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 artery disease. The most common underlying cause of heart attack is atherosclerosis, a condition in which a fatty substance called plaque builds up on the inside walls of blood vessels. When this occurs in the coronary arteries, it's known as coronary artery disease (CAD).
Coronary artery disease causes most heart attacks and is the most common form of heart disease. The types of heart disease include: Atherosclerosis is a buildup of cholesterol, calcium and blood clotting material on the walls of the arteries. The material that builds up is called plaque.