AGH is looking for a way to make pacemakers and MRIs compatible


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In the Allegheny General Hospital Emergency Room last week, 81-year-old Leonard Roth of Mt. Lebanon knew his pacemaker likely would prevent him from getting magnetic resonance imaging to determine why his legs were paralyzed.

For people with pacemakers and automatic implantable cardioverter defibrillators, MRIs are off limits. Their radio frequencies and electromagnetism damage the implanted devices' computerized electronics and can speed up pacemakers to 150 to 200 heartbeats per minute. An inadvertent MRI can put such patients into life-or-death situations.

"Keeping the heart beating takes precedence over using MRI to diagnose other health problems leading to widespread avoidance and fear of MRIs and pacemakers and AICDs," said Robert Biederman, medical director of the Cardiovascular MRI Center in Allegheny General Hospital's Cardiovascular Institute. "We essentially have two life-saving technologies that for decades now have been completely incompatible with each other. It is a clinical dilemma with potentially grave consequences that physicians face very day in hospitals around the country."

In the case of Mr. Roth, the ambulance took him to the right place at the right time.

Under Dr. Biederman's direction, AGH is a key participant in the MagnaSafe Registry -- the nation's largest prospective study -- to explore the safety and effectiveness of a procedure that makes it possible for a patient with implanted cardiac devices to undergo an MRI. Scripps Center in La Jolla, Calif., is coordinating the study involving 10 to 12 advanced Cardiac MRI medical centers nationwide.

The procedure involves scaling back MRI intensity and other modifications while putting the implanted device into a safe mode with other modifications. In some cases the device can be turned off during the procedure. Throughout the procedure the patient's function and heart rate are monitored closely. Operating under reduced power requires more time for the MRI to generate images of equal resolution with those done with full power.

The first 829 cases nationwide in the study resulted in no deaths, device failures, ventricular arrhythmias or losses of MRI images for those with implanted cardiac devices, the study's lead investigator, Robert Russo of Scripps Clinic, reported recently.

AGH has experienced similar success with 45 patients by using either its own protocol or more recently as part of the MagnaSafe Trial.

In a recent presentation to the Society of Cardiovascular MRI, Dr. Biederman reported no adverse clinical events associated with the new procedure and complete safety with the new procedure, while noting for the first time that significant life-saving or life-changing diagnoses were made possible in two-thirds of the cases. "The MRI made a dramatic impact on patient-care decisions in these cases," he stated. "Many patients with implantable devices, with proper physician care and expertise in the correct setting can safely undergo MRI."

For now, the process is being used on patients with implanted cardiac devices who face serious, generally life-threatening or life-affecting medical problems.

Recently Mr. Roth found himself unable to get out of a golf cart on June 12, prompting an AGH emergency room visit. He eventually returned home without a diagnosis. He returned to the emergency room last week with full paralysis in both legs, and after a battery of scans and other diagnostic tests, he was deemed to be a candidate for the new MRI procedure.

"They couldn't come up with a definitive diagnosis, and they told me I needed this," Mr. Roth said of the MRI. "If they did find something, maybe they could help me with it."

The process calls for doctors to evaluate the patient's cardiac health, the implanted cardiac device, and the patient's dependence on the device to maintain a proper health rhythm. Dr. Biederman and his team then decide whether to put the pacemaker into a safe mode of operation while minimizing the MRI's high energy output. The implanted device may be turned off for patients not fully dependent on the pacemaker or AICD.

The patient's heart function is monitored during the procedure, then the implanted device is reprogrammed to original settings afterward and rechecked for any effects from the MRI.

"We've been able to change people's lives," Dr. Biederman said. "Literally people have been on death's doorstep and now have come back for one or more MRIs in follow months while expressing their gratitude."

Three million Americans have an implanted cardiac device with hundreds of thousands more receiving them each year. Medtronic, which produces an MRI-compatible pacemaker, says a patient is denied MRI every five minutes because of an implantable cardiac device. An inability to undergo an MRI can pose serious health risks for such patients. An AGH press release says as many as 75 percent of people with implanted devices will require an MRI during their lifetime to help physicians diagnose a disease, pinpoint tumors or neurological problems, or evaluate critical injuries.

"Up until a few years ago, there was this considerable concern, reticence and, frankly, fear that the MRI could result in their death," Dr. Biederman said. "People in 99.9 percent of the places across the country can't have an MRI and are not able to be provided needed care."

Additional pacemakers and ICDs compatible with MRI technology are in development. Samir Saba, director of UPMC Cardiac Electrophysiology, said his department is participating in various trials to test MRI-compatible devices in line for FDA approval.

UPMC patients with implanted devices aren't denied MRIs if they need them. Dr. Saba said patients are evaluated to determine whether their devices can be placed in safe mode, while analyzing whether other scanning methods could work equally well.

"There are multiple projects we're involved in on the MRI front," Dr. Saba said. "Every device company recognizes that people need to have MRIs, with a growing percentage of people needing MRIs. All are working on devices." MRI-compatible implanted defibrillators aren't expected to be available for several years.

Most new devices being tested, Dr. Saba said, have upgraded software with fewer components made of ferromagnetic materials -- ones affected by magnetism. At UPMC, he said, some patients with implanted cardiac devices can undergo MRIs by using processes similar to those that AGH is using.

"We never rule it out," he said. "We weigh the plusses and minuses of an MRI and other methods, and we make the patient and family aware of the tradeoffs and what we are dealing with."

While UPMC is implanting the Medtronic pacemaker in new patients, those with devices incompatible with MRI will continue posing a health-care dilemma for doctors for years to come as they require careful assessment of risks and benefits. "It will not disappear immediately with the development of new devices," Dr. Saba said.

Mr. Roth, 99 percent dependent on his pacemaker to maintain a steady heart rhythm, said the MRI was "an effortless procedure," even if it did take a bit longer to complete.

The MRI aided in his diagnosis of an inoperable blood clot on the spinal cord that caused near sudden leg paralysis. Treatment, he said, is largely limited to rehabilitation.

"I'm not happy about it, but I understand it," he said. "But anything I can do to help other areas of the country to explore what Dr. Biederman is doing is worth it. It's a successful procedure.

"I went through it without any incident whatsoever."

For more information about AGH's program, call Andrea Jacobs at 412-359-4631 or Dr. Biederman at 412-359-8009.

health

David Templeton: dtempleton@post-gazette.com or 412-263-1578.


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