iPod MP3 music players may interfere with the functioning of implanted pacemakers. The observations are disconcerting because implantable pacemakers are common worldwide, and the iPod has become a ubiquitous personal digital entertainment device. Pacemaker malfunction caused by cell phones is known. American researchers from the University of Michigan looked at the effect of four different iPod models (third generation, photo, video and Nano) on implantable pacemaker function in 100 patients. A technician monitored electrocardiographs while each iPod was held near the chest for 5 to 10 seconds in the on and off position. It was found that the iPods, when held 2 inches from the patients' chest and as far as 18 inches, interfered with pacemaker function in about one third of patients. Pacemaker oversensing - incorrectly sensing a cardiac event - was seen in 19 percent of patients. Telemetry interference - defined as any other interference that did not affect pacing function and was not detected by pacemaker interrogation - occurred in 32 percent, and pacemaker inhibition in 1 percent. Oversensing and telemetry interference occurred more often with third generation and photo iPods than with the video or Nano iPods. The observed iPod interference did not cause any clinical symptoms. However, in one patient the iPod transiently inhibited pacemaker function. There is a concern that iPod interference might lead to an incorrect diagnosis of abnormal heart rhythm. If it is not taken into account that the patient has an iPod close to the pacemaker, one may falsely diagnose that the patient has an abnormal heart rate rhythm. However, more information and more studies are needed on interference due to iPods and other personal music devices, in pacemaker function, before anything can be said more conclusively.
Heart Rhythm Society,
May 2007