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Cardiac arrhythmias in children
Definition, identification and management
Emphasis on SVT
Otto H. P. Teixeira, MD, FRCPC, FACC
Conflict of interest
None
Conduction system of the heart
What is an
arrhythmia?
An arrhythmia is an abnormal heart rhythm • Sinus arrhythmia
• Premature ventricular beats (PVCs)
• Premature atrial beats (PACs)
What is an
Arrhythmia?
• An arrhythmia is an abnormal heart rhythm What is an
Arrhythmia?
• An arrhythmia is an abnormal heart rhythm • Bradycardia is when the heart rate is too
slow
What is an
Arrhythmia?
• An arrhythmia is an abnormal heart rhythm • Bradycardia is when the heart rate is too
slow
• Tachycardia is when the heart rate is too fast for the age
Normal heart rates in children
Nelson Textbook of Pediatrics 19th ed.
Elsevier/Saunders 2011: 1613‐16 AGE
Premature
0-3 mo
3-6 mo
6-12 mo
1-3 yr
3-6 yr
6-12 yr
12+yr
HEART RATE
120-170*
100-150*
90-120
80-120
70-110
65-110
60-95
55-85
Cardiac arrhythmia in children
What's "too slow" ?
• newborn: less than 80 beats a minute. • a trained teenage athlete: 50 beats a minute
Cardiac arrhythmia in children
Symptoms of bradycardia
•
•
•
•
•
Fatigue
Dizziness
Lightheadedness
Fainting or near‐fainting spells
In extreme cases, cardiac arrest may occur
Supraventricular tachycardia (SVT)
All forms of tachycardia except VT *
* Van Hare G. Supraventricular tachycardia. In: Kliegman, Stanton, St. Geme, Schor, Behrman, eds. Nelson Textbook of Pediatrics 19th ed. Elsevier/Saunders 2011: 1613‐16 SVT in children
 Most common form of tachycardia in children:  1 : 250‐1000 (Gillette & Garson) SVT in children
 Most common form of tachycardia in children:  1 : 250‐1000 (Gillette & Garson)  Narrow QRS complexes often with no discernible “P” wave
 HR: 150‐300 bpm and unvarying
Mechanisms of Arrhythmias
Classifying tachycardia: frequency
Common:
AV reentry
Less common:
atrial
Uncommon:
AV node reentry
Rare:
other
SVT in children
Re‐entrant:
with accessory pathway without pathway
SVT in children
Re‐entrant:
with accessory pathway without pathway
Ectopic or automaticity: AET, JET
AV re‐entrant tachycardias
Reentry: most common etiology in children AVRT, AVNRT: age dependent

Narrow QRS: usual

1:1 AV conduction: usual

Sudden onset and cessation
SVT in children
Etiology
Reentry:
AVRT: most common in infants
Accessory connection anywhere in the AV ring ‐ WPW, Mahaim tracts, others
AVNRT: adolescents and adults
AV peri‐nodal area: dual AV node “slow‐fast” AV node tracts
SVT in children
HR 215, occasional “P wave” seen
SVT in children
HR 187 bpm: P waves not discernible
AV re‐entrant tachycardias
• WPW: 1 : 1000 • 25 % of SVT

