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As with any medical or surgical procedure, getting a pacemaker has risks as well as benefits.

Some of the main risks are:

  • blood clots
  • infection
  • air leak
  • problems with the pacemaker

Emergency action required: Contact your GP or cardiologist as soon as possible if

you develop signs of a complication, including:

  • shortness of breath
  • dizziness
  • fainting
  • prolonged weakness
  • a swollen arm on the side of the pacemaker
  • chest pains
  • prolonged hiccups
  • a high temperature of 38 degrees Celsius or above
  • pain, swelling and redness at the site of the pacemaker

Blood clots

About 2% of people who have a pacemaker develop a blood clot. This is usually in the arm on the side where the pacemaker was fitted.

This may cause swelling in the arm. But it usually goes away in a few days. It's rarely a serious problem.

You may be given anticoagulant medication. This stops the clot getting bigger.

Pacemaker infection

Around 1% of people with a pacemaker develop a pacemaker infection. This usually happens within the first year of having the device.

Symptoms of a pacemaker infection include:

  • a high temperature of 38 degrees Celsius or above
  • pain, swelling and redness at the site of the pacemaker


Call your GP or cardiologist as soon as possible if you think you have an infection.

A pacemaker infection is usually treated by antibiotics and surgery. This is to replace the pacemaker.

If an infection is not treated, it could spread to:

  • your lungs and cause pneumonia
  • the lining of your heart and cause endocarditis
  • your blood and cause sepsis

Air leak

There's a risk of the lung being accidentally punctured during the procedure. This means air can leak from the lung into your chest.

This is known as pneumothorax. About 1% of people get it. The leak is usually very small. It gets better on its own and you will not need treatment.

If a lot of air leaks into the chest, this may need to be sucked out. This is done using a needle and a special drain in the chest. If you need a drain, you may need to stay in hospital for a day or two.

Problems with the pacemaker

As with any electronic device, there's a small chance your pacemaker could stop working. This is known as a pacemaker malfunction.

A pacemaker can go wrong if:

  • the lead gets pulled out of position
  • the battery of the pulse generator fails
  • the circuits that control the pacemaker are damaged after being exposed to strong magnetic fields
  • the pacemaker hasn't been properly programmed

Signs your pacemaker may have failed include:

  • your heart begins beating more slowly or quickly
  • dizziness
  • hiccups
  • fainting or nearly fainting

Urgent advice: Call 112 or 999 or go to your emergency department (ED) if:

  • you're concerned your pacemaker has failed

It may be possible to correct a pacemaker remotely using wireless signals or magnets. Otherwise, the pacemaker will need to be removed and replaced.

Content supplied by the NHS and adapted for Ireland by the HSE

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This project has received funding from the Government of Ireland’s Sláintecare Integration Fund 2019 under Grant Agreement Number 123.

Page last reviewed: 29 July 2021
Next review due: 29 July 2024