It is important to understand all the indications for emergent cath lab activation and the ECG patterns suggestive of occlusion MI.
Remember, the widely used "classic STEMI criteria" are simply not sensitive enough to rule out all types of occlusion MI!


Classic STEMI ECG criteria:

Fourth Universal Definition of MI (Thygesen et al., 2018):

New or presumed new, ST-segment elevation (STE) ≥ 1.0 mm (measured at the J-point in 2 contiguous leads) is required in all leads (except V2, V3, V3R, V4R, V7-V9)

Leads V2 & V3 are sex and age specific:

  • Women: ≥ 1.5 mm

  • Men ≥ 40 years old: ≥ 2.0 mm

  • Men < 40 years old: ≥ 2.5 mm

Right sided leads V3R & V4R (RV STEMI)

  • Women: ≥ 0.5 mm

  • Men ≥ 30 years old: ≥ 0.5 mm

  • Men < 30 years old: ≥ 1.0 mm

Posterior leads V7-V9 (Posterior STEMI)

  • Women: ≥ 0.5 mm

  • Men ≥ 40 years old: ≥ 0.5 mm

  • Men < 40 years old: ≥ 1.0 mm


Measure your ST segments accurately! The criteria state that ST elevation is measured at the J-Point, relative to the QRS onset (PQ junction). However, in patients with a stable baseline, the TP segment is a more accurate method to evaluate the magnitude of ST-segment deviation. Tachycardia and baseline shift can make this determination difficult.


Thygesen K, Alpert JS, Jaffe AS, et al. Fourth Universal Definition of Myocardial Infarction (2018). J Am Coll Cardiol 2018;72(18):2231–64. PMID: 3015396

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