Modified Sgarbossa Criteria (Smith)
Apply the modified Sgarbossa criteria (Smith) for diagnosing acute myocardial infarction in the presence of left bundle branch block or a ventricular paced rhythm.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Concordant ST elevation >= 1 mm in any lead
- Yes
Result: Positive (concordant ST elevation >=1 mm in at least one lead).
The tool opens with these values already filled in. Replace them with your own.
What the result means
- >=3
- Highly specific for acute myocardial infarction in the setting of LBBB or paced rhythm.
- 0-2
- Does not rule out MI; the modified Sgarbossa criteria may add sensitivity per source.
What you enter
- Concordant ST elevation >= 1 mm in any lead
- Concordant ST depression >= 1 mm in V1-V3
- ST/S ratio <= -0.25 with discordant ST elevation >= 1 mm
What this is
The three findings are: concordant ST elevation >=1 mm in any lead, concordant ST depression >=1 mm in V1-V3, and discordant ST elevation with an ST/S ratio <=-0.25 in any lead. Sophie Well presents each criterion as a checkbox and reports positive when any single finding is present. Source: Smith SW et al. Ann Emerg Med 2012;60:766-776.
When to use it
Use this when an ED or inpatient ECG shows LBBB or a paced rhythm and the clinical picture (ischemic chest pain, hemodynamic instability, or troponin elevation) raises the question of acute coronary occlusion. The original Sgarbossa rule had high specificity but poor sensitivity; the Smith-modified version replaces the discordant ST-elevation cutoff with the ST/S ratio and substantially improves sensitivity for occlusion MI without sacrificing specificity. A positive screen should prompt the same activation pathway as ST-elevation MI on a non-LBBB tracing.
How this is calculated
Smith SW et al. Modified Sgarbossa criteria. Ann Emerg Med 2012;60:766-776. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.
More in Cardiology.