I noticed the following disturbing story on the Daily Telegraph
website a few minutes ago:


Personal headphones could cause pacemakers to malfunction, study warns
Personal headphones could put patients with pacemakers at risk because
their strong magnets can make the devices malfunction, new research
suggests.


By Sarah Knapton
Last Updated: 3:22PM GMT 09 Nov 2008

An American study found that draping headphones over the chest or
putting them in a pocket while listening to music could change the
rate at which a pacemaker delivers signals to the heart.

Study leader Dr William Maisel, director of the Medical Device Safety
Institute at Beth Israel Medical Centre in Boston, said: "For patients
with pacemakers, exposure to the headphones can force the device to
deliver signals to the heart, causing it to beat without regard to the
patients' underlying heart rhythm,

"Exposure of a defibrillator to the headphones can temporarily
deactivate the defibrillator."

While pacemakers keep the heart beating at a regular rate, implantable
cardioverter defibrillators (ICDs) correct abnormal heart rhythms.
Sometimes both vital functions are incorporated into a single machine.

Earlier this year US regulators the Food and Drugs Administration
assured members of the public that digital music players were unlikely
to affect implanted heart devices.

But Dr Maisel's team investigated whether there might be a problem
with headphones since they produce a magnetic field.

The researchers tested eight different headphone models connected to
MP3 players, including clip-on and earbud varieties, on 60 pacemaker
and defibrillator patients.

"We placed the headphones on the patients' chests, directly over where
their devices are located, monitoring them for evidence of
interaction," said Dr Maisel.

In 15 per cent of pacemaker patients and 30 per cent of defibrillator
patients, the researchers detected interference.

Removing the headphones usually caused the device to function normally.

"Patients should not focus on the brands we tested but instead should
simply be instructed to keep their headphones at least three
centimetres from their implantable devices,' said Dr Maisal.

He warned patients to be careful not to carry headphones in a breast
pocket or draped over their chest.