What Is an Internal Cardiac Defibrillator?

An internal cardiac defibrillator, or ICD (Implantable Cardioverter-Defibrillator), is a life-saving device designed to diagnose and correct dangerously fast heart rhythms. It is different from a pacemaker which helps regulate the beating of the heart with the use of electrical signals.

Purpose

• The ICD is prescribed for patients at risk for ventricular tachycardia or ventricular fibrillation, the most dangerous rapid heart rhythms. The defibrillator corrects the heart rhythm by delivering precisely timed electrical pulses or shocks to restore a normal heartbeat.

Features

• The ICD consists of a battery and a control circuit in a small titanium case. Wires with electrodes on the ends are inserted into the heart through a vein in the upper chest.

Function

• When the circuit detects a fast ventricular rhythm, it may attempt to pace the heart at a slower rate (cardioversion) or deliver a shock to stop the heart (defibrillation), allowing a normal rhythm to resume.

Benefits

• When necessary, defibrillation can mean the difference between life and death. The ICD ensures this treatment is always available and instantly applied.

Considerations

• Only your doctor can tell you if you need an ICD. Open heart surgery is not required but even the surgery to implant the device poses some risk. Monitoring and replacement are required as the battery wears out, typically in three to five years.