Copyright 2008
Definition
Unstable angina is the clinical presentation of acute myocardial ischemia characterized by new onset chest pain within 1 month, chest pain at rest, chest pain lasting more than 20 minutes and not improving with nitroglycerin or chest pain more severe, more frequent and lasting longer than previously, without evidence of myocardial necrosis (no elevation of cardiac enzymes) and with or without EKG changes of ischemia. UA is a clinical diagnosis.