FDA Safety Communication: Check for premature battery depletion in certain Medtronic pacemakers

Batteries in certain Medtronic implantable pacemakers or cardiac resynchronization therapy pacemakers (CRT-Ps) could drain more quickly than expected and without warning to patients or healthcare providers, according to a safety communication issued by the Food and Drug Administration (FDA).

Implanted pacemakers and CRT-Ps have electronics and are powered by lithium-ion batteries. One of the key electronic components is a capacitor, which stores electrical energy. The FDA is aware of three medical device reports in which a Medtronic implantable pacemaker or CRT-P battery had fully drained because of a crack in the device’s capacitor, without any warning to the patient or healthcare provider. As of April 10, 2019, 131,889 have been sold in the U.S.

Medtronic’s implantable pacemakers or cardiac resynchronization therapy pacemakers (CRT-Ps) are devices that provide pacing for slow heart rhythms and heart failure. Pacemakers and CRT-Ps are both implanted under the skin in the upper chest area with connecting insulated wires called leads that go into the heart. A patient may need a pacemaker or CRT-P if their heartbeat is too slow (bradycardia) or needs coordination to treat heart failure.

Patients can use remote monitoring systems, such as Medtronic’s MyCareLink Monitor, to help their healthcare providers monitor battery status and general functioning of their implanted pacemaker or CRT-P. Healthcare providers receive CareAlert notifications through manual transmissions from the patient or wirelessly connecting to the patient’s implanted pacemaker or CRT-P when the patient’s device has CareAlerts programmed “ON.” The patient and health care provider receive an Elective Replacement Indicator (ERI) CareAlert notification when the battery level drops below a certain limit.

If a capacitor in an implanted pacemaker or CRT-P is cracked, it can create an electric short, which can cause a battery to drain earlier than expected. If the battery is completely drained, the device will no longer deliver pacing therapy. The patients who rely heavily on pacing or who are pacemaker dependent may be most at risk for having an adverse outcome.

In all three medical device reports the FDA received, Medtronic reported that healthcare providers were unable to communicate with the device due to battery depletion, resulting in loss of pacemaker function. Medtronic also reported these events occurred within one year after the patient was implanted with the pacemaker or CRT-P, on average within seven months of getting the device implanted. The devices are designed to last between approximately 7.5 and 15 years or 6 and 10 years before requiring battery replacement, depending on the device and the amount of pacing. One of the reported events resulted in the death of a pacemaker-dependent patient.

In a second reported event, the patient experienced dizziness during follow-up and the healthcare provider was unable to communicate with the device, which resulted in the patient getting their device replaced. In the third reported event, there was no harm to the patient because the device was not implanted when the healthcare provider became aware that a connection with the device could not be established.

This year, Medtronic received the FDA’s approval for a new step in the manufacturing process developed to better detect capacitor failures and for a different capacitor to reduce the risk of rapid battery depletion in newly manufactured devices. 

Recommendations for healthcare providers (visit FDA for model numbers):

·   Prophylactic removal and replacement of affected devices is NOT recommended, but the FDA recognizes that some patients who depend on pacing for survival may determine, in consultation with you, that device replacement is appropriate for their needs. Consider whether elective device replacement is warranted for any of your pacemaker patients due to pacemaker dependent status or other high-risk features.

·   Be aware of sudden battery level drops during follow up visits and remote transmissions. Watch for decreases in battery level out of proportion to the life of the device from the time of implant even if the level remains within the normal range.

·   Advise your patients to continue to use their remote monitors.

For Azure, Percepta, Serena, and Solara devices:

These devices have wireless CareAlerts programmed by the healthcare provider. The monitor must remain powered on to ensure automatically scheduled transmissions are sent. CareAlerts should be programmed to “ON.”

For Astra devices:

These devices do not have wireless capability and require manual transmission by the patient. To ensure timely transmission of any CareAlerts done manually by the patient, the patient should have a transmission schedule and CareAlerts should be programmed “ON.”

Replace the pacemaker or CRT-P immediately at the time of an ERI alert. Currently, there is not a factor, method, or test to identify when devices with this form of premature battery depletion are approaching ERI, or to accurately predict remaining battery life once ERI appears. Once ERI is reached, an affected device is unlikely to have the standard three months of battery life remaining.

Treat pacemaker-dependent patients with a device that has reached ERI as a medical emergency.