Dynamic ECG Changes…

by | Nov 4, 2021 | 0 comments

You’re working a night shift when you are handed the following ECG from triage in a 50 year old male, with no past medical history, presenting with chest pain:

 

ECG

 

What abnormalities do you notice? What is your approach?

 

Interpretation

  • Hyperacute T waves present in V2, V3
    • Hyperacute T waves are often one of the first (after QT prolongation) findings in ACS
    • They are broad based, symmetrical, usually have increased amplitude and often associated with depressed ST take off. 
    • They tend to be short lived and often rapidly progress to ST elevation.
  • ST depression V4-V6
  • T wave inversions inferior leads
  • Subtle STE in AVR

This ECG is concerning for ACS – so the patient is triaged to a monitored area, a repeat ECG ordered and urgent physician assessment.


15 minutes later the patient reports his pain is improving, and his ECG looks like this:

ECG

Thoughts?

Interpretation

Well… this looks a lot better. Previous abnormalities have corrected. ST/T wave segments are all flat. When you’re observing delta changes, the best course of action is to get another ECG.


15 minutes later, the patient reports his pain has resolved, and his repeat ECG looks like this:

ECG

Hmmmm..

Interpretation

This is a fairly classic ECG for a biphasic Wellens Syndrome – suggestive of a critical stenosis to the LAD.

The diagnostic criteria for Wellens Syndrome has previously been established: 

  • Deeply inverted or biphasic T waves in V2-V3 (may extend through all precordial leads)
  • ECG pattern must be present when the patient is pain-free
  • Isoelectric or minimally elevated ST segment
  • No precordial Q waves
  • Preserved precordial R wave progression
  • Recent chest pain history
  • Normal, or slightly elevated cardiac enzymes


As we were preparing to pick up the phone to call cardiology and initiate treatment for ACS, we were called STAT to the bedside:

The patient was found to have no pulse, CPR was started and he was defibrillated immediately with ROSC. He was alert and conscious at this point in time – he was treated for ACS, given anti-dysrhythmias and the Cath lab was activated. 

His post ROSC ECG was as follows:

ECG

Interpretation and case resolution

Unsurprisingly, the patient had a 100% LAD occlusion that was stented, and he returned home neurologically intact a few days later.

 

Conclusions

  • Hyperacute T waves are often one of the first (after QT prolongation) findings in ACS
    • They are broad based, symmetrical, usually have increased amplitude and often associated with depressed ST take off. 
    • They tend to be short lived and often rapidly progress to ST elevation.
    • Recognition is important
  • When you identify features concerning for evolving myocardial infarction, ensure you capture a delta ECG.
  • When you are having dynamic changes on ECGs, ensure to continue to perform delta ECGs until those changes resolve, or until diagnostic clarity has been achieved
  • Recognition of Wellens Syndrome is important, remembering that the ECG findings are only identified in a pain-free state

 

Author

  • Dr. Shahbaz Syed is a FRCPC Emergency Physician at the University of Ottawa, he is also the assistant director of Digital Scholarship and Knowledge Dissemination, and Co-Editor in Chief of the EMOttawa Blog.

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