Heart Attack – What is a Heart Attack? | Heart Attack Definition | Heart Attack Overview
The heart is a muscle like any other in the body. It needs blood flow to supply oxygen to allow it to do work. When there isn’t enough oxygen, the muscle starts to suffer, and when there is no oxygen, the muscle starts to die.Heart muscle gets its blood supply from arteries that start in the aorta and run on the surface of the heart, known as the coronary arteries. The right coronary artery supplies the right ventricle of the heart and the inferior (lower) portion of the left ventricle. The left anterior descending coronary artery supplies the majority of the left ventricle, while the circumflex artery supplies the back of the left ventricle.
Myocardial infarction (MI) or acute myocardial infarction (AMI), commonly known as a heart attack, is the interruption of blood supply to part of the heart, causing heart cells to die. This is most commonly due to occlusion (blockage) of a coronary artery following the rupture of a vulnerable atherosclerotic plaque, which is an unstable collection of lipids (fatty acids) and white blood cells (especially macrophages) in the wall of an artery. The resulting ischemia (restriction in blood supply) and oxygen shortage, if left untreated for a sufficient period of time, can cause damage or death (infarction) of heart muscle tissue (myocardium).
A heart attack occurs when the blood supply to part of the heart muscle itself — the myocardium — is severely reduced or stopped. The reduction or stoppage happens when one or more of the coronary arteries supplying blood to the heart muscle is blocked. This is usually caused by the buildup of plaque (deposits of fat-like substances), a process called atherosclerosis. The plaque can eventually burst, tear or rupture, creating a “snag” where a blood clot forms and blocks the artery. This leads to a heart attack.
If the blood supply is cut off for more than a few minutes, muscle cells suffer permanent injury and die. This can kill or disable someone, depending on how much heart muscle is damaged.
Sometimes a coronary artery temporarily contracts or goes into spasm. When this happens the artery narrows and blood flow to part of the heart muscle decreases or stops. We’re not sure what causes a spasm. A spasm can occur in normal-appearing blood vessels as well as in vessels partly blocked by atherosclerosis. A severe spasm can cause a heart attack.
The medical term for heart attack is myocardial infarction. A heart attack is also sometimes called a coronary thrombosis or coronary occlusion.
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- Left Circumflex Artery Blockage
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- left ventricle blockage

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