Sgarbossa's Criteria for MI in Left Bundle Branch Block

Criteria to diagnose acute MI in patients with prior LBBB.

Concordant ST elevation > 1mm in leads with a positive QRS complex

Concordant ST depression > 1 mm in V1-V3

Excessively discordant ST elevation in leads with a negative QRS

  • In proportion to the preceding S-wave as determined by:
    1. at least 1 mm of ST elevation AND
    2. an ST/S ratio ≤ -0.25


Source: Sgarbossa EB, Pinski SL, Barbagelata A, Underwood DA, Gates KB, Topol EJ, Califf RM, Wagner GS. Electrocardiographic diagnosis of evolving acute myocardial infarction in the presence of left bundle-branch block. GUSTO-1 (Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries) Investigators. N Engl J Med. 1996 Feb 22;334(8):481-7. Erratum in: N Engl J Med 1996 Apr 4;334(14):931. PubMed PMID: 8559200.