Calculations of potential distributions produced by implanted electrodes in a man model by finite elements

The finite-element (FE) method is used to analyze and determine the potential distribution produced by implanted stimulating electrodes used in conjunction with an implanted defibrillator. These electrodes are used to deliver an energy shock to halt ventricular fibrillation during fatal arrhythmias in human beings. The FE solution was obtained by solving the Laplace equation using a Galerkin procedure. An infinite cylindrical model having three coaxial layers of tissue with two electrodes was used to show preliminary results of the FE model. An analytical procedure was developed and used to validate the FE results. The overall objective of this study is to develop a computer model for the study of defibrillation fields. This model can be used to estimate the potential distribution and potential gradients on the heart for various electrode sizes and configurations for a given shock strength. The most promising variation of these defibrillation-electrode configurations can be chosen for experimental testing in laboratory animals and possibly in human beings