features:
# it occurs at rest (or with minimal exertion), usually lasting more than 10 minutes
# it is severe and of new-onset (i.e., within the prior 4-6 weeks)
# it occurs with a crescendo pattern (i.e., distinctly more severe, prolonged, or frequent than before).

UA may occur often unpredictably and even at rest, which may be a serious indicator of an impending heart attack. The primary factor differentiating unstable angina from stable angina (other than symptoms) is the underlying