This document provides an overview of Wolff-Parkinson-White Syndrome (WPW) and catheter ablation of accessory pathways. Some key points: 1) WPW is characterized by the presence of an accessory pathway that allows for pre-excitation and reentrant tachycardias. Accessory pathways can be located on the left or right side and have varying conduction properties. 2) Catheter ablation is successful in eliminating the accessory pathway in 93-95% of cases. Localization of the pathway involves analyzing electrocardiogram patterns and effective sites are identified using techniques like accessory pathway conduction block. 3) Multiple accessory pathways occur in 3-20% of cases and present additional challenges for localization

1. Wolff-Parkinson-White Syndrome
Yen-Bin Liu, 2013 March
Y.B. Liu

2. Outline
• General consideration of SVT
• WPW and accessory pathway
• Catheter ablation of accessory pathway
• Multiple accessory pathway
• Special considerations in WPW and AVRT
• Issue not covered in today’s talk
Y.B. Liu

3. General consideration of SVT
Y.B. Liu

4. Y.B. Liu

5. (AVNRT)
(decremental AP)
(fast-slow)
(slow-intermediate)
Y.B. Liu

6. Esophageal Lead
Y.B. Liu

7. SVT v.s. AV conduction
Y.B. Liu

8. (macro-reentry)
Y.B. Liu

9. Wide QRS tachycardia ( >120 ms)
• SVT with BBB
• Antidromic AVRT
• SVT (AT, AVNRT, orthodromic AVRT, AFL, AF) with
bystander manifest AP
• BBB reentry tachycardia
• VT
Y.B. Liu

10. WPW and accessory pathway
Y.B. Liu

11. Pre-excitation
Y.B. Liu

12. Re-entry
• Dural pathway
• Slow conduction zone
• Unidirectional block
Y.B. Liu

13. Tachycardia associated with AP
95% 5-10%
1/3
Y.B. Liu

14. Incidence
• Overall incidence of accessory pathway (AP)
– 0.1-0.3% of general population
• First-degreee relatives of patients with AP
– 0.55%
• Incidence of multiple APs
– 3-20% in surgical series
– 5-18% in RFCA series
Y.B. Liu

15. Classification of Accessory Pathway
• Anatomy:
– Left (mitral annulus) vs. right (tricuspid
annulus)
• Electrophysiology:
– Decremental vs. nondecremental
– 8% of AP with decremental characteristics
• Direction: Anterograde vs. retrograde
– Concealed: retrograde conduction only
– Manifest: bi-directional conduction
(* anterograde only: uncommon)
Y.B. Liu

16. Anatomy of Accessory Pathway
Y.B. Liu

17. Anterograde vs. Retrograde
Y.B. Liu

18. Decremental vs. nondecremental
Y.B. Liu

19. Intermittent Pre-excitation
• Weakness of accessory pathway conduction
• Strengthen of AV nodal conduction
Y.B. Liu

20. WPW syndrome
The diagnosis of WPW syndrome is
reserved for patients who have both
pre-excitation and tachyarrhythmias.
ACC/AHA/ESC Guidelines for the Management of Patients
With Supraventricular Arrhythmias; 2003
Y.B. Liu

21. WPW,
type A &B
Y.B. Liu

22. Localization of Accessory
Pathway in WPW syndrome
• Transition zone
• R in lead I
• Positive or
Negative vector
of delta wave in
II, III, aVF
[PACE 1995; 18: 1469-1473]
Y.B. Liu

23. Localization of Accessory Pathway in
WPW syndrome
Cardiovasc Electrophysiol. 1998;9:2-12 Y.B. Liu

24. Left lateral accessory pathway
Y.B. Liu

25. Right free wall accessory pathway
Y.B. Liu

26. Right anteroseptal accessory pathway
Y.B. Liu

27. Left posteroseptal accessory pathway
Y.B. Liu

28. Localization of AP by retrograde P wave
during AVRT
Anterior
Anterior
III. aVF (+)
anterior
anterior
Lateral Lateral
lateral
lateral
poterior
poterior
J Am Coll Cardiol Poterior III. aVF (-) Poterior
1997;29:394–402
J Interv Card
Electrophysiol (2008)
22:55–63
Y.B. Liu

29. Catheter ablation of accessory pathway
Y.B. Liu

30. Intracardiac ECG for Localization of AP
• Localization of AV rings
• AV fusion: anterograde and retrograde
• VA interval, HH interval, HA time
• Zone of transition
–Pattern of initiation and termination
–VEST or VPC during SVT
–BBB during SVT
–AV block during SVT
Y.B. Liu

31. Localization of AV rings
Y.B. Liu

32. Example: Ablation site
RAO view LAO view
Y.B. Liu

33. AV fusion: anterograde
Y.B. Liu

34. AV fusion: Retrograde
Y.B. Liu

35. Decremental Accessory Pathway
Y.B. Liu

36. Pattern of initiation
Y.B. Liu

37. Pattern of termination
Y.B. Liu

38. Ventricular extra-stimulus Reset Tachycardia
during His-refractoriness
Y.B. Liu

39. BBB during SVT
Y.B. Liu

40. Y.B. Liu

41. Y.B. Liu

42. Antidromic AVRT
Y.B. Liu

43. WPW with Atrial Fibrillation
Y.B. Liu

44. WPW with Atrial Fibrillation
Y.B. Liu

45. Endpoints of accessory pathway ablation
• Atrial pacing:
– No pre-excitation
– AV nodal decremental conduction (AH
prolongation in AEST)
• Ventricular pacing:
– Total VA block
OR
– VA nodal decremental conduction (be sure
site of Cs orifice and no SVT inducible)
Y.B. Liu

