Implanted Heart Defibrillator Problems. A manufacturer of implanted heart defibrillators said Friday that some older models may not charge properly, which might make it fail to deliver a needed shock to the heart. Medtronic Inc., of Minneapolis, said it had become aware of one injury and four deaths that may have been related to the failure of the equipment.
The company said the devices in question were implanted in 1997 and 1998 and are close to their normal replacement time. About 1,800 are thought to be still in use.
Medtronic said it is informing physicians that they should verify the charge time and battery voltage of each affected defibrillator.
Medtronic said it recommends replacement of any that exhibits an unsatisfactory charge time, but the decision is up to the physician and patient.
The problem involves Micro Jewel II Model 7223Cx and GEM DR Model 7271 implanted cardioverter defibrillators. The Micro Jewel II is no longer sold, and the GEM DR has limited distribution.
devices are used to shock the heart into normal rhythm after patients suffer irregular heartbeat
The devices are used to shock the heart into normal rhythm after patients suffer irregular heartbeat or fibrillation, which are rapid, life-threatening arrhythmias, originating in the lower chambers of the heart.
The defibrillators are implanted surgically in the chest. When a cardiac arrhythmia occurs, the capacitor is charged and the device delivers the appropriate shock.
With the suspect defibrillators, the capacitors may take longer than normal to charge near the end of the battery service life and could cause a delay in delivery or nondelivery of shock therapy, the company said.
Medtronic said it is working with the Food and Drug Administration to ensure that all physicians and their patients with these devices are notified of the problem.