Microstructurally Motivated Constitutive Modeling of Heart Failure Mechanics.

Area of Science:

• Cardiovascular Research
• Biomedical Engineering
• Cardiac Mechanics

Background:

• Heart failure (HF) is a major global health issue.
• HF involves microstructural remodeling, altering left ventricular geometry and cardiac function.
• The impact of myocardial remodeling on failing heart mechanics is not fully understood.

Purpose of the Study:

• To investigate the relationship between biomechanical function and tissue organization in cardiac muscle during HF.
• To develop and validate a structurally based constitutive model for healthy and failing hearts.
• To gain insights into the mechanisms of ventricular dysfunction in HF.

Main Methods:

• Quantified left ventricular geometry and myocardial microstructure remodeling using cardiac MRI and confocal microscopy in healthy and hypertensive rat hearts.
• Measured passive cardiac mechanical function via left ventricular pressure-volume compliance.
• Developed a novel structurally based biomechanical constitutive equation using collagen distribution data.
• Constructed 3D finite element models from subject-specific MRI data and integrated the constitutive equation.

Main Results:

• The developed constitutive equation, using a single set of material parameters, accurately reproduced experimental compliance measurements for all hearts.
• The model successfully simulated the mechanical behavior of both healthy and failing hearts.
• Demonstrated the ability to link myocardial microstructure to macroscopic mechanical function.

Conclusions:

• The study provides a novel, structure-based biomechanical model for understanding heart mechanics in HF.
• The model offers significant insights into the structure-function relationship of diseased myocardium.
• Findings pave the way for developing more effective therapeutic strategies for heart failure.