realizes part of occurrent angina pectoris unstable angina pectoris An angina that worsens. It has at least one of these three features: 1. it occurs at rest (or with minimal exertion), usually lasting >10 min 2. it is severe and of new onset (i.e., within the prior 4–6 weeks) 3. it occurs with a crescendo pattern (i.e., distinctly more severe, prolonged, or frequent than before). acute coronary syndrome acute disease course