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Supraventricular Tachycardia in Infancy and Childhood Terrence Chun, MD Pediatric Electrophysiology and Pacing.

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Presentation on theme: "Supraventricular Tachycardia in Infancy and Childhood Terrence Chun, MD Pediatric Electrophysiology and Pacing."— Presentation transcript:

1 Supraventricular Tachycardia in Infancy and Childhood Terrence Chun, MD Pediatric Electrophysiology and Pacing

2 Cardiac electrical anatomy

3 SVT - Overview Rapid rhythm that involves or is driven by structures in the upper heart Rapid rhythm that involves or is driven by structures in the upper heart Incidence up to 1:250 children Incidence up to 1:250 children Generally well-tolerated, even fast rates Generally well-tolerated, even fast rates Risk of life-threatening arrhythmias is uncommon Risk of life-threatening arrhythmias is uncommon

4 Narrow vs. Wide QRS Not all narrow QRS complex tachycardia is supraventricular tachycardia Not all narrow QRS complex tachycardia is supraventricular tachycardia Not all wide QRS complex tachycardia is ventricular tachycardia Not all wide QRS complex tachycardia is ventricular tachycardia

5 SVT Mechanisms - Overview Reentrant rhythms Reentrant rhythms Automatic rhythms Automatic rhythms

6 SVT mechanisms – Automatic Rhythms Originate from a particular focus Originate from a particular focus “Warm-up” and “cool-down” behavior “Warm-up” and “cool-down” behavior Respond to drugs and maneuvers that affect myocardial automaticity Respond to drugs and maneuvers that affect myocardial automaticity May be suppressed by faster rates May be suppressed by faster rates Usually do not respond to cardioversion (typically pause, then restart) Usually do not respond to cardioversion (typically pause, then restart)

7 SVT mechanisms – Automatic Rhythms Left atrial focus Left atrial focus 2:1 AVN conduction 2:1 AVN conduction

8 SVT mechanisms – Reentrant rhythms Requires a “circuit” of tissue to create repetitive activation Requires a “circuit” of tissue to create repetitive activation Must have appropriate conditions to perpetuate reentrant rhythm Must have appropriate conditions to perpetuate reentrant rhythm Usually abrupt onset and termination Usually abrupt onset and termination Regular, with little variation in rate Regular, with little variation in rate Often will respond to cardioversion Often will respond to cardioversion

9 SVT mechanisms – Reentrant rhythms

10 Diagnostic methods 12-lead electrocardiogram ! ! ! 12-lead electrocardiogram ! ! ! Post-op atrial/ventricular pacing wires Post-op atrial/ventricular pacing wires Esophageal pacing leads Esophageal pacing leads Adenosine can be diagnostic Adenosine can be diagnostic Invasive electrophysiology study Invasive electrophysiology study

11 Diagnostic methods Always Always Always record a rhythm strip during any intervention (adenosine, cardioversion, Valsalva, etc.) Always record a rhythm strip during any intervention (adenosine, cardioversion, Valsalva, etc.)

12 Diagnostic methods Record a rhythm strip Record a rhythm strip

13 ECG clues to diagnosis Wide vs. narrow complex Wide vs. narrow complex Regular vs. irregular Regular vs. irregular Abrupt vs. gradual Abrupt vs. gradual P wave relationship to QRS P wave relationship to QRS

14 Parade of Rhythms Automatic Arrhythmias

15 Automatic rhythms – Sinus Tachycardia Sinus node – fish-shaped structure with “head” at SVC-RA junction and “tail” extending along RA wall Sinus node – fish-shaped structure with “head” at SVC-RA junction and “tail” extending along RA wall S-tach usually due to increased sympathetic discharge, fever, anemia, hypovolemia, hyperthyroidism, etc. S-tach usually due to increased sympathetic discharge, fever, anemia, hypovolemia, hyperthyroidism, etc. Inappropriate sinus tachycardia - rare Inappropriate sinus tachycardia - rare

16 Automatic rhythms – Sinus Tachycardia Dx Dx Rate greater than normal range, but usually less than 200 Rate greater than normal range, but usually less than 200 P wave axis normal (0 ~ +90°) P wave axis normal (0 ~ +90°) PR interval normal PR interval normal Tx Tx Treat the cause Treat the cause

17 Automatic rhythms – Automatic Atrial Tachycardia Originates from a focus in either the right or left atrium, or atrial septum Originates from a focus in either the right or left atrium, or atrial septum Commonly from atrial appendages, crista terminalis, pulmonary veins Commonly from atrial appendages, crista terminalis, pulmonary veins Can also be due to central lines, etc. Can also be due to central lines, etc. Also called “ectopic atrial tachycardia” Also called “ectopic atrial tachycardia” although any automatic rhythm other than sinus rhythm is technically “ectopic” although any automatic rhythm other than sinus rhythm is technically “ectopic”

