Portable headphones can interfere magnetically with implanted cardiac devices

Issue: November 2009

The placement of portable headphones in the vicinity of an implantable cardioverter defibrillator or an implanted pacemaker can lead to magnetic interference with the cardiac device.

Researchers assessed the effects of magnetic interference from eight different models of headphones in 100 patients with implanted pacemakers (n=45) and ICDs (n=55). The researchers defined a device response as pacemaker or ICD magnetic responses, oversensing, undersensing or device reprogramming. Two different iPod MP3 players were also placed in proximity to the implanted devices for testing.

Magnetic interference was reported in 30% of patients. The researchers reported that magnetic interference tended to affect patients with ICDs more frequently than those with implanted pacemakers (21 of 55 patients vs. nine of 45 patients; P=.048). Headphones with a measured magnetic field strength of ≥10 gauss at 2 cm from the implanted device were more likely to interact with a pacemaker or ICD than those with lower magnetic field strength (30% of patients vs. 0% patients; P<.0001). Clinical evidence of magnetic interference was observed more frequently with clip-on headphones vs. earbud headphones (30% of patients vs. 0% of patients; P<.0001). The researchers also reported that MP3 players did not cause device magnet responses, oversensing or undersensing and that the incidence of symptoms due to magnetic interference was low (2%).

“The majority of these interactions are typical magnet responses, and in most cases device function returns to normal upon removal of the headphones,” the researchers wrote. “In vitro measurements of headphone magnetic strength at 2 cm accurately predict headphone clinical interactions with implanted cardiac devices. Patients with an implanted pacemaker or defibrillator should be advised to keep headphones at least 3 cm from their device.”

Lee S. Heart Rhythm. 2009;6:1432-1436.