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NEW PROCEDURES MAKE DEFIBRILLATORS AND PACEMAKERS MRI-SAFE, RESEARCHERS SAY

September 18, 2006

Researchers at Johns Hopkins University have come up with new procedures that allow clinicians to safely conduct magnetic resonance imaging (MRI) scans of patients implanted with any of 24 types of heart devices manufactured by St. Jude Medical, Guidant and Medtronic, a new study says.

The report in the Sept. 18 issue of the journal Circulation featured results from 55 of more than 100 patients implanted with defibrillators and pacemakers who were scanned by the Hopkins researchers using the new methods.

The team reprogrammed the implanted devices to reduce the potential for their electronics to confuse the MRI's radio frequency with an irregular heartbeat. They also turned off the defibrillators' shocking function during the scan, which can last 30 minutes to one hour, and reduced the amount of electrical energy used at the peak of the scan to half its strength.