Medtronic has sent a warning letter to physicians that approximately 37,000 Kappa and Sigma pacemakers may have a wiring defect, which can cause the device's battery to stop working.
The letter indicated that two reported deaths may be linked to the defect. According to the company, the total number of active devices now affected is 36,900--about 2 percent of all Kappa/Sigma devices implanted.
Most of the affected products, which began to be implanted in the late 1990s, were distributed outside of the U.S., according to Medtronic CEO Bill Hawkins.
More than 1.7 million of its Kappa and Sigma pacemakers have been implanted since 1997, and Medtronic said it first noticed wiring problems in some units in 2005. The faulty wiring can cause the pacemakers to fail at a higher-than-expected rate, the company said this week. A wire separation problem inside the pacemakers and issues associated with the use of a cleaning solvent during the manufacturing of the units are suspected of causing the wiring problems, the company said.
The Minneapolis-based company sent the "Dear Doctor" letter to physicians earlier this week. The letter advised physicians to advise their patients to seek medical attention immediately if they experience symptoms (e.g., fainting or lightheadedness); to consider device replacement for patients who are both pacemaker dependent and who have been implanted with a device in the affected subsets.