Forward Uncertainty Quantification and Sensitivity Analysis of the Holzapfel-Ogden Model for the Left Ventricular Passive Mechanics

Cardiovascular diseases are still responsible for many deaths worldwide, and computational models are essential tools for a better understanding of the behavior of cardiac tissue under normal and pathological situations. The microstructure of cardiac tissue is complex and formed by the preferential alignment of myocytes along their main axis with end-to-end coupling. Mathematical models of cardiac mechanics require the process of parameter estimation to produce a response consistent with experimental data and the physiological phenomenon in question. This work presents a polynomial chaos-based emulator for forward uncertainty quantification and sensitivity analysis of the Holzapfel-Ogden orthotropic constitutive model during the passive filling stage. The fiber orientation field is treated as a random field through the usage of the Karhunen-Loeve (KL) expansion. The response and uncertainty of the constitutive parameters of the model considered here are also investigated. Our results show the propagated uncertainties for the end-diastolic volume and fiber strain. A global sensitivity analysis of the constitutive parameters of the complete model is also presented, evidencing the model's key parameters.