Pre-Algebra on Khan Academy: No way, this isn't your run of the mill arithmetic. This is Pre-algebra. You're about to play with the professionals. Think of pre-algebra as a runway.
Heart attack - Causes. Heart attacks are caused by the blood supply to the heart being suddenly interrupted. Without this supply, heart muscles may be damaged and begin to die. Without treatment, the heart muscles will experience irreversible damage.
Other causes of early heart attacks in men include abnormalities of one or more arteries, blood clots that form elsewhere and are carried to the coronary arteries, disorders of the clotting system, spasm or inflammation of the arteries, chest trauma, and drug abuse.