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Pacemaker battery scandal

Posted on February 3, 2016 at 11:55 PM


Much can and should be done to maximise the longevity of existing devices

Imagine spending £3000 on a new watch with a battery embedded in the mechanism that cannot be replaced or recharged. Although the battery is predicted to last 10 years or more, after six years you discover that it is running flat and you’re advised to replace the watch immediately, even though it may keep good time for a year or more.

This mirrors the dilemma faced by all patients with cardiac implantable electronic devices such as pacemakers and implantable cardioverter defibrillators (ICD). But for them the stakes are much higher as replacing the battery exposes them to a risk of serious complications, including life threatening infection.

Over half of all patients with pacemakers require a replacement procedure because the batteries have reached their expected life.(Ref 1) Some 11-16% need multiple replacements.(Ref 2) The situation is worse for recipients of an ICD, since the risks of infection at the time of implant and device replacement are higher than with pacemakers and the batteries have a shorter life.(Ref 3)

What is the risk of infection?

With no standard definition or reporting system, infection rates vary widely, and the commonly quoted risk of 0.5% for new implants and 1-5% for replacement procedures may be wrong.(Ref 4) Infection, even if it seems superficial, usually necessitates extraction of the entire system. Simply treating the infection with antibiotics results in a much poorer outcome.(Ref 5) The increased risk of infection associated with battery replacement makes it critical that we prolong the life of implantable devices as much as possible. The health economic grounds for minimising the number of replacements are also compelling.(Ref 6)

The current financial model discourages the development of longer life devices. Increasing longevity would reduce profits for manufacturers, implanting physicians, and their institutions. With financial disincentives for both manufacturers and purchasers it is hardly surprising that longer life devices do not exist.

Patients are often assumed to prefer smaller devices, but when offered the choice, over 90% would opt for a larger, longer lasting device over a smaller one that would require more frequent operations to change the battery.(Ref 7) And given the risks that patients are exposed to during replacement, there is an urgent need to improve longevity by developing longer life batteries and using those in current devices more prudently.

What can be done now?

At present the main drive to improving longevity of pacemakers has been through programming changes aimed at reducing the amount of pacing8 or minimising the drain of current during pacing—for example, using high impedance leads. But devices are usually replaced when there is still substantial life left in the battery. For example, when a pacemaker reaches elective replacement indication, it is usually 3-12 months before it will reach its end of life. And even then, the battery may continue to function for several months. Early replacement may be reasonable for high risk patients (such as those who are entirely dependent on their pacemaker). However, we could delay replacement of the pulse generator until the batteries are virtually depleted in lower risk patients. The increasingly popular innovation of home monitoring of devices would facilitate this.

For ICDs the waste is even more striking; devices reach their elective replacement indication when they are still capable of delivering at least six full energy shocks. Each shock reduces the battery longevity by about 30 days. So for patients who receive no shock therapy we are prematurely discarding a device costing up to £25 000 (€33 000; $36 000), which could last at least another six months (current devices last four to seven years on average). We need to review the timing of replacement of implantable devices in all patients.

What could be done in future?

With existing technology engineers could design and build pacemakers that would last for 25 years or more, with an increase in volume of the device of about 40%. Further developments in battery technology might enable smaller or rechargeable devices.

There is an urgent need to minimise the requirement for replacement of these devices (box). Doing so will save lives, minimise suffering, and reduce costs.

Steps to minimise replacement of cardiac implantable electronic devices

  • Maximise the longevity of existing devices by:
  • Smart programming
  • Allowing batteries to deplete for longer before replacement
  • Invest more in research in rechargeable technology and energy harvesting
  • Manufacture pacemakers with a ≥25 year life expectancy so that patients can be offered this choice
  • Consider whether device replacement is necessary—every time


BMJ 2016;352:i228 4th February 2016

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