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Home > Wellness Resources > Health Library > Implantable Cardioverter-Defibrillator (ICD)
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).
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 example of
a life-threatening heart rhythm is ventricular tachycardia.
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.
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
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.
You can live a normal, healthy life with your ICD. A few tips for living well with your ICD include:
For more tips, see:
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.
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.
The U.S. National Heart, Lung, and Blood Institute
(NHLBI) information center offers information and publications about preventing
Other Works Consulted
Baddour LM, et al. (2010). Update on cardiovascular implantable electronic device infections and their management. A scientific statement from the American Heart Association. Circulation, 121(3): 458–477.
Epstein AE, et al. (2008). ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation,
117(21): e350–e408. [Correction in Circulation, 120(5): e34–e35.]
Lampert R, et al. (2010). HRS Expert Consensus Statement on the Management of Cardiovascular Implantable Electronic Devices (CIEDs) in patients nearing end of life or requesting withdrawal of therapy. Heart Rhythm, 7(7): 1008–1026.
Sears SF, et al. (2005). How to respond to an implantable cardioverter-defibrillator shock. Circulation, 111(23): e380–e382.
Sears SF, et al. (2011). Posttraumatic stress and the implantable cardioverter-defibrillator patient. Circulation: Arrhythmia and Electrophysiology, 4(2): 242–250.
Swerdlow CD, et al. (2012). Pacemakers and implantable cardioverter-defibrillators. In RO Bonow et al., eds., Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 9th ed., vol. 1, pp. 745–770. Philadelphia: Saunders.
Wilkoff BL, et al. (2008). HRS/EHRA expert consensus on the monitoring of cardiovascular implantable electronic devices (CIEDS): Description of techniques, indications, personnel, frequency, and ethical considerations. Heart Rhythm, 5(6): 907–925. Available online:
September 12, 2012
Rakesh K. Pai, MD, FACC - Cardiology, Electrophysiology & Stephen Fort, MD, MRCP, FRCPC - Interventional Cardiology
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