Attention, iPod users: Your music might be breaking Grandpa's heart - and not just because he doesn't care for the lyrics.
A study of 83 volunteers with pacemakers found the music devices interfered with the pacemakers nearly 30 percent of the time.
The results of the study, conducted by Michigan high school student Jay Thayer and Dr. Krit Jongnarangsin, a University of Michigan cardiologist, were presented Thursday at the Heart Rhythm Society meeting in Denver. The society is a professional group focusing on irregular heart rhythm.
In most cases, the iPod interference caused pacemakers to misread the heart's pacing. In one, the pacemaker stopped altogether.
The iPod - like microwave ovens, cellphones and other electronic devices - appears to cause a problem by creating an electromagnetic field that interferes with the electric function of the pacemakers, Thayer said.
"That seems to be the root," he said.
Thayer said the University of Michigan engineering department is looking into the electromagnetic effects of the iPod.
In the study, Thayer and Jongnarangsin placed iPods 2 inches from the chests of 83 volunteers with pacemakers and then turned on the music.
Thayer, 17, said the average age of volunteers in his study was 77.
"We set the headphones on their shoulders so we didn't blow out their eardrums," he said, and then turned up the Frank Sinatra tunes.
Most participants didn't use iPods, but "a lot of them had grandkids that use iPods," he said.
Thayer, who said he hopes to become a physician, like his mother and father, got interested in the iPod/pacemaker issue when one of his father's pacemaker-using patients raised the question.
Thayer said he and his father searched for an answer but couldn't find any research on the topic.
Apple reports that it has sold 100 million iPods since launching them in 2000. It's not clear how many iPod users have pacemakers.
Cupertino, Calif.-based Apple declined to comment.
Jongnarangsin said he treats many elderly patients with pacemakers but that none have ever inquired about the compatibility of the music devices.
The question the two researchers will now address is just how close is too close when it comes to iPods and pacemakers.
First, Thayer has to graduate from high school.