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Also known as: Angina pectoris; Stable angina; Unstable angina; Variant angina; Prinzmetal's angina

What is angina?

Angina is a term for chest pain caused by an inadequate supply of blood and oxygen to the heart. More than 7 million people in the United States are thought to have angina. It is usually associated with the narrowed arteries found in coronary artery disease. This narrowing is caused by the buildup of plaques (thickenings in the lining) in the arteries, due to a process called atherosclerosis. With angina, the affected person's heart may get sufficient blood for daily activities, but the arteries may not be able to deliver adequate blood and oxygen during times of increased demand, such as exercise, emotional or physical stress, and extremes of temperature.

Thumbnail diagram of heart

There are three main types of angina:

  • Stable angina is characterized by predictable patterns of symptoms and periods of discomfort that occur during exercise or periods of stress. This pain is usually relieved with rest and/or treatment with nitroglycerin or another appropriate medication. Many people with this type of angina can live a relatively normal life for many years, but some will progress over time, or relatively rapidly, to unstable angina. Stable angina is caused by the slow buildup of plaque composed primarily of fibrosis (scar tissue).
  • Unstable angina, one of the acute coronary syndromes that includes heart attack, is characterized by a change in the pattern of angina episodes, occurring more frequently, at rest, and/or not responding to treatment. It is usually a sign that the person's condition is worsening. The pain someone experiences with unstable angina may be more severe and prolonged than that of stable angina. People with unstable angina are at increased risk of a heart attack, severe cardiac arrhythmia, and cardiac arrest. This is an acute emergency and should be evaluated and treated immediately. Unstable angina is caused by plaque that contains more lipid and debris than found in the plaque of people with stable angina. When some of this material leaks into the vessel, clots form.
  • Variant angina (Prinzmetal's angina) almost always occurs during periods of rest, usually at night. The cause is a spasm of a coronary artery. Many people who have this type also have severe atherosclerosis in at least one major blood vessel on the heart. It can also occur, although much less often, in people with heart valve disease or uncontrolled high blood pressure (hypertension), and may be seen with the use of cocaine and methamphetamines. This type of angina is caused by spasm of the arteries, temporarily narrowing them but without producing any permanent damage.

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