An update of the existing comprehensive expert consensus on the definition of myocardial infarction (MI) incorporates recent developments in assays for biomarkers of myocardial necrosis.

As of this update, one of the following five sets of criteria must be met to confirm a diagnosis of MI:

a change (rise or fall) in cardiac biomarker (preferably cardiac troponin [cTn]) values, with at least one value higher than the 99th percentile upper reference limit (URL), and at least one of the following: ischemia symptoms, new ST-segment-T wave changes or new left bundle branch block (LBBB), pathological Q waves as detected on electrocardiogram (ECG), detection on imaging of a loss of myocardium or a regional wall-motion abnormality, or an intracoronary thrombus identified through angiography or at autopsy.

cardiac death occurring before biomarkers could increase or could be obtained but in the presence of symptoms of MI and a presumption of new ischemic ECG changes or new LBBB.

percutaneous coronary intervention-related MI, defined as elevated cTn values greater than five times the 99th percentile URL or a rise of more than 20% in cTn values and one of the following: symptoms of myocardial is-chemia, ischemic ECG changes, angiographic evidence of complication, or imaging showing a loss of myocardium or a new regional wall-motion abnormality.

stent thrombosis detected by coronary angiography or at autopsy with a change in cardiac biomarker values, with at least one above the 99th percentile URL.

coronary artery bypass grafting-related MI, defined as elevated cardiac biomarker values and one of the following: new pathological Q waves or LBBB, new graft or native coronary artery occlusion or a loss of myocardium or a regional wall-motion abnormality.

The consensus document also addresses the use of ECG to detect previous MIs, imaging techniques, recurrent MI, and more. It also notes that MI should be clearly defined in clinical trials to allow for appropriate interpretation and comparison across studies. The authors also recommend that educational materials and treatment guidelines be updated to align with the new MI definition.

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