VA ICU Report 8.18.17 – STEMI equivalents and the “subtle STEMI”

Case summary

Thanks to our excellent ICU team for presenting a fascinating case of a 70M who had an lumbar drain after spinal surgery who develop abdominal pain and AMS raising concern for ACS and low CSF pressure.

Top pearls

  1. While ST elevation in aVR does not technically meet STEMI criteria, it can provide key information about apical ischemia and is a marker of poor prognosis in ACS.
  2. ST elevations in two contiguous leads raises concern for total occlusion of the corresponding coronary vasculature. Other EKG manifestations of total occlusion are rare but include: (1) Wellen’s EKG (2) new LBBB and (3) De Winter’s EKG – see below
  3.  Suspect intracranial hypotension in patients who present with orthostatic headaches. This is a rare disease than occurs due spontaneous CSF leak or excessive removal of CSF in patients with a lumbar drain.

aVR in ACS

  • In patients diagnosed with ACS, ST elevation in aVR does not meet true “STEMI” criteria, but
    • Strongly predicts proximal LAD occlusion
    • ST elevation in aVR > ST elevation in V1 suggests acute left main occlusion
  • In patients with inferior STEMI, ST depressions in aVR suggests left circumflex infarction or large RCA infarction.

STEMI equivalents

ST elevations in two contiguous leads raises concern for acute total occlusion of the corresponding coronary artery.  While this is the most common EKG pattern of total occlusion, several other “STEMI equivalent” can also occur.

  • Wellen’s T waves (https://lifeinthefastlane.com/ecg-library/wellens-syndrome/)
    • Deep, symmetric (Type B, 75%) or Biphasic (+ then -, 25%) V2-3 (may extend to V1-6)
    • Isoelectric or minimally-elevated ST segment (< 1mm)
    • No precordial Q waves
    • Preserved precordial R wave progressions
  • De Winter’s pattern (https://lifeinthefastlane.com/ecg-library/de-winters-t-waves)
    • Concave ST depressions into tall, symmetric T waves in the anterior precordial leads
  • ST depressions in the anterior leads + tall R waves
    • Get posterior EKG looking for posterior STEMI
  • LBBB in the setting of acute chest pain
  • Subtle STEMI
    • 1/20 of all acute coronary occlusions do not meet criteria for STEMI, instead cause 0.7 – 0.9 mm ST elevations termed “subtle-STEMI”
    • In this setting, look for reciprocal depressions
    • The RCA is usually involved
      • ST depressions in inferior leads —> scrutinize the high lateral leads (I and aVL) for subtle ST elevations
      • ST elevations in inferior leads, scrutinize, the high lateral leads to ST depressions (>0.5 mm)

Subtle STEMI: Wei, Margaret, Daniel R. Sanchez, and Ivan Rokos. “Nondiagnostic ST Elevations With Chest Pain: The Subtle STEMI.” JAMA Internal Medicine177.4 (2017): 577-578.

 

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