The leads in a pacemaker (PM) is said to be the Achilles heel of those systems.A close runner up in the Achilles heel competition is the PM battery.
In 2019 Medtronic reported problems involving batteries.
In one case the problem did not pose an imminent threat to patients as the issue was that some of their units (manufactured between October 2018 and January 2019 ) were displaying erroneous estimates of battery life. The problem was said to be in the "programmers" and not in the units themselves and battery life was not altered. The term programmer here refers to the computers that are used to communicate with the PM in the doctor's office and to make programming changes and to make updates to firmware.
A much more serious battery issue also was reported in 2019.There were three reports of pacemaker batteries being completely drained resulting in one death.The devices involved with this problem were the following models: Astra,Azure,Percepta,Serena,and Solara.Damage to a capacitor in the units was said to be the cause of the battery drainage. Unfortunately there was no way to determined if a given Pacemaker was likely to have a battery failure.The FDA was not recommending replacing all of the units.Some 131,000 units were potentially affected.
PMs can be "interrogated" by bedside monitors providing various parameters of PM function including a value for battery life estimation.
In theory battery life determination seems simple.It is the battery drain rate divided into the battery capacity which is measured in ampere hours. The devil is in the denominator of the equation. How accurate are these estimations.
My own PM was implanted in October 2015.I am writing this in January 2021 .
An interrogation done on October 2016 gave an estimate of 2-2.5 years which corresponds to October 2018 to June 2019. An interrogation done October 2017 gave a estimation of 1.5 to 2.5 years which corresponds to June 2018 to June 2019.
So at least as regards my PM the estimations of battery life do not instill confidence.