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 is a major cause of heart attacks. Heart attacks can also be caused by blood clots that form as a result of the use of certain prescription drugs (Vioxx, Bextra, Celebrex and Zelnorm) that thicken the blood, making it stickier and more likely to clot.