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.
Heart Attack Causes. Most heart attacks are the result of coronary heart disease, a condition that clogs coronary arteries with fatty, calcified plaques. In the early 1980s, researchers confirmed that the immediate cause of nearly all heart attacks is not the obstructive plaque itself.ost heart attacks are the result of coronary heart disease, a condition that clogs coronary arteries with fatty, calcified plaques. In the early 1980s, researchers confirmed that the immediate cause of nearly all heart attacks is not the obstructive plaque itself.