A excellent description of the neonatal electrocardiogram has been made by Schwarz et al.[1][2]

Heart Axis

Normal heart axis values[3]
Age QRS Axis Normal Values Abnormal Values Description
Adult -30° to 90°
<-30°
-30° to -45°
-45° to -90°
90° to 120°
90° to 180°
Left-axis deviation
Moderate left-axis deviation
Marked left-axis deviation
Moderate right-axis deviation
Marked right-axis deviation
8 to 16 years 0° to 120° >120° Right-axis deviation
5 to 8 years 0° to 140° >140°

<0°

Right-axis deviation

Left-axis deviation

1 year to 5 years 5° to 100° >100° Right-axis deviation
1 mo to 1 y 10° to 120° >120°

<10° to -90°

Right-axis deviation

Left-axis deviation

Neonate 30° to 90° >190° to -90°

<30° to <-90°

Extreme right axis deviation

Left axis deviation

Conduction

RBBB: if consistent morphology and if QRS width >90ms in children < 4 years and >100ms in children 4-16 years[3] LBBB: if consistent morphology and QRS width >90ms in children < 4 years and >100ms in children 4-16 years[3]

Normal neonatal ECG standards

Normal neonatal ECG standards
Age group Heart rate
(beats . min-1)
Frontal plane
QRS axisa
(degrees)
P wave
amplitude
(mm)
P-R
intervala
(s)
QRS
durationa
V5
Q IIIc (mm) QV6c (mm) RV1b (mm) SV1b (mm) R/S V1c RV6b (mm) SV6b (mm) R/S V6c SV1 + RV6c (mm) R + SV4c (mm)
0–1 days 93–154 (123) +59 to +192 (135) 2·8 0·08–0·16 (0·11) 0·02–0·08 (0·05) 5·2 1·7 5–26 0–22·5 9·8 0–11 0–9·8 10 28 52
1–3 days 91–159 (123) +64 to +197 (134) 2·8 0·08–0·14 (0·11) 0·02–0·07 (0·05) 5·2 2·1 5–27 0–21 6 0–12 0–9·5 11 29 52
3–7 days
7–30 days 1–3 months

References

  1. Schwartz PJ, Garson A Jr, Paul T, Stramba-Badiale M, Vetter VL, Wren C, and European Society of Cardiology. Guidelines for the interpretation of the neonatal electrocardiogram. A task force of the European Society of Cardiology. Eur Heart J. 2002 Sep;23(17):1329-44. DOI:10.1053/euhj.2002.3274 | PubMed ID:12269267 | HubMed [schwarz1]
  2. Schwartz PJ, Paul AG Jr, Stramba-Badiale M, Vetter VL, Villain E, Wren C, and Task Force of the Comittee for Practice Guidelines and Policy Conferences of the European Society of Cardiology. Report from the Task Force of the European Society of Cardiology for the interpretation of the neonatal electrocardiogram. Cardiol Young. 2002 Dec;12(6):592-608. DOI:10.1017/s1047951102001087 | PubMed ID:12739597 | HubMed [schwarz2]
  3. Surawicz B, Childers R, Deal BJ, Gettes LS, Bailey JJ, Gorgels A, Hancock EW, Josephson M, Kligfield P, Kors JA, Macfarlane P, Mason JW, Mirvis DM, Okin P, Pahlm O, Rautaharju PM, van Herpen G, Wagner GS, Wellens H, American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology, American College of Cardiology Foundation, and Heart Rhythm Society. AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part III: intraventricular conduction disturbances: a scientific statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society: endorsed by the International Society for Computerized Electrocardiology. Circulation. 2009 Mar 17;119(10):e235-40. DOI:10.1161/CIRCULATIONAHA.108.191095 | PubMed ID:19228822 | HubMed [aha]

All Medline abstracts: PubMed | HubMed