eh-vee-arrr
The Case.
A 38 year old male presents to your ED with left sided chest heaviness which radiates to his left shoulder & down the arm. He has associated dyspnoea, nausea & vomiting. He looks unwell.
He underwent a CT-Coronary Angiogram 4 months earlier showing a Calcium-Score of 450 !! (‘Extensive plaque burden’. 8x increase in Framingham predicted risk). However, a Sestamibi study performed at the same time showed no evidence of inducible ischaemia.
This is his ECG…
[DDET What’s your interpretation ?]
my take…
- Sinus tachycardia at ~ 100bpm.
- Normal axis. Normal intervals.
- ~1.5mm STE in aVR, with widespread ST depression (V2-5, II, III, aVF).
- DDx. Left main ischaemia vs triple vessel disease !!
He was treated aggressively with aspirin, GTN infusion & heparin.
I elected to withhold clopidogrel (a decision backed by Cardiology).
As his pain settled the following ECGs are taken…
[/DDET]
[DDET Is it significant ???]
For me this case was all about…..
aVR
The right-ward facing unipolar lead.
Obtains information about the right, upper side of the heart including the right ventricular outflow tract and basal septum.
Why is it important ??
Toxicology (particularly Na-channel blockade), dysrhythmias (P-wave configuration, identification of AV dissociation etc.) & ischaemic chest pain ….
In the setting of cardiac ischaemia, ST-segment elevation in aVR can indicate left main coronary artery stenosis.
- Significant mortality (~70%)
- Medical therapy not helpful –> patients need cardiac catheterisation
- Other ECG features:
- Concurrent STE in aVL
- STE in aVR > STE in V1.
- The greater the ST-elevation, the greater the mortality !!
It may also indicate proximal LAD occlusion or triple-vessel disease.
[/DDET]
[DDET Where do we go from here ??]
A recent post by Dr Smith on aVR has bought to my attention this important paper…
An Early and Simple Predictor of Severe Left Main and/or Three-Vessel Disease in Patients With Non–ST-Segment Elevation Acute Coronary Syndrome Am J Cardiol. 2011 Feb 15;107(4):495-500
This study demonstrates that ST-segment elevation >1 mm in lead aVR and positive troponin on admission are highly suggestive of severe LMCA or triple vessel disease (the converse is also true). The negative predictive value of STE > 1mm in aVR was 98% !! The authors (as well as Dr Smith) suggest that with the subsequent increased need for CABG, these patients would benefit from withholding clopidogrel (reducing the risk of intra-operative bleeding).
The Follow-up.
- Patient is transferred pain-free to Coronary Care on GTN & Heparin infusions.
- HS-Troponins 8 –> 12 –> 24 (Normal < 5).
- The following morning he has an angiogram demonstrated significant 3-vessel disease.
He is now awaiting bypass-grafts….
[/DDET]
[DDET References]
References.
- Gorgels AP, Engelen DJ, Wellens HJ. Lead aVR, a mostly ignored but very valuable lead in clinical electrocardiography. J Am Coll Cardiol. 2001 Nov 1;38(5):1355-6.
- Kosuge M et al. An early and simple predictor of severe left main and/or three-vessel disease in patients with non-ST-segment elevation acute coronary syndrome. Am J Cardiol. 2011 Feb 15;107(4):495-500
- Dr. Smith’s ECG Blog: ST elevation in aVR, with widespread ST depression
- Life in the Fast Lane: Another Widow Maker.
- EMRAPTV Episode 68: aVR – Gets No Respect!
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