EDF-Gaz de France, Service des études médicales (SEM), 22-28 rue Joubert, 75009 Paris, Service de cardiologie, Hôpital Nord, CHU de Marseille, Chemin des Bourrely, 13915 Marseille, Service de rythmologie, Institut de cardiologie, Hôpital Pitié-Salpêtrière, 52-56, boulevard Vincent Auriol, 75013 Paris, EDF-Gaz de France, Service R & D, Avenue des Renardières, 77818 Moret-sur-Loing cedex
The objective of this study was to evaluate the behaviour of implanted pacemakers in the presence of a 50 Hz magnetic field of a magnitude of 100 μT, the maximum limit value set by European recommendation 1999/519/EC concerning public exposure to electromagnetic fields. The study included 265 patients with implanted pacemakers from different manufacturers. The subjects passed through and stood between a system of two coils generating a 50 Hz 100 μT magnetic field. Pacemaker functioning was assessed at the standard setting, the “medically correct” sensing parameters chosen by cardiologists for each patient, and was monitored during the tests by a cardiologist, blinded to the presence of any field. At the end of the tests, the pacemaker programme was verified and reprogrammed if necessary. Four different pacemaker models were influenced by the magnetic field. No reprogramming took place. Asynchronous mode reversion was recorded in 3 patients whose pacemakers had unipolar sensing. This persistent mode reversion was followed by symptomatic pacing inhibition in one case. Pacemakers with bipolar sensing were not affected, but one interacted with a specific capture threshold algorithm. All interference stopped when the field was turned off. Conclusion: current pacemakers are safe in the 50 Hz electromagnetic interference usually met in the environment. They are insensitive to it at their medically correct settings. In a few cases, interference produced transient reversion mode or modification of the autocapture programme. Both changes were reversible and neither was dangerous for the patients.