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The diagnosis and management of supraventricular tachycardia in infants Part II: Management options. Leonard Steinberg, MD Timothy Knilans, MD The Heart Center Children’s Hospital Medical Center Cincinnati, OH. Overview. Commonly available pharmacotherapies Acute management - PowerPoint PPT Presentation
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The diagnosis and management of supraventricular tachycardia in
infantsPart II: Management options
Leonard Steinberg, MDTimothy Knilans, MD
The Heart CenterChildren’s Hospital Medical Center
Cincinnati, OH
Overview
Commonly available pharmacotherapies
Acute management
Subacute management
Chronic management
Radiofrequency ablation
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
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 RPConsiderations
rapid metabolism > frequent dosing serum concentrations and ECG’s faster ventricular rates negative inotropy
Drugs: class IC (flecainide)
Action slows conduction in muscle, conduction
tissue, and AP’s suppresses automaticity
Indications primary atrial tachycardias (reentrant and
automatic) accessory pathway tachycardia, particularly
if short RPConsiderations
negative inotropy faster ventricular rates proarrhythmia serum concentrations and ECG’s
ensure proper dosingavoid in structural heart defects
Drugs: class II (propranolol)
Action suppresses automaticity (and ectopy) slows AV node conduction and prolongs
refractorinessIndications
automatic atrial tachycardia all reentrant tachycardias (reduces inciting
events)Considerations
QID dosing negative inotropy systemic effects
Drugs: class II (esmolol)
Action suppresses automaticity (and ectopy) slows AV node conduction and prolongs
refractorinessIndications
automatic atrial tachycardia all reentrant tachycardias (reduces inciting
events)Considerations
very short half life negative inotropy systemic effects
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
Drugs: class III (sotalol)
Action prolongs conduction and refractoriness
in all cardiac tissues suppresses automaticity
Indications second (and possibly 1st) choice for
many arrhythmiasConsiderations
proarrhythmia
Drugs: class IV (verapamil)
Action Prolongs conduction and recovery in AV
nodeIndications
? AV node reentry tachycardiaConsiderations
Circulatory collapse in infants
Drugs: digoxin
Action prolongs conduction of AV node shortens conduction and refractoriness of
muscle and accessory pathwaysIndications
reentrant tachycardias involving the AV node
rate control in primary atrial tachycardiaConsiderations
avoid in WPW positive inotropy
Drugs: adenosine
Action impairs conduction in AV node (and
some accessory pathways)Indications
acute termination of AV node dependent reentrant tachycardia
diagnosis of SVTConsiderations
very short half life use with caution in patients on
bronchodilators atrial fibrillation
Acute therapy
Vagal maneuversAdenosineAtrial pacingD/C cardioversionChronic (or sub-acute) therapyAddress underlying metabolic and
hemodynamic derangements
Always perform with continuous rhythm recording
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 diagnosisAdenosine response accessory pathwayWatch for adenosine side effects
Acute therapy: atrial pacing
Esophageal or post op atrial pacing wires
Termination of reentrant SVTDiagnostic toolNo termination of automatic tachycardiaOverdrive pacing of automatic junctional
tachycardia
EquipmentArrhythmias
Acute therapy: D/C cardioversion
Indicated for conversion of all reentrant tachycardias
First choice for hemodynamically unstable patient
0.5 Joules/kg for most SVT1 Joule/kg for atrial fibrillationUse previously required energy for
repeat cardioversion
Anterior posterior orientation
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
tachycardiasAmiodarone
tachycardias traditionally difficult to treat second line therapy severely depressed function
Chronic therapy: who to treat
No predictors of recurrence
ALL patients require close follow- up
Treat
•Poor function •Recurrent tachycardia
•Hemodynamic compromise•Structural heart disease
•SocialDon’t treat
•Well tolerated•Normal function•No recurrences
•Social
Automatic atrial tachycardia
Suppress automaticityControl ventricular rate
Propranolol Flecainide Sotalol
Special circumstances
Amiodarone
+/– Digoxin
Goals Drugs
“Reasonable” control may be a satisfactory
endpoint
Consideration
Reentrant atrial tachycardia
Suppress ectopyPrevent reentryControl ventricular rate
Propranolol Flecainide Procainamide Sotalol
Special circumstances
Amiodarone
+/– Digoxin
Goals Drugs
AV reentry tachycardia
Goals Drugs
Avoid digoxin when accessory pathway conducts antegrade
Suppress ectopyAttack pathway limb
Propranolol Digoxin Flecainide (short RP) Procainamide (short RP) Sotalol
Special circumstances
Amiodarone
Goals Drugs
Consideration
PJRT(permanent form of junctional reciprocating tachycardia)
Goals Drugs
May be refractory to multiple therapies
Suppress ectopyPrevent reentry
Propranolol Digoxin Flecainide Sotalol Amiodarone
Goals Drugs
Consideration
AV node reentry tachycardia
Suppress automaticityAttack AV node
Propranolol Digoxin Sotalol
Special circumstances
?? Verapamil Amiodarone
Goals Drugs
Automatic junctional tachycardia
Restore AV synchronySuppress automaticity
drugs reduce fever (post op) reduce catecholamine
state (post op)
Considerations
Amiodarone Flecainide Sotalol Procainamide +hypothermia
Goals Drugs
Life threatening tachycardiaVery difficult to treatPost op option: ECMOCongenital option: RFA
Considerations
Atrial fibrillation
Prevent re-entryControl ventricular rateEvaluate for congenital heart diseaseTreat metabolic and hemodynamic derangements
Amiodarone +/- Digoxin
Goals Drugs
Look for structural heart diseaseConsiderations
Chaotic atrial tachycardia
DigoxinPropranolol caution with lung disease
Goals
• Evaluate for respiratory illnesses, esp RSV• Tachycardia unlikely to recur once
respiratory illness resolves
Suppress automaticityControl ventricular rate
Goals Drugs
Considerations
Choosing a drug: other considerations
Use what works
Low threshold for in-patient monitoring
Digoxin & amiodarone do not depress function
START SAFE
Length of therapy
Indications ??Most would treat through the first year of
lifeHolter and event monitors helpfulInducibility ??Natural history favors discontinuing therapy
Therapy: radiofrequency ablation
No long term data in humans
No definitive indications established
WaitProceed
•Refractory tachycardia Hemodynamic compromise
±Hemodynamic catheterization•Impending loss of catheter
access
•Expanding lesions•Higher complication rate
•Natural history
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