Myocardial infarction

An angiography of a myocardial infarction: Right artery blocked (left), and reopened (right)

An acute myocardial infarction, also known as a heart attack, is a heart condition where blood cannot get to part of the heart. This causes cells in the heart to die and can cause the heart to fail. Most of the time, an artery in the heart is blocked by a blood clot. When this happens for more than about twenty minutes, the heart muscle is damaged.

The most common symptom is strong pains in the chest. The pain may also be present in the shoulders, the belly, and the mandible. In contrast to angina pectoris, a myocardial infarction always damages the heart muscle.

A myocardial infaction 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.

Symptoms

Chest pain has often been reported as a symptom. The areas shown dark red are those where the pain is felt more frequently; the areas in light red are those where fewer people reported feeling pain.

Signs that a person is having a heart attack become visible over several minutes, and rarely come straight away. 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

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. Other treatment modalities may also cause complications; the use of antithrombotics for example carries an increased risk of bleeding.

First aid

When a person starts experiencing symptoms of a myocardial infarction, many people wait three hours, on average, before asking for help when they should seek emergency assistance as soon as they can. Having the person sit in certain positions can help minimise 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.