Saturday, February 2, 2013

Right Bundle Branch Block with ST Elevation in V1?

There is a wide QRS with a tall R-wave in aVR and V1 and wide S-wave in lateral leads, leading one to believe this is RBBB.  There is ST elevation in V1, and ST depression in V4-V6, suggestive of ischemia/MI.   What is the Diagnosis? --see Below















This is a classic pseudoinfarction pattern -- hyperkalemia, with K of 6.9 due to DKA (pH 7.12, bicarb 6).  In this case the diagnosis was easy because the patient presented very ill with known Type I diabetes and with vomiting, not chest pain.

However, here are two from my files that presented with chest pain:

The peaked T-waves give it away, but the ST elevation in V1 and V2 is a little known pseudoinfarction pattern.  There was no MI here.

Thanks to K. Wang for this EKG.  Again, there was no MI, only hyperkalemia.


In all 3 of these cases, the findings disappeared with treatment of hyperkalemia, and the ECG normalized.
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8 comments:

  1. Nicolas PeschanskiFebruary 2, 2013 at 12:49 PM

    As U've always said: HyperK is the great imitator on the EKG

    ReplyDelete
  2. P HammarlundFebruary 2, 2013 at 5:47 PM

    What about the rhythm? Is it an atrial flutter with 2:1 conduction?

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    Replies
    1. Steve SmithFebruary 2, 2013 at 6:09 PM

      Well, it' embarrassing that I did not comment on that. It is sinus tach. The little bump just at the end of the large R-wave in V1 is a p-wave. The baseline ECG has an identical upright p-wave. Also, his rate gradually declined with therapy. Without that extra information, however, it would be a difficult diagnosis because it is hard to find a corresponding p-wave in lead II. On the other hand, I also can't find a pattern that would be fully consistent with flutter.

      Thanks for the great question.

      Steve Smith

      Delete
  3. UnknownFebruary 3, 2013 at 5:07 AM

    Dear Dr. Smith!

    I also wonder what the rhythm is. As you wrote gradual decline of the rate suggests sinus tachycardia.
    But as I looked carefully the ECG I found waves that are suspicious of being P waves.
    I marked them on this:

    http://kepfeltoltes.hu/130203/EKG_www.kepfeltoltes.hu_.png

    If they are P waves they do not seem to be linked to the QRS complexes, so I think there is AV dissociation, which is theoretically possible in supraventricular tachycardias that arise in the AV junction.
    And as far as I know there are nonparoxysmal junctional tachycardias in which the frequency gradually rise and decline.

    To have a much more complicated case there seem to be flutter waves in lead III...

    What is your opinion about this, Dr. Smith? Are they only artifacts?

    Thanks for your answer!

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    Replies
    1. Steve SmithFebruary 3, 2013 at 9:20 AM

      Marton, you may be right, but the p-waves you have marked out are very irregular, so I don't think so. I see what you mean about lead III, but, again, I don't think so: they should be more evident in lead II. Cannot say for certain.

      thanks!

      Steve Smith

      Delete
  4. ELFebruary 3, 2013 at 2:40 PM

    Steve, On the FIRST eKG: How do you know that the RATE (or electrolyte derangement) didn't precipitate a RBBB? Not only is the QRS wide, but there is right axis deviation. Also when I march out the end of the QRS complex it to me doesn't look like ST elevation or depression in the precordial leads, but just the end of the complex. I agree the second 2 eKGS are pretty cool!

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    Replies
    1. Steve SmithFebruary 3, 2013 at 3:27 PM

      El,
      Great question, which I had to think about for a moment: we know it's not RBBB because the r and S of rSR" in RBBB should both be narrow, and here they are both wide. So this is not just a rate-related RBBB + hyperK, but hyperK alone.
      Steve

      Delete
  5. Vince DFebruary 5, 2013 at 5:22 AM

    For the interested, here's another case of pseudo-septal STEMI, with a nice tracing for comparison after the patient received treatment.

    http://www.epmonthly.com/whitecoat/2013/01/whats-the-diagnosis-15/

    ReplyDelete

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