Making MRI safe for pacemakers

For years, older model, so-called legacy pacemakers were not compatible with MRIs because the metal in the pacemakers caused the magnetic resonance imaging devices to fail, lead tips to overheat, and caused discomfort in patients. Now, imaging experts have made adjustments so MRIs can be safe for more patients.

Twelve years ago, life-long runner Mike Unclebach was diagnosed with a heart blockage and got a pacemaker. Ten years later, his electro cardiologist told him the pacemaker indicated a problem. An MRI would help diagnose it, but MRIs were considered unsafe for older, legacy pacemakers. Doctors found one brave man.

“Somebody’s gotta be first,” Unclebach said.

Mike agreed to an MRI after new studies showed how the testing could be done safely by limiting the magnet strength, the MRI energy applied, and the duration of exposure.

Turns out, Unclebach’s MRI showed an even more serious problem, a thickening of the muscle wall of the left ventricle, a condition called atypical hypertrophic cardiomyopathy.

“We can see it’s severely thickened,” Haojie Wang said, MD Cardiologist, Medical Director of the Cardiovascular MRI Lab at Baylor Scott & White Health. “It’s about close to three centimeters or 30 millimeters in thickness. So this is abnormal.”

The pacemaker was removed and replaced with an implantable defibrillator that will shock Mike’s heart back to life if it suddenly stops. All made possible because of a safe MRI.

“We can see more we couldn’t see before with much higher resolution,” Dr. Wang said.

Just two weeks out of surgery, Unclebach is working out again, and plans to climb a mountain.

“I’m going to get to go be me,” Unclebach said.

Dr. Wang says newer model pacemakers pose no known hazards in an MRI environment. Patients with older pacemakers should work closely with their doctors to determine if they need an MRI, and how it can be done safely.