An implantable cardioverter defibrillator (ICD) is a small electronic device installed inside the chest to prevent sudden death from cardiac arrest due to life threatening abnormally fast heart rhythms (tachycardias). The ICD is capable of monitoring the heart rhythm. When the heart is beating normally, the device remains inactive. If the heart develops a life-threatening tachycardia, the ICD can attempt pacing to bring the heart rhythm back to normal, or it can deliver an electrical “shock(s)” to the heart to terminate the abnormal rhythm and return the heart rhythm to normal.
