II. Indications

  1. EKG criteria for diagnosis of acute Myocardial Infarction when Left Bundle Branch Block is present
  2. May also be used for Right Ventricular Pacemaker (artificial LBBB)
    1. Not applicable for left ventricular Pacemaker or biventricular Pacemaker

III. Criteria: Sgarbossa

  1. ST Segment Elevation of 1 mm or more if in same direction (concordant) as QRS Complex in any lead
    1. Score: 5 Points
  2. ST segment Depression of 1 mm or more in any lead from V1 to V3
    1. Score: 3 Points
  3. ST Segment Elevation of 5 mm or more in opposite direction (discordant) of QRS Complex
    1. Score: 1 Point
    2. 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)

  1. ST Segment Elevation of 1 mm or more if in same direction (concordant) as QRS Complex in any lead
    1. Score: 5 Points
  2. 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)
    1. Score: 3 Points
  3. ST Segment Elevation / S-wave amplitude = -0.25 (modified from original Sgarbossa)
    1. Score: 1 Point
    2. Excessive discordant elevation (any lead)
      1. Compare a downward deflected QRS with degree of ST Elevation in any lead
      2. ST Elevation >25% of the amplitude of the QRS is considered excessive discordant elevation
  4. References
    1. Smith (2012) Ann Emerg Med 60(6): 766-76 +PMID:22939607 [PubMed]
    2. Meyers (2015) Am Heart J 170(6): 1255 – 1264 [PubMed]

V. Interpretation

  1. Score of 3 or more suggests acute Myocardial Infarction
  2. 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

VII. References

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