The ABC of Pediatric ECG Mohamed Hamdan, MD, FAAP, FACC Assistant Professor of Pediatrics Columbia University College of Physicians and Surgeons, NY, USA Consultant Pediatric Cardiologist & Co-Director KidsHeart Medical Center Dubai-Abu Dhabi-Al Ain, UAE
Normal Values
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14-Lead EKG 6 Limb leads I, II, III: Simple avf, avr, avl: Augmented 6 Chest leads V1-V6 2 Right Chest leads V3R, V4R
Nomenclature Right leads avr, V1, V3R, V4R Left Leads I, avl, V6 Inferior Leads II, III, avf Transitional Leads V2-V5 IGNORE
Practical Approach A) Age/ Calibration/ Speed B) LIMB LEADS C) CHEST LEADS 1. Rate 1. T waves (V1 & V6) 2. Axis (P& QRS) 2. R & S (V1 & V6) 3. NSR 3. RSR (V1) 4. P waves & PR interval (II) 4. ST Segments 5. Q waves (III) 5. QTc
A) Age/ Calibration/ Speed A.1) Speed: 25 mm/sec 1 small box = 0.04 sec (or 40 msec) 1 large box = 0.2 sec (or 200 msec) A.2) Calibration: 1 mv = 10 mm 1 small box = 1 mm (0.1 mv) ½ standard: 1 mv = 5 mm 1 small box = 0.2 mv (voltages x 2)
Full Standard Calibration
1/2 Standard Calibration
Electronic Interpretation GOOD for: rate, axis, intervals, RVH OK for: LVH BAD for: ST changes, Q waves, rhythm, QTc 12
10 yrs
B) Limb Leads 1. Rate 2. Axis (P&QRS) in I & avf 3. NSR 4. P-waves & PR interval (II) 5. Q-waves
Heart Rate 60 000/ RR interval in msec. 1 small box = 0.04 sec = 40 mesc. The Box method 300/No. of large boxes 1500/No. of small boxes
B) Limb Leads 1. Rate 2. Axis (P&QRS) in I & avf 3. NSR 4. P-waves & PR interval (II) 5. Q-waves
B2) P-wave Axis -90 +180 Low LA Rhythm High LA Rhythm Low RA Rhythm Normal High RA Rhythm 0 P in Lead I +90 P in Lead avf
9 yrs + I Normal (High RA) + avf
6 yrs
6 yrs - avf Abnormal (Low RA) + I
B2) QRS Axis
QRS Axis NW Axis Superior Axis -90 +180 LAD LAD 0 Lead I RAD Normal Normal RAD +120 +90 Lead avf
Left Axis Deviation is NEVER normal (When QRS is ve in avf)
Causes of LAD in Pediatrics 1. AV canal (partial or complete) 2. Tricuspid atresia 3. WPW 4. Single ventricle 5. Left aneteior hemiblock 6. + LVH
20 months Left Axis Deviation
5 yrs Left axis deviation NW-axis
B) Limb Leads 1. Rate 2. Axis (P&QRS) (I & avf) 3. NSR (Normal Sinus Rhythm) 4. P-waves (II) 5. Q-waves
Normal Sinus Rhythm 1. Normal P-wave axis +ve in I & avf 2. One P : One QRS 3. Fixed P-wave morphology 4. Fixed PR interval I (+) avf (+)
2 yrs Normal sinus rhythm
7 yrs
7 yrs - avf Low RA rhythm + I
11 yrs
11 yrs Different P-wave axis Different P-wave morphology - avf + I Wandering Pacemaker
B) Limb Leads 1. Rate 2. Axis (P&QRS) (I & avf) 3. NSR 4. P-waves & PR interval (II) 5. Q-waves
B4) P-Waves Lead II Normal: 2.5 X 2.5 boxes 0.09 s X 2.5 mm Abnormal: RAE (P-pulmonale) LAE (P-mitrale)
2 month
2 yrs
B4) PR Interval Regardless the age: Normal 0.08-0.16 (2-4 small squares) Prolonged PR 1 st - degree AV block: No clinical significance Common in: ASD, repaired TOF Short PR interval: WPW Pompe
B) Limb Leads 1. Rate 2. Axis (P&QRS) (I & avf) 3. NSR 4. P-waves & PR interval (II) 5. Q-waves
B5) Q-Waves Not infarction Ventricular septum Look for lead III value for age Normal: Inferior leads, avr & V6 Up to 1 box wide X 5 boxes height (0.04 sec X 5 mm) Abnormal: Leads I & avl Wide (> small square = 0.04 sec.) Deep ((> 95 th percentile for age) (ALCAPA) (Infarction) (LVH)
2 yrs 2 years
4 months LVH
7 months ALCAPA
C) Chest Leads 1. T-waves (V1 & V6) 2. RSR 3. R & S (V1 & V6) 4. ST segments 5. QTc
C) Chest Leads 1. T-waves (V1 & V6) 2. RSR 3. R & S (V1 & V6) 4. ST segments 5. QTc
C1) T-Waves AGE V 1 V 6 < 1 wk + + 1 wk- adolescence - + > adolescence + +
1 day 1 day old Normal T-waves
3 months Normal T-waves
6 years Normal T-waves
15 yrs T-Waves Normal T-waves 3 wks
3 wks
3 wks Flat T-waves in V1: RVH
7 mo.
7 mo. +ve T-waves in V1: RVH
C) Chest Leads 1. T-waves (V1 & V6) 2. RSR (V1) 3. R & S (V1 & V6) 4. ST segments 5. QTc
C2) RSR Common in pediatrics: V 1 Can be: Normal RVH RBBB R R S
R R C2) RSR in V1 S QRS duration <= 0.08 sec 0.08-0.09 sec > 0.09 sec Height of R'? Incomplete RBBB RBBB < 10 mm >= 10 mm Normal RVH
6 yrs Normal QRS= 0.07 sec
16 mo. QRS= 0.05 sec RVH
3 yrs RBBB
8 yrs QRS= 0.12 sec.
8 yrs QRS= 0.12 sec.
8 yrs QRS= 0.12 sec. RBBB
C) Chest Leads 1. T-waves (V1 & V6) 2. RSR (V1) 3. R & S (V1 & V6) 4. ST segments 5. QTc
8 yrs S1 &/or R6 >98%: LVH R & S Waves
Normal Values
Normal Values in Neonates Age HR PR QRS Axis QIII RV1 SV1 RV6 SV6 <1 m 100-150 <150 ms <80 ms 0-150 <5 mm <20 mm <10 mm <10 mm <10 mm
C) Chest Leads 1. T-waves (V1 & V6) 2. RSR (V1) 3. R & S (V1 & V6) 4. ST segments 5. QTc
2 days ST depression or elevation >1mm DDx: Pericarditis, Strain, Non-specific
C) Chest Leads 1. T-waves (V1 & V6) 2. RSR (V1) 3. R & S (V1 & V6) 4. ST segments 5. QTc
How to calculate QTc Interval? 1. Find a nice Q & T 2. Find regular HR 3. Measure Q-T (multiply by 0.04) & 4. Measure preceding RR (multiply by 0.04) 5. Bazzet s formula: QTc= QT / RR
Step-Wise Approach A) Age/ Calibration/ Speed B) Limb Leads 1. Rate 2. Axis (P&QRS) 3. NSR 4. P waves & PR interval (II) 5. Q waves (III) C) Chest Leads 1. T waves 2. RSR (V1) 3. R & S in (V1 & V6) 4. ST segments 5. QTc
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