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Nightfloat Curriculum 2010-2011
LPCH Pediatric Residency Program
By Jennifer Everhart, MD
Learning Objectives
• Recognize common pediatric cardiac arrhythmias
• Recognize early signs of clinical
decompensation/hemodynamic instability
• Initiate management of arrhythmias in the
inpatient setting, including identifying and treating
reversible causes
• Review PALS algorithms for bradycardia &
Bradyarrhythmias - Symptoms
• General: altered LOC, fatigue,
lightheadedness, dizziness, syncope
• Hemodynamic instability: hypotension,
poor end-organ perfusion, respiratory
distress/failure, sudden collapse
Bradyarrhythmias - Causes
• 1º: Abnormal pacemaker/conduction system
(congenital or postsurgical injury),
cardiomyopathy, myocarditis
• 2º: Reversible Hs & Ts:
– Hypoxia
– Hypotension – H+ ions (acidosis)
– Heart block – Hypothermia – Hyperkalemia
– Trauma (head)
– Toxins/drugs (cholinesterase inhibitors, Ca++ channel blockers, βadrenergic blockers, digoxin, central α2-adrenergic agonists, opioids)
Bradyarrhythmias - Types
• Sinus bradycardia
– Physiologic (ie: sleep, athletes) vs. pathologic
(ie: abnormal lytes, infection, drugs,
hypoglycemia, hypothyroidism, ↑ICP)
• Sinus node block
↓Junctional beat
– Subsidiary pacemakers lead to atrial,
junctional, & idioventricular escape rhythms
Bradyarrhythmias – AV Blocks
EKG Findings
Prolonged PR interval
Causes include AV nodal disease, ↑vagal tone,
myocarditis, abn electrolytes (ie: ↑K+), MI, drugs (ie:
Ca++ channel blockers, β-blockers, digoxin), acute
rheumatic fever. Usually asymptomatic.
prolongation of PR
interval until atrial
impulse not conducted
to ventricles
Usually due to block within AV node. Caused by
↑parasympathetic tone, MI, drugs (ie: Ca++ channel
blockers, β-blockers, digoxin). Can cause dizziness.
Typically transient and benign; rarely progresses to
3rd degree heart block.
prolongation of PR
interval, inhibition of a
set proportion of atrial
Usually caused by defect in conduction pathway or
acute coronary syndrome, leading to block below AV
node & His bundle. Symptoms include palpitations,
presyncope, syncope. Can progress to 3rd degree
heart block; often requires pacemaker.
AV dissociation. No
atrial impulses are
conducted to the
Congenital or caused by conduction system disease
or injury (ie: surgery, MI). Most symptomatic form of
heart block: fatigue, presyncope, syncope. Usually
requires pacemaker (especially if acquired).
Mobitz type I
Mobitz type II
Causes & Clinical Significance
1st degree heart block
2nd degree heart block,
Mobitz I
2nd degree heart block,
Mobitz II
3rd degree heart block
Bradyarrhythmias - Management
• Stable patients:
– 12 lead EKG, +/- labs, consult cardiology
• Unstable patients:
– ABCs
– PALS Pediatric Bradycardia Algorithm
• Address reversible causes (Hs & Ts)
Tachyarrhythmias - Symptoms
• General: palpitations, lightheadedness,
syncope, fatigue, SOB, chest pain
– Infants: poor feeding, tachypnea, irritability,
sleepiness, pallor, vomiting
• Hemodynamic instability: respiratory
distress/failure, hypotension, poor endorgan perfusion, altered LOC, sudden
Tachyarrhythmias - Causes
• 1º: Underlying conduction abnormalities
• 2º: Reversible Hs & Ts
– Hypovolemia
– Toxins
– Hypoxia
– Tamponade (cardiac)
– H+ ions (acidosis)
– Tension pneumothorax
– Hypoglycemia
– Thrombosis (coronary, pulmonary)
– Hypothermia
– Trauma
– Hypo/Hyperkalemia
Tachyarrhythmias - Classification
• Narrow complex: sinus tachycardia,
