Saturday, January 16, 2016

Shouldn't need Modified Sgarbossa rule for cath lab here, but it does make the diagnosis certain!

I received this case from a medic (in quotes):

"Wanted to know your thoughts on this ECG." 

"Woman in early 70's with acute chest pain for the past 30 min. Vomited once. Looked sick. Pale and diaphoretic. Had hx of MI with stents one month ago. No old ECG to compare with. I interpreted the ECG as a LBBB with sinus tach but some thought it was VT. We administered Aspirin and transported to hospital."   

Here is the prehospital ECG and the only one he sent:
Smith comments:
There are clear P-waves (see arrows in image below) with a regular rhythm.  The computer interpretation is clearly wrong; it is clearly sinus tachycardia.  However, it does fairly accurately measure ST elevation at the J-point (this was printed out on the tracing!)
Notice there is LBBB.  There is subtle concordant ST elevation in leads I and aVL.
There is at least 2mm (I doubt 3.03) of STE in V3, with a 6 mm S-wave, for a ratio of 0.33
There is 1 mm of STE in V4 with a 1 mm S-wave, for a ratio of 1.0
It meets modified Sgarbossa in several leads

It is diagnostic of a proximal LAD occlusion in the setting of LBBB

Same ECG, annotated with arrows
See clear P-waves (arrows).
In V1, the P-waves are negative, as they should be (the later portion of the P-wave represents the left atrium and is normally negative).  This helps to verify they are P-waves.  

Whenever there is sinus tachycardia, one must consider whether the tachycardia is secondary to some other acute pathology (GI bleed?  Pulmonary embolism?  Ruptured AAA?  Sepsis?  etc.), and the ST elevation is due to the tachycardia and to this other illness (supply demand mismatch with demand ischemia and type II MI).  But this patient has a clear history of chest pain onset.  It is very typical of STEMI with acute cardiogenic shock.

Case continued:

"Upon arrival, she went into V Tach with a pulse and was cardioverted by attending and then coded. She was intubated and resuscitated."  

"What are your thoughts?  LBBB vs V Tach?  Any signs of potential MI?"

My answers are above.


"The medic tried to communicate his concerns to ED attending but was told it did not meet STEMI criteria. Patient arrested in ED and was resuscitated, intubated and admitted to ICU.  They did not take her to the cath lab. The next day troponin came back positive (not sure what value was) and like you said patient was in cardioogenic shock with severe acidosis and renal failure.  She arrested again in ICU and could not be resuscitated."

Learning Points:

1. Even had the ECG not been diagnostic, the history is classic for ACS with cardiogenic shock.  This is an unequivocal indication for emergent reperfusion therapy

2. This ECG is diagnostic of STEMI in the setting of LBBB.  It should erase any doubt about the etiology of shock

3. Listen to the medics!


  1. Thanks for sharing. We face lot of problems transferring cardiogenic shock due to stemi/acs to cath lab center.. either anesthesiologist doesn't agree to transfer or intervention cardio refuse to accept. . Reason : stabilize first.... practically its hard to transfer unstable pt

    1. Mateeq,
      such a patient can ONLY be stabilized by opening the artery. It is otherwise hopeless. Your anesthesiologists are "putting the cart before the horse."

  2. There is definitely a lost of discordance in leads V4 to V6 and in D1-aVL.

    There is definitely at least a proximal LAD occlusion at first sight.

  3. I simply do not understand anyone who takes care of patients especially in acute situations that does not continue to broaden their knowledge base. This EKG is obvious. LBBB or not. The morphology of the St segments in v2-v4 to me are very alarming. V4 actually was the first thing I noticed. Lead 1 and avl also have concordant st elevation. Sadly, I have had many situations like this. You try to convince someone of obvious pathology on an ekg and they won't listen. Sounds like this woman paid the price. Steve, I have 2 ekg's I would like to send you. They demonstrate another a situation just like this. Luckily, the patient lived. Thank you for your continued dedication to providing the rest of us with quality education.

    1. Dane,
      send to:


Recommended Resources