- Left Bundle Branch Blocks (LBBB) are uniquely challeging at interpreting for ischemic changes.
- ST changes are frequently seen in with LBBB that may or may not be related to ischemia.
- LBBB are always considered pathological but are not always associated with a myocardial infarction. Decisions regarding thrombolysis and cath lab activation can be difficult.
- Sgarbossa criteria first described by Elena Sgarbossa offers another tool for assessing for ischemic changes in the context of a LBBB or ventricular paced rhythm.
- Concordant ST-Elevation of 1 or more mm = 5 points
- Concordant ST-depression of 1 or more mm in V1-V3 = 3 points
- Discordant ST-elevation of more that 5 mm = 2 points
Score of 3 or more has a 90% specificity for myocardial infarction. Not sensitive.
Sgarbossa E.B. et al. Electrocardiographic diagnosis of evolving acute myocardial infarction in the presence of left bundle-branch block. GUSTO-1. N Engl J Med Feb 1996.