EMF interference detection utilizing the recording feature of cardiac pacemakers

Electromagnetic (EMF) interference with cardiac pacemakers may occur in various work environments. In the case of interfering external signals, the pacemaker may misinterpret the signal as a heart-related problem and initiate treatment procedures unnecessarily. We evaluated the applicability of the interference recording feature of cardiac pacemakers to identify the interfering sources. The pacemakers were exposed to a wide variety of magnetic fields in a sophisticated exposure setup in which the exposure was controlled by a computer programme. In cases where a pacemaker experienced interference, the time of interference was compared with the magnetic field exposure schedule. The study shows that interference recordings can be linked together with the exposure correctly, and it is possible to differentiate the EMF-induced pacemaker interference from other types of interference. At workplaces, an EMF recorder can be given to a pacemaker patient to wear for a few days, asking to keep a diary of his or her activities. After an appropriate time, the EMF recordings are read and compared with the interrogated pacemaker data. The interference source can be identified by combining the time of interference with the patient´s diary activities.