The formal definitions of a STEMI are the following:

New J point elevation, in the absence of LBBB and LVH of:

• Greater than or equal to 1 mm in at least 2 contiguous leads EXCEPT leads V2 and V3
• Leads V2-V3 require:
  • greater than or equal to 2.5 mm in men less than 40
  • greater than or equal to 2 mm in men over 40
  • greater than or equal to 1.5 mm in women

• Inferobasal STEMI’s (previously known as posterior infarcts):
  • Isolated ST depression greater than or equal to 0.5 mm in leads V1-V3
  • especially when the terminal T wave is positive
  • If these are present, STEMI is confirmed by STE in posteror leads (V7-V9), which should be obtained:
    • STE greater than or equal to 0.5 mm or
    • STE greater than or equal to 1 mm in men < 40

• Reference:
  • Govea A, et al. Interv Cardiol Clin. 2021 Jul;10(3):293:306.