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Arrhythmias
Clinical Diagnosis and Management
Normal ECGs in Pediatrics
• The normal ECG changes through development of the cardiac conduction system and evolving hemodynamics.
• Essential to understand normal before interpretation of abnormal rhythm.
Normal infant
Arrhythmia Analysis
May suspect arrhythmia with:• Irregular heart rate• Inappropriate rate for age• Unexplained heart failure• Known association of systemic or cardiac disease• Symptoms: syncope, palpitations, chest pain• Family history of arrhythmia or sudden death
Stable or Unstable?
Fast or Slow? Fast or Slow?
Wide or Narrow? Pulse or No Pulse? PacingAtropineAdrenalineIsoproterenol
PacingAtropineAdrenalineIsoproterenol
Consider CPR
ShockUnsynchronized2-4 j/kg
ShockSynchronized0.5-2 j/kg
SVT/VT VT/VFSVT
VTAberrated SVT
Regular or Irregular?
Vagal ManeuversAdenosine(therapeutic or diagnostic)
LidocaineSynchronizedcardioversion
Rate ControlConsider CV.
ECG!
Unstable Tachycardias
• Cardioversion will generally be indicated.
• Document rhythm and treatment with ECG.Limb leads (I, II and II) and
rhythm strips may be aqeduate.
• If patient has a pulse: synchronized cardioversion 0.5-2 j/kg.
• No pulse (VT/VF): unsynchronized cardioversion 2-4 j/kg.
Unstable Bradycardias
• Document rhythm and determine nature of bradycardia
• Pacing: external or esophageal• Atropine• Adrenaline• Isoproterenol
Sinus Node Dysfunction
• Rarely congenital.• Seen in association with atrial surgeries:
Mustard/Senning, Fontan, ASD repair.
• Therapy for symptomatic patients: pacing.
First Degree AV Block• Stable prolonged PR interval.• Can be seen as normal variant.• Possible causes:
Increased vagal tone
Medications
Non-sinus atrial rhythm
Conduction system disease or trauma
Type I (Wenckebach): Progressive lengthening of PR interval until non-conducted beat, with subsequent resetting of short PR. Causes grouped beats. Can be a normal variant, especially in sleep.
Second Degree AVB-Type II
Abrupt failure of AV conduction without prior PR prolongation. May progress to complete heart block.
Complete Heart Block
No atrial beats conduct to the ventricle.
Congenital Complete Heart Block
• Diagnosis in fetus : 85% born alive if normal fetal echo85% fetal death if structural heart disease
• Diagnosis in infants :85% survive beyond adolescence.
• Associated with maternal SLE, often asymptomatic.
Third Degree AV Block – Acquired
• Acquired CHB associated with:
Intracardiac surgeries
Muscular dystrophies
Myotonic dystrophy
Cardiomyopathy
Kearns-Sayre Syndrome
Infections: Acute rheumatic fever, Diptheria, Yersinia, RMSF, Lyme disease, bacterial endocarditis, viral myocarditis.
Third Degree AV Block - Management
• Initial: CPR, atropine, adrenergic agents, temporary pacing (transcutaneous or transvenous) may be indicated if patient symptomatic.
• Permanent pacing indicated for symptomatic CHB that is not expected to recover.
• Many infectious causes of CHB will recover with appropriate antimicrobial therapy.
Extrasystoles• Atrial
• Junctional
• Ventricular
Normal QRS tachycardias
• More accurate term than narrow• Re-entrant or Automatic?
Include:• Reciprocating• Primary Atrial• Automatic Junctional
Narrow QRS Tachycardia
Reciprocating
• Orthodromic Reciprocating Tachycardia• AV Nodal Reentry Tachycardia
Typical
Atypical• Permanent Junctional Reciprocating
Tachycardia
Re-entrant Circuit
Unidirectional block Slow retrograde conductionRapid conduction
Termination of re-entrant SVT
• Vagal maneuvers (ice bag to face in infants, Valsalva maneuvers in older children.)
• Adenosine
• If SVT reinitiates or does not respond, consider procainamide, esmolol or verapamil (only beyond infancy).
