Unstable angina is chest pain that occurs at rest or with less and
less exertion; the pain may become severe and last longer and it may not
respond to nitroglycerin or rest.
Unstable angina is a change from stable angina-a pattern of
predictable chest pain that is relieved by rest. Unstable angina is a warning
sign that blood flow to the heart has become more impaired and that a heart
attack may soon occur.
Unstable angina requires immediate medical evaluation.
