An incident of angina differs to myocardial infarction. However, for those who suffer it, it can be difficult to distinguish between the two. Angina is a squeezing, repetitive pain in the chest, behind the sternum. Angina occurs when the heart muscle (myocardium) doesn't get as much blood (hence as much oxygen) as it needs for a given level of work. The pain is pronounced during exercise (e.g. walking up the stairs). Usually, the pain is relieved after a few minutes of rest or after the use of angina medicines (sublingual tablets). Anyone who suffers from angina is at higher risk of myocardial infarction.