Sign In Home Contact Us Increase Type Size
Skip navigation links
Popular Resources
Making Healthcare Decisions
Health Information CentersExpand Health Information Centers
Health LibraryExpand Health Library
Health MultimediaExpand Health Multimedia
Health & Wellness DiscountsExpand Health & Wellness Discounts
Hill Health Magazine
Preventive GuidelinesExpand Preventive Guidelines
Interactive Health Tools
Nutrition & RecipesExpand Nutrition & Recipes
Contact Us

Implantable Cardioverter-Defibrillator (ICD)

An implantable cardioverter-defibrillator (ICD) is a small device that uses electrical pulses or shocks to help control abnormal heart rhythms, especially ones that can be life-threatening. An ICD is also known as an automatic implantable cardioverter-defibrillator (AICD).

An ICD is implanted under the skin in the chest. A wire threaded through a large vein connects the device to the heart.

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. If your heart is beating too slowly, the ICD acts as a pacemaker, sending mild electrical pulses to bring your heart rate back up to normal.

Last Revised: June 2, 2011

Author: Healthwise Staff

Medical Review: E. Gregory Thompson, MD - Internal Medicine & Rakesh K. Pai, MD, FACC

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.

© 1995-2013 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.