Influence of media parameters on potentials measured with an intracardiac conductance catheter-simulation studies

An intraventricular impedance imaging (III) system, that will be used for assessing electrical and mechanical cardiac properties, via an intraventricular catheter, is presently under development. There have not been sufficient published results on how the electrical properties of the media effect intraventricular potential measurements/calculations. The purpose of this work is to perform a sensitivity analysis on the myocardium and thorax resistivities and myocardium thickness, to determine how will changing these parameters effect the measured/calculated intraventricular potentials. Numerical simulations were performed using a model developed for a cylindrical catheter placed in an ellipsoidal heart ventricle. The simulations indicate that as the ratio of thorax to myocardium resistivity increases, the calculated potentials increase. The simulations also indicate that as the myocardium thickness increases, the calculated potentials decrease. An increase/decrease in the measured/calculated potentials would indicate an under/overestimation in ventricular volume by the III system