The Sgarbossa and Smith-modified Sgarbossa criteria have been documented to enhance the diagnosis of STEMI in the setting of LBBBs. However, there is a growing body of literature that suggests that these criteria can also be applied for the diagnosis of STEMI in patients with paced rhythms.
What criteria for a LBBB the ECG include?
The ECG criteria for a left bundle branch block include:
- QRS duration greater than 120 milliseconds.
- Absence of Q wave in leads I, V5 and V6.
- Monomorphic R wave in I, V5 and V6.
- ST and T wave displacement opposite to the major deflection of the QRS complex.
How can you tell the difference between STEMI and LBBB?
In LBBB, V1-V3 always have a predominant S-wave (QRS is predominantly negative) and therefore ST depression (STD) in V1-V3 is always concordant; ≥ 1 mm of STD in just one of these leads is diagnostic of STEMI (posterior STEMI, in fact).
What is modified sgarbossa?
The modified Sgarbossa criteria replaces the absolute 5mm discordant ST elevation with a proportion (ST elevation/S-wave amplitude ≤ -0.25). In other words, the modified Sgarbossa criteria only changes the last of the original Sgarbossa criteria with the first two criteria staying intact.
How many points is sgarbossa?
Three criteria are included in Sgarbossa’s criteria: ST elevation ≥1 mm in a lead with a positive QRS complex (ie: 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.
How do you determine ST elevation?
An ST elevation is considered significant if the vertical distance inside the ECG trace and the baseline at a point 0.04 seconds after the J-point is at least 0.1 mV (usually representing 1 mm or 1 small square) in a limb lead or 0.2 mV (2 mm or 2 small squares) in a precordial lead.
What is the difference between Rbbb and LBBB?
As seen, LBBB is characterized by deep and broad S-waves in V1/V2 and broad and clumsy R-waves in V5/V6. RBBB is characterized by rSR’ complex in V1/V2, meaning that there are two R-waves and a large S-wave. Furthermore, the S-wave in V5/V6 is typically very broad in the presence of RBBB.
How do you diagnose MI in the presence of LBBB?
The original three criteria used to diagnose infarction in patients with LBBB are:
- 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)
How do you diagnose MI in paced rhythm?
MI Diagnosis in LBBB or paced rhythm
- ST elevation > 1mm in leads with a positive QRS complex (concordance in ST deviation) (score 5)
- ST depression > 1 mm in V1-V3 (concordance in ST deviation) (score 3)
- ST elevation > 5 mm in leads with a negative QRS complex (inappropriate discordance in ST deviation) (score 2).
How specific is the Sgarbossa criteria for ACS in LBBB?
3 or more points has been shown to be highly specific (98%) for ACS in patients with LBBB [1]. Life on the Fast Lane has a great ECG database with a page about the Sgarbossa criteria.
What is Sgarbossa’s criteria for mi in left bundle branch block?
Sgarbossa’s Criteria for MI in Left Bundle Branch Block. In proportion to the preceding S-wave (or R-wave) as determined by 1) at least 1 mm of ST elevation (or depression) AND 2) an ST/S ratio ≤-0.25.
What is the original criteria for Sgarbossa infarction?
Original Sgarbossa Criteria. The original three criteria used to diagnose infarction in patients with LBBB are: Concordant ST elevation > 1mm in leads with a positive QRS complex (score 5) Concordant ST depression > 1 mm in V1-V3 (score 3)
What is the Sgarbossa’s score for mi?
Sgarbossa’s is a well accepted approach at determining which LBBB are having an MI. In the original Sgarbossa criteria, a score of <3 typically is not considered diagnostic of acute MI, but also does not rule out MI. In concerning patients, repeating ECGs and cardiac enzymes may be helpful, along with cardiology consultation.
