Medical devicemaker St. Jude Medical said Friday that background radiation can cause some of its older implantable defibrillators to lose power. The company said it knows of no serious injuries or deaths caused by the problem.
Testing showed that some 60 devices out of 36,000 might be affected, the company said. It estimated that 26,000 of the devices are still being used. The affected devices are the Photon DR, Photon Micro VR/DR and the Atlas VR/DR. According to a letter sent to doctors, background radiation can affect a memory chip in the devices, causing the battery voltage to drain rapidly. St. Jude began using a different memory chip from a different manufacturer in 2002. It said testing showed that the new chip does not have the same problem.
St. Jude recommended doctors remove the device if they find it has reset because of the voltage drain. For most patients, monitoring the device every three months should suffice, the company said.
St. Jude said the Food and Drug Administration may decide to recall the devices, which use a jolt of electricity on hearts that go into life-threatening irregular beats. FDA spokeswoman Julie Zawisza said only that the agency is looking into the matter.