An implantable cardiac defibrillator is a device that is placed in the abdomen or chest to help treat arrhythmias, explains the National Heart, Lung and Blood Institute. It is battery operated and connects to the heart with thin wires, states the American Heart Association.
If an implantable cardiac defibrillator detects an abnormal heart rhythm, it delivers an electric shock to restore a normal heartbeat, explains the American Heart Association. It is useful in preventing abrupt death in patients suffering from fibrillation or sustained ventricular tachycardia. Only patients with life-threatening arrhythmia are typically considered candidates for implantable cardiac defibrillators. The doctor must also rule out correctable causes for these irregular heartbeats, such as drug toxicity, an electrolyte imbalance, myocardial ischemia and acute myocardial infarction.