title: The role of the ECG in diagnosis, risk estimation, and catheterization laboratory activation in patients with acute coronary syndromes: a consensus document.
abstract: The electrocardiogram (ECG) is the most widely used imaging tool helping in diagnosis and initial management of patients presenting with symptoms compatible with acute coronary syndrome. Acute ischemia affects the configuration of the QRS complexes, the ST segments and the T waves. The ECG should be read along with the clinical assessment of the patient. ST segment elevation (and ST depression in leads V1 -V3 ) in patients with active symptoms usually indicates acute occlusion of an epicardial artery with ongoing transmural ischemia. These patients should be triaged for emergent reperfusion therapy per current guidelines. However, many patients have ST segment elevation secondary to nonischemic causes. ST depression in leads other than V1 -V3 usually are indicative of subendocardial ischemia secondary to subocclusion of the epicardial artery, distal embolization to small arteries or spasm supply/demand mismatch. ST depression may also be secondary to nonischemic etiologies, such as left ventricular hypertrophy, cardiomyopathies, etc. Knowing the clinical scenario, comparison to previous ECG and subsequent ECGs (in cases that there are changes in the quality or severity of symptoms) may add in the diagnosis and interpretation in difficult cases. This review addresses the different ECG patterns, typically seen in patients with active symptoms, after resolution of symptoms and the significance of such changes when seen in asymptomatic patients.
authors.affiliation: The Section of Cardiology, The Department of Medicine, Baylor College of Medicine, Houston, TX, USA.
authors.forename: Yochai
authors.initials: Y
authors.lastname: Birnbaum
authors.forename: Kjell
authors.initials: K
authors.lastname: Nikus
authors.forename: Paul
authors.initials: P
authors.lastname: Kligfield
authors.forename: Miguel
authors.initials: M
authors.lastname: Fiol
authors.forename: Jose Antonio
authors.initials: JA
authors.lastname: Barrabés
authors.forename: Alessandro
authors.initials: A
authors.lastname: Sionis
authors.forename: Olle
authors.initials: O
authors.lastname: Pahlm
authors.forename: J Garcia
authors.initials: JG
authors.lastname: Niebla
authors.forename: Antonio Bayès
authors.initials: AB
authors.lastname: de Luna
mesh_terms: D054058:Acute Coronary Syndrome / Q000175:diagnosis* / Q000503:physiopathology; D006328:Cardiac Catheterization; D004562:Electrocardiography; D006801:Humans; D018570:Risk Assessment; D014218:Triage
keywords: Acute coronary syndrome; ST depression; ST elevation; ischemia; myocardial infarction; noninvasive techniques-electrocardiography