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 cardioversion either Most common: AVRT Most common: EAT Mechanism of SVT
Re-entrant Automatic 90% <1% 10% AVN dependant AVN independant
AVRT Atrial flutter 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 arrhythmia: 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 Aorta
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 Heart 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 atrium to AVN ventricle, 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 palpitations 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 Ablation) 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 Lidocaine 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 Catheter 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 hearts 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 arrhythmias, 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 atrial fibrillation Short refractory period