Sgarbossa Criteria

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With left bundle branch block, expected ST/T changes include discordant ST depression and T wave inversion in the lateral leads (I, aVL, V5, V6). Discordance describe ST deviation in the opposite direction of the QRS complex (i.e., ST depression in leads with up-going QRS complexes and ST elevation in leads with down-going QRS complexes).

The Sgarbossa criteria are a set of rules to help identify acute myocardial infarction in the setting of a left bundle branch block. The original criteria are:

  1. Concordant ST elevation ≥ 1 mm
  2. Concordant ST depression ≥ 1 mm in V1, V2, or V3, or
  3. Excessively discordant ST elevation (> 5 mm)

The original criteria had a weighting system where excessive discordance was the least specific. The modified Sgarbossa criteria are more sensitive and specific than the original criteria. The first two concordant criteria are the same for the modified Sgarbossa criteria, but the third criterion for excessive discordance takes the concept of proportionality into consideration – excessively discordant ST elevation is defined as an ST/S ratio greater than 0.25.

 

Modified Sgarbossa criteria. ST/S ratio should be greater than 0.25 for excessive discordance.

Examples

ECG Showing Sgarbossa Criteria

Sgarbossa Criteria – Concordance

Concordant ST-elevation in I and aVL; concordant ST-depression in V3. This patient received percutaneous coronary intervention of an occluded first diagonal branch of the left anterior descending artery.
ECG Showing Sgarbossa Criteria

Sgarbossa Criteria – Concordance

Concordant ST-segment elevation in I, aVL in setting of left bundle branch block is specific for acute myocardial infarction. Left heart catheterization revealed diffuse disease and percutaneous intervention was performed to the left anterior descending and left circumflex arteries.
ECG Showing Sgarbossa Criteria

Sgarbossa Criteria – Excessive Discordance

The criterion for excessive discordance takes the concept of proportionality into consideration – excessively discordant ST elevation is defined as an ST/S ratio greater than 0.25. This patient met the modified criteria for excessive discordance in V3 and was found to have an occluded left anterior descending artery.

References

  1. Surawicz B, Childers R, Deal BJ, Gettes LS. AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram. Part III: Intraventricular Conduction Disturbances A Scientific Statement From the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. Journal of the American College of Cardiology. Published online 2009.
  2. Kusumoto FM, Schoenfeld MH, Barrett C, et al. 2018 ACC/AHA/HRS Guideline on the Evaluation and Management of Patients With Bradycardia and Cardiac Conduction Delay: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhyth. Circulation. 2019;140(8):e382-e482.
  3. Costa D Da, Brady WJ, Edhouse J. Bradycardias and Atrioventricular conduction block. British Medical Journal. 2002;324(March):535-538.
  4. Sgarbossa EB, Investigators G 1. Electrocardiographic Diagnosis of Evolving Acute Myocardial Infarction in the Presence of Left Bundle-Branch Block. New England Journal of Medicine. 1996;334(8):481-487.
  5. Meyers HP, Limkakeng AT, Jaffa EJ, et al. Validation of the modified Sgarbossa criteria for acute coronary occlusion in the setting of left bundle branch block: A retrospective case-control study. American Heart Journal. 2015;170(6):1255-1264.