Electrophysiological evaluation of accessory pathway

1. ELECTROPHYSIOLOGICAL
EVALUATION OF WPW
SYNDROME
-DR. ROHIT WALSE
SENIOR RESIDENT
DM CARDIOLOGY
SCTIMST

2. SCOPE OF DISCUSSION
• HISTORY
• TYPES OF BYPASS TRACTS
• BASELINE STUDY
• PACING MANEUVERS
• TACHYCARDIA STUDY
• POST ABLATION MANEUVERS

3. HISTORY
• The earliest description of an accessary pathway was reported by Stanley Kent
in 1893 who suggested that impulses can travel from A to V over a node like
structure other than AV node.
• Cohn & Fraser reported the first case of pre excitation syndrome in 1913.

4. • In 1930, Louis Wolff, Sir John
Parkinson and Paul Dudley White
published a seminal article
describing 11 young patients who
suffered from attacks of
tachycardia associated with an ECG
pattern of bundle branch block
with a short PR interval.

5. SUDDEN DEATH IN WPW SYNDROME
• The incidence of SCD – 0.15% to 0.39%
• Sudden death in WPW syndrome is related to the degeneration of atrial
fibrillation with high ventricular rates into ventricular fibrillation.
• It is unusual for cardiac arrest to be the first symptomatic manifestation of
WPW syndrome

6. TYPES OF BYPASS TRACTS
• AtrioVentricular bypass tracts
• AtrioNodal bypass tracts
• AtrioHisian bypass tracts
• Atypical bypass tracts

7. LOCATIONS OF AV BYPASS TRACTS
LAO VIEW

8. DISTRIBUTION OF BYPASS TRACTS
• Left free wall- 46-60%
• Posteroseptal- 25%
• Right free wall – 13-21%
• Right superoseptal -7%
• Midseptum <5%

9. WPW PATTERN
WPW SYNDROME
• ECG abnormalities related to presence of AV bypass tract
[Ventricular preexcitation: short PR, delta wave, wide QRS complex]
• Ventricular pre excitation +
documented tachyarrhythmia/symptoms of
tachyarrhythmia

10. EPIDEMIOLOGY
• Prevalence of WPW pattern- 0.1-0.3 % [M>F]
• Annual risk of developing SVT- 0.25 %
• Familial WPW- PRKAG2; BMP2 gene

11. GOALS OF ELECTROPHYSIOLOGICAL EVALUATION
• Confirm the presence of bypass tract
• Localization of BT
• Evaluation of refractoriness of BT
• Induction & evaluation of tachycardia
• Demonstration of BT role in tachycardia
• Termination of tachycardia

12. CATHETER PLACEMENT

13. ALL CATHETERS IN

14. BASAL INTERVALS

15. BASELINE OBSERVATIONS DURING SR
• Short HV interval/Negative HV
• QRS- fusion between AVN-HPS + BT conduction

16. BASAL STUDY- SHORT HV
H H H
V
V
V
A A A
HV

17. QRS FUSION
AVN AVN
AV+BT
BT

18. WAYS TO BRING OUT VENTRICULAR PRE EXCITATION
• Carotid massage
• AVN blockers
• Rapid atrial pacing

19. AVN BLOCK WITH ADENOSINE 12 MG IV

20. ATRIAL PACING MANEUVERS DURING SR
• Incremental rate atrial pacing (IAP)
• Progressively premature AES (ARP)
• Antegrade block in AVN
• Brings out pre excitation
• Retrograde H activation
• ERP of BT

21. IAP
A
V
A
V
A
V
A
V
A
V
A
V
A
V
A
V

22. IAP
A
V
A
V
A
V
A
V
A
V
A
V
A
V
A
V
A
V
A
V

23. FULLY PREEXCITED AT 260 MS

24. ARP- SHOWING MAXIMUM PREEXCITATION
V
V

25. TACHY ON ARP, ANTEROGRADE ERP OF PATHWAY
V
V

26. PROGRAMMED VENTRICULAR STIMULATION
DURING SR
• PATTERNS OF VA CONDUCTION:
• Exclusive conduction through AVN
• Retrograde conduction through BT+AVN [Long PCL/ long VES coupling interval]
• Exclusive conduction over BT [Short PCL/short VES coupling interval]
• VA conduction absent [Shorter PCL/very early VES]

27. IVP- ECCENTRIC ACTIVATION

28. ECCENTRIC VA

29. INDUCTION OF TACHYCARDIA
• Spontaneous-APC, VPC, Catheter placement
• By programmed atrial stimulation (ARP)
• By programmed ventricular stimulation (RRP)

