unstable angina

A form of pain that is prodromal to acute myocardial infarction. It typically has a sudden onset, sudden worsening, and stuttering recurrence over days and weeks. It carries a more severe short-term prognosis than stable chronic angina. Nearly one-third of unstable angina patients experience myocardial infarction within 3 months of the first episode.

Angina pectoris characterized by pain of coronary origin that occurs in response to less exercise or other stimuli than usually required to produce pain.