Sunday, April 6, 2014

Prehospital Inferior STEMI: Bedside Echo in ED is normal

A woman in her 60's complained of chest pain.  911 was called.  She had this prehospital ECG:
Obvious Infero-posterior and lateral STEMI

The cath lab was activated.

While waiting for the cath team to be ready, I recorded this bedside echo:

This shows excellent wall motion everywhere.  I was amazed and realized that she must have had spontaneous reperfusion.  (I cannot say for certain that a high quality echo with contrast would have been normal)

So I recorded an ED ECG:
This is near normal, except for the abnormal T-waves (down up in aVL, and note the abnormal T-wave in V2).

Here is an enlargement of V1-V3:

Note the morphology of V2, because this is a one of the typical morphologies seen early after reperfusion of the posterior wall. As time goes on, the T-wave will become fully upright and taller then normal, unless there is re-occlusion


So this patient had spontaneous reperfusion.  She went to the cath lab and by the time she arrived, the RCA was again 100% occluded.  There was ruptured plaque and thrombus.  It was opened rapidly.

Peak troponin I was 0.60 ng/ml.  Formal echo was normal except for a probable anterior wall motion abnormality, only seen on one view, and possibly pre-existing.  EF 66%.

Here was the post cath ECG:
Note the tall T-wave in V3.  This is tall because the an opposite view of an inverted posterior T-wave (which is positive) is superimposed on a normal upright anterior wall T-wave.  I call this "posterior reperfusion T-waves."  There is a Q-wave in V2 which would correlate with the echo finding.

 Lessons:

1. Spontaneous reperfusion normalizes BOTH the ECG and the echocardiogram.  Only if there is persistent myocardial stunning from ischemia (which usually is present with prolonged severe ischemia) is wall motion persistently affected.  If we had done an echo during the ST elevation, there would have been a wall motion abnormality, but it disappeared with reperfusion.
2.  Learn this reperfusion morphology in lead V2 from reperfused posterior STEMI. It is important in recognizing ACS if you do not have a recording during pain.
3. Down-up T-waves (e.g., aVL here) is almost always a reperfusion morphology (alternatively, it can be a U-wave masquerading as a T-wave)

7 comments:

  1. I have seen common practice to discharge patients with chest pain and concerning ECGs in the setting of normal ECHO ! Is echo very sensitive in the settings of unstable angina or NSTEMI?

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    1. In my experience, The cardiac ultrasound is only sensitive during active ischemia. That is to say, that it is sensitive when there are active ST segment and T-wave abnormalities. Once these have resolved, the echo cardiogram is no longer sensitive.

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  2. in my opinion, on echo inferoseptum is slightly hypokinetic

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    Replies
    1. Tazky,
      You may be right. But it is not obvious.
      Thanks, Steve Smith

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  3. Dr. Smith,

    If you were working in a area where a cardiac cath lab wasn't available and you had normalization of a STEMI ECG as in the case above, would there still be a place for thrombolytics?

    Please keep in mind getting access to a cath lab would take more than 24 hrs.

    thanks

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    Replies
    1. Good question. I don't think there is a solid answer to it. However, if I were there, I think I would treat with aspirin, Plavix, heparin, and eptifibatide. I would only give thrombolytics if the ST segments rose again.

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