Electromagnetic interference may occur in patients with pacemakers

Patients with pacemakers may experience harmful electromagnetic interference caused by power lines, household appliances, electric tools and entertainment electronics, according to an in vivo study.

Lead researcher Dominik Stunder, MSc, of RWTH Aachen University Hospital in Aachen, Germany, and colleagues published their results online in Circulation on Feb. 27.

The study included 119 patients with pacemakers, including five who had unipolar leads implanted and 114 who were implanted with bipolar leads with bipolar sensing.

“Electromagnetic interferences with pacemakers in everyday life can occur, however, harmful interferences are rare using vendors' recommended device settings,” Andreas Napp, MD, one of the study’s authors, said in a news release. “Dedicated device programming is an effective measure to reduce the individual risk of interference. For example, doctors can reprogram pacemakers to a lower sensitivity to reduce [electric and magnetic field] susceptibility.”

The patients were exposed to single and combined electronic and magnetic 50-Hz electric and magnetic fields, a frequency found in power lines, household appliances and other every day scenarios. They received increasing field strengths until their pacemaker senses failure or they reached the maximum field levels.

Electromagnetic interference occurred in all five patients with unipolar leads and 71.9 percent of patients with bipolar leads. Based on U.S. definitions of electromagnetic field limits for the general public, 34 percent of pacemakers were disturbed.

The researchers noted that ventricular oversensing was the most clinically relevant problem related to electromagnetic interferences and could cause palpitations, dizziness, syncope or other symptoms. They mentioned in the news releases that holding the electromagnetic field source at a distance greater than 12 inches can limit the risk of electromagnetic interference.

“To protect patients from [electromagnetic interference], adjusting pacemaker settings to a lower sensitivity, bipolar sensing, and keeping at a distance from [electric and magnetic fields] sources are effective measures,” the researchers wrote in the study. “The field strength decreases at least by half if the distance is doubled. Further actions to reduce susceptibility (for example, programming to VVI mode and improved lead placement) might be necessary in selected patients exposed to strong [electric and magnetic fields] in occupational environments.”