Chest pain, acute STEMI, and EMS-witnessed VF arrest – Part 2

This is Part 2 of Chest pain, acute STEMI, and EMS-witnessed VF arrest

Let’s take another look at the patient’s heart rhythm.

I can see why some of you thought this was Torsades de Pointes but the cyclic rate is over 300 and the underlying rhythm showed a normal QTc. It’s not unusual for the onset of VF to have a cyclic rate close to 300 and then accelerate to as high as 600 or 700.

I feel confident this is VF. Either way, it was pulseless.

The patient was shocked at 200 J.

Here is a 12-lead ECG of the post-shock rhythm.

I find it interesting that the limb leads become non-diagnostic during accelerated idioventricular rhythm (AIVR).

Several minutes and later the rhythm had stabilized.

The patient was delivered to a PCI-hospital where the interventional cardiologist was waiting.

Here is the 12-lead ECG captured prior to the procedure.


Here is the 12-lead ECG after stenting of the LCX.

These are the days that make it all worth while! Thanks for sharing the case, Phil.


  • Ben says:

    good case and looks like a good conclusion!

    Now one question I have is – on the pre-PCI 12 lead it shows ST depression V1-3 (?posterior) and some elevation in the inferior leads with reciprocal changes, if I remember my cardiac physiology right, aren’t these areas fed by the R coronary artery?

    Obviously I defer to the cardiologist and the vastly improved ECG!

  • Christopher says:

    Ben, I too was thinking RCA given STE III>II w/ posterior involvement (yet we have V5-V6 STE). Most folks are right dominant (PDA supplied by RCA). Tom has a great post which covers the algorithm for culprit artery in inferior MI’s.

    Perhaps this is a big LCX?

  • Phil says:

    Hey Ben, if the patient had a left dominent system, the LCX will supply the Posterior and approx 40% of the inferior L Ventricle. A left dominent system is found in roughly 10% of cases. The other 90% will indeed have these systems supplied by the RCA.

  • Ben says:

    Thanks Phil that clears it up 🙂

  • Brandon O says:

    Hey Tom, do you have any numbers on M&M for LCX occlusions?

  • Tom B says:

    Brandon O –

    No I don’t, but I’d be skeptical of any numbers, because STEMI in the distribution of the circumflex artery is under-reported. It seems likely that many are misclassified as NSTEMI.


  • Brandon O says:

    Yep. I’ll keep my ears peeled for any more numbers, it’s an interesting dark area.

  • i wish we had the 4th line on the tracing, the monitor lead. it certainly is useful.

  • Brandon says:

    Definately appeared to be subendocardial of a left main occlusion after the shock  but on the second 12 lead it looked like a classic inferioposterior rca occlusion. With the 15percent being left dominant and posterior wall fed by the circumflex it makes sense a LM occlusion would put that guy into VF. My question is, with the first 12 lead I would think it would have been a more proximally occluded LMCA, on the second 12 lead where the rhythm stabilized would it have been possible for the MI to have evolved further down and maybe at the junction of the LMCA and CXA????So without the angio results I would have said the first 12 lead was a Left Main occlusion, possibly even 3 vessel disease and the 2nd a RCA occlusion 

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