Tuesday, May 19, 2015

Is there ST Segment Depression here?

A middle aged male with a history of Hypertension, Diabetes, Hyperlipidemia, and CHF due to severe concentric LVH presented with severe substernal chest pain and SOB.   The blood pressure was 170/120.

There were B-lines on chest ultrasound, diagnostic of pulmonary edema.

Here is his initial ED ECG:
Sinus rhythm.  There is high voltage diagnostic of LVH.  With a large S-wave in V2 and V3, there should be baseline ST elevation of LVH in these leads.  However, the J-point in V2 and V3 is isoelectric.  This is abnormal.  This is highly suggestive of relative ST segment depression.


So the previous ECG was sought:
Here we see the expected ST baseline ST elevation of LVH in V1-V3.  It is proportional and appropriate.

This confirms that the presentation ECG shows relative ST depression, consistent with ischemia.  There was worry for subendocardial ischemia vs. posterior STEMI.  The elevated blood pressure makes one lean heavily towards subendocardial demand ischemia.

A review of the chart showed there was an angiogram from one year prior with no significant obstructive lesions, mild plaque only.  This does not rule out ACS as the etiology of ischemia, but makes it far less likely.

The patient was placed on a high dose nitro drip, and his BP dropped to 150/90.  His symptoms resolved.

Another ECG was recorded 40 minutes after the first:
The relative ST depression is resolved.


The patient had a mild rise in troponin to 0.084 ng/mL which was deemed due to demand ischemia, not ACS.  Of course there could possibly be ACS, but I think it is unlikely.

Learning Point:

1. An isoelectric J-point may represent ST segment depression in a patient with baseline ST elevation, and in a patient who should, due to QRS abnormalities such as LVH, have baseline ST elevation.






7 comments:

  1. Presumably, this "pseudo-isoelectric J point" may also apply to ischaemia/infarction in the presence of LBBB?

    ReplyDelete
    Replies
    1. Shiva,
      Definitely. I have many cases to demonstrate that.
      An isoelectric ST segment in LBBB should alert to relative ST elevation or depression, depending on the QRS.
      Steve

      Delete
  2. Don't you find also very suggestive of (subendocardial) ischemia the shape of the ST-T in V5-V6?

    ReplyDelete
    Replies
    1. Ricardo,
      I think it is pretty typical of an LVH ECG.
      Steve

      Delete
  3. if old ecg is not available & patient came with mid sternal chest pain with normal B.P than how can we proceed further on the base of ecg

    ReplyDelete
    Replies
    1. Still give nitro, aspirin, etc. The ST segments are clearly inappropriate. Verification, as here, is nice, but not necessary. So one would have to assume ischemic pain. If ischemic pain is from ACS (as likely if no elevated BP) and cannot be controlled medically, then need possible emergent cath. Would get emergent high quality contrast echocardiogram, or use speckle tracking strain echo, to look for wall motion abnormality. If present, then cath.

      Delete

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