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!