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.
A heart attack is injury to the heart muscle caused by a loss of blood supply. While heart attacks can be caused by an unhealthy life style, lack of exercise, poor diet, and stress, recently, heart attacks have been linked to a number of defective drugs, including Vioxx, Bextra, Celebrex and Zelnorm.