Saturday, November 18, 2023

Acute Dyspnea and Right Bundle Branch Block

I was texted this ECG just as I was getting into bed.

It is of an elderly woman who complained of shortness of breath and had a recent stent placed.

I was told that the Queen of Hearts had called it OMI with high confidence.

What do you think? 

Ken (below) is appropriately worried about pulmonary embolism from the ECG. What I had not told him before he made that judgement is that the patient also had ultrasound B-lines of pulmonary edema.

Here is my interpretation:

There is sinus rhythm with RBBB.  If you jump to looking at ST segments, you see "coved" ST in V3, V4, V5, with subtle ST Elevation.  This is HIGHLY suspicious for OMI.  

But you must look at the entire QRST: there are QR-waves in V1 and V2. LV aneurysm has QS-waves, so this couldn't be LV aneurysm, right?   WRONG!  RBBB makes it mandatory that there are R'-waves even in the presence of LV aneurysm.  A patient with normal conduction and QS-waves who then develops RBBB will have QR-waves!!  

See this post: Dyspnea, Right Bundle Branch block, and ST elevation

Moreover, the T-waves are not upright, so if this is OMI it is likely a reperfused OMI.  (IMPORTANT: in version 1, the Queen does not differentiate between active and reperfused OMI, so if this is a subacute OMI, she will still call it "OMI").

Additionally, it is very difficult to differentiate subacute reperfused OMI from LV aneurysm: both have Q-waves and inverted T-waves.  If it is subacute, the first troponin will be elevated, so a rapid troponin can be helpful. 

Also, we know the patient had a stent.

Finally, the presentation is dyspnea, not chest pain.  Patients with anterior LV aneurysm usually have poor LV function and heart failure.

I texted back: "It is really important to get a previous ECG for comparison, but I think this is LV aneurysm and not acute OMI."

This was what was found:

She had been at a different hospital less than a week ago at which time she had an an RCA stent for an lesion that had TIMI-3 flow.  A few days before that, she had had an LAD stent for LAD occlusion. 

The most recent ECG description (since the ECG image was not available) was RBBB with septal MI.

The most recent echo showed anterior and apical dyskinesis (this is the echo term for LV aneurysm).  

This is very early after an acute transmural MI to already have an LV aneurysm.

So I also texted back that the Queen's diagnosis depends on a high pretest probability, consistent with a patient who presents with chest pain (which has a much higher pretest probability than dyspnea) and that the Queen cannot see old or serial ECGs.

The patient's first hs troponin I was quite high, but this can be left over from the previous LAD occlusion.  If so, it should be dropping.  Here is the profile: 

1st trop: 2331 ng/L  

2nd trop: 2174

3rd: 2133

4th: 1694

The Queen of Hearts PM Cardio App is now available in the European Union (CE approved) the App Store and on Google Play.  

For Americans, you need to wait for the FDA.  But in the meantime:


If you want this bot to help you make the early diagnosis of OMI and save your patient and his/her myocardium, you can sign up to get an early beta version of the bot here.  It is not yet available, but this is your way to get on the list.


MY Comment, by KEN GRAUER, MD (11/18/2023):


Today's ECG provides unique insight into a less commonly seen manifestation of RBBB (Right Bundle Branch Block). It also highlights the importance of the History.

  • CREDIT to Dr. Smith — for his immediate recognition of LV Aneurysm as the most likely explanation for the ECG abnormalities in today's tracing.
  • I fully acknowledge that I initially "fell into the trap" of thinking acute PE as my 1st impression — primarily because of the inferior and anterior lead T wave inversion in this patient with new dyspnea, in association with significantly elevated Troponin values.

  • In Retrospect — What was my error?

For clarity in Figure-1 — I've labeled the ECG finding that I should have paid closer attention to. What is the Lesson to be learned?

Figure-1: I've labeled the initial ECG in today's case.

Closer LOOK at the ECG in Figure-1:
The ECG in Figure-1 shows sinus tachycardia — with QRS widening due to complete RBBB.
  • Q waves — are seen in lead III (and possibly in aVF) — with wide and deep Q waves in leads V1 and V2. In a patient with RBBB — these Q waves in leads V1,V2 are clear markers of anteroseptal infarction at some point in time.

  • I've added curved RED lines in Figure-1 to a total of 9/12 leads that manifest ST segment coving with slight ST elevation — that finishes with modest-to-moderate T wave inversion.

KEY Points regarding Today's CASE:
  • I thought this elderly woman's clinical presentation was clearly suggestive of acute PE as an important consideration because: i) Her chief complaint was shortness of breath; ii) Her ECG showed sinus tachycardia — RBBB — and T wave inversion in the inferior and anterior leads, which are the characteristic lead areas for RV "strain"andiii) An OMI seemed less likely to me, given her recent hospital admission for an acute event treated with cardiac stenting (with acute PE being a likely alternative cause for increased Troponin).

  • Historical information that I did not know at the time I first saw today's tracing included the fact that within the past 10 days she had 2 events (treated with RCA and LAD stenting) — and that her most recent ECG was described as showing "RBBB with septal MI" (but no mention of specific ST-T wave abnormalities).

My Retrospective Reflections:
  • Although true that acute RV "strain" is characterized by inferior and anterior T wave inversion — ST-T wave abnormalities usually do not extend out to the lateral chest leads, as they do in Figure-1.
  • While right-sided leads (ie, Leads III, aVR, V1)  may manifest some ST elevation with RV "strain" — ST depression (rather than ST coving with slight elevation) would be expected in other leads with RV "strain" from acute PE — such that the ST-T wave appearance in leads II, aVF, and V2-thru-V6 is in retrospect, not typical for acute PE.
  • A number of features about this case predisposed to development of LV Aneurysm — including: i) 2 recent cardiac events involving inferior and anterior lead areas; ii) Anterior and apical dyskinesis on the most recent Echo; iii) Persistently elevated Troponin values, more than a week after her events; andiv) Infarction Q waves in leads III, V1 and V2 + ST coving and elevation in so many leads that shouldn't still be showing this ... 

  • P.S.: To prove that the diffuse ST-T wave changes we see in today's tracing are solely the result of LV aneurysm — I'd like to see the actual most recent ECG reported as showing "RBBB with septal MI" — as well as obtaining a repeat ECG after the patient's heart rate slowed.

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