Subtle Anterior STEMI Calculator (4-Variable)
Differentiates normal variant ST elevation (benign early repolarization) from anterior STEMI, more sensitive than 3-variable version.
Note: this calculator replaces the older 3-variable version and is recommended by MDCalc and Dr. Stephen Smith. Before using this calculator, make sure the EKG shows ≥1 mm ST elevation (STE) in ≥1 of the precordial leads V2-V4. If it shows any one of the following, then it is NOT normal variant, and is very likely to be LAD occlusion; such cases were excluded from the study as "obvious" MI:
- >5 mm STE.
- Non-concave STE.
- Inferior reciprocal changes.
- Anterior ST depression.
- Terminal QRS distortion in V2 or V3:
- Q waves in any of V2 to V4.
- Any T wave inversion from V2 to V6.
Advice
- Cath lab activation is appropriate in Smith-positive patients, in the proper clinical context. At the very least, it should prompt very frequent serial EKGs and echocardiography.
- The formula is best used to identify patients with LAD occlusion initially thought to have normal variant early repolarization.
- If results indicate negative for STEMI, proceed with caution if STEMI was otherwise suspected.