iPods cause pacemaker malfunction

11 May 2007

MedWire News: Apple iPod mp3 players cause pacemakers to malfunction, researchers warned at the Heart Rhythm Society’s annual scientific sessions being held in Denver, Colorado, USA.

Their study showed that iPods held 2 inches from patients’ chests for 5-10 seconds interfered with telemetry equipment monitoring the heart, caused implantable pacemakers to misread pacing, and in one case stopped the device functioning.

The findings raise concern because of the widespread use of mp3 players and the potential for patients with cardiac devices to inadvertently come into close contact with them.

“For people depending on these pacing devices, iPod interference can lead physicians to misdiagnose the actual heart function,” said lead author Jay Thaker, a high school student from Okemos, Michigan, who instigated the study.

“Our findings are disconcerting because although typical pacemaker patients may not be an iPod users, they are often in close contact with grandchildren or other young people who are avid users.”

Thaker approached Krit Jongnaransin, from the University of Michigan in Ann Arbor, after hearing about pacemaker malfunction caused by cellular (mobile) telephones.

Jongnaransin and a team of physicians, including electrophysiologists, worked with Thaker to test iPods on 83 patients with dual chamber or single chamber pacemakers.

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, occurred in 20% of patients.

Meanwhile, telemetry interference, defined as any other interference not affecting a pacemaker and undetected by pacemaker interrogation was seen in 29% of patients.

Pacemaker inhibition – failure to pace when expected – occurred in 1.2% of patients.

Both oversensing and telemetry interference occurred persistently (more than half the time), while pacemaker inhibition was transient. In some cases, interference was detected even when iPods was held as far as 18 inches from the chest, the authors noted.

“We found interference in 50% of patients,” the team concluded, adding that other mp3 players may also interact with pacemakers.

Heart Rhythm Society Annual Scientific Sessions; Denver, Colorado, USA: 9-12 May 2007