The Food and Drug Administration Tuesday approved the first pacemaker that is specifically designed for use in a magnetic resonance imaging (MRI) environment. MRIs are an increasingly used tool for diagnosing ailments because they provide precise, detailed pictures of internal organs and soft tissues, but they generate powerful magnetic fields, as much as 30,000 times more powerful than the Earth's own magnetic field. That powerful field can interfere with a normal pacemaker's operation, damage its components, cause the pacemaker or its leads to become dislodged, or interfere with its ability to capture a signal from the heart. As a result, an estimated 200,000 Americans, most of them elderly, have to forgo an MRI scan each year because of their pacemaker.
The Revo MRI SureScan pacing system, developed by Medtronic Inc. of Minneapolis has hardware and leads that are designed to minimize these problems, the company said. Additionally, the device can be put into a "safe" mode before an MRI scan begins to protect it from malfunctioning and ensure that it doesn't deliver unneeded pacing therapy or withhold needed therapy. The FDA is requiring training for cardiologists and radiologists who use the system.
The FDA based its approval on a clinical trial of 484 patients. Of those, 464 were implanted with the device and randomized to receive or not receive an MRI. None of the 211 who received an MRI suffered any complications from the procedure.
Medtronic said it will start shipping the devices immediately. The company did not say how much they would cost compared with conventional pacemakers.