Monday, September 28, 2015

Unstable Angina: Again, it still exists......

A middle aged male with no coronary risk factors presented with new stuttering chest pressure, worse with exertion and better with rest, with some diaphoresis and SOB.  The pain is constant at presentation.

Here is the first ECG:
There is very subtle ST elevation in lead III, with reciprocal ST depression in aVL.
There is also ST depression in V3 and V4, so this is occlusion or near occlusion of a vessel supplying both inferior and posterior walls.
This is all but diagnostic of acute MI, though does not meet "STEMI" criteria.

Here is the previous ECG:
Normal


The emergency physicians immediately recognized the ECG signs of acute coronary occlusion (though not STEMI) and activated "Pathway B": immediate consultation with our cardiologist for possible cath lab activation.

NTG was given with some relief, then IV NTG was given with complete relief of pain.

A repeat ECG was recorded:
All ST segments have normalized.
This makes the first ECG even more diagnostic of ischemia.

All who were there agreed that this was acute coronary syndrome, but that the artery was open, the patient without symptoms, and that with dual antiplatelet therapy and heparin, the patient could wait until the next day for the cath lab.

Next day, the patient went for angiogram and had a 95 % thrombotic occlusion of the right posterior descending artery off the RCA.

All 4th generation (contemporary) troponins were negative:
 (level of detection 0.010 ng/mL, 99% = 0.030 ng/mL):

0 hours: undetectable
3 hours: undetectable
7 hours: 0.010
21 hours: 0.012
24 hours: 0.010
26 hours: undetectable
29 hours: undetectable.

The apparent slight rise and fall cannot be depended upon since the precision of the assay is not good at such low levels.  the 10% CV (good precision) is at 0.030 ng/mL.  At lower levels, the precision is much less.

If you used the HEART score on this patient, the score would have been 4 points, which suggests a 30 day major adverse events rate > 1%.  Therefore, in this case, even if the clinicians had not recognized the specificity of the ECG findings, further risk stratification (stress testing or CT coronary angiogram) would likely be done.

EDACS score = 19.  (greater than 15 is positive).  But, in addition, with EDACS: if the ECG shows specific findings, the score is positive no matter what the number.  This is not true with HEART score.  

But there are many who are calling for an end to such testing in patients with negative troponins.

That only works when the ECG is adequately interpreted.  

I would add that in anyone in whom you have a high suspicion based on the history, do not trust the risk scores.  This patient had a very high risk story.



5 comments:

  1. Last ECG: little T wave Inversion in III + more pronounced T wave in V2 = "little" infero-posterior Wellens's syndrome ?

    Thanks Dr Smith

    Al

    ReplyDelete
  2. First ECG : Can we say that there is a little bit of ST depression in the I lead also ? And for me, can I use Etinger when I feel sometimes uncertain of what happens in lead III ? Thanks a lot Dr Smith

    ReplyDelete
    Replies
    1. Yes, there is also some STD in I. What is Etinger?

      Delete
  3. pseudonormalization of T waves in inferior leads when compare first ech with baseline ecg suggesting ischemia in evolution

    ReplyDelete

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