Left Heart Hemodynamics Simulations With Fluid-Structure Interaction and Reduced Valve Modeling.

Area of Science:

• Computational fluid dynamics
• Biomedical engineering
• Cardiac mechanics

Background:

• Current reduced models for cardiac valve dynamics often simplify simulations but introduce issues like artificial pressure oscillations and missing isovolumetric phases.
• Existing models lack precise continuous formulation for valve laws, limiting accuracy in cardiac hemodynamics simulations.
• The one-way kinematic uncoupling of blood flow and electromechanics, while reducing complexity, presents significant shortcomings.

Purpose of the Study:

• To overcome limitations of existing reduced cardiac valve models, specifically artificial pressure oscillations, missing isovolumetric phases, and imprecise valve laws.
• To propose a novel reduced model for valve dynamics that enforces unidirectional flow in a mathematically sound manner.
• To mitigate computational cost while improving the accuracy of cardiac hemodynamics simulations.

Main Methods:

• Developed a novel reduced model for cardiac valve dynamics incorporating mathematically sound unidirectional flow enforcement.
• Implemented a fluid-structure interaction model coupling bi-ventricular electromechanics and blood flow in the left cavities to resolve artificial pressure oscillations.
• Employed an unconditionally stable loosely coupled scheme for partitioned interface coupling, validated with a priori energy estimates for continuous and numerical problems.

Main Results:

• The proposed model successfully overcomes artificial pressure oscillations and addresses missing isovolumetric phases inherent in previous reduced models.
• A mathematically sound formulation for unidirectional flow in valve dynamics was achieved, enhancing simulation accuracy.
• The fluid-structure interaction model effectively couples cardiac electromechanics and blood flow, demonstrating improved simulation fidelity.

Conclusions:

• The novel reduced model offers a significant advancement in cardiac hemodynamics simulations by providing a more accurate and robust representation of cardiac valve dynamics.
• The proposed approach effectively balances computational efficiency with improved accuracy, addressing key limitations of existing methods.
• The study demonstrates the benefits of integrating fluid-structure interaction and advanced modeling techniques for simulating complex cardiac phenomena.