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Electromagnetic interference from electronics may alter pacemaker functionality
Exposure to electromagnetic fields emitted from electrical tools, everyday household appliances and other common electronics may affect pacemakers, according to findings published in Circulation.
“Electromagnetic interferences with pacemakers in everyday life can occur; however, harmful interferences are rare using vendors’ recommended device settings,” Andreas Napp, MD, cardiologist at RWTH Aachen University Hospital in Germany, said in a press release.
Researchers analyzed data from 119 patients with pacemakers. Of these patients, five had unipolar leads (four ventricular pacing, one atrial pacing), and the other 114 patients had bipolar leads with bipolar sensing (18 ventricular pacing, three atrial pacing, 90 dual-chamber pacing, three cardiac resynchronization therapy pacemakers).
Patients were exposed to single and combined electromagnetic fields of 50 Hz, which was increased until the first pacemaker sensing failure was observed or the maximum levels (30 kVm-1 and 2,550 µT) were attained. Researchers performed these tests and analyzed the worst-case scenarios, which included maximal inspiration, whole-body exposure and continual pacing.
The interference levels were established with pacemakers that were programmed to various modes: nominal sensitivity, maximum sensitivity, dual-chamber pacing and ventricular pacing.
All patients with unipolar leads experienced electromagnetic interference at minimum and maximum sensitivity by 50-Hz electromagnetic fields. Electromagnetic interference occurred in 71.9% of those with bipolar leads at maximum sensitivity vs. 36% at nominal sensitivity.
Of the 111 patients with ventricular pacing, dual-chamber pacing or CRT pacemakers, 32.4% had ventricular electromagnetic interference at maximum levels and 3.6% at nominal levels. Atrial electromagnetic interference was noted in 72.9% of 96 devices (atrial pacing, dual-chamber pacing and CRT pacemakers) at maximum levels vs. 42.7% at nominal levels. Nine pacemakers in dual-chamber pacing mode resulted in ventricular electromagnetic interference. Pacemakers programmed to dual-chamber mode were more prone to interference, as the atrial channel had lower interference thresholds.
Electromagnetic field emissions of hand drills had a maximum field strength of 13 kVm-1 and 2,137 µT, and electromagnetic interference was observed at the maximum (61%) and nominal (16%) levels. The United States established electromagnetic field limits at 5 kVm-1 and 904 µT, and 34% of pacemakers were affected at maximum levels vs. 4.4% at nominal levels. Based on that information, researchers wrote that electromagnetic interference may happen when patients with pacemakers are close to everyday appliances and tools.
“In many cases, holding the appliance, tool or other [electromagnetic field] source at a forearm’s length distance limits the risk of electromagnetic interference,” Napp said in the release. “Further measures might be needed in environments with strong [electromagnetic fields], such as engines used in the processing or manufacturing industry.” – by Darlene Dobkowski
Disclosure : Napp reports receiving travel grants from Biotronik, Boston Scientific, Medtronic and St. Jude Medical. Please see the full study for the other researchers’ relevant financial disclosures.