Table 1.2. Classification of acute myocardial infarction according to triggering factors.

Classification (types)	Description
1	Spontaneous AMI related to myocardial ischemia secondary to a coronary event, such as rupture or erosion of coronary atherosclerotic plaque
2	AMI secondary to ischemia due to a myocardial oxygen supply/demand imbalance that is not directly related to coronary atherothrombosis
3	Sudden death with symptoms suggestive of ischemia accompanied by new ischemic changes in ECG or ventricular fibrillation before biomarkers are collected, if they are elevated, or in AMI confirmed by necropsy
4a	AMI associated with PCI ≤ 48 h, which is defined as a troponin increase > 5 times the 99th percentile of the upper reference limit or 20% over already elevated baseline levels, associated with one of the following findings: New ischemic change in ECG New pathological Q-wave in ECG Imaging results of a new change in contractility or loss of viable myocardium in a pattern consistent with myocardial ischemia Angiographic findings of complications related to coronary flow limitations (dissection, epicardial vessel occlusion, loss of collateral circulation and distal embolization)
4b	AMI associated with stent thrombosis confirmed by angiography or necropsy
4c	AMI related to intrastent or post-angioplasty restenosis without other lesions or intracoronary thrombi that can explain it
5	AMI associated with myocardial revascularization surgery ≤ 48 h, defined by a > 10-fold increase in the 99th percentile of the upper reference limit or 20% over already elevated baseline levels, associated with one of the following findings: New pathological Q-wave in ECG Imaging results of a new change in contractility or loss of viable myocardium in a pattern consistent with ischemic etiology Angiographic results showing the occlusion of a new graft or native coronary artery

Source: adapted from Thygesen K et al.⁴ AMI: acute myocardial infarction; ECG: electrocardiogram; PCI: percutaneous coronary intervention.