Pacemaker Battery Replacement: Signs of Low Battery

Why You Get A Whole New Pacemaker When Your Battery Is Low

Pacemakers are battery-run devices. And like all batteries, those in pacemakers eventually wear out. When that happens, the whole pacemaker—and not just the battery—has to be replaced.

This article discusses what pacemakers do, why they are replaced instead of recharged, and signs that indicate a pacemaker battery is low.

Doctor holding a pacemaker
Peter Dazeley / The Image Bank / Getty Images

Function of Pacemakers

Typically, the purpose of a pacemaker is to correct slow heart or irregular rhythms. This prevents symptoms such as lightheadednesspalpitations, or syncope (fainting). Some conditions that can cause a slow heart rate include sick sinus syndrome or heart block.

pacemaker consists of a tiny but sophisticated computer, software instructions for that computer, various delicate electronic components, and a battery. All these parts are enclosed within a small metal container. (A typical pacemaker today is about the size of a 50-cent piece, and about three times as thick.)

Pacemakers are usually implanted under the skin, just below the collarbone, and are connected by leads—or insulated wires—to your cardiac chambers.

The pacemaker monitors your heart rhythm, beat-by-beat, and makes moment-to-moment decisions about whether or not it should pace your heart. If your heart rate falls below a predetermined value, it "paces" by sending a tiny electrical impulse to your heart through the lead, thus stimulating your heart to beat.

The engineers who design pacemakers had to solve several difficult problems, one of the most difficult being how to keep the pacemaker functioning perfectly, inside the human body, for several years.

Why Pacemakers Are Replaced

Anyone who has spilled coffee on their laptop knows that fluids and electronic devices don't mix. Pacemakers are electronic devices that must spend their entire existence in a fluid environment. 

In fact, the inside of the human body is a warm, wet, and salty place—a very hostile environment for any electronic device. So among other things, a pacemaker must be hermetically sealed (to keep moisture and body fluids out). Its delicate electronic components must be designed to survive and function in this hostile environment for a long time.

Because of this environment, the whole pacemaker must be replaced when the battery is wearing out and not just the battery. If pacemakers were capable of being opened so that the battery could be replaced, adequate hermetic sealing would be next to impossible.

Instead of being removable, the battery must be permanently sealed within the device, along with all the other delicate electronic components.

How Often Pacemakers Need to Be Changed

Engineers have become very good at building these devices to last for many years, and the failure rate for pacemakers, in general, is well under 1% after five years of use. Still, a pacemaker battery typically works for about five to 10 years before the device needs to be replaced.

How to Know Your Pacemaker Battery Is Low

Your healthcare provider can check the battery's function during your regular appointments. They can also monitor device information remotely through a phone transmitter or the internet.

Usually, the device provides a warning several months before the battery will run out. Sometimes a pacemaker will beep when the battery is low.

This allows you and your healthcare provider to know to schedule the replacement procedure in the near future.

Signs of Pacemaker Failure

A low battery usually doesn't lead to complete failure of the pacemaker battery. However, it is possible for depletion of the battery to cause the pacemaker to malfunction or fail.

Other factors can also cause it to fail, including loose wires, electomagnetic interference from devices like power generators, or a change in your condition that requires different pacemaker settings.

A pacemaker failure can cause symptoms related to your heart condition. If you experience any of these symptoms, call 911:

  • Fainting or losing consciousness
  • Chess pain with weakness, dizziness, nausea, or vomiting
  • Trouble breathing
  • Heart palpitations (feeling of the heart beating fast, hard, or irregularly)
  • Slower heart rate than usual

Also, check with your healthcare provider if you have symptoms that seem unusual, such as frequent hiccups or constant muscle twitching in the chest or abdomen.

These symptoms may happen with total pacemaker failure, but they could also happen with low battery if the pacemaker is starting to malfunction.

In one study of pacemaker patients, 31% experienced symptoms when the battery indicated that it needed replacing.

Surgery to Replace a Pacemaker with a Low Battery

The surgery to replace a pacemaker with a low battery is typically less complex than the original surgery to place the device.

During a replacement, your surgeon will replace the pulse generator, a small metal box with electric circuits and the battery.

The generator is disconnected from the leads, the wires between the generator and your heart. The old leads are usually left in place, and the new generator is then attached to them.

The surgeon usually doesn't need to enter your chest cavity like they needed to during the original surgery. In rare cases you may need the leads replaced, too, which would lead to a more complex procedure.

Pacemaker replacement is usually done with local anesthesia as an outpatient procedure. It typically takes about two hours.

You will likely be able to go back to your usual routine within one week after the surgery. If your leads were also replaced, it may take two weeks to get back to normal activities.

Full recovery from pacemaker replacement due to low battery will probably be faster than the initial placement surgery, which is usually around one month.

Why Pacemakers Aren't Rechargeable

The technology for recharging batteries wirelessly (a process also known as inductive charging) has been around for several decades, and you can buy wireless rechargers for your cell phones today. However pacemaker batteries today are not able to be recharged.

The original implantable pacemakers from 1958 had rechargeable nickel-cadmium (NiCad) batteries. Most people believed that the use of rechargeable batteries would always be necessary for implantable electronic devices.

These pacemakers were recharged by holding an inductive coil up against the skin, near the pacemaker, for several hours. This procedure had to be repeated every few days.

Rechargeable pacemakers ultimately failed for two reasons. First, even though they're rechargeable, NiCad batteries have a relatively short service life, so these pacemakers still needed to be replaced pretty often.

But probably more importantly, with human nature being what it is, people with pacemakers occasionally failed to recharge their devices according to the rigorous schedule that was imposed upon them.

