American College of Cardiology

BRAUNWALD ET AL., MANAGEMENT OF PATIENTS WITH UNSTABLE ANGINA AND NON-ST-SEGMENT ELEVATION MYOCARDIAL INFARCTION UPDATE
http://www.acc.org/clinical/guidelines/unstable/incorporated/index.htm

ACC/AHA 2002 Guideline Update for the Management of Patients With Unstable Angina and Non-ST-Segment Elevation Myocardial Infarction

A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on the Management of Patients With Unstable Angina)

Figure 1. Nomenclature of ACSs. Patients with ischemic discomfort may present with or without ST-segment elevation on the ECG. The majority of patients with ST-segment elevation (large arrows) ultimately develop a Q-wave AMI (QwMI), whereas a minority (small arrow) develop a non–Q-wave AMI (NQMI). Patients who present without ST-segment elevation are experiencing either UA or an NSTEMI. The distinction between these 2 diagnoses is ultimately made based on the presence or absence of a cardiac marker detected in the blood. Most patients with NSTEMI do not evolve a Q wave on the 12-lead ECG and are subsequently referred to as having sustained a non–Q-wave MI (NQMI); only a minority of NSTEMI patients develop a Q wave and are later diagnosed as having Q-wave MI. Not shown is Prinzmetal’s angina, which presents with transient chest pain and ST-segment elevation but rarely MI. The spectrum of clinical conditions that range from US to non–Q-wave AMI and Q-wave AMI is referred to as ACSs. Adapted from Antman EM, Braunwald E. Acute myocardial infarction. In: Braunwald EB, ed. Heart disease: a textbook of cardiovascular medicine. Philadelphia, PA: WB Saunders, 1997.