Modeling effects of infarction on cardiac function with dynamic finite element analysis

A computational model has been developed that combines a 3D finite element model (FEM) of the left ventricle (LV) with an electrical analog model of the circulatory system. The model is used to assess the effects of infarction on LV function. LV geometry is modeled as a truncated ellipsoid. The stress-strain relationship for each element is assumed to be linear but with a time-varying Young´s modulus. For a given LV pressure (Plv) generated by the electrical analog model, LV volume (Vlv) is determined by a 3D model constructed from multiple 2D FEM slices. The left ventricular elastance (Elv), determined by Plv over Vlv, is used to drive the electrical analog model. Time-varying Young´s modulus functions over a cardiac cycle are assigned to normal and infarct finite elements, defining the infarct zone for a certain size and location. The model provided good representations of the LV geometry for normal and infarct cases. The LV ejection fraction, pressure, and volume curves were consistent with typical clinical observations. The dynamic finite element model developed in this study is effective and computationally efficient. The model can be used to relate regional LV impairments to overall circulatory dynamics.