Pediatric ECG

Originally published at Pediatric EM Morsels on September 7, 2017. Reposted with permission.

Follow Dr. Sean M. Fox on twitter @PedEMMorsels

Electrocardiograms are fun to look at: like abstract art that hangs in a fancy museum, their beauty is often in the eye of the beholder. That being said, they are a vital tool to interpret. There are several situations when the Pediatric ECGis an integral part of the evaluation (ex, Syncope / Hair grooming syncopeSubmersionsSeizures – not all that seizes is a seizureBRUEBreath Holding SpellsPericarditisALCAPA, and Chest Pain). Unquestionable, ECGs are more commonly encountered when evaluating adult patients, but the infrequent encounters with the Pediatric ECG may make us less comfortable with them. Let us take a minute to consume a morsel of the Pediatric ECG:


Pediatric ECG: Age Related Changes

  • Ventricular rate is faster at baseline for younger children.
    • Age related norms apply.
    • The younger the child, the higher the metabolic rate and lower vagal tone. [O’Connor, 2007]
  • Initial right ventricular (RV) dominance
    • In utero, blood was shunted away from the pulmonary vasculature.
    • In utero, high pulmonary pressures exist.
    • This leads to relatively thicker RV.
      • Initial Right Axis on ECG is normal.
      • Resolves over the first 6 months of life. [O’Connor, 2007]
        • Axis of -90-180 degrees.
        • Seen with AV canal or osmium primum atrial septal defects. [O’Connor, 2007]
  • AVF lead vector
    • A negative QRS vector in AVF can be seen with some cardiac malformations (ex, AV septal defects or single ventricle) [Evans, 2010]
    • A biphasic QRS in AVF can be normal, but needs to have pediatric cardiology review. [Evans, 2010]
  • Intervals are slightly different than adults.
    • PR interval is shorter.
      • Smaller muscle mass.
      • Young kids should have PR < 160 msec (<4 small boxes)
      • A PR > 200 msec (> 1 large box) is abnormal for any age
    • QTc is longer in the young.
      • Infants < 6 months should have a QTc of < 490 msec.
      • QTc becomes similar to adult after 6 months with it being < 440 msec.
  • T-wave inversions in anterior precordial leads is normal. [O’Connor, 2007]
    • During 1st 7 days of life, T waves are typically upright in most leads.
    • After 7 days of life, T waves become inverted in anterior precordial leads.
    • The inverted T waves typically become upright in adolescence, but can persist.


Pediatric ECG: Large Voltages?

  • The pediatric patient’s chest wall is typically thinner (although that is not always the case) than the adult’s.
    • The closer proximity of the ECG leads to the heart muscle can exaggerate the voltages.
    • V2 through V5 are the most likely to be artificially exaggerated.
  • Before becoming “excited” about the “large voltages” seen in the precordial leads, consider:
    • The ECG interpretation will often “over-report” left or right ventricular hypertrophy (don’t read the interpretation!).
    • Make sure the standardization marks are set to Full Standard (2 big boxes).
    • ECG does NOT diagnose LVH or RVH… LVH and RVH are anatomic conditions and ECGs do not determine anatomy.
  • There are several “rules” that help evaluate for abnormally large voltages on the pediatric ECG.
    • Most are complicated and less practical.
    • One practical approach is: [Evans, 2010]
      • Abnormal Left Ventricular Large Voltage (“LVH”)
        • Use only V6 (the left most precordial lead)
        • If R wave of V6 intersects with baseline of V5, then that is abnormal.
      • Abnormal Right Ventricular Large Voltage (“RVH”)
        • Use only V1 (the right most precordial lead)
        • Upright T wave in V1?
          • During 1st week of life, T wave can be upright in V1.
          • After 1st week of life, upright T wave in V1 is abnormal in children until adolescence.
        • With RSR’ is present, if R’ is taller than R wave, then this is abnormal.
        • A pure R wave in V1 in a child > 6 months of age is abnormal.


Moral of the Morsel

  • Children are not aliens… they are small humans… humans with hearts who have some subtle changes due to their anatomy and physiology compared to adults.
  • T wave inversions in precordial leads is not likely ischemia. Know what is normal.
  • Small chest walls will exaggerate precordial voltages. Know what is normal.



Evans WN1, Acherman RJ, Mayman GA, Rollins RC, Kip KT. Simplified pediatric electrocardiogram interpretation. Clin Pediatr (Phila). 2010 Apr;49(4):363-72. PMID: 20118092[PubMed] [Read by QxMD]

O’Connor M1, McDaniel N, Brady WJ. The pediatric electrocardiogram part III: Congenital heart disease and other cardiac syndromes. Am J Emerg Med. 2008 May;26(4):497-503. PMID: 18410822[PubMed] [Read by QxMD]

O’Connor M1, McDaniel N, Brady WJ. The pediatric electrocardiogram part II: Dysrhythmias. Am J Emerg Med. 2008 Mar;26(3):348-58. PMID: 18358948[PubMed] [Read by QxMD]

O’Connor M1, McDaniel N, Brady WJ. The pediatric electrocardiogram. Part I: Age-related interpretation. Am J Emerg Med. 2008 Feb;26(2):221-8. PMID: 18272106[PubMed] [Read by QxMD]

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