Definitions - cardiac arrest or heart attack? Sudden cardiac arrest occurs when the heart fibrillates - a chaotic, abnormal electrical activity of the heart -- which causes the heart to quiver in an uncontrollable fashion.

The person loses consciousness very quickly and unless the condition is reversed, death follows in a matter of minutes. Heart attack, on the other hand, occurs when the blood supply to part of the heart muscle itself is severely reduced or stopped because of an obstruction in an artery. A heart attack can trigger sudden cardiac arrest, but they are not the same things.

Mixing up the terms "heart attack" and "cardiac arrest" is quite common. In the media, reporters often misreport people dying from a "massive heart attack." Chances are, the reporter is actually referring to sudden cardiac arrest.

Making the distinction is important because, while both heart attack and cardiac arrest are medical emergencies, a person suffering cardiac arrest literally has minutes to live and responding with an AED within those minutes will mean the difference between life and death for the victim. -
Source: American Heart Association, 1999