64 year old female CC: Trouble Breathing – Conclusion

Lots of great comments and it was good to see the depth of discussion on the appropriate treatment and transport for this patient!

This is the conclusion to 64 year old female CC: Trouble Breathing.

When we left off our crew was attending to an elderly female patient in respiratory extremis. Pulmonary edema was present and their initial 12-Lead was concerning.

Many readers correctly noted the normal sinus rhythm, a 1° AV Block, and a wide QRS. Other readers pointed out the apparent Left Bundle Branch Block due to a negative QS complex in V1. Only a few readers picked up on the abnormal presentation of the LBBB: lead I has an rS complex and there is right axis deviation! Right axis deviation is a very uncommon finding in LBBB [1].

Just as it is important to know what a normal 12-Lead looks like, we also need to know what our abnormal 12-Leads should normally look like. In the case of LBBB, we expect V1 to be negative and leads I/V6 to have broad, monomorphic R-waves.

We also expect the T-waves to be discordant with the dominant deflection of the QRS. A picture is worth a thousand words in this case:

In our case we have three troubling findings:

  1. An rS complex in Lead I with Right Axis Deviation, which is very uncommon in LBBB.
  2. Concordant ST-segments in leads V5 and V6.
  3. Excessive ST-segement elevation in leads V2 through V4.

Many readers stated that a Left Bundle Branch Block is a STEMI mimic and precludes an activation of a STEMI alert until an old 12-Lead is used in comparison. However, criteria exists to diagnose a STEMI in the face of a LBBB or Paced rhythm.

Additionally, this patient's 12-Lead does not show a normal LBBB, but rather a non-specific intraventricular conduction defect or IVCD. Dr. Garcia would encourage, "considering the company it keeps," [2] which includes acute myocardial infarction!

Sgarbossa's criteria (and its modifications) for diagnosing STEMI in the face of LBBB or a Paced Rhythm has been covered in depth before so we'll only cover the positive criteria found on our 12-Lead:

  1. Is there ST-segment elevation ≥1 mm that is concordant with the QRS complex? Yes.

  2. Is there ST-segment depression ≥1 mm in leads V1, V2, or V3? No.
  3. Is there ST-segment elevation ≥5 mm, or ≥20% the depth of the S-wave, that is discordant with the QRS complex? Yes.

With 2 of the 3 criteria met (only 1 is required), we can be very confident that we're looking at a STEMI. Additionally, any concordant ST-elevation present should always suggest a STEMI.

The paramedic in this case recognized the concordant ST-elevation and the abnormal LBBB, called in a STEMI alert, and transported the patient to the PCI capable center. The patient improved significantly on the non-rebreather and CPAP was not necessary. Prior to arrival a second 12-Lead ECG was acquired:

Enroute the patient proved to be difficult for IV access, and received external jugular access in the ED. Labs were drawn while they waited for the cath lab team to arrive.

In the cath lab a 100% occlusion of the LAD was found and corrected with stenting.

For QA purposes an old ECG was retrieved after the call to compare to the field ECG:

Given this prior ECG, the new LBBB alone would likely cause a STEMI activation. However, in the absence of our more definitive changes this is a very weak criteria for activation [3].

Even without the prior ECG, we have an abnormal LBBB (most likely IVCD due to a peri-infarction block) with concordant ST-elevation and a patient presenting with signs of actue left sided heart failure: all of which point to an acute myocardial infarction!

This case highlights the importance of knowing what abnormal should normally look like and understanding that not every patient fits the protocol. We hope you enjoyed this case as much as we did, so be sure to continue the discussion below.

  1. Childers R, et al. Left bundle branch block and right axis deviation: a report of 36 cases. J Electrocardiol, 2000; 33 Suppl:93-102. [PubMed]
  2. The Art of Interpretation Series. http://www.12leadecg.com/
  3. Jain S, et al. Utility of left bundle branch block as a diagnostic criterion for acute myocardial infarction. Am J Cardiol, 2011; 107(8):1111-6. [PubMed]


  • Ken O. says:

    Great Case! I am constantly learning something new on your blog. Along with Dr. Garcia's book, they are the first references I go to. Thanks! Keep 'em coming!

