Hidden Attraction: Lesser-Known Magnetic Hazards That Can Affect Cardiac and Other Devices

The hazards of the magnetic fields generated by MR units, and the precautions required to avoid those hazards, are well known in healthcare. Less familiar are the hazards from other magnetic sources, both within and outside the facility. Certain health devices, such as continuous positive airway pressure (CPAP) helmets with magnetic clasps, can generate a magnetic field strong enough to interfere with the function of pacemakers. And even apparently innocuous household objects such as jewelry, power adapters, and toys can incorporate surprisingly strong magnets that can also affect some patient devices. Being less well known, these hazards can be harder to recognize and therefore harder to guard against.

The people most susceptible to these magnetic hazards are patients who have been implanted with cardiac rhythm management (CRM) devices—also known as cardiac implantable electronic devices (CIEDs). If these devices are exposed to a strong enough magnetic source, they can be inadvertently put into what is called magnet mode.

Magnet mode is often used to temporarily switch to asynchronous pacing or to deactivate shock delivery during certain procedures such as surgery. This mode can be useful to protect the patient or caregivers. However, if magnet mode is entered inadvertently, the disabling of defibrillation or the initiation of asynchronous pacing can be very hazardous to the patient. Therefore, it is important that patients avoid exposure to...