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 inside the chest. It's attached to one or two wires
(called leads) that go into the heart through a vein.
An ICD is also known as an
automatic implantable cardioverter-defibrillator (AICD).
Who needs an ICD?
You might need an ICD 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
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 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.
An ICD also can fix a heart rate that is too fast or too
slow. It does so without using a shock. It can send out electrical pulses to speed up a
heart rate that is too slow. Or it can slow down a fast heart rate by matching
the pace and bringing the heart rate back to normal.
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
Your doctor makes a small cut (incision) in your upper
chest. He or she puts one or two leads (wires) in a vein and threads them to
the heart. Then your doctor connects the leads to the ICD. Your doctor programs
the ICD and then puts it in your chest and closes the incision.
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
How does it feel to get a shock from an ICD?
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.
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
Always carry a card in your wallet that tells
what kind of device you have. Wear medical alert jewelry that says you have an
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.
Visit the American Heart Association (AHA) website for information on
physical activity, diet, and various heart-related conditions. You can search for information on heart disease and stroke, share information with friends and family, and use tools to help you make heart-healthy goals and plans. Contact the AHA to find your
nearest local or state AHA group. The AHA provides brochures and information
about support groups and community programs, including Mended Hearts, a
nationwide organization whose members visit people with heart problems and
provide information and support.
Heart Rhythm Society
1400 K Street NW
Washington, DC 20005
The Heart Rhythm Society provides information for
patients and the public about heart rhythm problems. The website includes a
section that focuses on patient information. This information includes causes,
prevention, tests, treatment, and patient stories about heart rhythm problems.
You can use the Find a Specialist section of the website to search for a heart
rhythm specialist practicing in your area.
National Heart, Lung, and Blood Institute
P.O. Box 30105
Bethesda, MD 20824-0105
The U.S. National Heart, Lung, and Blood Institute
(NHLBI) information center offers information and publications about preventing
Diseases affecting the heart and circulation, such as heart
attacks, high cholesterol, high blood pressure, peripheral artery disease, and
heart problems present at birth (congenital heart diseases).
Diseases that affect the lungs, such as asthma, chronic
obstructive pulmonary disease (COPD), emphysema, sleep apnea, and
Diseases that affect the blood, such as anemia,
hemochromatosis, hemophilia, thalassemia, and von Willebrand disease.
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Primary Medical Reviewer
Rakesh K. Pai, MD, FACC - Cardiology, Electrophysiology
Specialist Medical Reviewer
Stephen Fort, MD, MRCP, FRCPC - Interventional Cardiology
How this information was developed to help you make better health decisions.