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 Researchers tested how electric and magnetic fields impact
pacemakers, small battery-operated devices that help patients’
hearts beat in a regular rhythm, for 119 people under different
conditions.
The results suggest that electric and magnetic fields from sources
like power lines, household appliances, electrical tools and
entertainment systems might interfere with the devices, said lead
author Dr. Andreas Napp of the University Hospital Aachen in
Germany.
“Usually pacemakers programed to the vendor's recommended settings
are safe regarding electromagnetic interference in daily practice,”
Napp said by email.
“However, lots of electrical appliances from daily life emit strong
electromagnetic fields in very close proximity of the appliance,”
Napp added. “Pacemakers with electromagnetic interference usually
show inhibition of stimulating the heart or change the pacing mode
or induce a faster heart beat for the time of interference.”
For the study, researchers first exposed patients with pacemakers to
electrical and magnetic fields similar to frequencies typically used
by power grids, 50 Hertz or 60 Hz. Then, they increased the exposure
until they detected a pacemaker failure.
Five patients in the study had what’s known as unipolar leads, when
pacemakers have just one contact point with the heart. The remaining
114 participants had bipolar leads, with two points of contact.
In all five patients with unipolar leads, pacemakers set to either
basic or maximum sensitivity were impacted by the initial exposure
of 50 Hz, the study found.
For patients with bipolar leads, electromagnetic interference
occurred with about 72 percent of cases with maximum sensitivity and
36 percent of instances with nominal sensitivity, researchers report
in Circulation.
It’s possible that staying more than 12 inches away from an
electromagnetic source like an appliance or tool might limit the
potential for pacemaker interference, the authors note.
Still, the researchers conclude that people exposed to stronger
electromagnetic fields on the job, such as workers in certain types
of manufacturing, might need to consider the potential for pacemaker
malfunction.
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“Patients should inform the doctors before device implantation if
they are exposed to strong electromagnetic fields in daily practice
or in the work environment,” Napp said. “During follow up visits in
the pacemaker outpatient clinic, care must be taken while
reprogramming the sensitivity of the device.”
Welding in particular can expose patients to electromagnetic fields
that interfere with pacemakers, said Dr. Gordon Tomaselli, chief of
cardiology at Johns Hopkins Medicine in Baltimore.
“It’s not surprising that pacemakers could be coaxed to experience
electromagnetic malfunction,” Tomaselli, who wasn’t involved in the
study, said in a phone interview.
Most tools and appliances people use at home probably aren’t a
problem, Tomaselli added.
“Welders are a problem, but with most other tools people would use I
don’t prohibit that,” Tomaselli said. “But certainly if people are
feeling odd or fatigued or having symptoms like they had before they
got the pacemaker I tell them to see me or see their doctor.”
The study was funded by grants from the German Social Accident
Insurance Institution for the Energy, Textile, Electric, and Media
Products Sector and the Research Unit for Electropathology.
Dr. Napp and another author, Dr. Matthias Daniel Zink, have both
received various forms of support from pacemaker manufacturers.
SOURCE: http://bit.ly/1q3uqj1 Circulation, online February 27, 2017.
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