Internal Body Potentials and Currents from ELF Electric Fields and Household Appliances

Abstract

To provide quantitative data on the effects of electric fields from power lines and leakage currents from household appliances on patients with implanted pacemakers, a semi-empirical prediction method was de­ veloped. Input data to the prediction model included in vitro susceptibility bench tests on pacemakers, in vivo exposure measurements on baboons with implanted pacemakers, and nonhazardous, noninvasive tests on humans. The results show that widespread interference from 60 Hz electric fields or currents does not con­ stitute a problem for the vast majority of pacemaker patients. Several remedial approaches have been iden­ tified for the small group of patients where the possi­ bility of interference may occur. The paper describes the basic modeling concept for relating the fields and body currents to the voltage sensed by the implanted pacemaker. The methods used to obtain empirical data for the model and to verify the model by in vivo animal testing are described. The ex­ tension of the model to the human form is presented along with examples of predictions for electric field and body current excitation for various implant ar­ rangements and pacemaker sensitivities.