Experimental and theoretical investigation of implantable cardiac pacemaker exposed to low frequency magnetic field

This paper presents in vitro investigation of an implantable cardiac pacemaker exposed to low frequency magnetic fields. The method used in this study is based on the interaction by inductive coupling through the loop formed by the pacemaker and its loads and the surrounding medium. This interaction results in an induced electromotive force between the terminals of the pacemaker, which can potentially disturb its operation. The studied frequencies are 50/60 Hz and 10/25 kHz. The experimental tests were carried out on several cardiac pacemakers, single chamber, and dual chamber. The results show a window effect of the detection circuits of cardiac pacemakers for the four studied frequencies. The modelling of the test bed requires studying the effects of the induced currents generated by the application of a magnetic field. Analytical calculations and Numerical simulations were carried out. We modelled the interactions of the magnetic field with a simplified representation of pacemaker embedded in the medium. The comparison of the results in the air and in vitro enabled us to make an equivalent electric model. The results obtained in experimental and theoretical studies allowed us to validate the test bed. The method applied is valid for other medical implants such as cardiac defibrillators, implant hearing aids system...etc.