orthodromic: narrow QRS during tachycardia

antidromic: broad QRS (indistinguishable from VT)
WPW
AV re‐entrant tachycardias
Orthodromic tachycardia
using an accessory
pathway in WPW
Activation: AV node, HisPurkinje system, ventricle,
accessory pathway, atria. P
wave closely follows the
QRS PR > RP
AV re‐entrant tachycardias
Antidromic tachycardia:
antegrade conduction may lead
to atrial fibrillation and VF:
risk of SCD
AV nodal re‐entrant tachycardia: AVNRT
 Dual pathways within the AV node
“slow-fast” AV nodal tracts
More common in adolescents and adults
May cause syncope
May respond to beta blockers and
ablation*
* Teixeira OH, Bilaji, Gillette PC. RF catheter ablation of
atrioventricular nodal reentrant tachycardia in children. PACE 1994;
17:1621-1626.
Management: SVT in children  Evaluate
General: IV, O2, capillary filling, BP
12‐lead ECG (may double speed): REENTRY?
Stable?
1. Vagal maneuvers: infant ‐ modified diving reflex (ice to face); older ‐ gag, head immersion in water, Valsalva
Management (cont’d)
2. Adenosine: 0.1 mg/kg mx 6 mg
ECG rhythm should be running
Management (cont’d) • Adenosine: 0.1 mg/kg mx 6mg. ECG rhythm should be running
f a i l e d!?
• Check tracing: reentry? check IV
Double dose to mx. 12 mg
Management (cont’d)
3. Consider synchronized DC cardioversion:
0.5‐2 Joules/kg
failed!?
• Check: equipment, paddles, position, coupling gel, contact
• Repeat: double dose
4. Overdrive pacing: PM, esophageal lead
5. Other drugs:
• Amiodarone: 5 mg/kg IV over 20‐60 min
• Procainamide: 15 mg/kg IV over 30‐60 min
Question
• One month‐old male with narrow QRS heart rate of 320 bpm and tachypnea, poor peripheral pulse. Your treatment of choice includes all, EXCEPT:
• 1. Vagal maneuvers, ie, ice to face.
Question
• One month‐old male with narrow QRS heart rate of 320 bpm and tachypnea, poor peripheral pulse. Your treatment of choice includes all, EXCEPT:
• 1. Vagal maneuvers, ie, ice to face.
• 2. Adenosine 0.1‐0.2 mg/Kg IV push
Question
• One month‐old male with narrow QRS heart rate of 320 bpm and tachypnea, poor peripheral pulse. Your treatment of choice includes all, EXCEPT:
• 1. Vagal maneuvers, ie, ice to face.
• 2. Adenosine 0.1‐0.2 mg/Kg IV push
• 3. Verapamil 0.1 mg/Kg IV push
Question
• One month‐old male with narrow QRS heart rate of 320 bpm and tachypnea, poor peripheral pulse. Your treatment of choice includes all, EXCEPT:
• 1. Vagal maneuvers, ie, ice to face.
• 2. Adenosine 0.1‐0.2 mg/Kg IV push
• 3. Verapamil 0.1 mg/Kg IV push
• 4. Synchronized DC cardioversion: 0.5‐1.0 J/Kg
Ectopic or automaticity: AET, JET
SVT in children
Etiology
Automaticity: atrial ectopic tachycardia (AET)
junctional ectopic tachycardia (JET)
AET
 Atrial automatic focus: incessant , may be associated with cardiac dysfunction
 Insidious onset with “warm‐up” and “cool‐down”
 Abnormal “P” wave axis and PR interval
 Rate variation
 May have periods of sinus rhythm during sleep: P changes
The P wave morphology depends on the position of the focus May appear like sinus tachycardia: RP interval is longer than the PR. The P waves may be blocked (not shown).
AET
AET • Rarely needs emergency treatment
• Adenosine may work and helps diagnosis:
P waves revealed during adenosine ‐
induced AV block
Inappropriate sinus tachycardia (Bauernfeind R et al An Intern Med 1979; 91:702‐710)
Chaotic or multifocal AET
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•
•
•
•
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> 3 ectopic Ps
Frequent blocked Ps
Varying PR
Occurs mostly in infants < 1 yr
Difficult single drug management
May improve spont by 3 yr of age
Chaotic or multifocal AET
•
•
•
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•
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> 3 ectopic Ps
Frequent blocked Ps
Varying PR
Occurs mostly in infants < 1 yr
Difficult drug management
May improve spont by 3 yr of age
JET
• Uncommon; often post‐op
• EKG: narrow QRS with V rate faster than A, and AV dissociation
• Diff. to distinguish from VT: ”Why?”
• Rates 180‐240 bpm
• Congenital: rare may be seen pre‐natally: HR 370 bpm
JET
First‐degree AV block is typical and 2nd‐degree AVB is common. The tachycardia and degree of AV block are influenced by the autonomic tone
 Lead II of a ECG from a patient
with postoperative JET. “Ps”
are marked with blue lines
and QRS complexes are in red

JET
• Difficult management: post‐op
• several drugs may have to be tried in stepwise fashion: amiodarone, propafenone, sotalol
Question
In atrial ectopic tachycardia (AET):
• 1. The etiology is automaticity
Question
• In atrial ectopic tachycardia (AET):
• 1. The etiology is automaticity
• 2. Warm‐up and cool‐down may be seen
Question
•
•
•
•
In atrial ectopic tachycardia (AET):
1. The etiology is automaticity
2. Warm‐up and cool‐down may be seen
3. P wave is present
Question
•
•
•
•
•
In atrial ectopic tachycardia (AET):
1. The etiology is automaticity
2. Warm‐up and cool‐down may be seen
3. P wave is present
4. Blocked Ps may be seen
Question
•
•
•
•
•
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In atrial ectopic tachycardia (AET):
1. The etiology is automaticity
2. Warm‐up and cool‐down may be seen
3. P wave is present
4. Blocked Ps may be seen
5. All of the above
Atrial flutter
Reentry:
• Intra‐atrial reentry: note flutter waves (“saw‐tooth”), variable AV conduction
Atrial flutter
Atrial flutter: management
• 1. Synchronized DC cardioversion: choice treatment
• 2. Chronic flutter: risk of embolism > anticoagulartion
• Digoxin, B‐blockers, Ca blockers: delay AV node conduction
• Other drugs used to maintain sinus rhythm: procainamide, propafenene, amiodarone, sotalol
Atrial flutter: management
Atrial flutter: unstable
1. Synchronized DC cardioversion: half doses 2. Calcium channel blockers:
Diltiazem: 0.25‐0.35 mg/kg over 2‐15 min (may repeat) Drip: 0.5‐0.15 mg/kg/h
3. Overdrive pacing: PM, esophageal lead
4. Other drugs: procainamide, amiodarone, sotalol
Atrial flutter: management
• Neonatal flutter: digoxin for 1 yr after which arrhythmia may not recur
Atrial fibrillation
• Uncommon
• Often associarted with atrial problem: enlargement
• Seen in older children with atrial enlargement or, rheumatic valve stenosis or surgery
Atrial fibrillation: management
• Rate control: Ca blockers
• No digoxin if there is WPW
• Acute: Procainamide, amiodarone, DC cardioversion
Anticoagulation may be necesssary
Conclusions
SVT is the most common tachyarrhythmia in children
The etiology is primarily reentry
In older children it is usually well tolerated
In infants it may be a life‐threatening emergency
GOOD LUCK !
Nodal rhythm
Note AV dissociation with “Ps” appearing from time to time
Nodal bradycardia: HR 37bpm
3‐ year‐old girl with hyperthyroidism (Pediatr 1997; 100.2.e11). Flutter 1:1 conduction. Note negative flutter waves in V1‐V3 and II, III, aVF
ATRIAL FLUTTER