Sgarbossa Criteria

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).

  Sgarbossa's Criteria for MI in Left Bundle Branch Block

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... NOTE: the Modified Sgarbossa Criteria (which changes the third criteria) does not use the points system, it is positive if any criteria are met.

  Smith-Modified Sgarbossa Criteria

Concordant ST elevation ≥ 1 mm in ≥ 1 lead, Concordant ST depression ≥ 1 mm in ≥ 1 lead of V1-V3, Proportionally excessive discordant STE in ≥ 1 lead anywhere with ≥ 1 mm STE, as defined by ≥ 25% of the depth of the preceding S-wave.

Making Sense of Sgarbossa’s Criteria – Chest Pain and Left Bundle Branch Block – Part 1

Bundle branch blocks, paced rhythms, left ventricular hypertrophy, ventricular rhythms, and pre-excitation from Wolff-Parkinson-White syndrome all cause abnormal depolarizations, so to some degree they all display secondary ST/T-wave abnormalities. That’s why all of them can be STEMI mimics.

Making Sense of Sgarbossa’s Criteria – Chest Pain and Left Bundle Branch Block – Part 2

In Part 1 of this series we discussed why left bundle branch block presents a dilemma for clinicians who provide care for patients who suffer chest pain (or other signs and symptoms of ACS). Now I’d like to talk about “new” left bundle branch block.

Making Sense of Sgarbossa’s Criteria – Chest Pain and Left Bundle Branch Block – Part 3

In this final part of the series I’d like to talk about Smith’s modification to Sgarbossa’s criteria (PDF) and the importance of serial ECGs. If you recall there are two main problems with using 5 mm as an arbitrary cut-off for discordant ST-elevation in the presence of left bundle branch block. First, not all coronary occlusions will present with 5 mm of discordant ST-elevation (a problem with sensitivity). Second, many patients with 5 mm of discordant ST-elevation are not suffering acute STEMI (a problem with specificity).

Diagnosing STEMI in the presence of paced rhythm: dispelling the myth of the ‘uninterpretable paced ECG’

If a patient meets the Sgarbossa or Smith-modified Sgarbossa criteria in an appropriate clinical context, prompt cardiac catheterisation laboratory activation is appropriate.

Diagnosis of Myocardial Infarction in a Patient With Left Bundle Branch Block and Negative Sgarbossa Criteria

Left bundle branch block complicates electrocardiogram interpretation of acute myocardial infarction (MI) because ST segment elevations, commonly used as evidence of MIs, are largely hidden by the repolarization vector. To better diagnose acute MI in cases of left bundle branch block, modified Sgarbossa criteria can be used as a clinical tool to help diagnose or exclude MI with high specificity and sensitivity. However, while clinical tools are often helpful, a clinician cannot solely rely on clinical decision-making algorithms.

LBBB + Occlusion MI

Use the Smith-modified Sgarbossa criteria (concordant STE/STD, or excessively discordant STE/S >25% or STD/R>30%) to identify occlusion MI in the patient with ischemic symptoms and LBBB (whether new or old). Treat the patient: those with refractory ischemia and hemodynamic instability from suspected occlusion MI require cath lab activation regardless of the ECG. The Smith-modified Sgarbossa criteria replaced the absolute discordance of >5mm with a relative discordance of ST/S<-0.25 (i.e. amplitude of STE greater than 25% of the amplitude of the preceding S wave), and also included any excessive discordance (either STE >30% the preceding S wave, or STD>30% preceding R wave ) in any lead.

LBBB in Patients With Suspected MI: An Evolving Paradigm

Most cases of LBBB in suspected MI are therefore not a result of focal infarction. Instead, extensive myocardial damage involving a large portion of the distal conduction system is usually required to cause LBBB.

LBBB: is there STEMI?

Smith rule: Discordance should be proportional to the QRS, with an ST/S or ST/R ratio no greater than 0.25. Even anything greater than 0.20 is probably STEMI.

Left Bundle Branch Block in Myocardial Infarction: An Update

LBBB, although traditionally thought to be a STEMI equivalent, has recently been removed from AHA STEMI guidelines as an indication for catheterization lab activation. LBBB is associated with a variety of cardiac co-morbidities, and may or may not be an independent risk factor for AMI. Sgarbossa criteria are very specific for detecting AMI in patients with LBBB regardless of chronicity, and have been associated with higher mortality. In patients with a LBBB and suspected AMI, the presence of hemodynamic instability and/or the presence of concordance by Sgarbossa criteria should prompt strong consideration for emergent PCI.

New onset left bundle branch block: keep calm!

New onset LBBB represents a STEMI equivalent and, according to the current guidelines, this qualifi es for primary angioplasty. However, several conditions could provoke new onset LBBB such as hyperkalemia, hypercalcemia etc. Differential diagnosis is fundamental, especially in emergency condition, in order to avoid unnecessary or harmful treatment. Clinical evaluation and careful analysis of ECG often permitted the correct diagnosis.

ST Elevation Myocardial Infarction in LBBB

The presence of a Sgarbossa criteria score > 3 should prompt immediate cardiac catheterization lab activation. Application of the modified Sgarbossa criteria increases sensitivity of STEMI detection with little loss of specificity and should be incorporated into decision making.

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?

Prompt and accurate identification of ST-elevation myocardial infarction (STEMI) in the presence of left bundle-branch block (LBBB) remains difficult.