People with severe heart failure or serious arrhythmias (irregular heartbeats) may be candidates for defibrillator implants. These devices are surgically placed under the skin of the chest to monitor the electrical activity of the heart. When a life-threatening abnormal rhythm is detected, small electric shocks are delivered to the heart to return it to a normal heart rhythm, which can be life-saving.

Candidates for implantable defibrillators include patients who have serious episodes of abnormal heart rhythm and patients who are at risk for heart attack or have had a heart attack.