II. Indications
- EKG criteria for diagnosis of acute Myocardial Infarction when Left Bundle Branch Block is present
- May also be used for Right Ventricular Pacemaker (artificial LBBB)
III. Criteria: Sgarbossa
-
ST Segment Elevation of 1 mm or more if in same direction (concordant) as QRS Complex in any lead
- Score: 5 Points
-
ST segment Depression of 1 mm or more in any lead from V1 to V3
- Score: 3 Points
-
ST Segment Elevation of 5 mm or more in opposite direction (discordant) of QRS Complex
- Score: 1 Point
- Third criteria has poor efficacy and is replaced with third citeria in Modified Sgarbossa
IV. Criteria: Modified Sgarbossa (first 2 criteria are the same as with Sgarbossa)
-
ST Segment Elevation of 1 mm or more if in same direction (concordant) as QRS Complex in any lead
- Score: 5 Points
-
ST segment Depression of 1 mm or more in any lead from V1 to V3 (may be in any V1 to V6 lead if right ventricular pacer)
- Score: 3 Points
-
ST Segment Elevation / S-wave amplitude = -0.25 (modified from original Sgarbossa)
- Score: 1 Point
- Excessive discordant elevation (any lead)
- Compare a downward deflected QRS with degree of ST Elevation in any lead
- ST Elevation >25% of the amplitude of the QRS is considered excessive discordant elevation
- References
V. Interpretation
- Score of 3 or more suggests acute Myocardial Infarction
- Primarily focuses on the concordance of ST and QRS polarity (typically opposite or discordant in normal LBBB)
VI. Efficacy: Myocardial Infarction in Left Bundle Branch
- Test Specificity: 90%
- Test Sensitivity: 20%
VII. References
- Guest and Mattu in Swadron (2022) EM:Rap 22(11): 8-10
- Sgarbossa (1996) NEJM 334(8):481-7 [PubMed]
- Dodd (2021) Ann Emerg Med 78(4): 517-29 +PMID: 34172301 [PubMed]
