Sgarbossa Criteria for Myocardial Infarction in Left Bundle Branch Block

Evaluation and Management of ST-Segment Elevation Myocardial Infarction in the Emergency Department

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Sgarbossa Criteria for Myocardial Infarction in Left Bundle Branch Block


The Sgarbossa criteria score is used to diagnose acute myocardial infarction in patients with prior left bundle branch block.

About the Score

It is often difficult to identify a myocardial infarction (MI) in patients with existing left bundle branch block (LBBB). Approximately 1 in 200 patients with MI have LBBB. The use of the Sgarbossa criteria is a well-accepted approach for determining which patients with LBBB are having an MI.

A Sgarbossa score of ≥ 3 is 90% specific for MI, but is not sensitive (36% sensitivity). Therefore, a score ≥ 3 should be acted upon, but a lower score cannot be used to rule out MI. Clinicians should maintain a high index of suspicion if the patient’s clinical presentation is consistent with MI.

Calculator Review Authors

Graham Walker, MD

Department of Emergency Medicine,
Kaiser San Francisco Medical Center, San Francisco, CA

Evidence Appraisal

Sgarbossa et al developed and validated the Sgarbossa criteria in 1996, based on a set of electrocardiographic criteria for the diagnosis of acute MI in patients with chest pain and LBBB. The Sgarbossa criteria cannot rule out MI in patients with existing LBBB. Smith et al modified the Sgarbossa criteria by adjusting the component of excessively discordant ST-segment elevation (Smith 2012). This modification has been referenced by Dr. Sgarbossa (Cai 2013) and should be included in the Sgarbossa criteria.

Calculator Creator

Elena Sgarbossa, MD


Primary Reference

  • Sgarbossa EB, Pinski SL, Barbagelata A, et al. Electrocardiographic diagnosis of evolving acute myocardial infarction in the presence of left bundle-branch block. N Engl J Med. 1996;334(8):481-487. DOI: 10.1056/NEJM199602223340801

Validation Reference

  • Smith SW, Dodd KW, Henry TD, et al. Diagnosis of ST-elevation myocardial infarction in the presence of left bundle branch block with the ST-elevation to S-wave ratio in a modified Sgarbossa rule. Ann Emerg Med. 2012;60(6):766-776. DOI: 10.1016/j.annemergmed.2012.07.119

Additional Reference

  • Cai Q, Mehta N, Sgarbossa EB, et al. The left bundle-branch block puzzle in the 2013 ST-elevation myocardial infarction guideline: from falsely declaring emergency to denying reperfusion in a high-risk population. Are the Sgarbossa Criteria ready for prime time? Am Heart J. 2013;166(3):409-413. DOI: 10.1016/j.ahj.2013.03.032
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Publication Information

Marshall Frank, DO, MPH, FACEP; Carson Sanders, BS, NRP, CCEMT-P; Bryan P. Berry, MD, BCEM, FACEP

Peer Reviewed By

James Morris, MD, MPH; Douglas L. Robinson, DO, MS; Andrew Schmidt, DO, MPH

Publication Date

January 1, 2021

CME Expiration Date

January 1, 2024    CME Information

CME Credits

4 AMA PRA Category 1 Credits™, 4 ACEP Category I Credits, 4 AAFP Prescribed Credits, 4 AOA Category 2-A or 2-B Credits.

Pub Med ID: 33320487

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