The Sgarbossa criteria is used in the diagnosis of an acute myocardial infarction when a left bundle branch block is present.
Traditionally it has been taught that myocardial infarction is not able to be diagnosed via ECG in the presence of a left bundle branch block (LBBB), however Sgarbossa et al in 1996 described some ECG changes seen in those with LBBB and concomitant myocardial infarctions and devised a point scoring system. This is called the Sgarbossa criteria.
ST elevation > 1 mm and in the same direction (concordant) with the QRS complex. 5 points
ST depression > 1 mm in leads V1, V2, or V3. 3 points
ST elevation > 5 mm and in the opposite direction (discordant) with the QRS. 2 points
A score of 3 points is required to diagnose an acute myocardial infarction. Criteria #3 is under debate as to its usefulness, so basically you need to have either criteria 1 or criteria 2. Our patient just made 1 mm ST elevation in lead V5 and about 0.5 mm ST elevation in V6. This ECG was indeed from a patient with an acute left anterior descending thrombosis. Below is an image of ST elevation in V5 and V6 with a LBBB:
Note: The Cabrera's sign and Chapman’s sign have been used to diagnose acute myocardial infarction in the setting of a left bundle branch block as well.