Confirmation
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Sgarbossa Criteria
Definition
Used to identify AMI in the presence of LBBB or a paced rhythm.
History/Physical Exam
History and findings suggestive of acute coronary syndrome.
Key 12-Lead Features
|
ST elevation ≥ 1 mm in a lead with upward (concordant) QRS complex |
5 pts |
|
ST depression ≥ 1 mm in lead V1, V2, or V3 |
3 pts |
|
ST elevation ≥ 5 mm in a lead with downward (discordant) QRS |
2 pts |
≥ 3 points = 90% specificity of STEMI (sensitivity of 36%)
Smith’s Modified Sgarbossa
Replacement of Rule III: discordant ST-elevation measurement of > 5 mm with
Smith’s Rule: ST/S ratio greater than 0.25 = STEMI
- Measure the ST Segment Elevation in mm [X]
- Measure the height/depth of the S/R wave in mm [Y]
- X ÷ Y = Z
- Z > 0.25 = STEMI
Sensitivity: 91%
Specificity: 90%
Key Treatment Points
- Transmit as per current guidelines if believed ischemic
- Convey to PCI capable hospital
- Monitor for 12-lead changes and patient decompensation
- Treat as Acute Coronary Syndrome
- Patient advocacy at the hospital
12 Lead ECG Samples
Smith's Modified Sgarbossa
Despite lacking > 5 mm elevation, both complexes below shown are positive for STEMI, due to ratios exceeding 0.25
References
- Rodriguez, RM. Electrocardiographic Criteria for Detecting Acute Myocardial Infarction in Patients With Left Bundle Branch Block: A Meta-analysis. 2006. [Link]