46. Endpoint of RFCA
Y.B. Liu

47. Endpoint of RFCA
Y.B. Liu

48. Causes of failed ablation of accessroy pathway
Y.B. Liu

49. RFCA in WPW
•約有93-95% (87-99%)的成功率，而復發率則
約為7% (0-11%) 。
•手術的併發症發生率約為1-4%，主要和手術傷
口、電極導管的操作或高頻波的燒灼有關，約
有1%的機會發生心房室傳導阻斷，但會因RFCA
而發生致命性併發症的機率則很低 (<0.2%)。
•對AVRT而言，RFCA的成功率和復發率取決於是
否能精準的定位accessory pathway並加以燒
灼移除，因此，手術的結果和手術者的經驗十
分相關，而和病人的年齡則無明顯的關聯。
Y.B. Liu

50. Multiple accessory pathway
Y.B. Liu

51. Definition of multiple accessory pathway
• APs separated by 1-3 cm
• Multistranded or broad-banded bypass
tracts as wide as 3 cm had been reported
Y.B. Liu

52. Oblique accessory pathway
Y.B. Liu

53. ECG Clues to Multiple APs
• Variations in pre-excited QRS morphology
(esp. during A fib.)
• Atypical patterns of pre-excitation
• Antidromic AVRT using a posterior septal
AP
• Orthodromic AVRT with changing
retrograde P wave morphology
• Antidromic AVRT with varying degrees of
antegrade fusion
Y.B. Liu

54. Variations in pre-excitation
Y.B. Liu

55. Variations in pre-excitation
Y.B. Liu

56. Variations in pre-excitation
Y.B. Liu

57. Atypical patterns of pre-excitation
Y.B. Liu

58. EP Evidence of Multiple APs
• Chang in pre-excited morphology at
different pacing cycle length and sites
• Differing pattern of antegrade and
retrogade conduction
• Varying patterns of retrograde atrial
activation sequence during AVRT or V
pacing or from orthodromic to antidromic
AVRT
• Appearance of an AP after AAD or
ablation
Y.B. Liu

59. Differing pattern of antegrade and
retrogade conduction
Y.B. Liu

60. Appearance of an AP after Ablation
Y.B. Liu

61. Varying patterns of retrograde atrial
activation sequence
Y.B. Liu

62. Distribution
• R. free wall AP +R. posteroseptal AP
(manifest > concealed about 2: 1)
• 2 L. free wall
(concealed > manifest)
Y.B. Liu

63. Arrhythmias associated with multiple APs
• Orthodromic AVRT
• Antidromic AVRT
– 33% vs. 6%
• Atrial fibrillation
– More clinical AF
– More induced AF
– More AF after RV pacing and AVRT
• AP as a bystander
Sudden death?
Y.B. Liu

64. RFCA in multiple APs
• Longer procedure time
• Greater radiation time
• Higher recurrent rate
– per patient
– per AP
Dual AV nodal pathway, 10-20%
– Only 1 patient develop AVNRT
Y.B. Liu

65. Special considerations in WPW and AVRT
Y.B. Liu

66. WPW v.s. Sudden Death
Y.B. Liu

67. WPW and Sudden Cardiac Death
• 0.15% to 0.39% over 3 to 10 yr follow-up
• In case with SCD, half of them is the first
manifestation of WPW
• Risk factors:
–Shortest pre-excited RR<250 ms
–Symptomatic tachycardia
–Multiple APs
–Ebstein’s anomaly
–Familial WPW
Y.B. Liu

68. Pharmacological Treatment of WPW
Y.B. Liu

69. Pharmacological Treatment of WPW
• Pre-excited tachycardia
– Adenosine used with caution
– Verapamil, diltiazem, digoxin: Class III
• Long-term therapy
– Propafenon: 69% effective; side effects:25%
– Sotalol
– Amiodarone: not superior to other AAD
– Single use of verapamil, diltiazem, digoxin: not
recommended
• Pill-in-the-Pocket
– Diltiazem 120 mg + propranolol 80 mg
– 32 ± 22 min
Y.B. Liu

70. PSVT during Pregnancy
Y.B. Liu

71. RFCA in Asymptomatic WPW
但WPW發生心臟猝死猝死
的比例並不高 (約
0.15%)，而RFCA也的確
會有約2%的手術的併發
症發生率，因此對於預
防性的RFCA治療宜用於
特定高危險群之病人，
似乎尚未有足夠的證據
支持將其列為常規性的
治療。在北美心律學會
，把RFCA在無症狀的WPW
病人治療適應症列為
Class III。
Y.B. Liu

72. Issue NOT covered in today’s talk
Y.B. Liu

73. Unusual connection
Y.B. Liu

74. Unusual connection: Mahaim fiber
The true Mahaim fiber is the nodofascicular or nodoventricular connection faithful
to the original pathologic description. Over time, the term became a generic
description for any pathway with slow decremental conduction properties.
Y.B. Liu

75. Unusual location: Epicardial AP
With or without diverticulum in coronary veins
Y.B. Liu

76. Thank you for your attention !
Y.B. Liu