MDCalc

Modified Sgarbossa's Criteria for MI in Left Bundle Branch Block

Diagnoses acute MI in patients with prior LBBB.

Concordant ST elevation ≥1 mm in leads with a positive QRS complex
Concordant ST depression ≥1 mm in V1-V3
ST Elevation at the J-point, relative to QRS onset, is at least 1 mm AND has an amplitude at least 25% of the preceding S-wave
An ST/S ratio of 0.20 is also very high and almost as specific as a 0.25 ratio

Result:

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Advice
  • Positive result: Strongly consider initiating standard MI treatment, including immediate reperfusion therapy options (e.g., PCI), based on clinical context and in consultation with cardiology.
  • Negative result: If MI suspicion remains, pursue further assessment with serial ECGs, cardiac biomarkers, and potentially imaging (e.g., echocardiography to evaluate wall motion abnormalities).
  • This tool is best applied alongside clinical judgment, specialist input, and additional indicators, such as cardiac biomarkers. 
  • Sensitivity may improve with serial ECGs or comparison to previous ECGs.
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