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.
1 Atherosclerosis is also the most common cause of heart disease and heart attack. 2  High blood pressure: High blood pressure puts stress on the wall of the aorta. 3  Over many years, this stress can lead to bulging of the blood vessel wall. 4  This is the leading factor in development of aneurysms of the thoracic aorta.