Correlating with Local Variation in Collagen Level and Mechanical Properties of the Heart Tissues

The determination of the myocardium\u27s tissue properties is essential in constructing finite element (FE) models of the heart. To obtain accurate results, especially for functionally modeling the heart, we must determine the tissue properties in-vivo. The calculation of the heart tissue properties remains a challenging area as it is categorized as a heterogeneous, anisotropic, nonlinear soft tissue that undergoes large deformation. In this work, we tried to introduce and evaluated a finite element method to determine the mechanical properties of the cardiac tissue. The introduced method combined a finite element modeling with the experimentally obtained images from the left and right ventricles to develop a model for calculating the shear modulus, Young\u27s modulus, and the Poisson\u27s ratio of the ventricles leading to obtaining the constitutive matrices for each specimen. Tissue behavior was quantified under three different loading conditions: tensile loading in the x and y direction and shear loading. Statistical analysis reveals that the left ventricle demonstrates higher mechanical properties compared to the right ventricle. Additionally, the heart tissue\u27s mechanical properties were effectively used for studying the effects of the variation in the tissue\u27s composition, primarily collagen, on the myocardium behavior. Based on the obtained results, it was demonstrated that mechanical properties enhanced with increasing the collagen amount. The results indicated that the proposed model showed a good agreement with the previous studies and provided an ability to describe the heart tissue\u27s behavior precisely. It offers a new approach to the study of cardiac tissue properties, as it shows the cardiac tissue\u27s mechanical properties, including Young\u27s modulus, shear modulus, constitutive matrices, and their correlation with the change in the microstructure of the heart tissue