88 year old male CC: Chest pain – Conclusion

This is the conclusion to 88 year old male CC: Chest pain. You may wish to go back and review the history and clinical presentation.

First, let's look at the rhythm strip.

This shows an undetermined regular rhythm at a rate of about 60 with demand ventricular pacing. 

This is an oversimplification but as long as the intrinsic rhythm has an R-R interval of 1000 ms or less (blue arrows for reference) the pacemaker will inhibit itself because it's not needed.

Then we see the first 12-lead ECG.

Lead V1 is often a good place to see atrial activity. Now we can see flutter waves which explains why there is no atrial pacing (assuming this is a dual chambered pacemaker). You will note that the "wide" QRS complexes in the 12-lead ECG are exactly 1000 ms apart and are functioning in an apparent demand capacity which means these complexes are almost certainly paced.

As at least one person mentioned in the comments a typical paced rhythm with the pacing lead in the apex of the right ventricle will show LBBB morphology (this ECG shows RBBB morphology) so this is a bit unusual. However, in this modern day and age of mutlisite pacing none of these rules are set in stone.

I will say, however, that when I first saw this 12-lead ECG the T-waves in the right precordial leads (V1-V3) looked unusually large to me even though they are appropriately discordant with the QRS complex.

Now let's look at the next 12-lead ECG.

Interestingly, the intrinsic rhythm does not look particularly concerning in the right precordial leads (V1-V3). However, I do see a problem! To demonstrate I'm going to place leads V5 and V6 from 12-Lead 1 and 12-Lead 2 side-by-side.

This is a subtle finding but note the loss of upward concavity in the ST-segments between 12-Lead 1 and 12-Lead 2. In other words, there is a "straightening" of the ST-segment (it's not curved upward anymore) and that's bad! 

Now let's look at the final 12-lead ECG.

This ECG appears to show acute lateral STEMI. Would it be better to have seen a previous 12-lead ECG with paced rhythm in the left precordial leads (V4-V6)? Absolutely! But clearly there is excessive discordance in leads V5 and V6 and the T-waves look hyperacute.

Here is the ECG that was taken in the emergency department.

These changes were not appreciated by the paramedics, the ED physician or the cardiologist. 


@ 2245

  • CKMB 2.14
  • CPK 58
  • Trop < 0.01
  • K+ 2.8 (low)
  • Na 142 
  • Calcium 5.8 mg/dL (critical) – non-ionized
  • Renal profile WNL

@ 0535

  • CPK 254
  • CKMB 30.03
  • Trop 0.341

CT was negative for PE or aneurysm.

It was also noted in the chart that the patient had a history of AF and MVP S/P repair (could this explain the RBBB morphology with the paced rhythm?).

This was ultimately diagnosed as an acute coronary syndrome but not a STEMI. The case was handled medically (did not go to the lab) and the patient was discharged home.

Was it a missed STEMI? I can't say conclusively due to the abnormal lab values but I'm curious to hear what Stephen Smith, M.D. has to say!


  • Ken Grauer says:

    Very nice case Tom! I agree with each of the points you make in your excellent discussion. To me – the Final 12-lead ECG is highly suggestive of acute STEMI (especially in V5). It is not that common that pacer tracings show acute STEMI – but this one certainly does.
    The last tracing you show (the one from the ED in B & W) – to me, again in V5 (and also in V6) should strongly suggest the possibility of acute STEMI. In the context of V5,V6 – I interpret the ST-T wave in the paced complex in V3 as suggestive of reciprocal changes (seen through the paced beats) – and in the "retrospectoscope" – this should have been picked up in the ED.
    FINAL Point – There looks to be a PVC in V1,V2,V3 and also in V4,V5,V6 – with at least in V5, a highly suspicious ST segment (suggesting primary ST elevation) in the PVC from that lead. So – despite the relative infrequency of being able to identify acute STEMI from pacer tracings and from PVCs – this fascinating example to my eyes shows both! THANKS for sharing.
    I'm sure Steve Smith will have interesting input (as he ALWAYS does).

  • George Nikolic, FRACP, FACC says:

    Was the parient's total calcium (non-ionised, not non-iodised) only 5.8 mg/dL? What does "critical" mean in your hospital? If he was indeed hypocalcaemic, coronary spasm would be an attractive possibility.
    Electrocardiographically, spasm and STEMI look identical.

  • Hi, Ken! Thanks for the comments. Good point with regard to the PVC! Definitely appears to be some concordant ST-elevation there. These are the cases that "fall through the cracks" because they are classified as NSTEMI and so are not considered "fall-outs" even when they are cathed the next day (this one wasn't) and have a culprit artery. – Tom

  • George Nikolic, FRACP, FACC – I appreciate the comment and thanks for pointing out the typo! I think a critical lab value means that the lab has additional reporting requirments (an actual phone call to the unit to report the lab value) in addition to just printing the report. This may be a JCAHO requirement. May I please know in what country you reside? I think it's safe to assume the patient was hypocalcaemic. Interesting thought about coronary vasospasm! – Tom

  • George Nikolic, FRACP, FACC says:

    Tom, I live in Canberra, Australia. Most of my own ECG publications are in the Conundrum section of the Heart & Lung over the past 25 years.
    I have gretly enjoyed reding yours.

  • What a great case.  Clearly a missed STEMI.  It's hard to believe it could be missed. 

  • Collette Saxe says:

    Very interesting and over my head at the moment…but I will learn!  I am a basic EMT in Richfield Springs, NY.  Thanks for sharing

  • Igor says:

    no doubt, a missed STEMI revealed with the paced rithm. Hard to believe, indeed!

  • Pierre T. says:

    Thank very much (S Smith gave me your web site, I m from France). I dont agree – on the first 12-lead ECG – with the second part of statement that the “T-waves in the right precordial leads (V1-V3) looked unusually large to me even though they are appropriately discordant with the QRS complex”. According to my observations in RBBB pattern, in septal derivations, the axe of the ST-T wave must be discordant to the axe of the last deflexion of the QRS. Here, the T wave are indeed large, but concordant.

  • Pierre Taboulet –

    Thank you for the comments! I am assuming you are referring to this 12-lead ECG: http://ems12lead.com/files/2012/03/2012_03_19B_wm1.jpg

    We presume the rhythm is paced with RBBB morphology in leads V1-V3. In leads V1 and V2 the T-waves are clearly discordant with the terminal deflection (which is also the majority of the QRS complex). In lead V3 the T-wave is concordant with the terminal deflection but discordant with the majority of the QRS complex.

    There is much debate about which is appropriate, even with LBBB (since the terminal deflection usually — but not always — makes up the majority of the QRS complex). As a personal observation made over many years, it is not unusual for there to be an isolated concordant T-wave (concordant to the terminal deflection) in the transition lead (the lead where the terminal deflection transitions from negative to positive or positive to negative).

    In this ECG we see the following:

    V2 – positive QRS (negative T-wave)
    V3 – mostly positive with negative terminal deflecton (negative T-wave)
    V4 – negative QRS (positive T-wave)

    Hence, I am calling lead V3 the transition lead. If you look at a couple of dozen bifascicular blocks you will see that an isolated concordant T-wave in the transition lead is a not-uncommon finding. I am assuming this also applies to paced rhythms with RBBB morphology but again, I have not read about this phenomenon in any textbook. It’s just a personal observation.

    Best wishes,


  • Agus says:

    look like pace rythm, i dont understand when we call STEMI in pace rythm? 

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