A Passive Hybrid Model to Estimate the Elastic Performance of Left Ventricular Cardiac Fibres

The development of mathematical and numerical models of the human heart has become a matter of high relevance in the scientific community because of the difficulty of measuring the properties and performance of the cardiac tissue in vivo, and carrying out experimental tests under different healthy and pathological conditions. Several heart models have been proposed in the literature, but the results still differ from each other. In this paper, a new passive heart model to estimate the elastic behaviour of the left ventricular (LV) cardiac fibres is presented. The model is based on a hybrid approach that combines a theoretical approach to determine the equivalent material properties of each layer of the LV tissue, which represents an advantage with respect to other more elaborated or complex models, and an inverse finite element method (FEM) to determine the volume of the LV internal cavity under loading conditions. The proposed model uses the LV pressure and volume measurements along a real cardiac cycle as loading and target conditions, respectively. The results are analysed in terms of the elastic properties of the cardiac fibres and compared with the results obtained from other more complex and elaborated models reported in the literature. From this analysis it is observed that the new proposed model is reliable and able to estimate the elastic behaviour of the cardiac tissue.