Lawyers informed the pacemaker companies that if a patient suffered harm because his/her pacemaker stopped working—whether the failure was the fault of the company or because the patient neglected to recharge the device—subsequent lawsuits would likely produce bankruptcy.

Within a few years, mercury-zinc batteries were developed that could keep a pacemaker going for up to two years. Soon thereafter, lithium-iodide batteries were developed which could power a pacemaker far longer than that: for five to 10 years. So the pressing need for rechargeable pacemakers diminished, while the imminent threat of lawsuits did not.

Thanks to both technological advances and the legal profession, the idea of rechargeable pacemakers were quickly abandoned. It is an idea that is reconsidered by pacemaker developers every once and a while, but so far the potential risks (to the companies, at least), have outweighed the potential benefits.

Why Batteries Don't Last Longer

The fact is, they could make pacemaker batteries that last substantially longer than they do now.

In fact, in the 1960s and 1970s, a few pacemaker companies made nuclear-powered pacemakers that were powered by plutonium-238—which has a half-life of 87 years—so these pacemakers were virtually guaranteed not to run out of "juice" during the lifetime of the patient.

But, as you might imagine, there were some obvious problems with nuclear pacemakers. First, plutonium is a highly toxic substance, and even if a minuscule amount leaks into the bloodstream, death would rapidly ensue.

And because plutonium is obviously a substance of great interest to regulators (and to even the darker elements within our civilization), people with these pacemakers faced problems, for instance, when they attempted to travel overseas.

Physicians who implanted these devices were required, under a regulation enforced by the Nuclear Regulatory Commission, to recover the pacemakers upon the death of the patient, a requirement which (because patients move away and doctors retire), proved entirely impractical.

There's also a less obvious problem with pacemakers whose batteries last "forever.” The fact is that all electronic devices eventually fail. Sooner or later all electronic components break, or just wear out.

When a pacemaker fails because the battery wears out, at least that's a gradual and predictable event. By making periodic checkups, doctors have several months of warning that a battery is wearing down and is likely to need replacement. So an elective pacemaker replacement can be scheduled at a convenient time.

If your pacemaker were to fail because one of the other of its hundreds of electronic components suddenly stopped working, that could be catastrophic. The pacemaker could suddenly stop pacing, without any warning—and its owner could potentially suffer great harm.

If companies began building pacemakers whose batteries lasted substantially longer than five to 10 years, with the kinds of electronic components that exist today, too many pacemakers would suffer sudden, catastrophic failure.

Rather, pacemakers are designed so that the first component that is likely to "fail" is the battery, and since that "failure" can be predicted ahead of time, the device can be replaced before it stops working altogether.

It is possible, of course—and even likely—that in the future, other electronic components needed for building pacemakers will be made that are substantially more robust without being cost-prohibitive. When that day comes, engineers can design batteries that will last substantially longer than they do today.

With today's technology, a pacemaker that lasts five to 10 years turns out to be the engineering "sweet spot”—for now.

A Word From Verywell

Pacemakers are a marvel of engineering. Their effectiveness and reliability have improved tremendously since these devices were first invented. But there is still room for improvement.

A lot of research and development is being done by pacemaker manufacturers to develop devices that are easier to implant, are even safer, and will last a lot longer than they do today—potentially, for the life of the person who receives one

Frequently Asked Questions

  • How serious is surgery to replace a pacemaker because of a low battery?

    Replacing the pacemaker's pulse generator (which has the battery) is usually a simple outpatient procedure. That's because the surgery isn't done inside the chest cavity. The generator under your skin is replaced, but the leads, which are connected to your heart, are left in place.

  • What kind of anesthesia is used for pacemaker replacement?

    It's usually performed with local anesthesia. You'll be given medication to make you feel drowsy but still awake.

  • What should your heart rate be with a pacemaker?

    At rest, a pacemaker will usually be set for a typical heartbeat of 50 to 70 beats per minute.

8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Brignole M, Auricchio A, Baron-Esquivias G, et al. 2013 ESC Guidelines on cardiac pacing and cardiac resynchronization therapy: the Task Force on cardiac pacing and resynchronization therapy of the European Society of Cardiology (ESC). Developed in collaboration with the European Heart Rhythm Association (EHRA). Eur Heart J 2013; 34:2281. DOI:10.1093/eurheartj/eht150

  2. Medronic. Heart failure pacemaker with defibrillation: Patient manual.

  3. Fairview Health Services. Pacemaker failure.

  4. Liu J, Wen L, Yao S, Zheng P, Zhao S, Yang J. Adverse clinical events caused by pacemaker battery depletion: Two case reports. BMC Cardiovascular Disorders. 2020;20(1). doi:10.1186/s12872-020-01622-x

  5. Johns Hopkins Medicine. Implantable device replacement procedure.

  6. Kaiser Permanente. Pacemaker or ICD replacement: What to expect at home.

  7. Oklahoma Heart Hospital. Replacing a pacemaker or defibrillator.

  8. Infeld M, Avram R, Wahlberg K, et al. An approach towards individualized lower rate settings for pacemakers. Heart Rhythm O2. 2020;1(5):390-393. doi:10.1016/j.hroo.2020.09.004

Additional Reading
  • Tracy CM, Epstein AE, Darbar D, et al. 2012 ACCF/AHA/HRS Focused Update of the 2008 Guidelines for Device-based Therapy of Cardiac Rhythm Abnormalities: a Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society. Circulation 2012; 126:1784.

By Richard N. Fogoros, MD
Richard N. Fogoros, MD, is a retired professor of medicine and board-certified in internal medicine, clinical cardiology, and clinical electrophysiology.