Sunday July 08, 2007
iPods may interfere with pacemakers

Orginally reported at Reuters Health by By Megan Rauscher

Apple iPod MP3 music players may interfere with the functioning of implanted pacemakers, according to research reported at the Heart Rhythm Society's 28th annual scientific sessions in Denver, Colorado few weeks ago.

...............In their study, Dr. Krit Jongnarangsin of the University of Michigan, Ann Arbor and colleagues looked at the effect of four different iPod models (third generation, photo, video and Nano iPods) on implantable pacemaker function in 100 patients. A technician monitored intracardiac electrograms and a surface ECG while each iPod was held near the chest for 5 to 10 seconds in the on and off position.

The iPods, when held two inches from the patients' chest and as far as 18 inches, "interfered with pacemaker function in about one third of patients," Dr. Jongnarangsin noted in a telephone interview with Reuters Health. Pacemaker oversensing -- defined as spurious atrial/ventricular sensed events on the marker channel associated with atrial/ventricular inhibition, mode switching or high atrial/ventricular rates on rate histograms - was seen in 19% 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%, and pacemaker inhibition in 1%. Oversensing and telemetry interference occurred more often with third generation iPods and the photo iPod than with the video and Nano iPod.

The observed iPod interference did not cause any clinical symptoms. "However, in one patient the iPod transiently inhibited pacemaker function," Dr. Jongnarangsin pointed out.

There is a concern, he added, that iPod interference might lead to an incorrect diagnosis of abnormal heart rhythm. "If we don't take into account that the patient has an iPod close to the pacemaker, we may assume that the patient has an abnormal heart rate rhythm," Dr. Jongnarangsin said.

"We need more information and more studies on iPod interference in pacemaker function," he concluded.