Photo: The magnetic field that emanates from many headphones can disrupt pacemakers. Photo: J. Heuser,
Reading Headphones from MP3 players can interfere with implanted defibrillators and pacemakers. If the magnet built into the headset is closer than three centimeters to such a device, it may break the rhythm of the pacemaker or temporarily disable the defibrillator, researchers at William Hefel's Beth Israel Medical Center report at an American conference Heart Association in New Orleans. Both could have serious consequences for the person concerned. Most headphones of MP3 players contain a substance called neodymium, which has magnetic properties. The impact of this magnetic field on medical devices, the researchers tested with eight different headphone models to 60 patients with a defibrillator or pacemaker. To do so, they attached the handset immediately above the device to the chest. In 14 subjects, the scientists were able to observe a device malfunction. In 15 percent of the pacemaker patients and in 30 percent of the defibrillator patients, there was a reaction to the magnetic field emanating from the headphones. In most cases, however, the devices worked normally again after the handsets were removed.

Measuring the strength of the magnetic field resulted in a magnetic flux density of 20 millitesla or even more for some headphone models. For the tested devices, however, already 1 Millitesla could be enough to affect their function, the researchers say.

Although the measured values ​​were 20 times higher, researchers were unable to detect any interference when the headphones were at least three inches from the skin surface. Patients with such implants should not be too worried, explains Maisel. Rather, they should take care not to carry the handset in close proximity to the device. Too close physical contact with other people wearing headphones should also be avoided.

Contribution to the New Orleans American Heart Association (Abstract P662) ddp / science.de? Sonja Römer advertisement

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