Music headphones can interfere with heart devices

Nov 09, 2008

Headphones for MP3 players placed within an inch of pacemakers and implantable cardioverter defibrillators (ICDs) may interfere with these devices, according to research presented at the American Heart Association's Scientific Sessions 2008.

Researchers investigated the effects of MP3 player headphones, most of which contain the magnetic substance neodymium, on the operation of implanted cardiac devices.

An MP3 player is a popular digital music player. Earlier this year an FDA report concluded that interactions between MP3 players, such as the popular iPod, and implanted cardiac devices are unlikely to occur.

"We became interested in knowing whether the headphones which contain magnets — not the MP3 players, themselves — would interact with implanted cardiac devices," said William H. Maisel, M.D., M.P.H., senior author of the study and director of the Medical Device Safety Institute at Beth Israel Medical Center in Boston, Mass.

Maisel said doctors traditionally use magnets in the clinical setting to test pacemakers, which treat slow heart rhythms. When exposed to magnets, these devices automatically pace, sending low-energy signals to the heart to make it beat. Defibrillators, which treat slow and dangerously fast heart rhythms, send either low- or high-energy signals to the heart. However, ICDs near magnets may temporarily stop looking for abnormal heart rhythms.

Implanted cardiac devices that react in these ways to magnets outside the clinical setting can be potentially dangerous for patients who rely on their lifesaving technologies.

Researchers tested eight different models of MP3 player headphones (including both the clip-on and earbud variety) with iPods on 60 defibrillator and pacemaker 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.

The researchers found a detectable interference with the device by the headphones in 14 patients, (23 percent). Specifically, they observed that 15 percent of the pacemaker patients and 30 percent of the defibrillator patients had a magnet response, Maisel said.

"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," he said. "Exposure of a defibrillator to the headphones can temporarily deactivate the defibrillator." In most cases, removal of the headphones restores normal device function.

The researchers also tested the magnetic field strengths of each of the headphone models using a gauss meter, which measures the units of magnetic charge produced.
Field strength of 10 gauss at the site of the pacemaker or defibrillator has the potential to interact with the implantable device. The researchers found that some of the headphones had field strengths as high as 200 gauss or more.

"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."
Instead, patients should not place headphones in their pocket or drape them over their chest.

"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.

In two unrelated studies, researchers did not report adverse heart-related effects on implantable cardiac devices from other devices.

Researchers in Hyannis, Mass., found that cell phones equipped with wireless technology known as Bluetooth and pills swallowed to view internal organs are unlikely to interfere with pacemakers or ICDs.

Likewise, California researchers determined that electromagnetic interference from personal devices including iPod, iPod nano, iPhone, some cell phones (with and without Bluetooth technology), electric blankets and hand-held airport security metal detectors did not cause adverse effects to patients with pacemakers or ICDs.

Source: American Heart Association

Explore further: Liver transplant recipient marks 25th anniversary

add to favorites email to friend print save as pdf

Related Stories

US northeast braces for flooding after record snow

6 hours ago

Weather forecasters and emergency officials warned Sunday that melting snow would lead to heavy flooding in parts of the US northeast, with hundreds of thousands of people told to brace for fast-rising waters.

How the hummingbird achieves its aerobatic feats

13 hours ago

(Phys.org) —The sight of a tiny hummingbird hovering in front of a flower and then darting to another with lightning speed amazes and delights. But it also leaves watchers with a persistent question: How ...

'Mind the gap' between atomically thin materials

14 hours ago

In subway stations around London, the warning to "Mind the Gap" helps commuters keep from stepping into empty space as they leave the train. When it comes to engineering single-layer atomic structures, minding ...

Recommended for you

Doctor behind 'free radical' aging theory dies

Nov 25, 2014

Dr. Denham Harman, a renowned scientist who developed the most widely accepted theory on aging that's now used to study cancer, Alzheimer's disease and other illnesses, has died in Nebraska at age 98.

Mexican boy who had massive tumor recovering

Nov 25, 2014

An 11-year-old Mexican boy who had pieces of a massive tumor removed and who drew international attention after U.S. officials helped him get treatment in the southwestern U.S. state of New Mexico is still recovering after ...

New medical device to make the mines safer

Nov 21, 2014

Dehydration can be a serious health issue for Australia's mining industry, but a new product to be developed with input from Flinders University's Medical Device Partnering Program (MDPP) is set to more effectively ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

marksany
not rated yet Nov 10, 2008
ICDs (like mine) have a switch that is turned on by a magnet. Not surprising a headphone would do this, as it has a magnet in it. ICD and Pacemaker users are very aware of the magnet issue affecting their devices by design. Nothing else to see here, move on.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.