58 year old female CC: Chest pain – Conclusion

Here’s the conclusion to the 58 year old female with chest pain and left bundle branch block.

To refresh your memory here is the 12-lead ECG.


And for those of you who requested lead V4R.


This ECG meets all 3 of Sgarbossa’s criteria to identify acute STEMI in the presence of left bundle branch block.





Keep in mind, it only has to meet one criterion in one lead!

(Please note: One criterion has been modified from its original form. Instead of discordant ST-elevation > 5 mm we are looking for discordant ST-elevation > 0.2 the depth of the S-wave. This is known as the ST/QRS ratio. Credit to Dr. Smith of Dr. Smith’s ECG Blog.)

Angiography revealed 100% occlusion of the LCX and 99% occlusion of the RCA.

Thanks to everyone who commented on the case!


  • akroeze says:

    Thanks so much for this real world example Tom!I have actually made printouts of the graphics you use for the three criteria and taped them to the back cover of my protocol book since for some reason I have a hard time committing them to memory. I encourage others to do the same.I'm not sure how things will go the first time I find one of these though as the patient would not meet my current protocol… so I guess I would be at the mercy of the physician knowing what I'm talking about!

  • Tom B says:

    My pleasure, Alex. I'm amazed it took this long.

  • Do you have a refrencve for the "newer: criteria ST greater than 0.2 of S wave

  • Tom B says:

    Bostonmedic109 -Initially it was 0.25 the QRS complex.For a reference see:Circulation. 2008;118:S_578ACS: Initial Assessment-Old and New ToolsAbstract 551: Ratio of Discordant ST Segment Elevation or Depression to QRS Complex Amplitude is an Accurate Diagnostic Criterion of Acute Myocardial Infarction in the Presence of Left Bundle Branch BlockSince then Dr. Smith has reported on his blog that more cases and further analysis have revealed that using 0.2 increases the sensitivity while maintaining the same specificity.Tom

  • Vrhegyi Mrton says:

    Nice and useful article!:-)

    Any q/Q waves in left-sided leads (I, aVL, V5-6) and other markers of necrosis in LBBB (Cabrera's sign etc.) might also be important, however, can be the result of prior myocardial infarction or atypical form of LBBB.

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