About ICDs

The implantable cardioverter defibrillator (ICD) is a device used to treat dangerously fast heart rates that occur in the lower chambers of the heart (the main pumping chambers). The ICD system looks much like a pacemaker. The device is implanted under the skin and attached to one or more leads, which are placed in or on the heart muscle.

The ICD detects both bradyarrhythmia (slow heart rates) and tachyarrhythmia (fast heart rates) and delivers electrical therapy to treat these rhythm disorders and restore normal rate and rhythm to the heart. Learn more about normal rhythm and arrhythmias.

ICD therapy is often prescribed for patients who have experienced at least one episode of ventricular tachycardia or ventricular fibrillation, previous cardiac arrest, or drug therapy that was ineffective in controlling the tachyarrhythmia or that caused severe side effects. Though you may feel anxious about receiving an ICD, be assured that you are joining hundreds of thousands of people who now enjoy more normal and active lifestyles because of their ICDs.

The first step in preparing for ICD implantation is for you to become informed and comfortable with what will occur. This information is provided as an overview. Ask your physician about any specific questions you have.