Pediatric ECGs are useful screening tools that we like to use for cases of Syncope or Chest Pain. While we may be actively looking for signs of Prolonged QTc, Brugada Sign, WPW, or Pulmonary Embolism, what we may find, instead, is huge voltages that seem to dominate the entire sheet. We’ve discussed the differences that must be accounted for when evaluating the Pediatric ECG previously. Let us take a moment to reiterate the issues to contemplate when considering either Left or Right Ventricular Hypertrophy:

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.
      • If RSR’ is present and 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.

Hypertrophy Ddx (abridged)

• Right Ventricular “Hypertrophy”
  • Diagnosis should be made cautiously in children < 6 months (due to age dependent factors). [O’Connor, 2008]
  • After 6 months, consider:
    • Pulmonic Valve Stenosis
    • Tetralogy of Fallot
    • Pulmonary Hypertension (older child/adolescent)
      • Significant Left-sided obstructive lesions may also lead to evidence of RVH by creating Pulmonary Hypertension.

• Left Ventricular “Hypertrophy”
  • Always unusual in a newborn [O’Connor, 2008]
    • Aortic Stenosis
    • Coarctation
    • Ventricular Septal Defect (VSD)
    • Patent Ductus Arteriosus (PDA)
  • In older children may be a sign of:
    • Hypertrophic Obstructive Cardiomyopathy. [O’Connor, 2008]
    • Or delayed Dx of:
      • Aortic Stenosis
        Coarctation
        Ventricular Septal Defect (VSD)
        Patent Ductus Arteriosus (PDA)

Moral of the Morsel

• Small chest walls will exaggerate precordial voltages. Know what is normal.
• Know the Evans’ Rules! While there are other “rules” for RVH and LVH, the ones described by Evans et al. are very practical. 
• The ECG generates a DDx not a Dx. Use the ECG as a way to help generate and sort through your Ddx.

References