Myocardial infarction (MI) is a common cardiovascular disease and a leading cause of death worldwide. MI has different classification methods, which can be classified according to the disease phase, lesion range, electrocardiogram (ECG) expression, infarction location, and clinical type.

1 Disease Phase

(1) Acute MI (AMI): MI occurs within 28 days (related article: PMID:29083808);

(2) Old MI (OMI): also known as healed MI, prior MI or previous MI. Past MI diagnosed by ECG or other special investigation, but currently presenting no symptoms (related article: PMID:30153967);

(3) Subsequent MI: MI occurs again within 28 days after MI. It includes extension MI, and recurrent MI (related article: PMID:30153967).

2 Lesion Range

(1) Transmural MI: MI leads to the death of myocardial tissue from the endocardium to the epicardium (related article: PMID:11096506);

(2) Subendocardial MI: also known as non-transmural MI, a MI that involves the innermost layer and does not extend to the epicardium (related article: PMID:6723315).

3 Infarction Location

(1) Anterior MI: a MI with abnormal Q waves or QS waves in most of the chest leads (V1 ~ V5). It includes anterior, anteroapical, anterolateral, and anteroseptal MI (related article: PMID:13463910);

(2) Inferior MI: a MI with abnormal Q waves or QS waves in leads II, III, and aVF in the ECG. It includes diaphragmatic wall, inferior, inferolateral, and inferoposterior (related article: PMID:29262146);

(3) MI of other sites: including apical-lateral, basal-lateral, high lateral, lateral, posterior, posterobasal, posterolateral, posteroseptal, and septal MI.

4 ECG Expression

(1) ST elevation MI (STEMI): an MI with developing ST elevation in two contiguous leads. (related article: PMID:30335314);

(2) Non-ST elevation MI (NSTEMI): an MI without developing ST elevation in ECG. (related article: PMID:30020600);

5 Clinical Type

(1) Type I MI: a spontaneous MI caused by plaque erosion and/or rupture, fissuring, or dissection (related article: PMID:30153967);

(2) Type II MI: a MI related to ischemia, such as coronary palsy, anemia, arrhythmia,respiratory failure, high blood pressure or hypotension (related article: PMID:30153967);

(3) Type III MI: sudden cardiac death. A MI with ST-T wave changes in ECG, new complete left bundle branch block or coronary angiography or autopsy confirmed fresh thrombus, but without evidence of enzymology (related article: PMID:30153967);

(4) Type IV MI: a MI related with coronary angioplasty or stents

1) Type IVa: a MI related with percutaneous coronary intervention (PCI) (related article: PMID:30153967) ;

2)Type IVb: a MI related with stent thrombosis as documented by angiography or at autopsy (related article: PMID:30153967);

(5)Type V MI: a MI related with coronary artery bypass grafting (CABG) (related article: PMID:30153967).

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