1. Leonard Steinberg, MD Timothy Knilans, MD The Heart Center Children’s Hospital Medical Center Cincinnati, OH The diagnosis and management of supraventricular tachycardia in infants Part I: Establishing a diagnosis

2. Overview General information Categorizing tachycardia Diagnosis Therapy (part II)

3. General information Occurs in 1 in 250 to 1000 children 50% of cases occur in infants most present in first 3 months Low recurrence rate in infants AP 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 rate particularly if structurally normal heart

4. Possible presentations Incidental finding Lethargy Congestive heart failure  hydrops  diaphoresis  tachypnea  poor feeding  growth failure Shock Structural heart disease

5. 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

6. 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)

7. Categorizing tachycardia Mechanism Location Frequency Location Mechanism Re-entrant Automatic AtrialAtrial flutter Atrial fibrillation Automatic atrial tachycardia Chaotic atrial tachycardia AV Node and His Bundle AV node re-entry Junctional tachycardia Atrium and Ventricle WPW Concealed AP PJRT Mahaim

8. Classifying tachycardia: mechanism Re-entrant (1)reentrant atrial tachycardia (atrial flutter) (2) AV reentry a. WPW orthodromic antidromic “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

9. Categorizing tachycardia: mechanism Re-entrant (1)reentrant atrial tachycardia (atrial flutter)

10. Categorizing tachycardia: mechanism Re-entrant (1)reentrant atrial tachycardia (atrial flutter) (2) AV reentry a. WPW

11. Categorizing tachycardia: mechanism Re-entrant (1)reentrant atrial tachycardia (atrial flutter) (2) AV reentry a. WPW orthodromic

12. Categorizing tachycardia: mechanism Re-entrant (1)reentrant atrial tachycardia (atrial flutter) (2) AV reentry a. WPW orthodromic antidromic

13. Categorizing tachycardia: mechanism Re-entrant (1)reentrant atrial tachycardia (atrial flutter) (2) AV reentry a. WPW orthodromic antidromic “two pathway”

14. Categorizing tachycardia: mechanism x Re-entrant (1)reentrant atrial tachycardia (atrial flutter) (2) AV reentry a. WPW orthodromic antidromic “two pathway” b. concealed accessory pathway

15. Categorizing tachycardia: mechanism Re-entrant (1)reentrant atrial tachycardia (atrial flutter) (2) AV reentry a. WPW orthodromic antidromic “two pathway” b. concealed accessory pathway c. PJRT

16. Categorizing tachycardia: mechanism Re-entrant (1)reentrant atrial tachycardia (atrial flutter) (2) AV reentry a. WPW orthodromic antidromic “two pathway” b. concealed accessory pathway c. PJRT d. Mahaim

17. Categorizing tachycardia: mechanism Slow Fast Re-entrant (1)reentrant atrial tachycardia (atrial flutter) (2) AV reentry a. WPW orthodromic antidromic “two pathway” b. concealed accessory pathway c. PJRT d. Mahaim (3) AV node reentry a. typical

18. Categorizing tachycardia: mechanism Slow Fast Re-entrant (1)reentrant atrial tachycardia (atrial flutter) (2) AV reentry a. WPW orthodromic antidromic “two pathway” b. concealed accessory pathway c. PJRT d. Mahaim (3) AV node reentry a. typical b. atypical

19. Categorizing tachycardia: mechanism Re-entrant (1)reentrant atrial tachycardia (atrial flutter) (2) AV reentry a. WPW orthodromic antidromic “two pathway” b. concealed accessory pathway c. PJRT d. Mahaim (3) AV node reentry a. typical b. atypical (4) atrial fibrillation

20. Categorizing tachycardia: mechanism Re-entrant (1)reentrant atrial tachycardia (atrial flutter) (2) AV reentry a. WPW orthodromic antidromic “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

21. Categorizing tachycardia: mechanism Re-entrant (1)reentrant atrial tachycardia (atrial flutter) (2) AV reentry a. WPW orthodromic antidromic “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

22. Categorizing tachycardia: mechanism Re-entrant (1)reentrant atrial tachycardia (atrial flutter) (2) AV reentry a. WPW orthodromic antidromic “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

23. 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

24. Classifying tachycardia: frequency

25. Frequency accessory pathway SVT

26. Frequency atrial tachycardias

27. Frequency rare tachycardias AV node re-entry: frequency uncertain

28. Frequency rare tachycardias Atrial fibrillation Chaotic atrial Automatic junctional tachycardia Mahaim

29. Differential diagnosis ECG analysis Rate Atrial activity AV relationship Rhythm perturbations QRS morphology

30. ECG analysis: rate 200 250 150 300 500 600 Atrial Rate Automatic tachycardias Atrial reentry PJRT AVNRT AVRT

31. ECG analysis: rate 200 250 150 300 500 600 Atrial Rate Automatic tachycardias Atrial reentry PJRT AVNRT AVRT Constant rate Variable rate PJRT

32. 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

33. 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

34. 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

35. ECG analysis rhythm perturbations Tachycardia onset Bundle branch block Termination Vagal maneuvers Adenosine response

36. Tachycardia onset Bundle branch block Termination Vagal maneuvers Adenosine response Sinus PPAC ECG analysis rhythm perturbations

37. Tachycardia onset Bundle branch block Termination Vagal maneuvers Adenosine response aVF V1 Right Atrium ECG analysis rhythm perturbations

38. Tachycardia onset Bundle branch block Termination Vagal maneuvers Adenosine response P waveNo P wave ECG analysis rhythm perturbations

39. Tachycardia onset Bundle branch block Termination Vagal maneuvers Adenosine response P waveNo P wave ECG analysis rhythm perturbations

40. Tachycardia onset Bundle branch block Termination Vagal maneuvers Adenosine response ECG analysis rhythm perturbations

41. Considerations when terminating SVT  obtain rhythm recording  save vagal maneuvers for known diagnosis  adenosine response  accessory pathway  watch for adenosine side effects ECG analysis rhythm perturbations

42. ECG analysis QRS 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

43. Diagnosis noninvasive 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

44. Diagnosis minimally 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

45. The EP study Rarely required Usually 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 closure Palliation for complex congenital heart disease

46. Summary Accurate diagnosis as a prelude to therapy Classify ECG Other diagnostic modalities Structural heart disease