ECG lead reversals can cause significant changes in electrocardiographic tracings, leading to misinterpretation, such as mistaken diagnoses of infarction, blocks or other cardiac conditions.

Electrocardiographic Changes

Right Arm–Left Arm Reversal

  • Negative P wave and QRS complex in lead I and positive in aVR
Electrocardiogram with lead reversal

Lead reversal. Right arm–left arm reversal producing negative waves in lead I and positive waves in aVR.

Left Arm–Left Leg Reversal

  • P wave in lead I is taller than in lead II (Abdollah sign)
  • Inverted polarity of lead III

Right Arm–Left Leg Reversal

  • Negative P wave in I, II and III
  • Positive P wave in aVR
  • Negative QRS complexes in the inferior wall
Electrocardiogram with lead reversal

Lead reversal. Right arm–left leg reversal producing negative P waves and QRS complexes in I, II and III. The P wave is positive in aVR.

Right Arm–Right Leg Reversal

  • Isoelectric line in lead II

Left Arm–Right Leg Reversal

  • Isoelectric line in lead III
Electrocardiogram with lead reversal

Lead reversal. Left arm–right leg reversal producing an isoelectric line in lead III.

Reversal of Upper and Lower Limb Electrodes

  • Isoelectric line in lead I

References

  1. Scheffer MK, Ohe LN, de Alencar Neto JN. Manual Prático de eletrocardiograma. 2022.