What is an implantable cardioverter defibrillator (ICD)?

An implantable cardioverter defibrillator (ICD) is a small, battery-operated medical device. It is also sometimes called an AICD (automated implantable cardioverter defibrillator). It is placed in the body during surgery and connected to your heart. It detects and corrects abnormal rhythms of the heart.

What does an ICD do?

An ICD sits under the skin near your heart. It monitors the heart's rhythm 24 hours a day and detects abnormal rhythms in the ventricles — the parts of the heart that pump blood to the lungs and around the body.

Your heart needs to beat regularly and at a normal pace for blood to reach your organs and tissues. If your heart beats too fast or slow, or irregularly, blood may not be pumped properly around your body. Sometimes, an abnormal rhythm can make it too hard for the heart to pump blood at all.

If an ICD detects an abnormal heart rhythm, it can send an electrical impulse to your heart to return it to a normal rhythm — similar to how a pacemaker works. If those impulses don’t work, the ICD can send a stronger electric shock to jolt your heart back into a normal rhythm.

Do I need an ICD?

You might need an ICD if you have a heart arrhythmia, such as an abnormally fast or irregular heartbeat.

If you have a heart arrhythmia, your doctor will refer you for tests to identify the type and cause. The tests performed will vary depending on your individual circumstances. Tests may include an electrocardiogram (ECG) to check on your heart’s electrical activity. You may also have an ultrasound of your heart (echocardiogram) to look at the structure of your heart and check that it’s working normally.

How is an ICD fitted?

The ICD is inserted under the skin of your upper chest during a surgical procedure. This takes 1 to 3 hours to complete.

You might have a sedative medicine to relax you before surgery. In most cases, this surgery needs a local anaesthetic, but some people will have a general anaesthetic. Your doctor will discuss pain relief options with you.

Your doctor will make a small 5 to 10 centimetre (cm) incision (cut) to create a 'pocket' in your upper chest, below your collarbone.

Then, 1 or 2 electrical leads are guided through a vein, towards your heart, and are connected to the ICD. Your doctor will check the device to make sure it is working properly.

The ICD is tucked inside the pocket, and the incision is closed with sutures (stitches) and covered with a dressing. There will be a visible bulge under your skin where the ICD was inserted.

What are the complications and risks of an ICD?

As with any type of surgery, there are risks associated with ICD surgery.

The most common complication during the ICD procedure is swelling and bruising or bleeding from the wound.

Other less common complications include:

• puncture of the lung causing an air leak
• damage to your veins or heart valves from placement of ICD leads
• unintended movement of the ICD or its leads, which may need to be repositioned
• infection of the wound or wires
• ICD malfunction

What should I expect after an ICD fitting procedure?

You will have a dressing over your wound, and the site of the surgery may feel a bit sore. There may be some bruising. You should avoid wearing tight-fitting clothes while the wound is healing, as this might irritate your skin.

It may take a few weeks for you to return to normal activities after the procedure. Your doctor will give you advice on how to look after your wound and what exercises or movements you can do in the weeks immediately after the procedure.

Your doctor may recommend that you don’t lift anything heavy with the arm on the same side as the ICD. They might advise you not to push or pull things with that arm, and not to drive.

Always check with your doctor or clinic if you are unsure about what you should (or shouldn't) do.

What do I do if I get a shock from my ICD?

It’s possible that you will experience a shock from your ICD at some point. Having a plan for when this happens will help you know what to do to get the right medical help. Having a plan will also help reduce the stress you may feel if you get a shock.

Ask your doctor to help you make a plan for shocks. Although every person will have their own individual plan, this is what a typical plan may look like:

• If you get one shock from your ICD, and feel OK, call your heart doctor to discuss the shock.
• If you get 2 or more shocks within 48 hours, seek medical attention, even if you feel fine.
• Seek medical attention straight away if you get a shock and feel any of these symptoms:
  • chest pain or pressure
  • trouble breathing
  • abnormal heartbeat
  • dizziness
  • feeling unwell

Some ICD devices can be remotely monitored by your doctor. If not, your doctor will see you regularly so they can view what shocks your ICD has given you. Monitoring your device is important because you might not feel small shocks from your ICD.

When should I see my doctor?

If you are worried about your heart at any time, see a doctor. Your doctor will discuss treatment options and refer you to a heart specialist or surgeon if you need one. In some circumstances, your doctor may prescribe medicines for your condition.

If you have had an ICD fitted, and want to know more about how it works, or need advice on what to do after an ICD procedure, ask your health team. Call your doctor if:

• your wound becomes infected (it is red, swollen, warm or leaking fluid)
• you develop a fever up to 8 weeks after the procedure
• you continue to have any of the heart symptoms you had before the procedure
• you lose consciousness, either due to an arrhythmia or while receiving a shock
• you have any numbness or tingling in the arm closest to the ICD
• you hear a beeping noise coming from the ICD

How will life with an ICD be different?

Living with an ICD can be stressful. You may feel anxious for a little while after the procedure. Talk to your family and healthcare team about how you are feeling and any concerns you might have.

You will need to go to an ICD clinic for regular follow-up appointments and have 'device checks'. Device checks monitor the electrical functioning of your heart, your device settings and its battery life. Most ICD batteries will last between 5 and 15 years.

Create an action plan with your doctor so you know what to do if you get an electric shock from your ICD. Carry an ID card with your ICD details in your wallet or purse.

Tell all health professionals who treat you that you have an ICD.

When you have an ICD, you need to avoid certain types of electronic devices with strong magnetic fields. Devices with strong magnetic fields may cause your device to stop working. Tell your health team you have an ICD if you need a magnetic resonance imaging (MRI) scan.

Avoid household devices with a strong magnetic field.

Most items you use in daily life won’t cause any problems, but you should keep these items at least 15cm away from your ICD:

• mobile phones — use your phone on the opposite side of your body to the ICD and avoid putting it in a pocket near your device
• airport screening wands — let airport security know that you have an ICD

It is also recommended that you avoid using:

• industrial welders
• electric generators
• chainsaws
• magnetic mattresses and pillows

Talk to your doctor if your work involves any of these items, if you are a commercial driver or if you operate heavy machinery.

Resources and support

Talk to your health professional about the benefits and risks of getting a medical implant. Use the Therapeutic Goods Administration's guide on what to ask. The information is available in many community languages.

For more information about ICDs, including how they work, when they are recommended and living with an ICD, see the St Vincent's Hospital Heart Health website:

• Information about the implantable cardioverter defibrillator.
• Discover how to recover well after an implantable defibrillator.

The Heart Foundation offers a directory to find a cardiac rehabilitation service near you.

You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with you 24 hours a day, 7 days a week.

Information for Aboriginal and/or Torres Strait Islander peoples

Visit St Vincent's Hospital and the Heart Foundation's Aboriginal heart health website for information on implantable cardioverter defibrillators for Aboriginal and/or Torres Strait islander people.