Interpretation of ECG in children
Piotr Kędziora
•Department of Pediatric Cardiology and Rheumatology
•Medical University of Lodz
Conduction system of the heart
Normal
QRS<0,08
Wide
QRS>0,08
2
Determination of cardiac rhythm
Sinus rhythm:
HR is normal and regular
Each QRS complex is preceded by P wave.
P waves are positive (upright) in leads I i II,
and negative (inverted) in aVR.
Normal PR interval
3
Sinus tachycardia 182 bpm
• Normal P wave precedes each QRS with normal PR interval
• Sinus tachycardia rates vart with ages:<1 year >160-180
bpm, 1-3 y >150 bpm, >3 y >140 bpm, >12 y >100-120 bpm
• Associated with: crying, anxiety, pain, fever, hypovolemia,
exertion, anemia, heart failure
Sinus bradycardia
• Slow sinus rate for age: HR<100bpm age 0-3 years (80 during sleep),
HR<60-80 bpm age 3-9 years, HR<60 bpm age>9 years
• P waves of normal morphology and axis
• Constans, normal PR interval with 1:1 a-v conduction
• Commonly seen in athletes, in anorexia, sinus node dysfunction
• Sinus rhythm with phasic variation in heart rate
• Normal P wave precedes each QRS complex
• Normal PR interval
• Respiratory form of sinus arrhythymia: sinus rate gradually
increases during inspirations, slows down with expiration
• Very common in young children (2-10 years of age)
• Normal variant
Supraventricular (atrial) premature beats/contraction SVPB
Premature atrial complex (PACs)
• Premature P wave differs in axis and morphology from sinus
P waves, PR interval may be prolonged with PAC, premature
QRS is similar to or the same as normal QRS
• P positive (high part of atrium)
• S -premature beat (P in T before QRS)
•  -non-conducted PAC (P wave is buried in T wave of the
preceding beat and PAC is not conducted to the ventricle.
• A –PAC with aberrant conduction
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A
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A
Supraventricular premature beats/contraction
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Supraventricular premature beats/contraction SVPB
Premature atrial complex (PACs)
• P negative low part of atrium
• Supraventricular couplets
Wandering atrial pacemaker
• P wave morphology (shape) shifts (changes) gradually as
sinus rate slows down, P wave changes to become negative
(lead II). It is not associated with premature beats or
tachycardia
• (at least 3 morphology of P waves)
Supraventricular (atrial) tachycardia 225 bpm
• Regulary regular tachycardia, relationship between P and
QRS complex (P can be before QRS)
• SVT QRS complexes are smilar to or the same as normal
QRS complexes
• SVT starts and ends rapidly
Nodal tachycardia
premature QRS complex without preceding P wave
QRS morphology differs (is bizarre) from sinus conducted beat and long
in duration (wide QRS)
T waves point at the direction opposite to the QRS complex
full compensatory pause (two normal cycles 2xRR)
Ventricular premature contractions/beats (VPCs/VPB)
• Ventricular couplets (paired PVCs)
• Ventricular complex
Ventricular bigeminy
• Regulary irregular rhythm is present with the
abnormal beat (PVB) coming every other beat
Ventricular active rhythm
HR<120/min and/or similar to sinus rhythm
Ventricular tachycardia 140 bpm
• Ventricular tachycardia 220 bpm
• Regular wide complex tachycardia
• Atrioventricular dissociation
First degree atrioventricular (AV) block
 500ms
• Prolonged PR interval
• <1 year: PR>0,14-0,15sec, 1-5 years: PR>0,16 sec, >5 year: PR>0,18 sec
• when: high vagal tone, acute rheumatic fever, hyper/hypo-kalemia,
hypermagnesema, ASD, AVSD
Second degree atrioventricular (AV) block
I type: Mobitz I (Wenckebach phenomenon)
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Progressive PR lenthening prior to block
Normal finding during sleep
Second degree atrioventricular (AV)
II type block (Mobitz II 2:1)
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• No change in PR interval before block
• 2:1 a-v block: every other P wave followed by QRS
• Second degree atrioventricular (AV)
II type block (Mobitz II 3:1)
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Third degree a-v block
Complete dissociation between P waves and QRS
complexes and atrial rate is faster than ventricular rate
escape rhythm may be junctional or ventricular
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• Maternal autoimmune disorder, LQTS,
• structral heart disease (AVSD,HLHS, TGA)
• Myocarditis, Lyme disease (Lyme borreliosis)
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preexcitation
Preexcitation
• Anomalous atrioventricular conduction
• Rapid conduction pathway between atrium and ventricle,
bypassing normal AV node with slower conduction
•P
P
P
P
P
Short PR interval
• adults PQ < 120 ms
• Children PQ < 90 ms)
Wide QRS
• adults QRS >120 ms
• children QRS > 90 ms)
Delta wave
Wolff-Parkinson-White type
• Short PR interval, less than lower limits of normal
for the patient’s age: <12 months 0,075 sec, 1-3
years 0,08 sec, 3-5 years 0,085 sec, 5-12 years
0,09 sec, 12-16 years 0,095 sec, adults 0,12 sec
• Delta wave (initial slurring of QRS complex)
• Wide QRS duration (beyond the upper limits of
normal)
WPW syndrome
• Short PR
• Delta wave
• Wide QRS
•WPW
Atrio-ventricular reentry tachycardia
AVRT
Reentry mechanism
Ortodromic
tachycardia
80%
Antydromic
tachycardia
Atrio-ventricular reentry tachycardia
AVRT 190bpm
•I
• How to stop supraventricular (atrial, nodal,
atrio-ventricular) tachycardia
• Non-pharmacological methods
• Pharmacological methods
Vagal Maneuvers
• Valsalva maneuver (voluntary forced exhalation
against a closed glottis which is similar to bearing
down as if having a bowel movement)
• Carotid massage
• Deep inspiration with short breath holding
• Thermal shock (drinking icy water or putting bag
with ice cubes on face or chest)
• Provoking vomits
Adenosine (ADP)
I dose of adenosine (Adenocor 0,1mg/kg iv)
after 3 min. II dose of adenosine (Adenocor 0,2mg/kg)
III dose 0,3mg/kg
Amiodaron (non-competitve inhibitor of adrenegic
receptors)
5mg/kg in 5% glucose iv over 10min
next 5mg/kg iv for 2 hours
after 12 hours the same dose
(I day: 15mg/kg, II day: 10mg/kg, III day 5mg/kg)
Interrupt SVT in (WPW)
adenosine ADP (purine nucleoside) Adenocor(0,1 mg/kg)
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HR=600/2 or 3000/10 = 300/min