Study: MRIs safe for patients with pacemakers, defibrillators

Researchers have found in a recent study that MRIs appear to be safe for patients with cardiac implantable electronic devices, even for chest imaging. Photo courtesy Intermountain Medical Center Heart Institute

Oct. 1 (UPI) — Researchers at Intermountain Medical Center Heart Institute have found that magnetic resonance imaging may be safe for patients with cardiac pacemakers and defibrillators.

A new study, published Thursday in the Journal of Clinical Electrophysiology, suggests that MRIs are safe for patients with cardiac implantable electronic devices such as pacemakers and defibrillators.

“Magnetic resonance imaging has become very popular,” Dr. Jeffrey Anderson, cardiologist at the Intermountain Medical Center Heart Institute, said in a press release. “It’s excellent for looking at soft tissue changes. But it involves very high-strength magnetic fields, which means if a patient has any implanted metal devices containing iron, it could potentially cause harm.”

MRIs had been considered dangerous for people who have cardiac implantable electronic devices due to the fear that the generator circuits of a pacemaker or defibrillator could be disrupted, that its metal leads could be pulled out of place by the magnetism, or that the lead tips could become hot and scar surrounding tissues.

Some newer devices have been made and tested for safe use with MRIs under certain conditions in magnetic fields. This category of devices, conditional cardiac implantable electronic devices, or CIEDs, has been approved for MRI use by the U.S. Food and Drug Administration.

Most patients with implantable defibrillators and pacemakers, however, do not have the newer — and more expensive — conditional devices.

A previous study, the multicenter MagnaSafe Registry study, showed that non-conditional devices can be safely imaged by MRI when scanning parts of the body not in direct proximity to one of the devices.

For the new study, researchers widened the number of patients they considered to those receiving scans of the lungs, heart or other organs within the chest.

When evaluating 212 MRI scans taken between February 2014 and August 2016 of 178 patients with a cardiac implantable electronic device, the researchers did not find a single problem requiring remediation, which involved a total of 418 implanted leads.

“That’s a pretty big number of leads exposed to these very strong MRI fields. You would think if there was even a 1 percent chance of having a problem, it would have shown up,” Anderson said. “Not even one generator or lead needed more than a minor adjustment, if any at all.”

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