ICD

Overview

Implantable cardioverter-defibrillator (ICD)Enlarge image

An implantable cardioverter-defibrillator (ICD) is a small battery-powered device placed in the chest to detect and stop irregular heartbeats (arrhythmias). An ICD continuously monitors the heartbeat and delivers electric shocks, when needed, to restore a regular heart rhythm.

You might need an ICD if you have a dangerously fast heartbeat that keeps your heart from supplying enough blood to the rest of your body (such as ventricular tachycardia or ventricular fibrillation) or if you are at high risk of such a heart rhythm problem (arrhythmia), usually because of a weak heart muscle.

An ICD differs from a pacemaker — an implantable device that can prevent dangerously slow heartbeats.

Types

An ICD is a type of cardiac therapy device. There are two basic types:

  • A traditional ICD is implanted in the chest, and the wires (leads) attach to the heart. The implant procedure requires invasive surgery.

  • A subcutaneous ICD (S-ICD) is another option that's implanted under the skin at the side of the chest below the armpit. It's attached to an electrode that runs along the breastbone. An S-ICD is larger than a traditional ICD but doesn't attach to the heart.

Why it's done

An ICD constantly monitors for irregular heartbeats and instantly tries to correct them. It helps when the heart stops beating effectively (cardiac arrest).

Your health care provider may recommend an ICD if you've had signs or symptoms of a certain type of irregular heart rhythm called sustained ventricular tachycardia, including fainting. An ICD might also be recommended if you survived a cardiac arrest. Other reasons you may benefit from an ICD are:

  • A history of coronary artery disease and heart attack that has weakened the heart

  • An enlarged heart muscle

  • A genetic heart condition that increases the risk of dangerously fast heart rhythms, such as some types of long QT syndrome

  • Other rare conditions that may affect the heartbeat.

A health care provider may recommend an S-ICD if there are structural defects in the heart that prevent attaching wires to the heart through the blood vessel.