Finite element model applications in defibrillation and external cardiac pacing

The authors have applied finite-element computer models to electrode design problems in defibrillation, external cardiac pacing, and electrosurgery. These models solve Laplace´s equation to determine voltage and current density distribution throughout the body and electrodes. The models are flexible (easily modified) and have proved to be an effective tool in evaluating electrodes, predicting their performance, and designing better and safer electrodes. In addition, physical modeling techniques for measuring current density profiles under the actively driven electrodes have been developed to verify computer simulation results and to test electrodes as they are constructed. The authors have used both numerical and experimental techniques in determining relative performance rankings of three types of internal defibrillation electrodes. To facilitate the widespread use of these techniques in other research and clinical applications, the authors have ported the finite-element model programs from their traditional mainframe environment to a far less expensive personal computer environment.<>