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.
Coronary artery disease. The most common underlying cause of heart attack is atherosclerosis, a condition in which a fatty substance called plaque builds up on the inside walls of blood vessels. When this occurs in the coronary arteries, it's known as coronary artery disease (CAD).
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.