18 Automatic rhythms – Automatic Atrial Tachycardia Dx Dx Speeds-up and slows-down, rates vary Speeds-up and slows-down, rates vary P wave axis abnormal P wave axis abnormal PR interval may be abnormal (it is a function of distance from focus to AVN) PR interval may be abnormal (it is a function of distance from focus to AVN) May see 2° AV block (e.g. Wenckebach or 2:1 at higher atrial rates) May see 2° AV block (e.g. Wenckebach or 2:1 at higher atrial rates) Adenosine  P waves “march through” despite AV block Adenosine  P waves “march through” despite AV block

19 Automatic rhythms – Automatic Atrial Tachycardia

20 Tx Tx Remove source (check CXR and pull back PICC) Remove source (check CXR and pull back PICC) Beta-blockers Beta-blockers Esmolol infusion in ICU setting Esmolol infusion in ICU setting propranolol, atenolol propranolol, atenolol Amiodarone, others Amiodarone, others Catheter ablation Catheter ablation

21 Automatic rhythms – Junctional Tachycardia Originates from around the AV junction Originates from around the AV junction Also called “JET” (Junctional Ectopic Tachycardia), because it sounds cool Also called “JET” (Junctional Ectopic Tachycardia), because it sounds cool Rate Rate Most commonly seen post-operatively, usually self-limited Most commonly seen post-operatively, usually self-limited Congenital forms, more persistent Congenital forms, more persistent

22 Automatic rhythms – Junctional Tachycardia Dx Dx AV dissynchrony AV dissynchrony Sinus P wave at different rate than narrow QRS Sinus P wave at different rate than narrow QRS Atrial wire ECG (in post-op with pacing wires) Atrial wire ECG (in post-op with pacing wires) “Cannon a-waves” on CVP monitor “Cannon a-waves” on CVP monitor Retrograde P waves (abnormal Pw axis) Retrograde P waves (abnormal Pw axis) May be on top, before, or after QRS May be on top, before, or after QRS

23 Automatic rhythms – Junctional Tachycardia Cannon a-waves Cannon a-waves

24 Automatic rhythms – Junctional Tachycardia Tx Tx Reduce catecholamines Reduce catecholamines Decrease inotropic drips Decrease inotropic drips Pain control and sedation Pain control and sedation Cooling/hypothermia Cooling/hypothermia Drugs (amiodarone) Drugs (amiodarone) ECMO ECMO Catheter ablation(?) Catheter ablation(?)

25 Parade of Rhythms Reentrant Arrhythmias

26 Reentrant rhythms – Pathway Mediated Tachycardia Bypass tract of conductive tissue connects atrium to ventricle Bypass tract of conductive tissue connects atrium to ventricle Most common mechanism of SVT in children Most common mechanism of SVT in children Rate Rate May be “manifest” (e.g. WPW) or concealed (no preexcitation) May be “manifest” (e.g. WPW) or concealed (no preexcitation) Pathway can be anywhere on mitral or tricuspid annuli, usually left-sided Pathway can be anywhere on mitral or tricuspid annuli, usually left-sided

27 Reentrant rhythms – Pathway Mediated Tachycardia Orthodromic reciprocating tachycardia Orthodromic reciprocating tachycardia “Runs correctly” with normal conduction “Runs correctly” with normal conduction Down AV node (narrow QRS) Down AV node (narrow QRS) Up accessory pathway (retrograde) Up accessory pathway (retrograde) Retrograde P waves may be visible after QRS Retrograde P waves may be visible after QRS Antidromic reciprocating tachycardia Antidromic reciprocating tachycardia “Runs against” normal conduction “Runs against” normal conduction Down accessory pathway (wide QRS) Down accessory pathway (wide QRS) Up AV node (retrograde) Up AV node (retrograde) Less common Less common

28 Reentrant rhythms – Pathway Mediated Tachycardia Dx Dx Electrocardiogram Electrocardiogram Rhythm strips of start and stop of SVT Rhythm strips of start and stop of SVT

29 Reentrant rhythms – Pathway Mediated Tachycardia Tx Tx Valsalva maneuvers, Ice to face Valsalva maneuvers, Ice to face Adenosine (technique matters!) Adenosine (technique matters!) Antiarrhythmic drugs Antiarrhythmic drugs Beta blockers (watch blood glucose in infants!) Beta blockers (watch blood glucose in infants!) Digoxin (limited value; digitalization only in difficult situations) Digoxin (limited value; digitalization only in difficult situations) Others (Verapamil, Flecainide, Sotolol, etc.) Others (Verapamil, Flecainide, Sotolol, etc.) Catheter ablation Catheter ablation

30 Reentrant rhythms – Wolff-Parkinson-White Syndrome Electrocardiogram findings Electrocardiogram findings Short PR interval Short PR interval Wide QRS complex Wide QRS complex Delta wave Delta wave

31 Reentrant rhythms – Wolff-Parkinson-White Syndrome

32 Clinical symptoms Clinical symptoms Palpitations Palpitations SVT SVT Note narrow QRS and lack of delta wave! Note narrow QRS and lack of delta wave!