30. SPONTANEOUS INDUCTION OF TACHY WITH VPC
V
SR TACHY

31. RRP

32. NCT INDUCED ON RRP

33. TACHYCARDIA FEATURES
• A:V relationship
• VA interval
• Atrial activation sequence
• Effects of BBB
• Entrainment response

34. WCT- ANTIDROMIC AVRT

35. TACHYCARDIA

36. ?WHERE DO WE MEASURE VA INTERVAL IN
TACHYCARDIA

37. TACHY STUDY: SEPTAL VA 116 MS, ECCENTRIC ATRIAL
ACTIVATION, EARLIEST A IN CS 3,4

38. EFFECT OF DEVELOPMENT OF BBB ON TACHYCARDIA
• Coumel’s law
• Increase in TCL with
development of ipsilateral
bundle branch block indicates
that tachycardia circuit belongs
to that sided ventricle.

39. INCREASE IN TCL WITH DEVELOPMENT OF LBBB

40. Text
RBBB AND EFFECT ON TCL

41. RBBB DURING TACHY

42. NO INCREASE IN TCL WITH DEVELOPMENT OF RBBB

43. VENTRICULAR ENTRAINMENT
• Done by overdrive pacing usually from the RV apex (can be from other sites to gain
specific information)
• Pace at a CL 10-40ms faster than the TCL
• Entrainment is confirmed when
• Atria accelerate to the pacing CL
• Tachycardia continues once pacing is stopped
• Entrain multiple times, at different CLs to confirm a consistent entrainment
response

44. ENTRAINMENT- POINTS TO FOCUS
• VAHV versus VAAV response
• PPI-TCL
• SA-VA

45. AT VERSUS AVRT/AVNRT
• The VAAV response indicate the sequence of events happening after the last
entrained beat
• In AT, the last paced beat (V) traverses up the HPS->AVN->A and makes the
AVN refractory and hence it cannot echo back to the ventricles . The SVT
continues after cessation of pacing and causes the next A in the sequence
which is conducted down to the ventricles (V)

46. THE VAAV (OR AAV/AAHV) RESPONSE

47. THE VAAV RESPONSE
• The atrial activation pattern
has changed
• This is best evident in
HRA and His
• This confirms a true VAAV,
and hence an AT

48. AVRT/AVNRT VERSUS AT
• AVRT/AVNRT gives a VAV (VAHV) response after entrainment
• The last entrained paced beat (V) goes up the accessory pathway (AVRT) or
the fast pathway (AVNRT) and reaches the atria (A) comes down the AVN
(slow pathway in the case of AVNRT), HPS (H) and reaches the ventricles (V)

51. ENTRAINMENT – VAV RESPONSE

52. CONCEPT OF POST PACING INTERVAL

53. ENTRAINMENT RESPONSE
• AVRT
• PPI- TCL <115 msec
• SA-VA <85 msec
• AVNRT
• PPI- TCL >115 msec
• SA-VA >85 msec

54. ENTRAINMENT

55. ENTRAINMENT

56. ENTRAINMENT RESPONSE

57. EFFECT OF HIS REFRACTORY PVC
• AVRT:
• Pacing at parahisian region with PCL 10-30 msec
shorter than TCL leads to early activation of A
(Advancement)

58. ZIPES PVC

60. PARAHISIAN PACING- NODAL RESPONSE
W
W N N

61. PARAHISIAN PACING – EXTRANODAL RESPONSE
W W
N

62. RFA
• RV PACING
• SR
• TACHYCARDIA

63. VA FUSION
A
V

64. VA FUSION
A
V

65. GOOD SIGNAL, VA FUSION
A
V

66. POSTERIOR SEPTUM, GOOD FUSED VA SIGNALS
A
V

67. RF SIGNAL IN SINUS RHYTHM -AV FUSION
A V

68. RFA DURING RV PACING

69. RFA DURING SR

70. RFA DURING SR

71. RFA DURING TACHYCARDIA

72. POST ABLATION

73. ADENOSINE INDUCED AV BLOCK, NO CONDUCTION
OVER PATHWAY
A A A A A A
V
V
V

74. PARAHISIAN PACING- NODAL RESPONSE

75. PACING MANEUVERS
• RRP
• ARP
• ANTEGRADE AND RETROGRADE WENCKEBACK POINT
• CONCENTRIC ACTIVATION

76. THANK YOU