Normal paediatric ECG

ECG Features

The following electrocardiographic features may be normal in children:

  • Heart rate > 100 beats/min
  • Apparent right ventricular strain pattern:
    • Dominant R wave in V1
    • RSR’ pattern in V1
  • Marked sinus arrhythmia
  • Short PR interval (< 120ms) and QRS duration (<80ms)
  • Slightly peaked P waves (< 3mm in height is normal if ≤ 6 months)
  • Slightly prolonged QTc (≤ 490ms in infants ≤ 6 months)
  • Q waves in the inferior and left precordial leads


At birth, the right ventricle is larger and thicker than the left ventricle, reflecting greater physiological stresses placed upon it in utero (i.e. pumping blood through the relatively high-resistance pulmonary circulation).

This produces an ECG picture reflecting that of a right ventricular strain pattern in adults:

  • T-wave inversions in V1-3
  • Right axis deviation
  • Dominant R wave in V1

Conduction intervals (PR interval, QRS duration) are shorter than adults due to the smaller cardiac size.

Heart rates are highest in neonates and infants and decrease with age:

  • Newborn: 110 – 150 bpm
  • 2 years: 85 – 125 bpm
  • 4 years: 75 – 115 bpm
  • > 6 years: 60 – 100 bpm

The right ventricular dominance of the neonate and infant is gradually replaced by left ventricular dominance so that by 3-4 years of age, the paediatric ECG largely resembles that of adults.

ECG Examples
Example 1
ECG Incomplete RBBB Normal Pediatric 2 year old

This ECG of a healthy 2-year old boy displays many of the typical features of the paediatric ECG:

  • Heart rate of 110 bpm (normal for age)
  • Juvenile T-wave pattern (T wave inversion in V1-3)
  • Dominant R waves in V1-3
  • RSR’ pattern (partial RBBB morphology) in V1

Further normal ECG examples
Normal ECG : 1 Year
ECG Normal Pediatric ECG aged 1 year
  • Sinus rhythm ~150 beats/min
  • Right axis deviation
  • T wave inversion in V1-3
  • Dominant R wave in V1
  • Narrow QRS complex
Normal ECG : 2 Years
ECG Normal Pediatric ECG aged 2 years
  • Similiar findings to above, now with borderline right axis deviation and an upright T wave in V3
Normal ECG : 5 Years
ECG Normal Pediatric ECG aged 5 years
  • Rate has slowed, axis is normal, and QRS width has begun to normalise
  • Persisting T wave inversion in V2
Normal ECG : 10 Years
ECG Normal Pediatric ECG aged 10 years


Advanced Reading



LITFL Further Reading


MBBS (UWA) CCPU (RCE, Biliary, DVT, E-FAST, AAA) Adult/Paediatric Emergency Medicine Advanced Trainee in Melbourne, Australia. Special interests in diagnostic and procedural ultrasound, medical education, and ECG interpretation. Editor-in-chief of the LITFL ECG Library. Twitter: @rob_buttner

Emergency Physician in Prehospital and Retrieval Medicine in Sydney, Australia. He has a passion for ECG interpretation and medical education | ECG Library |

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