Myocardial infarction

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Myocardial infarction
Classification and external resources

Heart attack
ICD-10 I21.-I22.
ICD-9 410
DiseasesDB 8664
MedlinePlus 000195
eMedicine med/1567 emerg/327 ped/2520
MeSH D009203

An acute myocardial infarction, also known as a heart attack, is when a blood vessel within the heart suddenly becomes blocked, and the flow of oxygenated blood to part of the heart is stopped. The most common cause of the block are blood clots. If the blood flow is not restored quickly, the muscle in that area of the heart begins to die.

Heart attacks most often happen as a result of coronary heart disease. In coronary heart disease a wax-like substance called plaque begins to accumulate on the inside walls of arteries within the heart; this is called atherosclerosis. Plaque is made of cholesterol and other cells. This plaque build-up usually occurs over a period of time, making the interior of the blood vessel narrower. The plaque deposit restricts the flow of blood and may cause blood platelets to begin accumulating in front of the plaque deposit forming a clot. If the clot breaks free and gets stuck in the area of the blood vessel made narrower by the plaque, a heart attack happens.

A myocardial infarction is considered a medical emergency. The first few minutes can be essential for the survival of a patient; within the first hour, there are good chances to reverse some of the damage done. The most common symptom is strong pains in the chest. The pain may also be present in the shoulders, the belly, and the jaws. In contrast to angina pectoris, a myocardial infarction always damages the heart muscle.

Most heart attacks are a result of coronary heart disease, which is one of the cardiovascular diseases (CVD). Cardiovascular disease is the number one cause of death in the world, and coronary heart disease is the deadliest CVD, followed by stroke. Most cases of coronary heart disease, which leads to heart attacks are a result of persons behaviors and lifestyle. This includes eating unhealthy foods, not exercising, smoking cigarettes and drinking too much alcohol.

Symptoms[change | change source]

Heart attack
(myocardial infarction)
Warning signs in women.
Coronary heart disease: Plaque builds up in blood vessels in the heart making them narrow,
Heart attack: in this instance, a blood clot suddenly gets stuck in one of the narrow blood vessels.

Signs that a person is having a heart attack become visible over several minutes, and rarely come immediately. Most people having a heart attack experience chest pain. Chest pain can be caused by ischaemia (a lack of blood and oxygen) of the heart muscle; this is called angina pectoris. Pain can often also be felt in the left arm, and sometimes in the lower jaw, the neck, the right arm, the back, and in parts of the abdomen.

Many women have different symptoms than men. The most common symptoms include shortness of breath, weakness, and feeling tired. Some women feel tired, do not sleep properly, and experience shortness of breath for up to a month before they have a heart attack.

Treatment[change | change source]

The animation shows how plaque buildup or a coronary artery spasm can lead to a heart attack and how blocked blood flow in a coronary artery can lead to a heart attack.

A heart attack is a medical emergency that needs to be taken care of as quickly as possible. The ultimate goal of the management in the acute phase of the disease is to save as much myocardium as possible and prevent more complications. As time passes, the risk of damage to the heart muscle increases.

The treatments itself may have complications. If medics try to get the blood flowing again after only a few hours, the result is reperfusion injury instead of amelioration.[1] Other treatment modalities may also cause complications; the use of antithrombotics for example carries an increased risk of bleeding.

First aid[change | change source]

When a person starts experiencing symptoms of a myocardial infarction, they should seek emergency assistance as soon as they can. However, the average person waits about three hours before asking for help.[2] Having the person sit in certain positions can help minimize breathing difficulties. A half-sitting position with knees bent is often recommended. The person should also be given access to more oxygen. Aspirin, which reduces the amount of platelets in the blood, can help prevent more blood clots from forming inside the arteries and the heart.

References[change | change source]

  1. Faxon DP. "Coronary interventions and their impact on post myocardial infarction survival." Clin Cardiol 2005; 28(11 Suppl 1):I38-44. PMID 16450811
  2. Heart attack first aid. MedlinePlus. Retrieved December 3, 2006.