Patients Warned Not to Keep These Near Heart Device
While many people enjoy music from their MP3 players or iPods, a new study says that people with pacemakers or implanted defibrillators should be careful where they store their headphones.
Why? The headphones associated with the music devices contain magnets that may cause interference if placed directly on the chest above the heart device, according to research presented at the American Heart Association’s Scientific Sessions 2008.
The headphones contain the magnetic substance neodymium, which researchers found can temporarily stop defibrillators from detecting abnormal heart rhythms. As for pacemakers, which are designed to boost slow heart rhythms, they may deliver signals telling the heart to beat faster when exposed to magnets.
"For defibrillator patients, it is a much bigger concern because the magnet can temporarily deactivate it," says the study's senior author, Dr. William H. Maisel, director of the Medical Device Safety Institute at Beth Israel Deaconess Medical Center in Boston, Massachusetts.
For the study, researchers attached eight types of MP3 player headphones (earbuds and clip-ons) to iPods and tested them on sixty pacemaker and defibrillator patients.
“We placed the headphones on the patients’ chests, directly over where their devices are located, monitoring them for evidence of an interaction,” Maisel said.
Researchers found interference 14 patients, or 23 percent. To be more specific, they observed that 15 percent of the pacemaker patients and 30 percent of the defibrillator patients had a magnet response.
“For patients with pacemakers, exposure to the headphones can force the device to deliver signals to the heart, causing it to beat without regard to the patients’ underlying heart rhythm,” Maisel said. “Exposure of a defibrillator to the headphones can temporarily deactivate the defibrillator.” In most cases, removing the headphones restored the heart device to normal.
Researchers also tested the magnetic field strengths of each of the headphone models. “Even at those high levels, we did not observe any interactions when the headphones were at least 3 cm, or about 1.2 inches, from the skin’s surface,” Maisel said.
“Patients should not focus on the brands we tested but instead should simply be instructed to keep their headphones at least 3 cm from their implantable devices.”
Patients are advised not to place the headphone directly on their chest or in their pockets. “For family members or friends of patients with implantable defibrillators, they should avoid wearing headphones and resting their head right on top of someone’s device,” he said.
Source: American Heart Association Press Release