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.
Review Date 7/7/2020
Updated by: Thomas S. Metkus, MD, Assistant Professor of Medicine and Surgery, Johns Hopkins University School of Medicine, Baltimore, MD. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.