Myocardial infarction (MI) means that part of the heart muscle suddenly loses its blood supply. Without immediate treatment, this can lead to damage to the affected part of the heart. An MI is often called a heart attack or a coronary thrombosis.

The heart pumps blood into arteries (blood vessels) which take the blood to every part of the body. The heart muscle, like all muscles, always needs a good blood supply. The coronary arteries take blood to the heart muscle. The main coronary arteries branch off from the aorta. (The aorta. is the large artery that takes oxygen-rich blood from the heart chambers to the body.) The main coronary arteries divide into smaller branches then take blood to all parts of the heart muscle.

If someone has an MI, a coronary artery, or one of its smaller branches is suddenly blocked. The part of the heart muscle supplied by this artery loses its oxygen and blood supply. This part of the heart muscle is at risk of dying, unless the blockage is quickly undone. The word ‘infarction’ means death of some tissue due to a blocked artery which stops blood from getting past.

If one of the main coronary arteries is blocked, a large part of the heart muscle is affected. If a smaller branch artery is blocked, a smaller amount of heart muscle is affected. In people who survive an MI, the part of the heart muscle that dies (‘infarcts’) is replaced by scar tissue over the next few weeks.

A small MI occasionally happens without causing pain (a ‘silent MI’). It may be pain-free, or sometimes the pain is mild and you may think it is only heartburn or ‘wind’. Collapse and sudden death may occur with a large or severe MI.

MI’s are easier to diagnose these days due to the increase in technology advances. They may become avoidable through greater education and healthier choices in lifestyle.