1. No category

Interpretation of arrhythmias in
the pediatric population
Rajesh Shenoy, M.D.
The Children’s Hospital at Montefiore
Pediatric ECG
Standardization
Paper speed is 25 mm/sec
1 large square = 0.2 sec
1 small square = 0.04 sec
Voltage 10 mm/mv
Algorithm for reading ECGs
• Rhythm : Sinus or Non-sinus
• Rate: 1500/ R-R interval (mm)
• Axis:
– QRS axis
– T axis
• Waves:
–
–
–
–
–
P wave (Atrial depolarization)
QRS complex (Ventricular depolarization)
ST segment
T wave (Ventricular depolarization)
U wave (Late phase of ventricular depolarization)
• Intervals:
– PR
– QRS
– QT/QTc
Rate
• Calculate both the ventricular and atrial rate
• In sinus rhythm, both are the same
• Many methods
– Heart rate scale
– Adults: 300/(No. of large squares b/w R-R)
– Children:1500/(No. of small squares b/w R-R)
Pediatric ECG – QRS Axis
Hexaxial Reference System
Pediatric ECG – Determining Axis
Using the Hexaxial Reference System
Normal axes
P wave axis: In sinus rhythm, 0 to +90
QRS axis:
1st month
+30 to +180
1-3 months
+10 to +125
3 mo-3 years
+10 to +110
> 3yrs
+20 to +120
Adults
-30 to +105
T wave axis:
Positive in I and aVF
Pediatric ECG – Whats the Axis?
What is the QRS Axis in this ECG?
Pediatric ECG – P Wave
• Tall P waves ( > 3 mm) indicative of
right atrial enlargement (P pulmonale)
• Wide P waves ( > 0.10 sec) indicative of
left atrial enlargement (P mitrale)
Pediatric ECG – PR Interval
• Beginning of the P wave to beginning of QRS
complex
• Normal PR interval
0 – 1 mo 0.12
6 – 12 mo0.14
3 – 8 yr 0.17
12 – 16 yr0.19
• Prolonged PR
•
•
•
•
Myocarditis
Rheumatic Fever
Digitalis toxicity
Hyperkalemia
• Short PR
• Preexcitation
• Pompe disease
1 – 6 mo
1 – 3 yr
8-12 yr
Adult
0.14
0.15
0.18
0.21
Pediatric ECG – QRS Complex
• Q wave is narrow (0.02 sec) and short
(5 mv)
• Deep Q wave in left precordial leads =
LVH
• Q waves present in right precordial
leads = RVH
QRS Duration
Normal values
< 3 yrs
3 – 8 yrs
8 – 12 yrs
> 12 yrs
0.07 s
0.08 s
0.09 s
0.10 s
Prolonged QRS
Bundle branch block
WPW syndrome
R and S waves
• R/S progression: In older children,
adolescents and adults – the R voltage
increases, S voltage decreases
• Voltage: Useful in determining
hypertrophy of ventricles
Criteria for ventricular hypertrophy
• RVH
• LVH
Tall R in V1 or deep S in V6
Upright T wave in V1 after 48-72 hrs
Deep q wave in V1
RAD or strain pattern of T wave
Tall R in V1 or deep S in V6
Deep q wave in V6
LAD or strain pattern of T wave
Pediatric ECG – ST segment
• Normally isoelectric
• Depression/Elevation of 1 mm in limb
leads and 2 mm in precordial leads
normal
• Abnormalities
• Pericarditis
• Myocardial infarction
• Digitalis
Pediatric ECG – T wave
• Tall peaked T waves
• Hyperkalemia
• LVH
• Flat low T waves
•
•
•
•
•
•
Normal newborns
Hypokalemia
Digitalis
Pericarditis
Myocarditis
Hypothyroidism
• Inverted T wave in V1 normal in children
QTc interval
Select the longest QT interval
Measure QT interval from beginning of Q
wave to end of T wave
Measure R-R interval from the complex in
which QT is measured to preceding R
QTc interval (s)=
QT interval (s)
R-R interval(s)
QTc interval
• Normal QTc interval varies depending
on age
• QTc prolonged
>460 msec for male
>450 msec for female
• Causes of QTc prolongation
– Prolonged QT syndrome
– Macrolide antibiotics
– Antifungals
Algorithm for interpretation of
arrhythmias
R-R interval
Regular
QRS rate?
Irregular
Continuously
Irregular
Intermittently
Irregular
P-P regular?
QRS premature
Or delayed?
QRS duration
P-wave morphology, P-wave mean vector, P-QRS
R-R interval
Regular
QRS Rate
Decreased
Normal
Increased
QRS Duration
Normal
Normal
Normal
P-wave morphology, P-wave mean vector, P-QRS relationship
Normal
Normal
Normal
Sinus
bradycardia
Normal sinus
rhythm
Sinus
tachycardia
R-R interval
Regular
QRS Rate
Normal
QRS Duration
Prolonged
P-wave morphology, P-wave mean vector, P-QRS relationship
Normal
Bundle branch block
W-P-W morphology
RBBB
LBBB
WPW
R-R interval
Regular
QRS Rate
Normal
QRS Duration
Normal
P-wave morphology, P-wave mean vector, P-QRS relationship
Abnormal
Atrial flutter
Atrial fibrillation
Atrial flutter
Atrial fibrillation
R-R interval
Regular
QRS Rate
Normal
QRS Duration
Normal
P-wave morphology, P-wave mean vector, P-QRS relationship
Abnormal
Left atrial rhythm (high or low)
Low right atrial rhythm
Normal sinus rhythm
High left atrial rhythm
Low left atrial rhythm
Low right atrial rhythm
Junctional rhythm, retrograde ‘P’
R-R interval
Regular
QRS Rate
Normal
QRS Duration
Normal
P-wave morphology, P-wave mean vector, P-QRS relationship
Abnormal
Junctional rhythm
Mobitz type II block
Complete heart block
Fixed type II 2O AV Block
3O AV Block (AV dissociation)
R-R interval
Irregular
Continuously irregular
P-P interval
Regular
Irregular
2O AV block, type I
Sinus arrhythmia
2O AV block, type II
Wandering atrial pacemaker
Sinus arrhythmia
Type I 2O AV Block (Wenckebach)
Type II 2O AV Block
R-R interval
Irregular
Intermittently irregular
QRS premature
QRS duration
Normal
Conducted PAC
Premature junctional beat
Increased
PAC with aberration
PVC
Premature supraventricular beat, conducted
Premature junctional beat
Premature ventricular beat
R-R interval
Irregular
Intermittently irregular
QRS delayed
QRS duration
Normal
Type II AV block
Non-conducted PAC
Sinus pause+atrial escape
Sinus pause+junct escape
Increased
Sinus pause+vent escape
PAC, non-conducted
Sinus pause, atrial escape
Sinus pause, junctional escape
Sinus pause, ventricular escape