Topic Overview

An implantable cardioverter-defibrillator (ICD) is a battery-powered device that can fix an abnormal heart rate or rhythm and prevent sudden death. The ICD is placed under the skin of the chest. It's attached to one or two wires (called leads). Most of the time, these leads go into the heart through a vein.

An ICD is also known as an automatic implantable cardioverter-defibrillator (AICD).

When is an ICD used?

An ICD might be an option if you have had a serious episode of an abnormally fast heart rhythm or are at high risk for having one. If you have coronary artery disease, heart failure, or a problem with the structure or electrical system of the heart, you may be at risk for an abnormal heart rhythm.

An example of a life-threatening heart rhythm is ventricular tachycardia.

• Heart Failure: Should I Get an Implantable Cardioverter-Defibrillator (ICD)?
• Heart Problems: Should I Get an Implantable Cardioverter-Defibrillator (ICD)?

How does an ICD work?

An ICD is always checking your heart rate and rhythm. If the ICD detects a life-threatening rapid heart rhythm, it tries to slow the rhythm with electrical pulses to get it back to normal. If the dangerous rhythm does not stop, the ICD sends an electric shock to the heart to restore a normal rhythm. The device then goes back to its watchful mode.

Some ICDs also can fix a heart rate that is too slow. The ICD does so without using a shock. It can send out electrical pulses to speed up a heart rate that is too slow.

Whether you get pulses or a shock depends on the type of problem that you have and how the doctor programs the ICD for you.

How is an ICD placed?

Your doctor will put the ICD in your chest during minor surgery. You will not have open-chest surgery. You probably will have local anesthesia. This means that you will be awake but feel no pain. You also will likely have medicine to make you feel relaxed and sleepy.

Your doctor makes a small cut (incision) in your upper chest. For one type of ICD (transvenous), your doctor puts one or two leads (wires) in a vein and threads them to the heart. For another type (subcutaneous), the lead is placed under the skin so that it lies near your heart. Then your doctor connects the leads to the ICD. Your doctor puts the ICD under the skin of your chest and closes the incision. Your doctor also programs the ICD.

In some cases, the doctor may be able to put the ICD in another place in the chest so that you don't have a scar on your upper chest. This would allow you to wear clothing with a lower neckline and still keep the scar covered.

Most people spend the night in the hospital, just to make sure that the device is working and that there are no problems from the surgery.

You may be able to see a little bump under the skin where the ICD is placed.

How does it feel to get a shock from an ICD?

The shock from an ICD hurts briefly. It's been described as feeling like a punch in the chest. But the shock is a sign that the ICD is doing its job to keep your heart beating. You won't feel any pain if the ICD uses electrical pulses to fix a heart rate that is too fast or too slow.

There's no way to know how often a shock might occur. It might never happen.

It's possible that the ICD could shock your heart when it shouldn't. You also might be afraid or worried about when the ICD might shock you again. But you can take simple steps to feel better about having an ICD. These include having your ICD checked regularly by your doctor and making an action plan for what to do if you get shocked.

How do I live a normal, healthy life with an ICD?

You can live a normal, healthy life with your ICD. A few tips for living well with your ICD include:

• Avoid strong magnetic and electrical fields. These can keep your device from working right. Most office equipment and home appliances are safe to use. Learn which things you should use with caution and which you should stay away from.
• Know what to do when you get a shock from your ICD.
• Be sure that any doctor, dentist, or other health professional you see knows that you have an ICD.
• Always carry a card in your wallet that tells what kind of device you have. Wear medical alert jewellery that says you have an ICD.
• Have your ICD checked regularly to make sure it's working right.
• It's common to be anxious that the ICD might shock you. But you can take steps to think positively and worry less about living with an ICD.

Talk with your doctor about the possibility of turning off the ICD at the end of life. Many people consider turning off the ICD when their health goals change from living longer to getting the most comfort possible at the end of life. Turning off your ICD is legal. It isn't considered suicide. The decision to leave on or turn off your ICD is a medical decision that you make based on your values. You can put your wishes in an advance directive.

For more tips, see:

• Heart Problems: Living With an ICD.