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. 2024 Feb 12;65(2):111–118. doi: 10.4103/singaporemedj.SMJ-2023-039

Table S1.

Classification of Myocardial Infarction (MI)

a) 4th Universal Definition of MI: aetiological classification (1)

Category Description MI criteria Treatment

Troponin criteria Supporting Evidence of Myocardial Ischaemia
Type 1 MI Spontaneous MI due to primary coronary occlusion from acute plaque rupture, erosion causing coronary artery thrombosis > 20% rise and/or fall of troponin levels with at least one value > 99th percentile of upper reference limit Clinical symptoms of myocardial ischaemia; new ischaemic ECG changes; imaging evidence of new regional wall motion abnormalities or new loss of viable myocardium or angiographic finding of intra-coronary thrombus Coronary revascularisation, guideline-directed medical therapy (DAPT +/- heparin, ACEIs, BBs, statins)
Type 2 MI Secondary to a clinical event that causes myocardial oxygen supply/demand mismatch (e.g. anaemia, hypotension/hypertension, cardiac arrhythmias, sepsis) > 20% rise and/or fall of troponin levels with at least one value > 99th percentile of upper reference limit Clinical symptoms of myocardial ischaemia; new ischaemic ECG changes; imaging evidence of new regional wall motion abnormalities or new loss of viable myocardium Treat underlying cause of myocardial ischaemic imbalance, consider judicious use of BBs to reduce myocardial oxygen demand
Type 3 MI Sudden cardiac death (e.g. cardiac arrest) based on clinical symptomatology, electrocardiographic findings or presence of new coronary artery thrombus identified by angiography or at postmortem examination, without the availability of cardiac biomarkers Not applicable Clinical symptoms of myocardial ischaemia; new ischaemic ECG changes or presence of ventricular fibrillation; postmortem analyses revealing intra-coronary thrombus Not applicable
Type 4 MI 4a - MI occurring within 48 hours of PCI > 20% rise in post- procedural troponins to at least 5x upper reference limit New ischaemic ECG changes; imaging evidence of new regional wall motion abnormalities or new loss of viable myocardium; angiographic finding of post-procedural flow-limiting complication (coronary thromboembolism, dissection) Same as for type 1 MI
4b - MI due to coronary in-stent thrombosis (acute -> 0 to 24 hours, subacute - >24 hours to 30 days, late - >30 days to 1 year, very late - more than 1 year) Same as for type 1 MI Same as for type 1 MI Same as for type 1 MI
4c - MI due to coronary in- stent re-stenosis Same as for type 1 MI Same as for type 1 MI Same as for type 1 MI
Type 5 MI MI after CABG surgery > 20% rise in post- procedural troponins to at least 10x upper reference New ischaemic ECG changes; imaging evidence of new regional wall motion abnormalities; angiographic finding of either graft vessel or native coronary artery occlusion Same as for type 1 MI

*ACEIs: ACE inhibitors; BBs: beta blockers; CABG: coronary artery bypass graft; DAPT: dual antiplatelet therapy; MI: myocardial infarction; PCI: percutaneous coronary intervention