On Tuesday, the U.S. Food and Drug Administration approved the first pacemaker designed to be used safely during magnetic resonance imaging (MRI) scans. The device, the Revo MRI SureScan Pacing System by Medtronic, was first recommended for approval by an FDA panel in March 2010.
Pacemakers are surgically implanted devices that use electrical impulses to treat irregular or stalled heart beats, according to the FDA. But because MRIs generate a powerful magnetic field and radio frequency pulses to image internal organs, soft tissues and bone, patients with pacemakers are advised not to undergo MRI — even though about half of the 3 million patients worldwide who have a pacemaker may benefit from the test. (More on TIME.com: Weight-Loss Surgery May Change the Shape of the Heart)
The MRI can disrupt the pacemaker’s setting or cause wires to overheat, resulting in unintended heart stimulation, device electrical failure, or tissue damage, according to an FDA release.
The Revo device works the same way as a traditional pacemaker, but contains an optional “SureScan” mode that can be turned on at the time of a patient’s MRI and is designed to eliminate interference with electrical currents and radiofrequency emissions.
In a clinical trial of 484 patients reviewed by the FDA, 464 received the Revo device, 211 of whom were randomized to undergo MRI. None of those patients had complications due to MRI. However, the Revo pacemaker has been tested only with MRI scans above the neck and below the lower back. It has not been tested against MRI scans of the torso, including the heart area. (More on TIME.com: Could Mom’s Stroke Predict Her Daughter’s Heart Attack?)
The FDA said the pacemaker’s use in MRIs is “limited to certain patients, certain parts of the body and certain scanning parameters. The FDA also is requiring training for cardiologists and radiologists who use the system.”