Have you ever gotten an ekg while working in the Peds ED and thought, "uhhhh, this ekg looks concerning" and then you hand it to the Peds ED attending who shrugs and says, "relax, that's normal."? Just me? Okay, cool then stop reading this POTD and continue on with your day!
This POTD will focus on the Juvenile T-wave pattern, but I'll briefly note some other ekg features that may be normal in children.
EKG features that may be normal:
Heart rate > 100 beats/min
Apparent right ventricular strain pattern: T wave inversions in V1-3 (“juvenile T-wave pattern”), Right axis deviation, 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
Background
At birth, the right ventricle is larger and thicker than the left ventricle, which is due to the greater physiological stress placed upon it in utero (i.e. pumping blood through the relatively high-resistance pulmonary circulation). This produces an ekg picture similar to that of a right ventricular strain pattern in adults:
T-wave inversions in V1-3
Right axis deviation
Dominant R wave in V1
The right ventricular dominance of the neonate and infant is slowly replaced by left ventricular dominance. By ages 3-4, the pediatric ekg will largely resemble an adult's.
References:
Paediatric Electrocardiography by Steve Goodacre and Karen McLeod, from the BMJ’s “ABC of Clinical Electrocardiography” series (2002)
O’Connor M, McDaniel N, Brady WJ. The pediatric electrocardiogram. Part I: Age-related interpretation. Am J Emerg Med. 2008 Feb;26(2):221-8
Evans WN1, Acherman RJ, Mayman GA, Rollins RC, Kip KT. Simplified pediatric electrocardiogram interpretation. Clin Pediatr (Phila). 2010 Apr;49(4):363-72.