Lead avR in STEMI & NSTEMI

Why is STE in lead avR important?

1) Increased mortality with this finding

2) Avoid thienopyridine (e.g., clopidogrel) administration in such patients who are likely to need CABG

avR STE in STEMI:

  • STE in aVR of at least 0.5 mm in anterior STEMI predicts septal AMI (occlusion of the LAD proximal to the first septal perforator)
  • STE in aVR is negatively correlated with a long (vs. short), or wraparound, LAD that affected the inferior wall.
  • This is intuitive, as a proximal occlusion would lead to basal wall STEMI, and distal occlusion of a wraparound (long, “type III”) LAD would lead to inferior STE which would reciprocally attenuate the STE in aVR, or lead to STD in aVR.
  • avR STE means LMCA occlusion?
    – Most of the patients with LMCA occlusion do not survive to cath lab.
    – ECG picture in LMCA occlusion = anterior STEMI + high lateral STEMI. avR STE is due to transmural infarction of the basal wall, not reciprocal to STD in other leads (STE is indicative of direct injury).
    – STE in avR > V1 does not always predict LMCA occlusion.

avR STE in NSTEMI

  • Diffuse ST depression has a good PPV and NPV for 3-vessel and left main disease (not occlusion!)
  • The degree of STE in aVR, though not independent of ST depression, has strong association with outcome independent of clinical factors such as Killip class and blood pressure.
  • STE in avR in this case is reciprocal to STD in other leads and due to subendocardial ischemia due to left main INSUFFICIENCY !

Learning points

  1. avR is important. STE in avR in both STEMI and NSTEMI gives a poor prognosis.
  2. Avoid thienopyridine (prasugrel, clopidogrel) in patients presenting with avR ST elevation. They will likely need CABG and these drugs will increase the bleeding risk.

Reference: http://hqmeded-ecg.blogspot.my/2014/08/the-difference-between-left-main.html

 

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