Modeling of the cardiovascular system with integrated finite element and electrical analog methods.

摘要

In this study, a model of the cardiovascular system was developed by integrating a finite element model of the left ventricle (LV) with an electrical analog model of the circulatory system. The integrated model related the regional LV wall impairment with its overall hemodynamic consequences. The model and simulation system was completely implemented in customized C++ software. Applications of the model for studying cardiovascular dynamics and surgical ventricular restoration were demonstrated.; A finite element method was applied to a two-dimensional (2D) long-axis slice of the LV wall. The three-dimensional (3D) LV geometry was interpolated from two LV slices, one representing normal myocardium and the other including an infarct zone. The material properties of the myocardium were assumed to be linear and isotropic, and homogenous. The contractility of the myocardium over a cardiac cycle was represented by a time-varying Young's modulus function. A previously developed electrical analog model of the circulatory system was used to produce the instantaneous LV pressure and fed it to the finite element model. The resulting LV volume from the finite element model was used to derive LV elastance, which in turn drove the electrical analog model to the next time step. This interaction loop was solved every 5 milliseconds for the entire cardiac cycle.; The validity of model was supported by good agreement between the model predicted result and the clinical data reported in the literature for the LV ejection fraction and end-diastolic and end-systolic volumes as functions of the LV infarct size.; The model was used to determine the optimal operating points for infarct removal in surgical ventricular restoration and to assess the relative severity of infarction at various locations of the LV wall.