Lower sensitivity and bipolar sensing recommended
• by Nicole Lou
Reporter, MedPage Today/CRTonline.org February 27, 2017
Like implantable cardioverter-defibrillators (ICDs) before them, pacemakers were found to be susceptible to interference from electromagnetic fields emitted from personal electronics, household appliances, and power lines, German researchers reported.
In the study by Andreas Napp, MD, of RWTH Aachen University in Germany, and colleagues, 119 individuals with pacemakers were subjected to stepwise increases in electromagnetic exposure. Exposure was tested under worst-case scenario conditions: whole-body exposure, maximal inspiration, and sustained pacing. Interference was defined as sensing failure (over- or under-sensing) by the pacemaker.
Emissions from an electric drill would have interfered with 61% and 16% of pacemakers at maximal and nominal sensitivity, respectively, according to the research letter in the Feb. 28 issue of Circulation.
Additionally, American limits for daily exposure to electromagnetic radiation would have interfered with 34% and 4.4% of pacemakers at maximal and nominal sensitivity, respectively.
“To protect patients from electromagnetic interference, adjusting pacemaker settings to a lower sensitivity, bipolar sensing, and keeping at a distance from electromagnetic field sources are effective measures. The field strength decreases at least by half if the distance is doubled. Further actions to reduce susceptibility (e.g., programming to VVI mode and improved lead placement) might be necessary in selected patients exposed to strong electromagnetic fields in occupational environments,” the authors suggested.
Among the majority of participants that had bipolar leads with bipolar sensing (n=114), 71.9% and 36.0% had sensing failures within the study limits of electromagnetic exposure when devices were programmed at maximum and nominal sensitivity, respectively. All 5 unipolar leads showed signs of interference over the study.