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.
Coronary artery disease, one type of heart disease, is the leading cause of heart attacks. The most common cause of coronary artery disease is atherosclerosis, a condition that occurs when plaque builds up in the arteries that supply blood to the heart.