Effects of fat resistivity changes on measurement sensitivity of impedance cardiography determined by a 3D finite element model of the Visible Human Man

A detailed three-dimensional physiologically accurate computer thorax model based on finite difference element method (FDEM) is developed using the National Library of Medicine's (NLM) Visible Human Man (VHM) data for calculation of the measurement sensitivity of conventional impedance cardiography (ICG). The effect of the body and heart fat resistivity changes on measurement sensitivity and signal formation are determined based on the reciprocity theorem and lead field analysis. The results obtained show that the sensitivity of ICG to measure conductivity changes in the region of the heart and large arteries and veins changes considerably with different fat resistivity values. The results also show that the basal impedance values lie within the normal range with different fat resistivities.