Sudden cardiac arrest (SCA) is an event caused by a problem with the heart's "electrical" system. SCA occurs when the heart suddenly stops beating. The heart’s electrical system sends signals to the heart to beat much too fast. The heart cannot beat that fast, so the heart muscle just quivers. Blood and oxygen do not reach vital organs like the brain. Then it stops altogether. The heart needs immediate treatment from an electrical shock (defibrillation) to restart the electrical system. If SCA is not treated within 7-10 minutes, it leads to sudden cardiac death.