Heart Attack Causes
Heart attacks are caused by the blood supply to the heart being suddenly interrupted. Like all other tissues and organs in the body, the heart needs a constant supply of oxygen-rich blood. Without this supply, heart muscles may be damaged and begin to die. If this is not treated, heart muscles will experience irreversible damage. If a large portion of the heart is damaged in this way, the heart will stop beating (known as a cardiac arrest), resulting in death. A substance called plaque can build up in the walls of your coronary arteries. This plaque is made up of cholesterol and other cells.
A heart attack occurs when one or more of your coronary arteries become blocked. Over time, a coronary artery can narrow from the buildup of various substances, including cholesterol (atherosclerosis). This condition, known as coronary artery disease, causes most heart attacks.
During a heart attack, one of these plaques can rupture and spill cholesterol and other substances into the bloodstream. A blood clot forms at the site of the rupture. If large enough, the clot can completely block the flow of blood through the coronary artery.
Another cause of a heart attack is a spasm of a coronary artery that shuts down blood flow to part of the heart muscle. Use of tobacco and of illicit drugs, such as cocaine, can cause a life-threatening spasm. A heart attack can also occur due to a tear in the heart artery (spontaneous coronary artery dissection).
A tear in the plaque occurs. This triggers blood platelets and other substances to form a blood a clot at the site that blocks blood from flowing to the heart. This is the most common cause of heart attack.
A slow buildup of plaque may narrow one of the coronary arteries so that it is almost blocked.
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