MedWire News: The use of iPods and other similar music players is unlikely to interfere with the effectiveness of cardiac pacemakers, a study by the US food and Drug Administration suggests.

Cardiac pacemakers are sophisticated electronic devices that analyse the heart's electrical system and, when necessary, send small, precisely-timed electrical signals to correct abnormalities in heartbeat rates.

However, recent reports have indicated that the small electromagnetic fields produced by portable mp3 players may interfere with the function of pacemakers.

To investigate further, Dr Howard Bassen, from the Food and Drug Administration in Rockville, Maryland, USA, measured the electromagnetic fields emitted by four types of Apple iPod - an iPod Nano, an iPod shuffle, an iPod Video with a 30 GB hard drive and a standard iPod with a 15GB hard drive.

Analysis revealed that, within 10 mm of the devices, none of the iPods studied produced electromagnetic fields that were powerful enough to affect the function of pacemakers.

Indeed, the greatest magnetic field strength produced by the iPods was 0.2 millionths of a Tesla - a strength hundreds of times lower than that needed to interfere with the function of a pacemaker.

Dr Bassen writes in the journal BioMedical Engineering OnLine: "Our data indicate that all iPods we studied emit very weak fields.

"We conclude that no interference effects can occur in pacemakers exposed to the iPod devices we tested."