A high-resolution computational model of the deforming human heart

Area of Science:

• Computational mechanics
• Biomedical engineering
• Cardiovascular modeling

Background:

• Cardiac tissue mechanics are complex due to anisotropy, incompressibility, and active stress.
• Current models often face limitations in degrees of freedom (DOF) for active force simulation.
• High-resolution modeling is crucial for understanding ventricular function.

Purpose of the Study:

• To develop a novel, efficient computational approach for high-resolution modeling of heart ventricles with active stress.
• To overcome the limitations of direct solvers in handling large systems of equations in cardiac mechanics.
• To enable accurate simulation of active cardiac contraction in detailed anatomical models.

Main Methods:

• A hex-dominant finite element mixed formulation was developed.
• A Krylov subspace iterative method (Flexible GMRES) with nonlinear preconditioning was employed.
• Passive tissue modeled as hyperelastic, incompressible with orthotropic properties; active stress incorporated; coupled with a lumped circulatory model.

Main Results:

• The developed solver efficiently handles high-resolution models (1.7M displacement DOF) with active stress.
• Demonstrated effectiveness for simulating active ventricular contraction.
• Verification against benchmark problems and existing codes (Chaste) confirmed solver accuracy.

Conclusions:

• This iterative solver represents a significant advancement for efficient, high-resolution cardiac modeling.
• It enables simulations previously limited by computational cost.
• Opens avenues for future research in detailed ventricular mechanics and disease modeling.