Safety of implanted cardiac devices and MRIs: An update

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Contrary to conventional wisdom, most people with older implanted cardiac devices may be able to safely get a magnetic resonance imaging (MRI) scan, according to a study in the Feb. 23, 2017, New England Journal of Medicine.

The devices, which include pacemakers and implantable cardioverter-defibrillators (ICDs), help regulate and restore the heart's normal rhythm. Concerns that the powerful magnets in MRIs could damage these battery-operated devices led to the development of newer, MRI-safe devices. But an estimated two million people in the United States have one of the older devices, and at least half of them might need an MRI in the future.

The study included 1,000 people with pacemakers and 500 with ICDs who received MRIs that did not involve the chest. Researchers used a special device-programming protocol designed to reduce the risk of harm from MRI effects. There were no serious adverse events, such as deaths or dangerous heart rhythms, although one ICD malfunctioned and required immediate replacement. The findings suggest that MRIs done on parts of the body other than the chest can be done reasonably safely in people with pacemakers and ICDs, assuming the devices are adjusted properly.