Leonard Steinberg, MD Timothy Knilans, MD The Heart Center Children’s Hospital Medical Center...

Leonard Steinberg, MDTimothy Knilans, MD

The Heart CenterChildren’s Hospital Medical Center

Cincinnati, OH

The diagnosis and management of supraventricular tachycardia in

infantsPart I: Establishing a diagnosis

Overview

General information

Categorizing tachycardia

Diagnosis

Therapy (part II)

General information

Occurs in 1 in 250 to 1000 children50% of cases occur in infantsmost present in first 3 months

Low recurrence rate in infantsAP mediated tachycardia recurrences

uncommon by 1 year

some infants have no recurrences at least 30% of infants with an accessory

pathway are non-inducible at 1 year no known predictive factors for recurrence

automatic atrial tachycardias less likely to resolve

Low death rateparticularly if structurally normal heart

Possible presentations

Incidental findingLethargyCongestive heart failure

hydrops diaphoresis tachypnea poor feeding growth failure

ShockStructural heart disease

Heart disease associated with SVT

Accessory pathways Ebstein’s anomaly tricuspid atresia mitral atresia (hypoplastic left heart syndrome) corrected transposition of the great arteries

(L-TGA)

Automatic atrial tachycardias cardiomyopathy / myocarditis

ANY incessant tachycardia can CAUSE cardiomyopathy

Atrial fibrillation always associated with congenital heart

disease

Associated with VERY poor prognosis

Other diseases associated with SVT

Chaotic (or other automatic) atrial tachycardia

RSV

tachycardia unrelated to ß-agonists or hypoxia

patients with structurally normal hearts do not have recurrences

cocaine (in utero)

Categorizing tachycardia

MechanismLocationFrequency

Loc

atio

n

Mechanism

Re-entrant AutomaticAtrial Atrial flutter

Atrial fibrillationAutomatic atrial tachycardiaChaotic atrial tachycardia

AV Node andHis Bundle

AV node re-entry Junctional tachycardia

Atrium andVentricle

WPWConcealed APPJRTMahaim

Classifying tachycardia: mechanism

Re-entrant

(1) reentrant atrial tachycardia (atrial flutter)

(2) AV reentry a. WPW

orthodromicantidromic“two pathway”

b. concealed accessory pathway c. PJRT d. Mahaim

(3) AV node reentry a. typical b. atypical

(4) atrial fibrillation

Automatic

(1) automatic atrial tachycardia(2) automatic junctional tachycardia(3) chaotic (multifocal)

atrial tachycardia

Categorizing tachycardia: mechanism

Re-entrant



Re-entrant




Re-entrant



orthodromic


Re-entrant



orthodromicantidromic


Re-entrant





x

Re-entrant




b. concealed accessory pathway


Re-entrant




b. concealed accessory pathway c. PJRT


Re-entrant






Slow

Fast

Re-entrant





(3) AV node reentry a. typical


Slow

Fast

Re-entrant







Re-entrant








Re-entrant







Automatic

(1) automatic atrial tachycardia


Re-entrant







Automatic

(1) automatic atrial tachycardia(2) automatic junctional tachycardia


Re-entrant







Automatic

(1) automatic atrial tachycardia(2) automatic junctional tachycardia(3) chaotic (multifocal)

atrial tachycardia

Classifying tachycardia: location

Atrium automatic atrial tachycardia reentrant atrial tachycardia chaotic atrial tachycardia atrial fibrillation

AVN and His bundle AV node reentry tachycardia automatic junctional

tachycardia

Atrium and ventricle accessory pathway tachycardia concealed WPW PJRT Mahaim

Classifying tachycardia: frequency

Common: AV reentry

Less common: atrial

Uncommon: AV node reentry

Rare: other

Frequencyaccessory pathway SVT

Concealed

WPW

PJ RT

Frequencyatrial tachycardias

Atrial reentry

Automatic atrial

Frequencyrare tachycardias

AV node re-entry:frequency uncertain

Frequencyrare tachycardias

Atrial fibrillation

Chaotic atrial

Automatic junctional tachycardia

Mahaim

Differential diagnosisECG analysis

Rate

Atrial activity

AV relationship

Rhythm perturbations

QRS morphology

ECG analysis: rate

200

250

150

300

500

600A

tria

l R

ate

Automatictachycardias

Atrial reentry

PJRT

AVNRT

AVRT

ECG analysis: rate

200

250

150

300

500

600A

tria

l R

ate

Automatictachycardias

Atrial reentry

PJRT

AVNRT

AVRT

Constant rate Variable rate

PJRT

ECG analysis: atrial activity

Where on the ECG shorter diastolic interval compare QRS high frequency activity in T waves look for 2:1 conduction

Where in the atrium (p wave axis) inferior: must be primary atrial

tachycardia superior axis indicates pathology check V1 & V2 when tachycardia looks

like sinus rhythm variable: chaotic atrial tachycardia

ECG analysis: AV relationship

More A’s than V’s

AV reentry •

AV node reentry •Junctional tachycardia •

Primary atrial tachycardia •

More V’s than A’s

•AV reentry•Primary atrial tachycardia

•AV node reentry

•Junctional tachycardia. Wide complex is ventricular until proven otherwise

Excluded

Unlikely

Probably

ECG analysis: the RP interval

Useful in distinguishing AV reentry from AV node reentry tachycardias

70 msec traditionally associated with AVNRT

> 70 msec accessory pathway

> PR interval PJRT or atypical AVNRT

ECG analysisrhythm perturbations

Tachycardia onsetBundle branch blockTerminationVagal maneuversAdenosine response


Sinus P PAC



aVF

V1

Right Atrium



P wave No P wave


Considerations when terminating SVT

obtain rhythm recording

save vagal maneuvers for known diagnosis

adenosine response accessory pathway

watch for adenosine side effects


ECG analysisQRS morphology

Narrow complex (normally conducted QRS) cannot be antidromic tachycardia

Wide complex any narrow complex tachycardia with aberrant

conduction (more frequently LBBB in infants) any narrow QRS tachycardia mechanism with an

antegrade bystander AP antidromic AV reentrant tachycardia (including Mahaim tachycardia-rare)

* VENTRICULAR TACHYCARDIA* ventricular complexes and aberrantly conducted

supraventricular complexes may have “narrow QRS” appearance

Diagnosisnoninvasive modalities

Holter and event monitors occasionally helpful in establishing

diagnosis evaluate therapeutic effect

Echocardiography incessant tachycardia diminished function structural heart disease prior to EP study

in utero tachycardia

Diagnosisminimally invasive modalities

Atrial electrogram

esophageal lead or atrial pacing wires

identify atrial activity evaluate antegrade conduction over an

accessory pathway effectiveness of therapy

pace terminate re-entrant arrhythmias

The EP study

Rarely requiredUsually performed in association with need

for definitive therapy

Indications refractoriness to multiple medical regimens hemodynamic compromise or poor function concurrent need for hemodynamic

catheterization impending loss of catheter access

ASD closurePalliation for complex congenital heart disease

Summary

Accurate diagnosis as a prelude to therapy

Classify

ECG

Other diagnostic modalities

Structural heart disease

Leonard Steinberg, MD Timothy Knilans, MD The Heart Center Children’s Hospital Medical Center...

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