What is an Implantable Cardioverter Defibrillator? (ICD)

Updated:Dec 9,2015

An ICD is a device placed under the skin that keeps track of your heart rate. Two thin wires connect the ICD to one or more of the chambers in your heart. The heart sends electric signals to the ICD. The ICD can deliver an electric pulse or shock to help restore a normal heartbeat to your heart if it is beating chaotically and much too fast. Cardiac defibrillation is a way to return an abnormally fast or disorganized heartbeat to normal with an electric shock.

How does it work?

  • The ICD goes under your skin, usually beneath your collarbone or in your abdomen (stomach area) beneath your ribs. It is connected to your heart by one or more wires called ‘leads.’
  • It knows when the heartbeat is not normal.
  • It tries to return the heartbeat to normal.
    • When your heartbeat is too slow, many ICDs can also work as a pacemaker and send tiny electric signals to your heart.
    • When your heartbeat is too fast or chaotic, it gives defibrillation shocks to stop the abnormal rhythm.
  • It works 24 hours a day.

How do I live with it?

  • Visit your doctor regularly. ICD batteries last 4 to 7 years. Doctors should check them every 3 to 6 months.
  • Talk to your doctor about your activities.
  • Stay away from magnets and strong electrical fields.
  • At the airport, tell security screeners if you have an ICD. Ask the guards not to use hand-held metal detectors on you.
  • Tell your other doctors and your dentist that you have an ICD.
  • If you go to a hospital, tell the doctors and nurses that you have one.
  • Carry an ID card so others know that you have a defibrillator.

Doctor’s orders

You most likely can resume a near normal lifestyle. But, it is best to ask your doctor what types of machines or equipment you should avoid. Also ask what you can and cannot do when you have an ICD.

Can I use a cell phone or microwave oven if I have an ICD?

Microwave ovens, electric blankets, remote controls for TV and other common household appliances won’t affect your ICD. 

You can use a cell phone, too, if you take these steps:

  • Hold the phone to the ear on the side of your body opposite from your ICD.
  • When your phone is on, try to keep it at least six inches away from your ICD. For example, don’t carry your phone in your breast pocket over your ICD.
How can I learn more?
  1. Call 1-800-AHA-USA1 (1-800-242-8721), or visit heart.org to learn more about heart disease and stroke.
  2. Sign up to get Heart Insight, a free magazine for heart patients and their families, at heartinsight.org.
  3. Connect with others sharing similar journeys with heart disease and stroke by joining our Support Network at heart.org/supportnetwork.
We have many other fact sheets to help you make healthier choices to reduce your risk, manage disease or care for a loved one. Visit heart.org/answersbyheart to learn more.

Do you have questions or comments for your doctor or nurse?

Take a few minutes to write your own questions for the next time you see your healthcare provider. For example:

Does the shock hurt?

Can I swim?

©2015, American Heart Association 

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