November 10, 2008
Headphones connected to MP3 music players have become a ubiquitous
feature of modern life. You see them everywhere, on all types of
people.
But people with heart pacemakers are being cautioned to use care in where they carry those headphones when they aren't listening to music. These headphones, researchers warn, may interfere with heart pacemakers and defibrillators.
Dr. William Maisel, part of the Medical Device Safety Institute at Beth Israel Medical Center in Boston, led the research team that tested eight different types of headphones, including clip-on and earbud types. Also taking part in the experiment were 60 defibrillator and pacemaker patients.
It isn't the players causing the problem.
The researchers, presenting their findings at an American Heart Association meeting in New Orleans, say each set of earphones contains tiny, but very strong, magnets. These magnets, if placed to close to a pacemaker, can cause interference.
In the experiment, the researchers placed the headphones on patents' chests, directly over the pacemakers.
In about 25 percent of the patients, the headphones caused interference. Since pacemakers are designed to keep a patient's heart beating at a regular rhythm, the interference could be a serious matter.
Maisel says pacemaker patients don't have to avoid using headphones, since wearing them on their head will keep them far enough away from the device to cause problems. Instead, he says, people with heart pacemakers need to be aware of the potential interference, and keep them away from their chest area.
Despite the headphones' tiny size, Maisel says they have surprisingly strong magnetic fields, often 20 times higher than the minimum level for causing interference with a pacemaker or defibrillator.
