A heart attack (also called a myocardial infarction or MI) occurs when a clot forms in one of the heart's coronary arteries and blocks the blood supply to part of the heart muscle. The blood clot develops on a narrowing of the coronary artery caused by fat deposition called atherosclerosis or atheroma. The blockage destroys heart tissue and can be fatal if not treated within an hour or two.
The acute coronary syndrome (ACS) is a group of symptoms and signs including sudden chest pain which often spreads to the jaw, arm or shoulder caused by insufficient blood flow to heart muscle. Anyone with ACS should be taken to hospital as an emergency to find out whether the cause is a heart attack, unstable angina or a problem outside the heart. The tests done in patients presenting to hospital with a suspected heart attack often include an electrocardiogram (ECG) and measurement of heart muscle proteins in blood.
There are two main lines of treatment to restore the heart muscle’s blood supply after a heart attack: drugs to dissolve the clot and surgery called coronary angioplasty to widen the coronary artery.