Heberden was the first to describe the clinical presentation of a patient with unstable angina in 1772.Since that time, the syndrome has been refined, but the clinical features remain 1 of 2 forms of angina requiring hospitalization, (i.e., worsening angina [crescendo] and new onset of prolonged angina, usually recurring rest angina).Many have contributed to the understanding of therapy of acute coronary syndromes.Patients are not homogeneous.Patients can be risk stratified based on simple clinical parameters as well as cardiac markers and ventricular function.Numerous randomized clinical trials have improved management strategies and understanding of the pathologic and pathophysiologic mechanisms responsible for acute coronary syndromes.The weight of evidence favors aggressive medical therapy plus revascularization; however, judgment is still necessary for clinical decision making in the individual patient and is based on several factors.These factors include clinical presentation, electrocardiogram (ECG) changes, serum cardiac markers, known risk factors, extent of ischemia, ventricular function, and the nature of the coronary artery disease determined by coronary angiography.