What is an implanted cardioverter defibrillator (ICD)?

An implanted cardioverter defibrillator (ICD) is a small electronic device implanted permanently inside your body. It is like a pacemaker but has several extra features. It is usually inserted under the skin in the area of your upper chest, near your left shoulder (Figure 14). This procedure is performed by a cardiac electrophysiologist,

who is a heart doctor that specializes in the electrical disturbances of the heart.

An ICD continually monitors your heart rhythm (the pattern and speed of your heartbeat). If your heart rhythm becomes too slow or too fast, the ICD sends out electrical signals to restore your rhythm back to normal. Depending on the type of abnormal heart rhythm, this electrical impulse is referred to as a “cardioversion” or a

“defibrillation.” Sometimes, these abnormal rhythms are very dangerous, and an ICD could save your life.

If your heartbeat becomes too slow (known as “bradycardia”), the ICD sends out electrical impulses to bring the rhythm back up to a normal rate. This is referred to as “pacing” and is the same feature that is found in a standard pacemaker. If your heartbeat becomes dangerously fast (known as “tachycardia”), the ICD can send impulses to slow it down. It can also deliver a small shock to return the heart back to a normal rhythm again.

If you have a cardiomyopathy or heart failure, you may be at increased risk of these dangerous arrhythmias (heart rhythm problems). Your doctor may recommend that you have an ICD implanted to protect you from any of these rare but serious life-threatening heart rhythm disturbances. If these dangerous abnormal heart rhythms are not corrected quickly, they could lead to cardiac arrest. An ICD can protect you from these problems.