The time and mode of death are unexpected. Cardiac arrest occurs instantly or shortly after symptoms appear. If the heart’s electrical impulses suddenly become chaotic, blood flow to the brain stops abruptly. The victim then collapses and quickly loses consciousness. Death usually follows unless a normal heart rhythm is restored within minutes. An AED is the only effective treatment for restoring a regular heart rhythm during sudden cardiac arrest and is an easy-to-operate tool for someone with no medical background.

Although a heart attack may cause cardiac arrest and sudden death, the term does not mean the same thing. Heart attacks are caused by a blockage that stops blood flow to the heart and not necessarily resulting in the death of the victim. Most heart attacks involve discomfort in the center of the chest that lasts more than a few minutes, or that goes away and comes back. It can feel like uncomfortable pressure, squeezing or pain.