COMPARISON OF CARDIAC-INDUCED ENDOGENOUS FIELDS AND POWER FREQUENCY INDUCED EXOGENOUS FIELDS IN AN ANATOMICAL MODEL OF THE HUMAN-BODY

Time-domain potentials measured at 64 points on the surface of a large canine heart, considered comparable with those of a human heart, were used to calculate the electric fields and current densities within va rious organs of the human body. A heterogeneous volume conductor model of an adult male with a resolution of approximately 6 mm(3) and 30 se gmented tissue types was used along with the admittance method and suc cessive over-relaxation to calculate the voltage distribution througho ut the torso and head as a function of time. From this time-domain vol tage description, values of \E(t)\ and \J(t)\ were obtained, allowing for maximum values to be found within the given tissues of interest. F requency analysis was then used to solve for \E(f)\ and \J(f)\ in the various organs, so that average, minimum and maximum values within spe cific bandwidths (0-40, 40-70 and 70-100 Hz) could be analysed. A comp arison was made between the computed results and measured data from bo th EKG waveforms and isopotential surface maps for validation, with go od agreement in both amplitude and shape between the computed and meas ured results. These computed endogenous fields were then compared with exogenous fields induced in the body from a 60 Hz high-voltage power line and a 60 Hz uniform magnetic field of 1 mT directed from the fron t to the back of the body. The high-voltage power line EMFs and I mT m agnetic field were used as 'bench' marks for comparison with several s afety guidelines for power frequency (50/60 Hz) EMF exposures. The end ogenous electric fields and current densities in most of the tissues ( except for organs in close proximity to the heart, for example lungs, liver, etc) in the frequency band 40-70 Hz were found to be considerab ly smaller, between 5% and 10%, than those induced in the human body b y the electric and magnetic fields generated by the 60 Hz sources desc ribed above.