ICD is a battery-powered life saving device placed under the skin that keeps track of the heart rate. Thin wires connect the ICD to the heart like pacemaker. If an abnormal heart rhythm is detected the device will deliver an electric shock to restore a normal heartbeat if the heart is beating chaotically and much too fast.

ICDs are used in preventing sudden death in patients with known, sustained ventricular tachycardia or fibrillation. They also have a role in preventing cardiac arrest in high-risk patients who are at risk for life-threatening ventricular arrhythmias.