Medtronic warns of potential battery problem in 340,000 defibrillators

Medtronic has issued a warning about rapid unexpected battery depletion that may happen in seven kinds of implantable defibrillators, affecting nearly 340,000 implanted devices worldwide.

The Food and Drug Administration sent out e-mail alerts Monday about a Class I recall notice triggered by a Medtronic letter to health care providers in February, pertaining to the device maker's Evera and Visia implantable cardioverter defibrillators (ICDs) and Claria, Amplia, Compia, Viva and Brava cardiac resynchronization therapy defibrillators (CRT-Ds).

Class I recalls are the most serious type, reserved for situations when there's a reasonable probability that use of the product will cause serious health problems or death, the FDA says.

Although the FDA classified Medtronic's letter to doctors as a "recall," Medtronic is not recommending doctors remove devices from patients unless they see a sign of a potential problem, like an unexpected battery warning.

An ICD is an implantable heart device that can deliver strong jolts to defibrillate a stopped or quivering heart, or mild electric pulses to regulate a heart beat that is too fast or too slow. A CRT-D is a more complicated version that also treats advanced heart failure by delivering pulses to both sides of the heart.

The implantable devices are powered by lithium batteries. Normally, a battery might last from seven to 12 years, depending the device model and settings.

Medtronic's letter to implanting physicians says that before March 2019, some of the devices in question had batteries that were vulnerable to sooner-than-expected depletion, caused by an internal short-circuit involving lithium plating inside the device.

As a result of the short, the devices' "recommended replacement time" (RRT) warning may go off earlier than expected.

"If the user does not respond to the first warning, the device may stop functioning," the FDA's recall announcement says.

The FDA said there have been 444 reports of battery problems with the ICDs and CRT-Ds and 18 reports of health problems, including people whose slow heartbeats went untreated because their device batteries were depleted. Medtronic said there are no patient fatalities or permanent injuries.

Medtronic, run from offices in Minnesota, says there are 339,900 devices that are susceptible to the issue implanted in patients worldwide. Based on rates of confirmed events from the field, Medtronic projects about 0.2% of the affected devices may experience this issue.

For devices in which RRT was triggered earlier than expected, the median time to when the battery no longer worked was 14 days. Devices that do more pacing have a lower probability of having the problem, while devices used less often have a higher probability.

"Importantly, the probability of this issue developing is constant after approximately three years of service time," Medtronic's announcement said.

Medtronic recommends patients use the CareLink home monitoring system to check battery levels and contact their doctor if they hear an audible alert from the implanted device. That's especially true now, as patients may be delaying normal clinic visits because of the COVID-19 pandemic.

Medtronic does not recommend replacing any devices solely because they are identified in the FDA's recall notice.

But if the RRT warning goes off earlier than expected, Medtronic recommends immediate device replacement in patients who are "pacemaker dependent," and replacement within one week for other patients.

Patients and doctors can look up their device by serial number to see if its affected by going to wwwp.medtronic.com/productperformance.

Joe Carlson • 612-673-4779