With reversal of the LA and RA electrodes, Einthoven’s triangle flips 180 degrees horizontally around an axis formed by lead aVF.
This has the following effects on the ECG:
- Lead I becomes inverted.
- Leads II and III switch places.
- Leads aVL and aVR switch places.
- Lead aVF remains unchanged.
Quick guide to spotting LA/RA reversal
- Lead I is completely inverted (P wave, QRS complex and T wave).
- Lead aVR often becomes positive.
- There may be marked right axis deviation.
LA/RA reversal may simulate dextrocardia. However, in contrast to dextrocardia there is normal R wave progression in the precordial leads.
- Lead reversals: Limb Lead Reversals (overview)
- The power of social media leads to reversal – LITFL
- Batchvarov VN, Malik M, Camm AJ. Incorrect electrode cable connection during electrocardiographic recording. Europace. 2007 Nov;9(11):1081-90. PMID 17932025
LITFL Further Reading
- ECG Library Basics – Waves, Intervals, Segments and Clinical Interpretation
- ECG A to Z by diagnosis – ECG interpretation in clinical context
- ECG Exigency and Cardiovascular Curveball – ECG Clinical Cases
- 100 ECG Quiz – Self-assessment tool for examination practice
- ECG Reference SITES and BOOKS – the best of the rest
- Brady WJ, Truwit JD. Critical Decisions in Emergency and Acute Care Electrocardiography
- Surawicz B, Knilans T. Chou’s Electrocardiography in Clinical Practice: Adult and Pediatric
- Wagner GS. Marriott’s Practical Electrocardiography 12e
- Chan TC. ECG in Emergency Medicine and Acute Care
- Rawshani A. Clinical ECG Interpretation
- Mattu A. ECG’s for the Emergency Physician
- Hampton JR. The ECG In Practice, 6e