Supraventricular Tachycardia: From Fetus to Adult

Mohamed Hamdan, MD Learning Objectives

Define type of SVT by age Describe clinical approach Describe prenatal and postnatal management of SVT

2 SVT Across the Ages

Narrow-complex  Wide complex: VT Tachycardia  HR >160: fetuses  HR >220: infants  HR >180: children  HR >120: adults Above AV junction Types of SVT

Re-entrant Automatic

1. Sudden onset and 1. Warms-up and cools offset down 2. Accessory pathway 2. Sensitive to 3. Terminates with catecholamines adenosine or 3. Does not respond to either Most common: AVRT Most common: EAT Mechanism of SVT

Re-entrant Automatic 90% <1% 10% AVN dependant AVN independant

AVRT AET AVNRT Atrial fib. CAR PJRT SNRT JET Mahaim Tachycardia IART

5 Re-entrant Automatic Fetal SVT

Definition  HR > 160 not associated with contraction or periodic decelerations Epidemiology  Incidence ~1/1000 of all pregnancies  Fetal : 1/3 of referrals to fetal echo lab  CHD in 3%

Copel et al., Am J Obstet Gynecol 2000 7 Clinical Approach to Fetal SVT

1. Define type  SVT vs Flutter vs Fibrillation 2. Define absolute HR 3. Presence of CHD 4. Presence of hydrops

8 1. Type of SVT

Best: 16-32 weeks Methods  Phonocardiography  Fetal echo  Magnetocardiography (MCG)

 Fetal scalp electrode Fetal QRS

Maternal QRS

9 Assessment of Rhythm by Fetal Echo Doppler

SVC

PAC Normal

10 Assessment of Rhythm by Fetal Echo

M-Mode

RV

RA

Atrium Rate~ 500

Ventricle Rate~240 11 2. Determine HR

Atrial Rate Variability A:V Ventricular (bpm) Conduction Rate Normal 120-160 >10 bpm 1:1 120-160

Sinus 180-220 5-15 bpm 1:1 180-220 tachycardia SVT >220 No 1:1 >220 Atrial flutter 300-500 No 2-5:1 60-200 Atrial 300-500 Yes, due to 2-5:1 60-200 fibrillation variable AV conduction

Bergmans et al., Obstet Gynecol Surv 1985

12 3. Structural Disease

Incidence of CHD in fetal SVT: is 0.5-5% Worse outcome Mot common:  Ebstein malformation: SVT, flutter  Cardiac tumors: Rhabdomyoma  AV canal

13 Complete AV Canal Rhabdomyoma

LA RA RA LA LV LV RV RV

Ebstein

RA LA

LV RV

14 4. Presence of Hydrops

The most important factor in deciding  Delivery time  Treatment  Prognosis Risk factors  HR >230  Sustained tachycardia >12 hrs  Lower GA

15 Postnatal SVT Epidemiology Incidence: 1/1000 The most common cause in children is Atrio-ventricular Re-entrant Tachycardia (AVRT)  AP outside AV node (eg: WPW) In adults: AVNRT (AV Node Re-entrant Tachycardia)  AP within the AV node Accessory pathway, either concealed, or manifest (WPW) 25% have associated structural heart disease AVRT vs AVNRT

AVRT: Atrio-Ventricular AVNRT: Atrio-Ventricular Re-entrant Tachycardia Nodal Re-entrant Tachycardia

Accessory Accessory Pathway Pathway within AVN

18 SVT 19

Sinus Tachycardia vs SVT

Sinus Tachycardia SVT

Heart Rate <220 infants 230-300 infants <200 children 200-240 children QRS complex Narrow Usually narrow

P waves Present, normal axis (0-90) Absent, or after ORS, superior (180-270) Regularity Regular, slows gradually Sudden onset and offset, ‘monotonus’

Etiology Fever, anemia, infection, … Accessory pathway What is Accessory Pathway?