supraventricular tachycardia, atrial
• Wide complex: ventricular tachycardia,
supraventricular tachycardia with
aberrant intraventricular conduction
Tachyarrhythmias - Types
• Sinus tachycardia
– Usually <220 bpm in
infants, <180 bpm in children
– P waves present and normal (upgoing in I, II,
AVF), narrow QRS, beat to beat variability
– Response to body’s need for increased
cardiac output or oxygen delivery (ie:
hypoxia, hypovolemia, fever, pain, anemia)
Tachyarrhythmias - Types
• Supraventricular tachycardia
– >220 bpm in infants, >180 bpm in children
– Abrupt onset; occurs intermittently
– Usually narrow QRS, absent or abnormal P
waves, no beat to beat variability
– Caused by accessory pathway reentry (ie:
WPW), AV nodal reentry, ectopic atrial focus
Tachyarrhythmias - Types
• Atrial flutter
– Sawtooth pattern on EKG
– Atrial rate 350-400/min; ventricular rate varies
• Ventricular tachycardia
– Wide QRS (>0.08 sec), P
waves may be unidentifiable or not related to QRS
– Caused by underlying heart disease, post-heart
surgery, myocarditis, cardiomyopathy, ↑QTc, ↑K+,
↓Ca++, ↓Mg++, drug toxicity
Tachyarrhythmias - Types
• Torsades de Pointes
– Variable polarity & amplitude of QRS, appearing
to rotate around the EKG isoelectric line
– A type of polymorphic VT
– Caused by long QT syndromes, ↓Mg++, drug
toxicities (including antiarrhythmics)
– Can deteriorate to ventricular fibrillation
Tachyarrhythmia vs. Artifact
• Differentiating arrhythmia from artifact:
– Sharp spikes from QRS complexes
superimposed on “arrhythmia”
– Wandering baseline
– Normal QRS complexes
in some leads
• Causes of artifact:
– Simultaneous use of other equipment,
muscle contractions, movement
Tachyarrhythmias - Management
• ABCs
• If pulse → PALS tachycardia algorithms
– Poor perfusion → Pediatric Tachycardia
With Pulses and Poor Perfusion algorithm
– Adequate perfusion → Pediatric Tachycardia
With Adequate Perfusion algorithm
• If no pulse → PALS Pediatric Pulseless
Arrest algorithm
Tachyarrhythmias - Management
• In general…
– Attach monitor/defibrillator, pulse ox;
establish vascular access
– Obtain appropriate labs (ie: blood gas, lytes)
– Identify & treat any reversible causes
• Torsades de Pointe or VT due to ↓Mg++
– Magnesium sulfate
Tachyarrhythmias – Management
• SVT with adequate perfusion
– Vagal maneuvers while preparing adenosine
• SVT with poor perfusion
– Immediate adenosine or cardioversion
• Consider vagal maneuvers if no delay
– Adenosine
• Rapid bolus then flush using proximal PIV or CVL
• 0.1 mg/kg; max 1st dose 6 mg; additional 0.2 mg/kg
if needed (max 2nd dose 12 mg)
– Cardioversion (0.5-1 J/kg; sedate if possible)
Case #1
• 9 year old boy admitted for asthma
exacerbation, noted to have heart rate
of 55.
Case #2
• 3 month old girl brought to ED for poor
feeding and fussiness, noted to have
heart rate of 230.
American Heart Association. 2005 American Heart Association (AHA)
Guidelines for Cardiopulmonary Resuscitation (CPR) and Emergency
Cardiovascular Care (ECC) of Pediatric and Neonatal Patients: Pediatric
Advanced Life Support. Pediatrics 2006;117;e1005-1028.
Fleisher GR, et al. Textbook of Pediatric Emergency Medicine 5th Edition.
Lippincott Williams & Williams, 2006.
Pediatric Advanced Life Support. American Heart Association, 2006.
Thaler MS. The Only EKG Book You’ll Ever Need 4th Edition. Lippincott
Williams & Williams, 2003.
Zaoutis LB and Chiang VW. Comprehensive Pediatric Hospital Medicine.
Mosby Elsevier, 2007.