- BOSTON (Reuters) - Magnetic fields created by anti-theft gates guarding
store exits can make implanted pacemakers and defibrillators go haywire,
sometimes with fatal results, doctors said. In the first of two reports
in Thursday's edition of the New England Journal of Medicine, a 72-year-old
man, who had a defibrillator to automatically shock his heart whenever
it beat improperly, suffered four unnecessary shocks as he stood near an
anti-shoplifting gate.
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- The electromagnetic field apparently
fooled the defibrillator into thinking the heart was beating improperly.
An alert nurse pulled him away from the gate and probably saved his life,
said a group led by Dr. Peter A. Santucci of the Rush-Presbyterian-St.
Luke's Medical Center in Chicago. In another case, two doctors trying to
explain why a 30-year-old woman with a pacemaker felt nauseous, breathless,
and dizzy whenever she passed through electronic surveillance gates at
stores discovered that the anti-theft devices made her pacemaker send out
improper signals. Not all types of anti-theft surveillance systems create
the type of magnetic interference that can disrupt pacemakers, said the
authors of the second report, Dr. Michael McIvor of the Heart Institute
of St. Petersburg, Florida, and Dr. S. Sridhar of Affiliated Cardiologists
in Phoenix.
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- However, they warned, ``patients with
pacemakers, particularly those who are dependent on them, should take care
to minimize their contact'' with such systems ``by passing quickly through
the gates.'' Even then symptoms can occur, they warned. Newer systems ``can
be unobtrusive, located behind walls or beneath flooring,'' McIvor and
Sridhar said and they urged the areas where the strong magnetic fields
are present be clearly marked for customers. In addition, ``merchandise
should not be displayed next to electronic surveillance equipment,'' Santucci's
team said. ``With the increasing use of both implantable defibrillators
and anti-theft surveillance devices, potentially serious interactions may
be more common in the future unless preventive measures are undertaken,''
they said.
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- About 400,000 electronic anti-theft surveillance
devices are present in stores, libraries and other locations worldwide.
Other sources of electromagnetic interference, such as slot machines and
remote control devices for toys, are also known to disrupt devices designed
to sense and correct erratic heart rhythms. ^REUTERS@
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