A heart attack (also known as a myocardial infarction)
occurs when the blood flow to part of the heart is interrupted. Blockage of
the coronary artery deprives the heart muscles of blood and oxygen, causing
injury to some of the heart muscles. This injury causes severe chest pain
and chest pressure sensation. If the flow of the blood is not restored
within 20 to 40 minutes, irreversible death of the heart muscle will begin
to occur. The muscles continue to die for six to eight hours at which the
heart attack is complete.
Causes of Heart Attack
Most of the heart attacks are result of coronary artery disease (CAD).The
coronary artery disease is build up over time with material called plaque on
the inner walls of the coronary arteries. Eventually, a section of plaque
can break open, causing a blood clot to form at the site. The heart attack
may occur if the clot becomes large enough to cut off most or all of the
blood flow through the artery.
Heart attack can also occur due to problems with the very small,
microscopic blood vessels of the heart. This condition is known as
microvascular disease. This condition is more common in women than in men.
Another cause of heart attack is a severe spasm (tightening) of a coronary
artery that cuts off blood flow. Most of the time it is not clear what
causes a coronary artery spasm, but it can be related to:










