A new study finds that MR can be safe with older “legacy” pacemakers and defibrillators.

The findings are good news for patients and doctors needing a scan and faced with such implantable heart devices, according to the report in The New England Journal of Medicine.

The study “confirms that pretty much anybody who has a pacemaker or implanted defibrillator can, with very few restrictions, safely get an MRI scan if they need it,” as long as settings for the devices are correct for scanning and adequate precautions are taken, co-author Dr. Henry Halperin, professor of medicine, radiology and biomedical engineering at Johns Hopkins University told Reuters.
Researchers set these legacy devices to a standard heart rhythm and blocked other settings that could let them react to erratic signals during the MR procedure. After the scan, the devices got reset to proper daily settings.

The issue is not just about health – the U.S. Centers for Medicare and Medicaid Services (CMS) only covers FDA-determined “MR-conditional” scans, co-author Dr. Saman Nazarian, of the University of Pennsylvania Perelman School of Medicine, told Reuters.

This study follows a similar one that revealed that legacy devices were safe, which has led Nazarian to suggest that, given these reports, the agency's position is “hard to understand,” according to the news wire.

This latest study looked at approximately 200 of 1,509 pacemaker and defibrillator patients who received chest scans using a 1.5 Tesla machine.

No scanning, to chest or elsewhere, led to any “significant problems,” according to Nazarian.

Nine legacy devices were triggered by the scans but restarted to backup mode successfully.

A single device had to be replaced, which had a low battery – but “pacemakers do funny things when the battery is low,” observed Halperin.

He noted that most heart devices, pacemakers and defibrillators passed by the FDA from 2000 on are better able to handle the energy inside an MR, adding, “and we program them to avoid most any problems that might happen.”

For patients with an unrated device, Nazarian recommended that, “many centers across the U.S. are capable of performing safe imaging despite your device.”

The issue is bound to continue to impact more patients, as the global cardiac pacemaker market is set to nearly double by 2023, according to a Stratistics MRC report last month.

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