Angina is pain, discomfort, or pressure in the chest that is caused by ischemia, an insufficient supply of oxygen-rich blood to the heart muscle. It is sometimes also characterized by a feeling of choking, suffocation, or crushing heaviness. This condition is also called angina pectoris.
Often described as a muscle spasm and choking sensation, the term angina is used primarily to describe chest (thoracic) pain caused by insufficient oxygen to the heart muscle. An episode of angina is not an actual heart attack, but rather pain that results when the heart muscle temporarily receives too little blood. This temporary condition may be the result of demanding activities such as exercise and does not necessarily indicate that the heart muscle is experiencing permanent damage. In fact, episodes of angina seldom cause permanent damage to heart muscle.
Angina can be subdivided into two categories: angina of effort and variant angina.
Angina of effort
Angina of effort is a common disorder caused by the narrowing of the arteries (a condition called atherosclerosis) that supply oxygen-rich blood to the heart muscle. In the case of angina of effort, the coronary arteries can provide the heart muscle (myocardium) adequate blood during rest but not during periods of exercise, stress, or excitement. The resulting pain is relieved by resting or by administering nitroglycerin, a medication that relaxes the heart muscle, opens up the coronary blood vessels, and lowers the blood pressure—all of which reduce the heart's need for oxygen. Patients with angina of effort have an increased risk of heart attack (myocardial infarction).
Paula Ford-Martin, Teresa G. Odle, The Gale Group Inc., Gale, Detroit,