Angina pectoris is a severe chest pain which is caused by a lack of blood and hence oxygen supply to the myocardium, generally due to obstruction or spasm of the coronary arteries. This lack of blood supply is called ischemia. Coronary artery disease, the main cause of angina, is due to atherosclerosis of the cardiac arteries. The Latin word angina means "infection", and the Latin pectus "chest". There is a weak relationship between severity of pain and degree of oxygen deprivation in the heart muscle. Major risk factors for angina include cigarette smoking, diabetes, high cholesterol, high blood pressure, sedentary lifestyle and family history of premature heart disease.
Most patients suffering form angina pectoris complain at the beginning of chest discomfort rather than actual pain, such as a pressure, heaviness, tightness, squeezing, burning, or choking sensation. Apart from chest discomfort, anginal pains may also be experienced in the epigastrium (upper central abdomen). Ischemia of the myocardium arises when the the heart muscles receive insufficient blood and oxygen to function normally. This inadequate perfusion of blood and the resulting reduced delivery of oxygen and nutrients is directly correlated to blocked or narrowed blood vessels.