Pediatric ECGs

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	90–166 (129)	+77 to +187 (132)	2·9	0·08–0·14 (0·10)	0·02–0·07 (0·05)	4·8	2·8	3–24	0–17	9·7	0·5–12	0–9·8	10	25	48
7–30 days	107–182 (149)	+65 to +160 (110)	3·0	0·07–0·14 (0·10)	0·02–0·08 (0·05)	5·6	2·8	3–21·5	0–11	7	2·5–16	0–9·8	12	22	47
1–3 months	121–179 (150)	+31 to +114 (75)	2·6	0·07–0·13 (0·10)	0·02–0·08 (0·05)	5·4	2·7	3–18·5	0–12·5	7·4	5–21	0–7·2	12	29	53
a 2nd–98th percentile (mean) b 2nd–98th percentile (1 mm=100 µV) c 98th percentile (1 mm=100 µV)

Distinguishing tachyarrhythmias in infants

Distinguishing tachyarrhythmias in infants

	Sinus tachycardia	SVT	Atrial flutter	VT
History	Sepsis, fever, hypovolaemia, etc.	Usually otherwise normal	Most have a normal heart	Many with abnormal heart
Rate	Almost always <230 b/min	Most often 260–300 b/min	Atrial 300–500 b/min. Vent. 1:1 to 4:1 conduction	200–500 b/min
R-R interval variation	Over several seconds may get faster and slower	After first 10–20 beats, extremely regular	May have variable block (1:1, 2:1, 3:1) giving different ventricular rates	Slight variation over several beats
P wave axis	Same as sinus almost always visible P waves	60% visible P waves, P waves do not look like sinus P waves	Flutter waves (best seen in LII, LIII, aVF, V1)	May have sinus P waves continuing unrelated to VT (AV dissociation), retrograde P waves, or no visible P waves
QRS	Almost always same as slower sinus rhythm	After first 10–20 beats, almost always same as sinus	Usually same as sinus, may have occasional beats different from sinus	Different from sinus (not necessarily ‘wide’)
SVT = Supraventricular tachycardia VT = ventricular tachycardia

References

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