# Sgarbossa's criteria

Sgarbossa's criteria
Other names: Smith-modified Sgarbossa criteria,[1] modified Sgarbossa criteria[2]
An ECG showing 3 to 4 mm of ST depression in the same direction as the QRS complex in leads V2 and V3[3]
CalculatorMDCalc
PurposeIdentify acute myocardial infarction in LBBB or right ventricular pacing[4]
Based onECG[4]

Sgarbossa criteria are specific electrocardiographic (ECG) changes, in the presence of a left bundle branch block (LBBB) or right ventricular pacing (RVP), that are equivalent to an ST elevation myocardial infarction (STEMI).[4] They represent a sudden blockage of a coronary artery.[4]

In LBBB an acute MI is present when there is 1) ST elevation of at least 1 mm in the same direction as the QRS in at least one lead 2) ST depression of at least 1 mm in the same direction as the QRS in one of leads V1 to V3 3) ST elevation in the opposite direction of the QRS that is at least 25% the size of the S wave in one lead.[4] In RVP the second criteria can be applied to leads V1 to V6.[2]

Reperfusion efforts, such as percutaneous coronary intervention (PCI) or fibrinolysis, are recommended if the person has a suspected MI based on symptom and is hemodynamically unstable, has positive Sgarbossa criteria, or has an ultrasound of the heart that shows a STEMI.[5] If one of the three Sgarbossa criteria is present it generally indicate an acute MI, while their absence indicates that the risk is low.[4]

The criteria were first descried by the cardiologist Elena Sgarbossa in 1996.[1][6] Modifications to the third criteria were proposed by Smith in 2012.[4] While historically, a presumed new LBBB was considered a STEMI equivalent, this is no longer the case as of 2013.[5]

## Criteria

### Smith modification

Smith modified Sgarbossa's original criteria by adjusting the third criteria.[7]

Smith modified Sgarbossa rule:

• ST elevation ≥1 mm in a lead with a positive QRS complex (i.e.: concordance) (Sgarbossa criterion 1) or
• concordant ST depression ≥1 mm in lead V1, V2, or V3 (Sgarbossa criterion 2) or
• proportionally excessively discordant ST elevation in V1-V4, as defined by an ST/S ratio of equal to or more than 0.20 and at least 2 mm of STE. (this replaces Sgarbossa criterion 3 which uses an absolute of 5mm)

### Original

Three criteria are included in the original Sgarbossa's criteria:[6]

• ST elevation ≥1 mm in a lead with a positive QRS complex (i.e.: concordance) - 5 points
• concordant ST depression ≥1 mm in lead V1, V2, or V3 - 3 points
• ST elevation ≥5 mm in a lead with a negative (discordant) QRS complex - 2 points

≥3 points = 90% specificity of STEMI (sensitivity of 36%)[6]

A high take-off of the ST segment in leads V1 to V3 is well-described with uncomplicated LBBB, such as in the setting of left ventricular hypertrophy. In a substudy from the ASSENT 2 and 3 trials, the third criteria added little diagnostic or prognostic value.[8]

A Sgarbossa score of ≥3 was specific but not sensitive (36%) in the validation sample in the original report.[6] A subsequent meta-analysis of 10 studies consisting of 1614 patients showed that a Sgarbossa score of ≥3 had a specificity of 98% and sensitivity of 20%.[9] The sensitivity may increase if serial or previous ECGs are available.[10]

### Other

Wackers et al. correlated ECG changes in LBBB with localization of the infarct by thallium scintigraphy.[11] The most useful ECG criteria were:

• Serial ECG changes — 67 percent sensitivity
• ST segment elevation — 54 percent sensitivity
• Abnormal Q waves — 31 percent sensitivity
• Cabrera's sign — 27 percent sensitivity, 47 percent for anteroseptal MI
• Initial positivity in V1 with a Q wave in V6 — 20 percent sensitivity but 100 percent specificity for anteroseptal MI

## References

1. Cadogan, Mike; Buttner, Robert; Buttner, Mike Cadogan and Robert (1 August 2020). "Sgarbossa Criteria". Life in the Fast Lane • LITFL. Archived from the original on 17 August 2022. Retrieved 20 December 2022.
2. "Modified Sgarbossa Criteria for Ventricular Paced Rhythms". JournalFeed. 6 August 2021. Archived from the original on 24 September 2022. Retrieved 21 December 2022.
3. "MI Diagnosis in LBBB or paced rhythm". Archived from the original on 20 October 2021. Retrieved 20 December 2022.
4. Khawaja, M; Thakker, J; Kherallah, R; Ye, Y; Smith, SW; Birnbaum, Y (17 November 2021). "Diagnosis of Occlusion Myocardial Infarction in Patients with Left Bundle Branch Block and Paced Rhythms". Current cardiology reports. 23 (12): 187. doi:10.1007/s11886-021-01613-0. PMID 34791609.
5. "LBBB in Patients With Suspected MI: An Evolving Paradigm". American College of Cardiology. Archived from the original on 10 August 2022. Retrieved 21 December 2022.
6. Sgarbossa, Elena B.; Pinski, Sergio L.; Barbagelata, Alejandro; Underwood, Donald A.; Gates, Kathy B.; Topol, Eric J.; Califf, Robert M.; Wagner, Galen S. (1996). "Electrocardiographic Diagnosis of Evolving Acute Myocardial Infarction in the Presence of Left Bundle-Branch Block". New England Journal of Medicine. 334 (8): 481–487. doi:10.1056/NEJM199602223340801. ISSN 0028-4793. PMID 8559200.
7. Smith, Stephen W.; Dodd, Kenneth W.; Henry, Timothy D.; Dvorak, David M.; Pearce, Lesly A. (2012). "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". Annals of Emergency Medicine. 60 (6): 766–776. doi:10.1016/j.annemergmed.2012.07.119. ISSN 0196-0644. PMID 22939607.
8. Al-Faleh, Hussam; Fu, Yuling; Wagner, Galen; Goodman, Shaun; Sgarbossa, Elena; Granger, Christopher; Van de Werf, Frans; Wallentin, Lars; W. Armstrong, Paul; et al. (2006). "Unraveling the spectrum of left bundle branch block in acute myocardial infarction: Insights from the Assessment of the Safety and Efficacy of a New Thrombolytic (ASSENT 2 and 3) trials". American Heart Journal. 151 (1): 10–15. doi:10.1016/j.ahj.2005.02.043. ISSN 0002-8703. PMID 16368285.
9. Tabas, Jeffrey A.; Rodriguez, Robert M.; Seligman, Hilary K.; Goldschlager, Nora F. (2008). "Electrocardiographic Criteria for Detecting Acute Myocardial Infarction in Patients With Left Bundle Branch Block: A Meta-analysis". Annals of Emergency Medicine. 52 (4): 329–336.e1. doi:10.1016/j.annemergmed.2007.12.006. ISSN 0196-0644. PMID 18342992.
10. E. B. Sgarbossa (2000). "Value of the ECG in suspected acute myocardial infarction with left bundle branch block". Journal of Electrocardiology. 33 Suppl: 87–92. doi:10.1054/jelc.2000.20324. PMID 11265742.
11. F. J. Wackers (August 1987). "The diagnosis of myocardial infarction in the presence of left bundle branch block". Cardiology Clinics. 5 (3): 393–401. doi:10.1016/S0733-8651(18)30529-0. PMID 3690603.