MYOCARDIAL INFARCTION

HARIKRISHNA.S512

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At the end of session each student should be able to:-Define Myocardial infarctionExplain causes of Myocardial infarctionList the Pre-disposing factors of Myocardial infarctionDescribe the pathophysiology of Myocardial infarctionMention sign and symptoms of Myocardial infarction

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Normal Heart

Myocardial infarction is commonly known as a heart attack, “Myo” means muscle “cardial” pertains to the heart and “infarction” means death of tissue due to lack of blood supply.

The heart like any organ requires blood for oxygen and other nutrients, so it can do its work.

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Coronary Arteries for the heartCoronary Arteries for the heart

Myocardial infarction (MI) or heart attack is a medical emergency condition in which the blood supply to the heart suddenly reduces or stop, causing the myocardium to die from lack of oxygen.

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Heart is the main organ in cardiovascular system, which includes different types of blood vessels.

Some of the most important vessels in your body are the Coronary arteries. They take blood, rich in oxygen, to every location in the body.

When arteries become blocked or restricted by buildup, they can cause blood flow to stop or decrease significantly.

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Several factors may cause a heart attack:Bad Cholesterol: - Also called low-density lipoprotein (LDL), is

one of the leading problems that cause blockage.

Cholesterol can stick to the walls of the arteries and produce plaque. Plaque is a hard matter that blocks blood flow in the arteries.

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Saturated Fats (found mostly in meat):- May contribute to the buildup of plaque in the

coronary arteries. Saturated fat may lead to acute myocardial

infarction by increasing the amount of bad cholesterol in the blood system and reducing the good HDL (high-density lipoprotein) cholesterol.

Certain risk factors may make to susceptible forheart attack which includes:-

High Blood PressureObesityDiabetes or High Blood SugarSmokingOverweightExcessive alcohol intakeStress

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The most common cause of an MI is a blood clot (thrombosis) that forms inside a coronary artery, or one of its branches.

This blocks the blood flow to a part of the heart.

Blood clots do not usually form in normal arteries. However, a clot may form if there is some atheroma within the lining of the artery.

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Atheroma is like fatty patches or plaques that develop within the inside lining of arteries. (This is similar to water pipes that get furred up.)

Plaques of atheroma may gradually form over a number of years in one or more places in the coronary arteries.

Each plaque has an outer firm shell with a soft inner fatty core.

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What happens is that a crack develops in the outer shell of the atheroma plaque. This is called plaque rupture.

This exposes the softer inner core of the plaque to blood.

This can trigger the clotting mechanism in the blood to form a blood clot. Therefore, a build-up of atheroma is the root problem that leads to most cases of Myocardial Infarction.

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The diagram below shows four patches of atheroma as an example. However, atheroma may develop in any section of the coronary arteries.

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