Question – STEMI criteria are insensitive for all cases of acute coronary artery occlusion. Among patients with chest pain, what are the other criteria for cath lab activation?

Let’s talk more ACS.

Patients that need emergent reperfusion therapy are those that have an acute coronary occlusion. ECG findings of ST-elevation will not catch all cases of acute coronary artery occlusion, and may routinely miss 25-30% of cases of this process [3]. Acute coronary occlusion is dynamic and may manifest no ECG changes because the patient may be reperfusing, may be having an MI in electrocardiographically silent territory (e.g. high lateral MI, posterior MI) or there may be a small MI.

Which of these patients benefit from cath lab activation?

The most concise recommendations I’ve found are by Dr. Steven Smith in conjunction with EMCrit (EMCrit 146/147). For a nice review of all of the evidence, please refer to Pendell Meyers’s OMI Manifesto. Activate the cath lab for:

  1. Clear STEMIs + STEMI Equivalents De Winter’s T waves (prox LAD occlusion). Get a cath consult for Wellens.
  2. STEMI with Q waves – Q waves can develop within 1 hour of occlusion. Still require the cath consult.
  3. Subtle ST Elevations (get q5-15 min ecgs here) or depressions with intractable symptoms
  4. Posterior MI Depressions in V1-V4 – get posterior leads to evaluate for posterior MI
  5. RV Infarct – Inferior MI with elevation in V1. Get right sided leads.
  6. High Lateral MIs (look at example 3 for a subtle case) – any STE in AVL with reciprocal STD in inferior leads, esp lead III
  7. Hyperacute T waves – should clue you in of an impending acute coronary occlusion. Look for T waves that are proportionally large to the QRS. Get serial ECGs and a potassium level. Perform an echo to look or a wall motion abnormality.
  8. STE in AVR with diffuse ST Depressions – indicates L main or LAD insufficiency.
  9. LBBBs activate if any of the Sgarbossa Criteria are met.
  10. New RBBB + L Anterior Fasicular Block – associated with proximal LAD occlusions.
  11. NSTEMIs – call for patients that have refractory pain or hemodynamic/electrical instability despite maximal medical therapy (antiplatelet agents, antithrombotics, IV NTG)
  12. LVH look for concordant ST changes. Perform the echo to screen for a wall motion abnormality.
  13. LV Aneurysm v STEMI at least one lead must have a T-wave amplitude/QRS ratio > 0.36.

The cheatsheet.


  1. EmCrit 146-147 
  2. Dr. Smith’s ECG blog
  3. Emcrit – OMI Manifesto
  4. Rokos et al 2010 – Appropriate Cath Lab Activation
  5. Life In the Fast Lane for ECG examples
June 2024