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Electrocardiogram in the prognosis of myocardial infarction or unstable angina

Ary L Goldberger, MD
Section Editor
Juan Carlos Kaski, DSc, MD, DM (Hons), FRCP, FESC, FACC, FAHA
Deputy Editor
Gordon M Saperia, MD, FACC


The electrocardiogram (ECG) is a mainstay in the diagnosis of acute and chronic syndromes due to coronary artery disease. The findings depend upon several key factors including the duration (hyperacute/acute versus evolving/chronic), extent (Q wave versus non-Q wave), and localization (anterior versus inferior-posterior and the size of the ischemic or infarcted region) of ischemia or infarction, as well as the presence of other underlying abnormalities [1]. The ECG also provides information on prognosis.

The use of the ECG for prognosis in myocardial infarction or unstable angina will be reviewed here. Use of the ECG for diagnosis is discussed separately. (See "Electrocardiogram in the diagnosis of myocardial ischemia and infarction".)

In addition to the findings on the ECG, a number of other parameters are of prognostic importance in patients with myocardial infarction or unstable angina. Among the poor prognostic factors are cardiogenic shock, a reduced left ventricular ejection fraction, and certain types of arrhythmias.

Clinicians need to be aware that the ECG findings due to atherosclerotic-related ischemia, including ST-T deviations and even Q waves, may be exactly simulated by those associated with acute “stress” (takotsubo) cardiomyopathy, as discussed separately. (See "Clinical manifestations and diagnosis of stress (takotsubo) cardiomyopathy".)


The process of risk stratification in a patient who has had an acute myocardial infarction (MI) has several components:


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Literature review current through: Sep 2016. | This topic last updated: Jun 23, 2014.
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