Check out the comments from our original post here.
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- 66 bpm
- Sinus rhythm
- PR - Normal (120ms)
- QRS - Normal (80ms)
- QT - 400ms (QTc Bazette 420 ms)
- T wave inversion leads I, aVL, V1
- Negative P waves lead I, aVL
- Notched P wave inferior leads
- Q waves infero-lateral leads (leads II, III, aVF, V4-6)
- Narrow Q waves
- Depth ~2 mm but maximal in V5 at 3mm. All <25% of QRS voltage
- Early R wave transition
- RA-LA lead reversal
- Infero-lateral Q waves
- Normal variant vs structural disease
The presence of complete inversion (P-QRS-T) of any lead, expect aVR, should alert to potential lead reversal as should an ECG with abnormal axis.
RA-LA is probably the most commonly encountered lead misplacement and results in:
- Inversion of lead I
- With resultant RAD, assuming native axis is normal
- Leads II & III switch places
- Leads aVR & aVL switch places
We've had multiple examples of lead reversals in some of our previous cases listed below.
More examples of RA-LA lead reversal
- ECG of the Week - 27th October 2014 - Interpretation
- ECG of the Week - 9th July 2012 - Interpretation
- ECG of the Week - 10th September 2012 - Interpretation
A cautionary case of LA-LL reversal
This is a case of dextrocardia which also results in an apparent RA-LA reversal
For a complete review of all lead reversal possibilities check out this extensive review at Life in the Fast Lane:
- Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.