Angina pectoris is a symptomatic condition of attacks of chest pain, often debilitating. It is caused by a decreased supply of blood to the heart, such as that which might occur in coronary artery disease. The usual treatment of angina pectoris is designed to relieve the symptoms. It includes avoidance of activities that produce the discomfort and the use of nitroglycerin and beta blocking drugs. Soon after the introduction of coronary bypass surgery, many doctors enthusiastically adopted this approach in treating patients with unstable angina.