All concepts, explanations, trials, and studies have been
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Magnets in Unexpected Places Can Interfere With ICD
and Pacemakers

December 22, 2006 - There is now widespread use of
inexpensive magnets called NdFeB magnets. These are
common in hard drives and other computer parts, audio
and video electronics, lab equipment, EYEGLASSES
AND JEWELRY, toys, CLOTHES, workplace ID
badges, and many other products. They are often not
seen and there are often no warnings about their existence.
	Some of these magnets are strong enough to
interfere with ICDs and pacemakers. This could range
from pretty much no effect all the way to life-threatening
according to a new trial.

Researchers studied the effects of a magnetic name tag
and different-sized round (bead sized) NdFeB magnets
at different locations around device patients and at
different distances from their skin, near device implant
sites on the chest.
	Forty-one pacer patients and 29 ICD patients
were included. Magnetic interference was found at skin-to-
magnet distances of up to 3 cm (just over one inch), with
an average maximum interference distance of 2.1 cm
(almost an inch) cm for pacemakers and 1.7 cm for ICDs.
	None of the patients experienced symptoms
during the testing, and the implanted devices resumed
normal function after the magnets were removed. The
devices were all affected about the same regardless of
device manufacturer.
	Interference strength depended on the magnets'
size, shape, and position on the chest. Only small magnets
weighing up to 8 g (roughly 1/3 oz) were tested. Larger
NdFeB magnets probably cause interference at greater
distances according to the researchers.

In an editorial, Dr Huagui Li said that up to 11% of device
patients may be affected in real life. Regular exposure to
such magnets could shorten device battery life and possibly
cause a pacemaker to increase heart rate or even cause an
arrhythmia. ICDs might stop working correctly, leaving
a patient open to sudden death.

Source : Medscape
Source: Heart Rhythm 2007; DOI:10.1016/j.hrthm.2006.09.012.
Title: Potential interference of small neodymium magnets
with cardiac pacemakers and implantable cardioverter-
defibrillators.
Authors: Wolber T, Ryf S, Binggeli C, et al.
Source: Heart Rhythm 2007, doi:10.1016/j.hrthm.2006.09.026.
Author: Li H.
Title: Magnet decoration, beautiful but potentially dangerous
for patients with implantable pacemakers or defibrillators.