1. INTERPRETING
PEDIATRIC
EKG’S
12 SEPTEMBER 2012
JOSEPH MAY, MD, MPH

2. REMEMBER THE
BASICS
1. Rate
2. Rhythm
3. P wave, PR interval
4. QRS axis, QRS interval
5. T wave, ST segment, QTc

3. CASE #1 14 year old 42 kg girl presents to ED
with dizziness

4. Divide 300 by “large” box count: 300, 150,
RATE 100, 75, 60, 50…

5. CASE #2 11 year old male while asleep

6. SINUS RHYTHM
• P wave before every QRS
• QRS after every P
• All P waves look the same
• Normal P wave axis (0 to 90 ) with upright
P in leads I and aVF

7. DIAGNOSIS:
SINUS RHYTHM?
Respiratory sinus arrhythmia
2

8. SINUS ARRHYTHMIA
• NORMAL variant in HR with respiration
• Increases with inspiration and decreases
with expiration
• Variation can be up to 100%
• More pronounced in younger patients

9. HEART BLOCK

10. HEART BLOCK

11. ATRIAL ARRHYTHMIAS

12. VENTRICULAR ARRHYTHMIAS

13. DIAGNOSIS: WOLFF-PARKINSON-WHITE WITH
INTERMITTENT PRE-EXCITATION 4
CASE #3 14 year old girl presents to ED with
pounding in her chest

14. PR INTERVAL
• Time required for atrial depolarization and
conduction through the AV node
• Varies with age and heart rate (increases
with age and slow heart rate)
• Shortened: WPW, normal variant, glycogen
storage disease
• Lengthened: 1st Degree Heart Block

15. WPW

16. WPW + SVT

17. AFIB in WPW
WPW + A FIB

18. P WAVE MORPHOLOGY
ATRIAL ENLARGEMENT
RIGHT ATRIAL ENLARGEMENT
• Tall P waves > 3mm (3 boxes)
Right atrial enlargement = tall P waves (> 3 boxes)
• most often in lead II or V1, but can be seen in any
• Usually in lead II or V1 lead

19. LEFT ATRIAL ENLARG
ATRIAL wave duration > 0.08 sec (2 boxes w
• P ENLARGEMENT
<12 mo
Left atrial enlargement = wide P waves
• P wave duration > 0.10 sec (2.5
• P wave duration > 0.08 sec (2 boxes wide) in infant boxes
< 12 months mo
>12
• > 0.10 sec (2.5 boxes wide) in child > 12 months
• most often in lead II or V1, but can be s
lead
• P wave often notched or diphasic

20. 3
Northwest axis (left axis deviation)
CASE #4
DIAGNOSIS:
2-hr old male born to a G4P4 51 yo

21. ay be affected by ventricular
hypertrophy, bundle branch block,
AXIS
or other conduction disturbances
AXIS
• Determined using the limb leads
AXIS
aVR The aVL
opposite side
Axis is of each lead
etermined
using the
also has an
I
mb leads axis angle.
This
aVF portion
III II
is designated
the negative
pole of the
lead. 7

22. AXIS
AXIS LEAD I LEAD aVF
O to +90
0 to -90
+90 to ±180
-90 to ±180

23. AXIS AXIS
AXIS
Compare
the axis to
normal
values for
the
patient’s
age

24. QRS FORCES FORCES
QRS
Right ventricular forces Left ventricular forces
R waves in V4R, V1, V2 R waves in V5, V6
S waves in V5, V6 S waves in V4R, V1, V2
LV FORCE
RV FORCE

25. DEXTROCARDIA
DEXTROCARDIA
If the heart is positioned in the right side of
the chest, voltages in V3R and V4R will be
larger than voltages in V3 and V4

26. DEXTROCARDIA
DEXTROCARDIA

27. HYPERTROPHY
RVH
• Large R in V1 for age
• Upright T in V1 after 3 days of age (normally may
become upright again as early as 6 years old)
• Q wave in V1, V3R, or V4R
• Pure R wave in V1 in child older than 6 months
LVH
• Large R in V6 for age

28. LEFT VENTRICULAR HYPERTROPHY
DIAGNOSIS:
8
ECG DONE AT HALF STANDARD
NORMAL?

29. RIGHT BUNDLE BRANCH BLOCK
Usually rSR’ in V1, V2 Slurred S in V5, V6
BBB
LEFT BUNDLE BRANCH BLOCK
Wide S in V1, V2 Usually rSR’ in V5, V6
LEFT BUNDLE BRANCH BLOCK

30. CASE #5 16 year old male in ED following CPR

31. REPOLARIZATION
T wave in V1
• Upright at birth
• Inverts after 1-3 days of life
• Stays inverted until preteen
• Flips back upright as teen/adult

33. LQTS

34. BRUGADA