Clinical implications of the Third Universal Definition of Myocardial Infarction

The definition of myocardial infarction (MI) continues to evolve as refined ECG criteria, more advanced imaging, and more sensitive and specific biomarkers are developed. The acceptance globally of a clinically practical standard definition for everyday practice would allow for better comparisons across clinical experiences and further facilitate research in this critical area. Because of the evolution of better diagnostic tools and more information about the value and limitations of previous definitions, there was a need to update the Universal Definition of MI published in 20071 and this has recently been accomplished.2 Great efforts were made by the taskforce that developed these guidelines to establish clinical criteria which correspond to the contemporary management of patients suspected of having MI. Therefore, a combination of clinical symptoms, cardiac biomarkers, and ECG changes indicative of myocardial ischaemia are central to the 2012 Third Universal Definition of MI. It stresses the importance of a careful clinical history of 20 min of ischaemic symptoms which may not be classical chest discomfort in all instances, an appreciation of the clinical setting (eg, in the critically ill), and careful interpretation of the ECG. Biomarkers are central to the diagnosis, and imaging has received more emphasis (box 1). Box 1 ### Definition of myocardial infarction (MI)