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.
No. But a heart attack can cause a cardiac arrest. Heart attacks are caused by a blockage that stops blood flow to the heart. Cardiac arrest is caused when the heart's electrical system malfunctions.