaction between the heart and the circulatory system that determines pressures and volumes loads in the heart chambers; (ii) reconstructing the muscular fiber architecture that drives the electrophysiology signal and the myocardium contraction. In this work, we present a 3D biventricular electromechanical model coupled with a 0D closed-loop model of the whole cardiovascular system that addresses the two former crucial factors. With this aim, we introduce a boundary condition for the mechanical problem that accounts for the neglected part of the domain located on top of the biventricular basal plane and that is consistent with the principles of momentum and energy conservation. We also discuss in detail the coupling conditions behind the 3D and the 0D models. We perform electromechanical simulations in physiological conditions using the 3D–0D model and we show that our results match the experimental data of relevant mechanical biomarkers available in the literature. Furthermore, we investigate different arrangements in cross-fibers active contraction. We prove that an active tension along the sheet direction counteracts the myofiber contraction, while the one along the sheet-normal direction enhances the cardiac work. Finally, several myofiber architectures are analyzed. We show that a different fiber field in the septal area and in the transmural wall affects the pumping functionality of the left ventricle.

Highlights

Over the years, computational models of cardiac electromechanics (EM) [1,2,3,4,5,6,7] have been developed with increasingly biophysical detail, by taking into account the interacting physical phenomena characteristic of the heart EM — electrophysiology, active contraction, mechanics [8,9,10,11,12]
With the aim of facing the computational challenges formerly described, our contributions in this paper move along two strands: (i) on the one hand, we present a biophysically detailed 3D biventricular EM model coupled with a 0D closed-loop lumped parameters model for the hemodynamics of the whole circulatory system; (ii) on the other hand, we investigate the effect of different myofiber architectures, by considering three type of LDRBMs, on the biventricular EM
We provide a detailed description of the multiphysics and multiscale 3D biventricular EM model coupled with a 0D closed-loop hemodynamic model of the whole cardiovascular system, including the heart blood flow

Summary

Introduction

Computational models of cardiac electromechanics (EM) [1,2,3,4,5,6,7] have been developed with increasingly biophysical detail, by taking into account the interacting physical phenomena characteristic of the heart EM — electrophysiology, active contraction, mechanics [8,9,10,11,12]. 3D EM models are coupled with Windkessel-type preload/afterload models for the circulatory system [33,34,35,36,37,38]. In these models, the different phases of the pressure– volume loop (PV-loop) are managed by solving different sets of differential equations, one for each phase [14, 39,40,41]. To the best of our knowledge, this coupled problem has been so far addressed only in a few works, namely [15,25,28,29]

Methods

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Discussion

Conclusion