33 Reentrant rhythms – Wolff-Parkinson-White Syndrome Sudden death(!) Sudden death(!) Atrial fibrillation Atrial fibrillation Rapid conduction over bypass tract Rapid conduction over bypass tract Ventricular fibrillation Ventricular fibrillation Risk % per year Risk % per year

34 Reentrant rhythms – Wolff-Parkinson-White Syndrome Tx Tx Tachycardia control Tachycardia control Recognition Recognition ±Drugs (patient/family choice) ±Drugs (patient/family choice) Digoxin generally contraindicated Digoxin generally contraindicated Risk stratification Risk stratification Holter Holter Exercise testing Exercise testing Invasive electrophysiology testing Invasive electrophysiology testing Catheter ablation Catheter ablation

35 Reentrant rhythms – AV Node Reentry Tachycardia More common in teens and adults More common in teens and adults Tachycardia circuit contained within atrioventricular node Tachycardia circuit contained within atrioventricular node Activates atria at the “top” of the circuit, ventricles at “bottom” of circuit, nearly simultaneously Activates atria at the “top” of the circuit, ventricles at “bottom” of circuit, nearly simultaneously Rate Rate Usually cannot see retrograde P waves Usually cannot see retrograde P waves

36 Reentrant rhythms – AV Node Reentry Tachycardia

37 Tx Tx Adenosine Adenosine Cardioversion Cardioversion ±Pharmacotherapy ±Pharmacotherapy Beta blockers Beta blockers Digoxin Digoxin Others Others Catheter ablation Catheter ablation

38 Reentrant rhythms – Atrial Flutter “Flutter” circuit around anatomic structures in atrium “Flutter” circuit around anatomic structures in atrium Eustachian valve Eustachian valve Crista terminalis Crista terminalis Fossa ovalis Fossa ovalis Surgical incisions Surgical incisions

39 Reentrant rhythms – Atrial Flutter Atrial rate ~300 (higher in neonates) Atrial rate ~300 (higher in neonates) Ventricular rate depends on AV node conduction Ventricular rate depends on AV node conduction 1:1  300/min 1:1  300/min 2:1  150/min 2:1  150/min 3:1  100/min 3:1  100/min May be 3:1 then 2:1 then… May be 3:1 then 2:1 then…

40 Reentrant rhythms – Atrial Flutter Sawtooth “flutter” waves (may or may not be helpful) Sawtooth “flutter” waves (may or may not be helpful)

41 Reentrant rhythms – Atrial Flutter Dx Dx Electrocardiogram Electrocardiogram Adenosine blocks AV node; flutter waves continue Adenosine blocks AV node; flutter waves continue Tx Tx Rate control – digoxin, beta blockers, etc. Rate control – digoxin, beta blockers, etc. Overdrive pacing Overdrive pacing DC cardioversion DC cardioversion Catheter ablation Catheter ablation

42 Threatening Rhythms Atrial fibrillation in high-risk WPW Atrial fibrillation in high-risk WPW Danger of ventricular fibrillation Danger of ventricular fibrillation Persistent prolonged SVT Persistent prolonged SVT Tachycardia induced cardiomyopathy (reversible) Tachycardia induced cardiomyopathy (reversible) SVT in compromised cardiac status SVT in compromised cardiac status Syncope or cardiovascular collapse Syncope or cardiovascular collapse

43 Treatment Pearls

44 Adenosine mg/kg/dose mg/kg/dose Very short half-life (seconds) Very short half-life (seconds) Central administration can be helpful, but not necessary Central administration can be helpful, but not necessary Rapid saline bolus (5-10 ml) essential Rapid saline bolus (5-10 ml) essential Stopcock on venous access is helpful Stopcock on venous access is helpful

45 DC Cardioversion Dose Dose Cardioversion J/kg Cardioversion J/kg Defibrillation 1-2 J/kg Defibrillation 1-2 J/kg Synchronized (avoids making worse) Synchronized (avoids making worse) Paddles – front+apex Paddles – front+apex Patches Patches Front+apex Front+apex Front+back Front+back

46 Catheter Ablation Multiple catheters Multiple catheters Size limitations Size limitations Ideally > 15 kg, but can be done in infants if necessary Ideally > 15 kg, but can be done in infants if necessary Can be curative Can be curative ~95% success rate in children ~95% success rate in children

47 Record a Rhythm Strip! Especially during interventions Especially during interventions Most SVT in infants and children is hemodynamically well-tolerated Most SVT in infants and children is hemodynamically well-tolerated Proper diagnosis can guide appropriate therapy Proper diagnosis can guide appropriate therapy RA/LA/RL/LL limb leads give 6 electrograms (I, II, III, aVL, aVR, aVF) RA/LA/RL/LL limb leads give 6 electrograms (I, II, III, aVL, aVR, aVF)


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