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.
Understand Heart Attack Heart attacks are caused by heart disease, which is the number one cause of death among both men and women in the United States. According to the American Heart Association, every year in the United States roughly 785,000 people will have their first heart attack.