Sgarbossa Criteria Calculator (MI in LBBB)
The Sgarbossa criteria help diagnose acute myocardial infarction when a left bundle branch block obscures the usual ST changes. Three ECG findings carry weighted points — concordant ST elevation (5), concordant ST depression in V1–V3 (3), and discordant ST elevation of 5 mm or more (2). A total of 3 or more is highly specific for acute MI.
Quick answer
The Sgarbossa criteria add weighted points for three ECG findings in left bundle branch block: concordant ST elevation of 1 mm or more (5 points), concordant ST depression of 1 mm or more in V1–V3 (3 points), and discordant ST elevation of 5 mm or more (2 points). A total of 3 or more is highly specific for acute myocardial infarction, but a low score does not rule it out.
ECG criteria (in left bundle branch block)
Score < 3 — criteria not met (does not rule out MI)
The Sgarbossa score is 0/10: score < 3 — criteria not met (does not rule out mi). A total of 3 or more is highly specific for acute MI in left bundle branch block.
The criteria are specific but not very sensitive, so a score under 3 does not rule out an MI. This tool reports the original weighted Sgarbossa score (the modified Smith rule uses a proportion instead of the 5 mm criterion). A clinician interprets the full ECG.
How to use the Sgarbossa calculator
- 1Review the ECG in LBBB. With a known or new left bundle branch block, look for the three Sgarbossa findings.
- 2Tick the criteria present. Tick concordant ST elevation (5), concordant ST depression in V1–V3 (3), and discordant ST elevation of 5 mm or more (2) as they apply.
- 3Read the score. The tool totals the points. A score of 3 or more meets the criteria and is highly specific for acute MI. A clinician interprets the ECG in full.
Medical disclaimer: This is general health information, not medical advice. It does not diagnose or treat any condition, and the results are estimates based on public reference formulas. Always consult a qualified doctor about your individual health. If you think you may have a medical emergency, contact your local emergency services immediately.
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Book a consultationFrequently asked questions
What Sgarbossa score is positive?⌄
A total of 3 or more is considered positive and is highly specific for acute myocardial infarction in left bundle branch block. Because the criteria are not very sensitive, a score under 3 does not exclude an MI.
What is the modified (Smith) Sgarbossa rule?⌄
The modified rule replaces the absolute 5 mm discordant-elevation criterion with a proportion (ST elevation 25% or more of the preceding S-wave depth), which improves sensitivity. This tool reports the original weighted Sgarbossa score.
Do the Sgarbossa criteria apply to paced rhythms?⌄
They were derived in left bundle branch block. Modified versions have been studied in ventricular-paced rhythms, but a clinician should interpret paced ECGs with that context in mind.
Is my data stored?⌄
No. The calculator runs entirely in your browser; nothing you enter is sent to a server.
Sources & validation
This calculator reproduces the published Sgarbossa score, validated for diagnosis of acute myocardial infarction in left bundle branch block.
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