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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 , 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 .

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.

Ventricular electromagnetic interference occurred in 32.4% and 3.6% of devices at maximum and nominal sensitivity; atrial electromagnetic interference was more likely at 72.9% and 42.7%. Atrial interference was especially likely when programmed to DDD mode, Napp's group found.

"Among the electromagnetic interference effects, ventricular oversensing is the clinically most relevant problem, which may cause asystole in the case of pacing inhibition with symptoms such as palpitations, dizziness, or syncope in pacemaker-dependent patients," they wrote.

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