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, heart attack, and high blood pressure are the main causes and risk factors of heart failure. Other diseases that damage or weaken the heart muscle or heart valves can also cause heart failure. Heart failure is most common in people over age 65, African-Americans, and women.oronary artery disease is the end result of a complex process called atherosclerosis (commonly called hardening of the arteries). It is the most common cause of heart attack and involves the build-up of unhealthy cholesterol in the arteries, with inflammation and injury in the cells of the blood vessels.