Realistic modelling of interference in pacemakers by ELF magnetic fields

Many experimental studies gave different proofs on the pacemaker´s susceptibility by ELF magnetic fields, nevertheless it´s still difficult to trace currents and voltages that invade the pacemaker input stage, determining in this way anomalies in the implantable device. Luckily, modern computational resources, joined to the detailed conductivity models of human body, with a precision of the fraction of millimeter, make of the numerical models a valid technique for the valuation of the various interferences. In this way, in the present work, a vectorial simulator was developed. It´s able to determine, to compute and to plot the electromagnetic parameters (current density, electric field, magnetic field, voltage) induced in any biological volume, where a representative structure of pacemaker is inserted, all of this is plunged in a time-varying magnetic field. A numerical model of Maxwell equations were introduced and computing techniques for the solution of sparse systems were implemented in C programming language. Programs for the definition of the conductivity outline whether for the biological tissues or the metallic and insulating structures where also developed. Finally a powerful graphic interface were applied with all the capabilities of visualization that a vectorial 3-D plotter can offer with great effectiveness