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.
The most common cause of a heart attack (myocardial infarction) is a blood clot that lodges in an artery and blocks blood flow to the heart muscle.This often causes a painful pressure, cramping or squeezing sensation in the chest. The discomfort can refer from your chest into your back.he most common cause of a heart attack (myocardial infarction) is a blood clot that lodges in an artery and blocks blood flow to the heart muscle.