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Electrocardiogram Validity

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Electrocardiogram Validity, EKG Validity, EKG Lead Reversal, EKG Electrode Misplacement

  • See Also
  1. Electrocardiogram
  • Criteria
  • EKG Validity
  1. Limb Lead I is mirror of aVR
  2. R Wave Progression across precordial leads
    1. R Wave more prominent by lead V4
    2. Poor progression in anterior Myocardial Infarction
  3. Voltage standardization mark at 1 mv
    1. Two big boxes tall (10 mm)
    2. Five small boxes wide (25 mm/sec)
  1. Lead I Inverted
  2. Lead II and Lead III switched
  3. Lead aVR and aVL switched
  4. Precordium (V1 to V6) with Dominant S Wave and Poor R Progression
  • Criteria
  • Lead Reversals
  1. Left Arm - Right Arm Reversal (LA-RA Reversal)
    1. Nearly identical to Dextrocardia EXCEPT Precordium is unaffected in LA-RA reversal
    2. Lead I Inverted (affecting all complexes: P-QRS-T)
    3. Lead II and Lead III switched
    4. Lead aVR and aVL switched
  2. Left Leg - Right Leg Reversal (LL-RL Reversal)
    1. Right leg (RL) is a grounding lead and its reversal with left leg (LL) results in no EKG changes
  3. Left Arm - Left Leg Reversal (LA-LL Reversal)
    1. Lead III inverted (affecting all complexes: P-QRS-T)
    2. Lead I and Lead II switched
    3. Lead aVF and aVL switched
  4. Left Arm - Right Leg Reversal (LA-RL Reversal)
    1. Lead I appears similar to Lead II
    2. Lead III flatline (pseudo-Asystole with difficult to discern P, QRS and T complexes)
    3. aVR similar to inverted Lead II
    4. aVF and aVL appear similar
  5. Right Arm - Left Leg Reversal (RA-LL Reversal)
    1. Lead II inverted (affecting all complexes: P-QRS-T)
    2. Lead I and Lead III are switched and inverted versions of one another
    3. Lead aVF and aVR switched
  6. Right Arm - Right Leg Reversal (RA-RL Reversal)
    1. Lead I appears similar to inverted Lead III
    2. Lead II flatline (pseudo-Asystole with difficult to discern P, QRS and T complexes)
    3. aVL appears similar to inverted Lead III
    4. aVR and aVF appear similar to one another
  7. Left Arm - Left Leg AND Right Arm - Right Leg Reversal (LA-LL + RA-RL Reversal)
    1. Lead I flatline (pseudo-Asystole with difficult to discern P, QRS and T complexes)
    2. Lead II appears similar to inverted Lead III
    3. Lead III inverted (affecting all complexes: P-QRS-T)
    4. aVR and aVL appear similar to one another
    5. avF appears similar to inverted Lead III
  • References
  1. Berberian (2023) Crit Dec Emerg Med 37(6): 12-3