Oxygen in the blood cannot reach the heart muscle and the heart muscle is damaged. In contrast, sudden cardiac arrest occurs because of an electrical problem in the heart. Just like a water pump needs an energy force to make it work, the heart's pumping mechanism is powered by electrical signals. During sudden cardiac arrest, the electrical system to the pump suddenly becomes irregular. Of greatest concern in the first few minutes is that blood flow to the brain will be reduced so drastically, a person loses consciousness.
Death follows unless emergency treatment is begun.
There are no prior symptoms of sudden cardiac arrest. However, these risk factors have been identified as increasing the potential for sudden cardiac arrest. An external defibrillator is needed to restart the heart. After the heart is in a normal rhythm, medications and an implantable defibrillator may be prescribed.