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 heart disease. Coronary heart disease (CHD) is the leading cause of heart attacks. CHD is a condition in which the coronary arteries (the major blood vessels that supply the heart with blood) get clogged up with deposits of cholesterol. These deposits are called plaques.
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.