Sudden cardiac arrest is the sudden, unexpected loss of heart function, breathing and consciousness. Sudden cardiac arrest usually results from an electrical disturbance in your heart that disrupts its pumping action and causes blood to stop flowing to the rest of your body.
Sudden cardiac arrest is different from a heart attack, which occurs when blood flow to a portion of the heart is blocked, depriving the heart muscle of necessary oxygen. Like a heart attack, however, sudden cardiac arrest almost always occurs in the context of other underlying heart problems, particularly coronary artery disease.
Sudden cardiac arrest is a medical emergency. If not treated immediately, it is fatal, resulting in sudden cardiac death. With fast, appropriate medical care, survival is possible. Administering cardiopulmonary resuscitation (CPR) — or even just rapid compressions to the chest — can improve the chances of survival until emergency personnel arrive.