1996 – Sgarbossa proposed three absolute criteria used to diagnose AMI in patients with LBBB based on review of GUSTO-1
- Concordant ST elevation > 1mm in leads with a positive QRS complex (score 5)
- Concordant ST depression > 1 mm in V1-V3 (score 3)
- Excessively discordant ST elevation > 5 mm in leads with a -ve QRS complex (score 2).
- These criteria are specific, but not sensitive for myocardial infarction. A total score of ≥ 3 is reported to have a specificity of 90% for diagnosing myocardial infarction.
2012 – SW Smith modified the third component of the original criteria criteria from absolute (>5mm discordant ST elevation) to proportional (any ST segment to S-wave ratio less than -0.25, with at least 1 mm ST elevation) improved prediction of acute coronary occlusion.
- ≥ 1 lead with ≥1 mm of concordant ST elevation
- ≥ 1 lead of V1-V3 with ≥ 1 mm of concordant ST depression
- ≥ 1 lead anywhere with ≥ 1 mm STE and proportionally excessive discordant STE, as defined by ≥ 25% of the depth of the preceding S-wave.
‘Replacement of the absolute ST-elevation measurement of greater than or equal to 5 mm in the third component of the Sgarbossa rule with an ST/S ratio less than -0.25 greatly improves diagnostic utility of the rule for STEMI. An unweighted rule using this criterion resulted in excellent prediction for acute coronary occlusion.’
- Sgarbossa EB et al. Electrocardiographic diagnosis of evolving acute myocardial infarction in the presence of left bundle-branch block. GUSTO-1. N Engl J Med 1996 Feb 22; 334(8) 481-7. [PMID:8559200]
- Smith SW, Dodd KW, Henry TD, Dvorak DM, Pearce LA. 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 Dec;60(6):766-76. [PMID 22939607]
- Smith SW. STEMI in the Presence of LBBB. EP Monthly April 2015.
- Cai Q, Mehta N, Sgarbossa EB, Pinski SL, Wagner GS, Califf RM, Barbagelata A. 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 Sep;166(3):409-13. [PMID 24016487]
- Sgarbossa EB. Sgarbossa’s Criteria for MI in Left Bundle Branch Block. MDCalc