A framework for biomechanics simulations using four-chamber cardiac models

Abstract

Computational cardiac models have been extensively used to study different cardiac biomechanics; specifically, finite-element analysis has been one of the tools used to study the internal stresses and strains in the cardiac wall during the cardiac cycle. Cubic-Hermite finite element meshes have been used for simulating cardiac biomechanics due to their convergence characteristics and their ability to capture smooth geometries compactly-fewer elements are needed to build the cardiac geometry-compared to linear tetrahedral meshes. Such meshes have previously been used only with simple ventricular geometries with non-physiological boundary conditions due to challenges associated with creating cubic-Hermite meshes of the complex heart geometry. However, it is critical to accurately capture the different geometric characteristics of the heart and apply physiologically equivalent boundary conditions to replicate the in vivo heart motion. In this work, we created a four-chamber cardiac model utilizing cubic-Hermite elements and simulated a full cardiac cycle by coupling the 3D finite element model with a lumped circulation model. The myocardial fiber-orientations were interpolated within the mesh using the Log-Euclidean method to overcome the singularity associated with interpolation of orthogonal matrices. Physiologically equivalent rigid body constraints were applied to the nodes along the valve plane and the accuracy of the resulting simulations were validated using open source clinical data. We then simulated a complete cardiac cycle of a healthy heart and a heart with acute myocardial infarction. We compared the pumping functionality of the heart for both cases by calculating the ventricular work. We observed a 20% reduction in acute work done by the heart immediately after myocardial infarction. The myocardial wall displacements obtained from the four-chamber model are comparable to actual patient data, without requiring complicated non-physiological boundary conditions usually required in truncated ventricular heart models.

Electro-Mechanical Whole-Heart Digital Twins: A Fully Coupled Multi-Physics Approach

“…For simulations spanning multiple heart beats, a closed-loop model is required to preserve the total blood volume in the circulatory system. Several closed-loop models of the circulatory system have been proposed [15,18,23,24,65] and all of them share some of their structure. However, in all cases, the circulatory system was only coupled to the finite element model of one or both of the ventricles, while the atria were represented by a time-varying elastance.…”

A publicly available virtual cohort of four-chamber heart meshes for cardiac electro-mechanics simulations

“…in mesh generation complexity [66,68]. Tetrahedral elements offer a detailed representation of the whole heart.…”

Virtual reality in cardiac interventions—New tools or new toys?

“…To take advantage of different modalities simultaneously, fusion of imaging modalities has been proposed, e.g., fusion of echocardiography and fluoroscopy for mitral interventions 8 or fusion of invasive coronary angiography and myocardial perfusion imaging 9 and others. With the increasing computing power of computers, the use of medical images is now reaching new possibilities: The available data is used to segment cardiac structures or even whole hearts 10–12 . These geometric models can then be used for further applications, such as simulating cardiac interventions 13–15 or 3D printing to better understand complex anatomies.…”

“…With the increasing computing power of computers, the use of medical images is now reaching new possibilities: The available data is used to segment cardiac structures or even whole hearts. [10][11][12] These geometric models can then be used for further applications, such as simulating cardiac interventions [13][14][15] or 3D printing to better understand complex anatomies. The latter became popular before interventions involving congenital heart defects, 16 as these are highly individual from patient to patient.…”