The diagnosis and management of supraventricular tachycardia in infants Part II: Management options

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The diagnosis and management of supraventricular
tachycardia in infantsPart II Management options

• Leonard Steinberg, MD
• Timothy Knilans, MD
• The Heart Center
• Childrens Hospital Medical Center
• Cincinnati, OH

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Overview

• Commonly available pharmacotherapies
• Acute management
• Subacute management
• Chronic management
• Radiofrequency ablation

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Therapy commonly used drugs

• Class I sodium channel blockers
• procainamide
• flecainide
• Class II ß-blockers
• propranolol
• esmolol
• Class III
• amiodarone
• sotalol
• Class IV Ca channel blockers
• verapamil
• Miscellaneous
• digoxin
• adenosine

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Drugs class IA (procainamide)

• Action
• slows conduction and prolongs refractoriness in
  muscle, specialized conduction tissue, and
  accessory pathways
• Indications
• atrial re-entry atrial fibrillation, atrial
  flutter
• accessory pathway tachycardia, particularly if
  short RP
• Considerations
• rapid metabolism gt frequent dosing
• serum concentrations and ECGs
• faster ventricular rates
• negative inotropy

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Drugs class IC (flecainide)

• Action
• slows conduction in muscle, conduction tissue,
  and APs
• suppresses automaticity
• Indications
• primary atrial tachycardias (reentrant and
  automatic)
• accessory pathway tachycardia, particularly if
  short RP
• Considerations
• negative inotropy
• faster ventricular rates
• proarrhythmia
• serum concentrations and ECGs
• ensure proper dosing
• avoid in structural heart defects

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Drugs class II (propranolol)

• Action
• suppresses automaticity (and ectopy)
• slows AV node conduction and prolongs
  refractoriness
• Indications
• automatic atrial tachycardia
• all reentrant tachycardias (reduces inciting
  events)
• Considerations
• QID dosing
• negative inotropy
• systemic effects

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Drugs class II (esmolol)

• Action
• suppresses automaticity (and ectopy)
• slows AV node conduction and prolongs
  refractoriness
• Indications
• automatic atrial tachycardia
• all reentrant tachycardias (reduces inciting
  events)
• Considerations
• very short half life
• negative inotropy
• systemic effects

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Drugs class III (amiodarone)

• Action
• slows conduction and prolongs refractoriness in
  all cardiac tissues
• suppresses automaticity
• Indications
• second choice therapy for many arrhythmias
• primary choice under special circumstances
• Considerations
• no negative inotropy proarrhythmia
• multiple systemic effects long half life

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Drugs class III (sotalol)

• Action
• prolongs conduction and refractoriness in all
  cardiac tissues
• suppresses automaticity
• Indications
• second (and possibly 1st) choice for many
  arrhythmias
• Considerations
• proarrhythmia

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Drugs class IV (verapamil)

• Action
• Prolongs conduction and recovery in AV node
• Indications
• ? AV node reentry tachycardia
• Considerations
• Circulatory collapse in infants

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Drugs digoxin

• Action
• prolongs conduction of AV node
• shortens conduction and refractoriness of muscle
  and accessory pathways
• Indications
• reentrant tachycardias involving the AV node
• rate control in primary atrial tachycardia
• Considerations
• avoid in WPW
• positive inotropy

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Drugs adenosine

• Action
• impairs conduction in AV node (and some accessory
  pathways)
• Indications
• acute termination of AV node dependent reentrant
  tachycardia
• diagnosis of SVT
• Considerations
• very short half life
• use with caution in patients on bronchodilators
• atrial fibrillation

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Acute therapy

• Vagal maneuvers
• Adenosine
• Atrial pacing
• D/C cardioversion
• Chronic (or sub-acute) therapy
• Address underlying metabolic and hemodynamic
  derangements
• Always perform with continuous rhythm recording

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Acute therapy adenosine and vagal maneuvers

• Indicated in AV nodal dependent tachycardias
• Adenosine may terminate reentrant atrial
  tachycardias
• No therapeutic benefit in automatic tachycardias
• Save vagal maneuvers for known diagnosis
• Adenosine response ? accessory pathway
• Watch for adenosine side effects

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Acute therapy atrial pacing

• Esophageal or post op atrial pacing wires
• Termination of reentrant SVT
• Diagnostic tool
• No termination of automatic tachycardia
• Overdrive pacing of automatic junctional
  tachycardia
• Equipment
• Arrhythmias

