Sunday, July 28, 2019

What is the Diagnosis in this 70-something with Chest Pain?

This is a very commonly missed ECG of a terrible condition.  In this case, it was almost dismissed.  I present many other similar ECGs at the bottom that were indeed missed or dismissed.


I was texted this ECG from a physician assistant who works by himself in several small Emergency Departments.

He is a particularly smart and well trained emergency medicine PA (because he trained at Hennepin).

He added the words:

"What do you think?  70-something male with DM, HTN, no previous MI, with Chest pain"
What do you think?

Here was my response:

"Definite Huge Occlusion MI (OMI). STEMI! This is a bad one.  There is RBBB with Left Anterior Fascicular Block (LAFB) which is a very ominous sign."

He texted back:

"That's what I thought but the cardiologist (at the receiving facility) was not convinced."

This is an obvious diagnosis to me.  Unambiguous.  Can't be anything else.
There is RBBB with LAFB with huge ST Elevation seen in V2-V4, (also subtle STE in aVL).

(The rhythm is uncertain, but it is supraventricular and probably atrial bigeminy (with P-waves that are not well seen), but the rhythm diagnosis is NOT critical in making the OMI diagnosis.)

Here I have put a line at the end of the QRS and beginning of the ST segment, so that you can assess for ST Elevation:
The image is distorted because it was a photo of a paper ECG.  
That is why the lines are not parallel.
Note that the QRS itself can mimic ST deviation; this is especially seen in inferior lead here.

Also note that the Elevated ST Segments in V2 and V3 are downsloping.  In the many cases of RBBB + LAFB in anterior MI that I have seen, this is the rule rather than the exception.  

Case continued:

The PA transferred the patient and, on arrival, the ECG was reportedly even more obvious.  The patient went to the cath lab:

Proximal LAD: 90% with thrombus
Mid LAD: 80% with thrombus
Distal LAD: 80% with thrombus

3 stents were placed.  Peak hs Troponin T was 23,070 ng/L (equivalent to 23 ng/mL; this is an enormous infarct!).

Echo showed anterolateral and septal wall motion abnormalities and an ejection fraction of 29%.


Some ECG findings which are very clear to me are not clear to others.  I try not to post cases that are easy.  This one I would have thought was easy.  But apparently it is not, as ECGs like this are very often missed, by all kinds of providers, including cardiologists.

More similar cases

Other examples of RBBB/LAFB OMI in which the cardiologist contradicted the interpretation of the emergency provider and disagreed with cath lab activation:

I had just resuscitated this patient from VF cardiac arrest after 68 minutes of CPR:

I told the cardiologist that it is a proximal LAD occlusion and he rolled his eyes, and said "Maybe."  It was indeed acute LAD OMI


Here is another example in which the cath lab was activated, then de-activated by the cardiologists, with the ST Elevation annotated below it:

This patient died 8 hours after cath lab de-activation.

With markup

Wide Complex Tachycardia; It's really sinus, RBBB + LAFB, and massive ST elevation


Here is another that was missed:

Resuscitated from ventricular fibrillation: what is the ECG Diagnosis?


Finally, this one

Here is a case of a young woman who presented with acute pulmonary edema.  The ECG was recorded during the pulmonary edema.  Cath lab was activated, then she arrested, and, after 30 minutes of resuscitation, achieved ROSC but was in severe shock.
Sinus tachycardia (NOT VT!).  See P-waves in lead II across the bottom.
RBBB and LAFB (wide complex)
There is clear STE in aVL, V2, and V3.
There is deep reciprocal ST depression in II, III, aVF.

The cath lab was de-activated.  She died of a 100% left main occlusion and peak troponin I of 500 ng/mL (the highest troponin I have ever heard of).


Here is another that was missed by the ED providers:

This is a patient with chest pain and the following prehospital ECG:

Here are lines that mark the end of the QRS and beginning of the ST segment:
This also has RBBB and LAFB with ST Elevation, but more subtle
This STEMI was not recognized and the patient arrested and could not be resuscitated.

Learning Points:

1.  Level of training does not predict ability to diagnose OMI from the ECG. Paramedics and PA's can be outstanding at this.

2.  Beware RBBB with LAFB.  ST Elevation may not be obvious, or it may be.  It does distort the ECG and it confuses many ECG interpreters.


  1. To me the QRS in lead I is downgoing and makes it difficult for me to appreciate the LAFB. The rest of the morphologies in the inferior leads fit but I would have a hard time identifying the LAFB and might have called it LPFB with concern for severe RAD. thoughts? Are you calling lead I QRS upgoing primarily?

    1. the RBBB is what is distorting lead I. Look at aVL, which has a qR (almost all positive), and inferior leads which have an rS (almost all negative)

  2. Tired to post this once, so forgive me if this is posted twice!

    I have to ask, how do you deal with the cardiologist who rolled his eyes at you during that proximal LAD case? (Or the PA who handled the cardiologist at the receiving facility in this case). That would be so frustrating to me but it seems that you handled this quite often!

    1. just use powers of persuasion. One is this: "the art of diplomacy is letting other people have your way" In other words, make them think it is their idea. Or make a plea for help: "I need your help on this." People respond to being needed. If that fails, you say: "I am writing that I strongly believe this patient needs an emergent angiogram, right now. If you don't do it, and you're wrong, you will look very bad"

  3. thanks again, steve... very helpful

  4. Hi! I follow your amazing blog for a while now and I’m really grateful for the way you changed and enriched my poor interpretation practice.

    My question: Is the presence of RBBB + LAFB in an Chest-Pain-Setting enough to suspect an OMI or is STE required to make that claim?

    PS. Is there a discussion of criteria for LAFB somewhere in your blog? I feel like the way I was taught (QRS-Axis ~ -45° & S in V6) isn’t the way you use to diagnose it?

    Thanks so mouch!

    1. Hellow Jona. THANK YOU so much for your comments! Regarding your 1st question — an excellent general rule regarding determining the clinical significance of any conduction defect (ie, BBB or Hemiblock or combination thereof) — is that it depends on the CLINICAL SETTING. In reading all ambulatory tracings for 35 providers over 30 years — I would very OFTEN see the combination of RBBB/LAHB in patients without new or recent symptoms, who had manifested this form of bifascicular block for many years. So the presence of RBBB/LAHB by itself is NOT enough to suspect OMI. It all depends on: i) the clinical History; and ii) IF there are any acute changes on the ECG. The problem with this 2nd point — is that whether or not there are ST-T wave abnormalities depends on the skill of the interpreter — since it is often much more challenging to recognize potentially acute ST-T wave changes when there is underlying BBB + hemiblock. In my experience — in addition to a history of recent or acute symptoms — there will USUALLY be (to “my eye” — and the eye of Drs. Meyers & Smith) at least some ECG abnormalities that provide support if this is an acute case. PLEASE send us tracings IF you have an example of new-onset symptoms with RBBB/LAHB in which you are uncertain if acute changes are present.

      Regarding the ECG diagnosis of the Hemiblocks — I discuss “My Take” on this subject in detail HERE = — The first half of this blog post reviews my thoughts on Axis determination. IF you are only interested in ECG diagnosis of the Hemiblocks — SCROLL DOWN all the way until you get to the Section entitled "HEMIBLOCKS: The Ventricular Conduction System". The 1st Figure in this sections is Figure-12. Let me know if after reading this you still have questions regarding the ECG diagnosis of the Hemiblocks.


DEAR READER: I have loved receiving your comments, but I am no longer able to moderate them. Since the vast majority are SPAM, I need to moderate them all. Therefore, comments will rarely be published any more. So Sorry.

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