Adenosine• Slow or block conduction at the AV node.• Slow or block conduction at sinus node.• Very short acting.• Do not refrigerate.• Rapid IV bolus 0.1 mg/kg with rapid flush to
follow, both needles in hub of IV or with three-way stopcock, via proximal IV.
• Look for cough, flushing, change in ECG to indicate proper administration.
Adenosine effects
• None or transient slowing:
Sinus tachycardia or EAT
Inadequate dose or failed administration.
• Flutter waves/atrial fibrillation revealed.• Sudden termination:
Re-entrant rhythm involving AV node.
-Can resume almost immediately.
Adenosine effect on re-entrant SVT
Further Management
Patient/parent education: arrhythmia recognition and vagal maneuvers.
Medication: beta blockers, verapamil in older patients, digoxin less effective.
Digoxin and verapamil are contraindicated in preexcited patients.
Primary Atrial Tachycardias
• Atrial Flutter and Intraatrial Re-entry• Atrial Fibrillation• Automatic Ectopic Atrial Tachycardia• Chaotic Atrial Rhythm
Atrial Flutter on adenosine
Management of A-fib/flutter
• Termination: Rule out atrial thrombus
Ca++ Channel blockade for rate control
Synchronized cardioversion
Ibutilide/Pacing • Chronic therapy: Consider anticoagulation
Anti-arrhythmics
Anti-tachycardia pacing
Radiofrequency ablation (a-flutter)
Ectopic Atrial Tachycardia
• Automatic foci within the atrium.• Chronic, often incessant (risk of
tachycardiomyopathy).• Can be difficult to distinguish from sinus
tachycardia due to mild elevation in rate and subtle alterations in P wave morphology.
Management: anti-arrhythmics, ablation.
Ectopic Atrial Tachycardia
Junctional Ectopic TachycardiaAutomatic Mechanism
Congenital or Post-operative
Wide QRS Tachycardias
• Supraventricular tachycardias with aberrant conduction to the ventricle.
• Ventricular tachycardias.
Must assume all wide QRS tachycardias are ventricular in origin until proven otherwise!
Sustained Wide QRS Tachycardia
Stable Wide QRS Tachycardia
Regular Irregular
May try Adenosine firstConsider Lidocaine and
Procainamide
Do not use Adenosine:May be pre-excited Afib
Always have cardioversion available before administration of any medication.
Sedation/amnestic essential when cardioverting.
12 lead ECG
Aberrantly Conducted SVT
• Tachycardias with fixed or functional bundle branch block.
• Must have 1:1 AV relationship• Preexcited tachycardias:
Antedromic reciprocating tachycardias
Antedromic tachycardia via Mahaim
Bystander accessory pathways
Preexcitation
• Wolff-Parkinson-White Syndrome• Mahaim fibers
Nodo-fascicular connections
Nodo-ventricular connections
WPW syndrome
• Ebsteins anomaly• Corrected TGA• Mitral valve prolapse• Hypertrophic cardiomyopathy• Cardiac rhabdomyoma
ISOLATED IN >90% OF PATIENTS
WPW syndrome in corrected TGA
Ventricular Tachycardias
• Nonsustained• Sustained monomorphic reentry• Catecholamine-induced • Torsades de Pointes• Fascicular reentry• Incessant VT• Rapid polymorphic, ventricular flutter or
ventricular fibrillation
Chronic Management of VT
• Required for sustained VT, symptomatic patients.
• Will vary depending of type of VT.• Consider pediatric cardiology consultation.• Therapies include medication, surgical
interventions, ablation, and implantable cardioverter defibrillators.
Long QT syndrome
TORSADES DE POINTES
After the arrhythmic event
• Consider referral to pediatric cardiology• Consider esophageal or intracardiac EP
study• Medications• RFCA
Stable or Unstable?
Fast or Slow? Fast or Slow?
Wide or Narrow? Pulse or No Pulse? PacingAtropineAdrenalineIsoproterenol
PacingAtropineAdrenalineIsoproterenol
Consider CPR
ShockUnsynchronized2-4 j/kg
ShockSynchronized0.5-2 j/kg
SVT/VT VT/VFSVT
VTAberrated SVT
Regular or Irregular?
Vagal ManuversAdenosine(therapeutic or diagnostic)
LidocaineSynchronizedcardioversion
Rate ControlConsider CV.
ECG!