The third version of the Universal Definition of
Myocardial Infarction (MI) was published in 2012. The diagnosis of acute
myocardial infarction (AMI) should only be made in a clinical setting consistent with acute myocardial ischaemia when evidence of myocardial
necrosis is present. The diagnostic criteria for MI are fulfilled when a rise and/or fall of cardiac
biomarkers (preferentially
troponins) occurs with at least one value above the 99th percentile of the upper reference limit. In addition, there should be symptoms of ischaemia, new changes in electrocardiogram (ECG), imaging evidence of a new loss of viable myocardium or new regional wall motion abnormality, or the identification of an intracoronary
thrombus by angiography or autopsy. This revised definition updates previous versions by including changes to diagnostic ECG criteria, placing a higher emphasis on cardiac imaging, modifying the criteria for subtypes of MI and implementing high sensitivity cardiac
troponin (
cTn) assays. A guideline-based algorithm for management of patients with suspected
acute coronary syndrome allowing "early rule-in" and "rule-out" of non-
STEMI with high sensitivity
cTn assays is also presented.