Electromagnetic Interference of an Implantable Cardiac Pacemaker by conductive currents of high frequency surgical equipment using Finite Element Method

High frequency surgical equipments have been reported to exert electromagnetic interference on implanted cardiac pacemakers because of the conductive currents. We proposed a methodology to evaluate the electromagnetic interference possible to simulate the complex anatomy using the Finite Element Method (FEM) and examined its feasibility. We performed an inhibition test and an asynchronous test using a phantom as the standardized Irnich human body model. We injected 10W of electrical energy (515 kHz, 270mARMS) using a high frequency surgical equipment, and measured the potential at 18 measuring electrodes placed in the phantom and the voltage between the electrodes of the pacemaker. A three-dimensional FEM model of phantom had been developed using 193 slices of X-ray CT images taken in 2mm pitch. Electrical potentials at each electrode were estimated using the FEM model and compared with experimental results. If output of the high frequency surgical equipment became more than 7W, the asynchronous test was positive. The maximum error was 25% between measured voltages and estimated voltages using FEM analysis, and average error was 13%. Those results demonstrate that the FEM analysis method is useful to investigate the electromagnetic interference on pacemakers by conductive currents, determining the presence or absence of electromagnetic interference.