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, 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.