The term CARDIAC ARREST is a medical emergency in which the heart suddenly stops beating. It is caused by an electrical malfunction in the heart that disrupts its normal rhythm. If not treated immediately, it can lead to death. Cardiac ARREST is a leading cause of death in the United States and other countries. Treatment for cardiac ARREST includes cardiopulmonary resuscitation (CPR) and defibrillation, which is the use of an electric shock to restore the heart's normal rhythm.