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Acute therapy D/C cardioversion

• Indicated for conversion of all reentrant
  tachycardias
• First choice for hemodynamically unstable patient
• 0.5 Joules/kg for most SVT
• 1 Joule/kg for atrial fibrillation
• Use previously required energy for repeat
  cardioversion
• Anterior posterior orientation

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Sub-acute therapy IV drugs

• Esmolol
• automatic atrial tachycardia
• Procainamide
• atrial and AV reentrant tachycardia
• Digoxin
• primary atrial tachycardias (rate control)
• occasionally for AV node dependent tachycardias
• Amiodarone
• tachycardias traditionally difficult to treat
• second line therapy
• severely depressed function

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Chronic therapy who to treat
ALL patients require close follow- up

• Well tolerated
• Normal function
• No recurrences
• Social

• Poor function
• Recurrent tachycardia
• Hemodynamic compromise
• Structural heart disease
• Social

Dont treat
Treat
No predictors of recurrence
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Automatic atrial tachycardia
Goals
Drugs

• Propranolol
• Flecainide
• Sotalol
• Special circumstances
• Amiodarone
• / Digoxin

• Suppress automaticity
• Control ventricular rate

Consideration
Reasonable control may be a satisfactory
endpoint
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Reentrant atrial tachycardia
Goals
Drugs

• Propranolol
• Flecainide
• Procainamide
• Sotalol
• Special circumstances
• Amiodarone
• / Digoxin

• Suppress ectopy
• Prevent reentry
• Control ventricular rate

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AV reentry tachycardia
Goals
Drugs
Drugs
Goals

• Suppress ectopy
• Attack pathway limb

• Propranolol
• Digoxin
• Flecainide (short RP)
• Procainamide (short RP)
• Sotalol
• Special circumstances
• Amiodarone

Consideration
Avoid digoxin when accessory pathway conducts
antegrade
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PJRT(permanent form of junctional reciprocating
tachycardia)
Goals
Drugs
Drugs
Goals

• Suppress ectopy
• Prevent reentry

• Propranolol
• Digoxin
• Flecainide
• Sotalol
• Amiodarone

Consideration
May be refractory to multiple therapies
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AV node reentry tachycardia
Goals
Drugs

• Propranolol
• Digoxin
• Sotalol
• Special circumstances
• ?? Verapamil
• Amiodarone

• Suppress automaticity
• Attack AV node

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Automatic junctional tachycardia
Goals
Drugs

• Restore AV synchrony
• Suppress automaticity
• drugs
• reduce fever (post op)
• reduce catecholamine state (post op)

• Amiodarone
• Flecainide
• Sotalol
• Procainamide
• hypothermia

Considerations
Considerations
Life threatening tachycardia Very difficult to
treat Post op option ECMO Congenital option RFA
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Atrial fibrillation
Goals
Drugs

• Prevent re-entry
• Control ventricular rate
• Evaluate for congenital heart disease
• Treat metabolic and hemodynamic derangements

• Amiodarone
• /- Digoxin

Considerations
Look for structural heart disease
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Chaotic atrial tachycardia
Goals
Drugs
Goals

• Digoxin
• Propranolol
• caution with lung disease

Suppress automaticity Control ventricular rate
Considerations

• Evaluate for respiratory illnesses, esp RSV
• Tachycardia unlikely to recur once respiratory
  illness resolves

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Choosing a drug other considerations

• Use what works
• Low threshold for in-patient monitoring
• Digoxin amiodarone do not depress function
• START SAFE

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Length of therapy

• Indications ??
• Most would treat through the first year of life
• Holter and event monitors helpful
• Inducibility ??
• Natural history favors discontinuing therapy

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Therapy radiofrequency ablation
No definitive indications established

• Refractory tachycardia
• Hemodynamic compromise
• Hemodynamic catheterization
• Impending loss of catheter
• access

• Expanding lesions
• Higher complication rate
• Natural history

Proceed
Wait
No long term data in humans
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Summary

• Therapy for SVT in infants can be divided into
  acute, sub-acute, chronic, and RF ablation
• Acute interventions should be performed with
  continuous rhythm monitoring to assist in
  diagnosis
• Use sub acute therapy when acute therapies fail
• Individualize chronic therapy to the infant and
  the tachycardia mechanism
• RF ablation rarely indicated