A viscoelastic model for human myocardium.

Area of Science:

• Biomechanics
• Biomaterials science
• Computational biology

Background:

• Accurate constitutive equations are crucial for computational biomechanical models of the heart.
• Current models often neglect viscoelastic phenomena in cardiac muscle, limiting their predictive power.
• Understanding heart tissue biomechanics is vital for diagnosing and treating heart failure.

Purpose of the Study:

• To develop and validate a fractional nonlinear anisotropic viscoelastic constitutive model for human myocardium.
• To improve the accuracy of computational models for assessing heart failure therapies.
• To integrate the viscoelastic response of heart tissue into cardiac mechanics models.

Main Methods:

• Developed a fractional nonlinear anisotropic viscoelastic constitutive model based on experimental data from human myocardium and its hierarchical structure.
• Validated the model against biaxial stretch, triaxial cyclic shear, and triaxial stress relaxation experiments.
• Compared the model's performance against existing hyperelastic constitutive models.

Main Results:

• The proposed fractional viscoelastic model replicated experimental data with a mean error of approximately 7.68%.
• The model demonstrated significant improvements over hyperelastic models, which had a mean error of approximately 24%.
• Model sensitivity, fidelity, and parameter uniqueness were successfully demonstrated across various loading conditions.

Conclusions:

• The fractional viscoelastic model provides a more accurate representation of passive cardiac muscle function compared to current models.
• This approach enhances the understanding of myocardial tissue biomechanics in both healthy and diseased states.
• The model offers a platform for developing personalized treatments for heart failure by improving therapy assessment.