 Specialized tissue capable of antegrade (down) and/ or retrograde (up) conduction

 Connect to AVN , bypassing AV node and AV bundle  Fast (non- decrimental) with slow recovery Manifest AP: WPW Concealed AP SVT

WPW: Manifest AP SVT

No WPW: Concealed AP Wolff-Parkinson-White

The most common form of manifest AP Incidence:  0.2 % in general population  0.5 % in patients with CHD  25% of infants with SVT Association  Ebstein anomaly of the TV  Hypertrophic CMP Mostly sporadic, but can be familial Risk of sudden death Wolff-Parkinson-White

2 1.Delta wave 1

3. Wide QRS 2. Short PR 3 5 4. Left axis deviation

4 5. Absent Q in V6 Clinical Approach to SVT

History  Sudden onset and offset  Non-specific symptoms Irritability Poor feeding  Associated symptoms Pre-syncope, syncope Chest pain Examination  Usually normal Work Up

Baseline electrolytes EKG  At baseline: Wolff or no Wolff?  During SVT: Mechanism of SVT  During SVT break: Presence of WPW + Mechanism Echo  Only at baseline  Structural heart disease (25%)  LV function  Exclude cardiomyopathy Others: Holter, Stress Test, Cardiac Event Monitor Ebstein

RA LA

LV RV

Hypertrophic CMP Dilated CMP

RA LA

LA RA

LV LV RV RV 24-hour ECG (Holter)

Look for SVT Look for WPW Look for abnormal P-wave axis & frequent PAC’s Control after medications

Cardiac Event Monitor Exercise Stress Test

Can induce SVT Essential in WPW  Characteristics of accessory pathway  Identify risk of sudden death  Low vs high risk  Depends on refractory period of AP . Cut-off: 250 msec. (240 bpm) Management of SVT Prenatal Management

Rate control  Maternal Digoxin, Flecainide, Sotalol, Amiodarone Atrium Flec, Sotalol, Amio Accessory AV Node Dig, Sotalol, Amio Pathway

Ventricle

37 Effect of Maternal Drugs

Lisowski et al., JACC 2000; Krapp et al., Heart 2003; Strasburger et al., Circulation 2004; Oudijk et al., Circulation 2000; Krapp et al., Ultrasound Obstet Gynocol 2002 38 LA LA

RA RA LV LV RV RV

39 Postnatal Management

Acute  Terminate tachycardia X  Depends on hemodynamics Adenosine X Cardioversion Amiodarone Chronic  To prevent recurrence  Treat complications Definitive  RFA (Radiofrequency ) Postnatal Management: Acute Treatment

Vagal maneuvers  Diving reflex  Valsalva  Gag reflex  ‘Standing on the head’  Works better in infants Adenosine Adenosine

SVT 42 Post Adenosine Case Report Atrial rate= 500

Ven. Rate= 150-240

43 Adenosine

SVT 44 Adenosine: The 3 Commandments Central or upper limb access

Run EKG strip

Keep defibrillator standby Omar: SVT Omar: SVT

Adenosine Post Chronic Treatment

Symptomatic or Infants No or little symptoms

Baseline EKG No Treatment

WPW No WPW

1st line: Dig, ß-blockers, Flec 1st line: Dig, ß-blockers, Flec 2nd line: Sotalol, Amio 2nd line: Sotalol, Amio Re-entrant SVT (AVRT or AVNRT)

Atrium Block/Slow AV Node Block Accessory Dig, -Blockers, ß Pathway CCB, Sotalol, Amio AV Node (Vagal, Adenosine, Flec, Sotalol, Amio Cardioversion)

Accessory Pathway Ventricle Definitive Treatment

Radiofrequency Ablation In older children & adults Success rate >80% Complication rate <5% SVT 52 Radiofrequency Ablation

AP Lateral RA Coronary Sinus

LA

His Bundle

RV

SVT 53 Septal pathway

Earliest wave

SVT 54 Post ablation

SVT 55 Prognosis

 Variable  Re-entrant: Good, as most patients have normal  Automatic: Guarded, but worse (difficult control)  For re-entrant, better prognosis if:  Onset in infancy  Absence of pre-excitation  Absence of structural heart disease  Onset of SVT <2 m  disappears in > 50% by age 1 yr Onset of SVT > 5 yrs  persists in 80%  30% recurrence rate in childhood Take Home Message

In fetuses, infants & children:  SVT = AVRT (accessory pathway) In adults: more commonly AVNRT (slower) Management depends on whether WPW is present on baseline EKG Adenosine is good therapeutic & diagnostic tool In all , you’re friends are: ß-Blockers Thank You..

Cape of Good Hope Automatic SVT (E.A.T.)

Atrium Block/ Slow Ectopic Focus

ß-Blockers , Flec, Sotalol, Slow AV Node AV Node Amio Dig, ß-Blockers, CCB, Sotalol, Amio

Ventricle Incidence of Fetal Arrhythmia

n=1384

Kleinman et al., Ultrasound Obstet Gynecol 1991 60 Wolff-Parkinson-White

Risk of sudden death:  Symptomatic 0.6% per year  Asymptomatic 0.1% per year Risk increases with:  Age (adults>adolescents>children)  Presence of  Short refractory period