  • Thanks for the feedback Ken! Let us know if there's anything you'd like us to cover, we've got a lot of cases in the wings.

  • Simon M says:

    The efforts you put in running this blog is not in vain. It is read world wide!
    To this case: it's nice to know that Sgarbossa's criteria can be used for IVCD!
    The right axis deviation was then caused by lateral MI?

  • Ken O. says:

    So tell me, among ER docs, is Sgarbossa pretty widely accepted or will I be looking forward to an eye roll and that "another know-it-all paramedic"  look if I try to lay it on a doc? I mean it wasn't all that long ago when we were taught that LBBB= too wide to read. Period.

  • Simon M,

    My understanding of this situation is we have a peri-infarction block primarily affecting the left bundle branches. The forces are directed away from the infarction area, which in this case ends up having a right axis. This is different than the case of an existing left bundle branch block with an infarction overlaid.

  • Ken O,

    Sgarbossa's criteria has been validated muiltple times, but did not make it into the last ACC/AHA Guidelines (2004). Beyond LBBB, numerous appropriate criteria are missing from the traditional definition. Rokos et al (2010) proposed the addition of 5 criteria and the removal of 1 criteria to the existing definition of "STEMI". They broke it down into Classic STEMI, STEMI Equivalent, and No STEMI.

    Classic STEMI includes AWMI, IWMI, and LWMI defined in a manner which is widely accepted (>=1mm STE 2+ contiguous leads).STEMI Equivalent includes LBBB with concordant STE, isolated PWMI (ST-depression in V1-V3), LMCA occlusion (STE in aVR>V1), de Winter ST/T-waves (hyperacute precordial T-waves with >=1mm STD), and hyperacute STEMIs. They demoted New LBBB to No STEMI if it does not meet Sgarbossa's criteria.

    They went further to define appropriate, reasonable, and inappropriate cath lab activations. While something like Tako-Tsubo may not truly be a STEMI, it is reasonable to activate a Code STEMI due to the difficulty in differentiating it from an AWMI on the surface ECG. Their definitions of appropriate and reasonable would include activation based on Sgarbossa's criteria. The good news is certain areas are using this definition. The bad news is, as you noted, many are not!

    Hopefully we can work to change this through case studies like this one.

  • robert says:

    Here's an interesting video on new LBBB's & the assumption of STEMI. Not so much the case any more. Cheers!

  • Robert,

    Great video, even highlights the concordant ST-elevation which indicates STEMI!

  • John says:

    Fantastic case!  I really enjoyed this one and passed it around my company amongst the Medics and challenged everyone.  What I find intersting is the vast difference in education amongst all the Paramedics in the field nationwide and just in my company!  A lot of Paramedics are not taught axis deviation which just shocks me.  I took it upon myself to learn it, it was hammered to us during my critical care paramedic course and proved useful in this situation as that was one of the first things that made me go hmmm…. Keep up the great work on this site and I can't wait to see what you'll throw at us next!

  • Michael says:

    Many thanks for the great review on this case!  An avenue to receive detailed and scholarly feedback like this on ECGs is whats been missing in my professional career. Reading this blog should be a job requirement for EMS professionals.

  • akroeze says:

    Ken O,
    My experience has been more of the eye rolling side or "I don't know, that is for the cardiologist to decide" side.

  • Jeff says:

    Under what criteria is this considered a LBBB.  I"m failing to reach a QRS complex of 120ms which would indicate a NSR with ST segment elevation and not a LBBB. Could someone just clarify where this is coming from?

  • Jeff,

    That's a fair question!

    I mark it out (using V1, the widest appearing lead) right at 3 small boxes (120ms) and the computer calculated it at 124ms then at 130ms. There is a clean baseline without artifact, so the computerized calculation is likely to be very accurate. That being said, one could just as easily see this at say 110ms and consider it an "incomplete LBBB" and call the STEMI anyways due to the ST-elevation.

    Does that help?

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