Head Phones Interfere with Implanted Heart DevicesNov 10, 2008 | Parker Waichman LLP
A new study has revealed that some headphones can interfere with implanted heart devices such as pacemakers or defibrillators, when the headphones and the devices are in close proximity, such as when the headphones are in a shirt pocket or when they are draped around the neck. And, the interference can also occur when the headphones are disconnected.
The headphones might even prevent a defibrillator from delivering a lifesaving shock, say the doctors involved in the study. "Headphones contain magnets, and some of these magnets are powerful," said the study's leader, Dr. William Maisel, a cardiologist at Beth Israel Deaconess Medical Center in Boston, Massachusetts. Dr. Maisel is also a heart device consultant to the federal Food and Drug Administration (FDA). "It's smart to keep small electronics at least a few inches from implanted medical devices, and not let someone wearing headphones lean against your chest if you have one,” he said. "The headphone interaction applies whether or not the headphones are plugged in to the music player and whether or not the music player is on or off," Dr. Maisel noted.
Dr. Maisel's research was presented over this past weekend at an American Heart Association conference. The study noted that, globally, nearly two million people have been implanted with pacemakers, defibrillators, or other cardiac devices to enable their hearts to beat faster, slower, or with more regularity.
The FDA conducted tests earlier this year and found that iPods and other such music players tested posed no threat to the cardiac devices as long as they were used properly. Maisel and other doctors were curious to learn if this also applied to headphones and tested eight models—earbuds and those headphones that hook over the ear—in 60 people who were implanted with heart devices. What they found was that when headphones were placed approximately one inch away from the cardiac device, interference was detected in nearly one-quarter of all cases, in four of the 27 pacemaker patients, and also in 10 of the 33 patients implanted with defibrillators. In one case involved in the study, a patient’s pacemaker reset itself
Patients experiencing such interference might not feel anything, or they may experience heart palpitations; however, the interference could temporarily deactivate a defibrillator, which could prevent it from delivering a lifesaving shock when needed. The magnet's effect decreases rapidly when it reaches distance from the device, and the heart device function returns to normal as soon as the headphone is out of range.
The study did not test larger or noise-canceling headphones, but did note that the size of the headphone did not always correlate to its magnetic strength; small, portable devices generally use neodymium, one of the most powerful and concentrated magnetic substances, Maisel said. Dr. Kenneth Ellenbogen, a heart device expert at Virginia Commonwealth University and a spokesman for the heart association, said the solution is simple: "Keep your headphones on your ears and when they're not on your ears, you shouldn't put them over your chest or your pacemaker."