An implantable cardioverter-defibrillator (ICD) is a device that detects a life-threatening, rapid heartbeat, called an arrhythmia. If such a heartbeat occurs, the ICD quickly sends an electrical shock to the heart to change the rhythm back to normal.
Update Date 8/12/2014
Updated by: Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.