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ECG Findings (dependent on which leads are reversed)

  • Reversal of the left arm (LA) and right arm (RA) most common

    P, QRS, and T predominantly downgoing in lead I

    P, QRS, T upgoing in lead aVR

    Precordial leads unaffected

  • Reversal of the leg leads (left leg [LL] and right leg [RL])

    Does not commonly produce ECG changes because RL is used as a grounding electrode

  • Reversal of LA-LL

    Transposition of leads I and II and leads aVF and aVL with reversal of lead III

  • Reversal of RA-RL

    Transposition of aVR and aVL and inversion of lead II

  • Incorrect precordial lead placement

    Isolated reversal of the usual R-wave progression from V1 to V6


  1. If the ECG seems to have an unusual axis or appearance, especially when compared with a prior ECG on the same patient, consider a lead misplacement and repeat the tracing, confirming correct lead positions.

  2. A “reversed” lead I with normal-appearing V leads strongly suggests accidental limb lead reversal as opposed to dextrocardia. Dextrocardia features a “reversed” lead I, while QRS deflections in V4 to V6 appear small and downgoing.


Limb Lead Reversal (LA to RA). (ECG contributor: Michael L. Juliano, MD.)


The P wave, QRS, and T wave are inverted in lead I in this ECG. Normal-appearing V leads in the 12-lead ECG above suggest limb lead reversal rather than dextrocardia. The arm leads were indeed reversed, and correction produced a normal-appearing tracing.

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