Q: How many types of Myocardial Infarction (MI) has been defined?


Answer:  Five

According to Joint Task Force of the European Society of Cardiology, American College of Cardiology Foundation, the American Heart Association, and the World Heart Federation, MI can be subtyped into five categories according to their cause

Type 1 - MI due to to a pathologic process in the wall of the coronary artery like plaque erosion, fissuring, or dissection.

Type 2 -  MI consequent to increased oxygen demand or decreased supply 

Type 3 -  Sudden unexpected cardiac death before biomarkers could be checked

Type 4a  - MI related to PCI

Type 4b  - MI related to stent thrombosis

Type 5 - MI related to CABG


Reference: 

1. Thygesen K, Alpert JS, White HD, Joint ESC/ACCF/AHA/WHF Task Force for the Redefinition of Myocardial Infarction. Universal definition of myocardial infarction. Eur Heart J 2007; 28:2525.

2. Thygesen K, Alpert JS, Jaffe AS, et al. Third universal definition of myocardial infarction. Circulation 2012; 126:2020.