A transmurally heterogeneous orthotropic activation model for ventricular contraction and its numerical validation

Area of Science:

• Computational mechanics
• Biomedical engineering
• Cardiac physiology

Background:

• Accurate cardiac mechanics models require precise activation mechanisms to represent myocardial stress-strain relationships.
• Existing models struggle to account for transmural heterogeneities in myocardial strain measurements.

Purpose of the Study:

• To propose a novel activation model for cardiac mechanics.
• To incorporate transmural heterogeneities and anisotropy into cardiac muscle contraction modeling.
• To improve the accuracy of simulated myocardial strain distributions.

Main Methods:

• Developed a new activation model based on an active strain formulation.
• Utilized multiplicative decomposition of the deformation gradient tensor.
• Compared the model against existing anisotropic models and experimental data.

Main Results:

• Current models show discrepancies with experimental measurements of myocardial strain.
• The proposed transmurally heterogeneous orthotropic activation model enhances accuracy.
• Improved simulation of shear strains associated with in-plane rotations and torsion.

Conclusions:

• The novel activation model provides a more accurate representation of cardiac mechanics.
• Accounting for transmural heterogeneities is crucial for realistic myocardial strain prediction.
• This model offers improved insights into cardiac muscle contraction and function.