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.
Heart attack - Causes. Heart attacks are caused by the blood supply to the heart being suddenly interrupted. Without this supply, heart muscles may be damaged and begin to die. Without treatment, the heart muscles will experience irreversible damage.
The most common causes of heart failure are: 1  coronary artery disease and heart attack (which may be silent) 2  cardiomyopathy. 3  high blood pressure (hypertension)  heart valve 1  disease. congenital heart disease.  alcoholism and drug abuse.