New Delhi: US Food and Drug Administration (FDA) has recently issued safety alarm about premature battery depletion without warning patients or health care providers in certain Medtronic pacemaker models, which could lead to devices losing power quickly and triggering a medical emergency.
The Medtronic devices potentially affected with premature battery depletion include the Azure, Astra, Percepta, Serena, and Solara models. As of April 2019, more than 131,000 of the potentially affected pacemaker and CRT-P devices have been sold in the United States.
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.
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.
Patients can use remote monitoring systems, such as Medtronic’s MyCareLink Monitor, to help their health care providers monitor battery status and general functioning of their implanted pacemaker or CRT-P. Health care 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.
However, 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 a pacing therapy. The patients who rely heavily on pacing or who are pacemaker dependent may be most at risk for having an adverse outcome.
Till date, there have been 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 health care provider. One patient died as a result of the damaged device and another patient experienced dizziness in a follow-up that led to device replacement.
In all three medical device reports the FDA received, Medtronic reported that health care 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.
The FDA is not recommending prophylactic removal and replacement of the pacemakers, but they recognize that “some patients who depend on pacing for survival may determine, in consultation with you, that device replacement is appropriate for their needs.”
For patients, the FDA is asking that they ensure home-monitoring transmissions are successful and occurring at the prescribed times so physicians can receive notifications if the battery levels decrease. Because of the low frequency of device failure, remotely monitoring battery status is appropriate given the greater risk of complications from removal, according to the agency.
The FDA recently approved a new step in Medtronic’s manufacturing process to better detect capacitor failures in new devices and also approved the use of a different capacitor to reduce the risk of premature battery depletion.
In the context of actions, USFDA states, “The FDA will continue to work with Medtronic to monitor affected pacemakers and CRT-Ps for any adverse events related to premature battery depletion. The FDA will keep the public informed as new information becomes available.”
On the other hand, Medtronic’s official statement reads, ” Medtronic has published a Performance Note about a rare mode in a population of pacemakers and cardiac resynchronization therapy pacemakers. While the devices continue to perform well within reliability projections, we have made this information available on our website.”
“We received three complaints out of approximately 266,700 devices distributed worldwide since February 2017. The projected rate of occurrence for this issue is 0.0028 per cent, with the most susceptible period being the first 12 months after a device is implanted. Based on the low predicted rate of failure, we expect few, if any, additional events to occur. In consultation with our Independent Physician Quality Panel, we do not recommend device replacement and advise physicians to continue normal patient follow-up in accordance with standard practice and, where possible, to continue with remote monitoring, ” the statement adds.
The company further informed that “Potentially affected devices include a population of Azure and Astra pacemakers, and Percepta, Serena and Solara cardiac resynchronization therapy pacemakers (CRT-P), of which only the following brands are available in India – Astra pacemaker, Solara CRT-P and Serena CRT-P.”