1. This document provides an overview of a training course on complex supraventricular tachycardia (SVT) differentiation. It discusses various SVT etiologies and electrocardiogram patterns. 2. Mechanisms of SVT discussed include atrioventricular nodal reentrant tachycardia (AVNRT), atrioventricular reentrant tachycardia (AVRT), and atrial tachycardia (AT). The document also reviews electrophysiology study findings that help differentiate the mechanisms. 3. Case examples are presented to demonstrate electrophysiology study techniques for SVT diagnosis and ablation, including ventricular overdrive pacing, ventricular extrastimuli, and induction protocols.

1. Complex SVT
with differentiation
Advanced Cardiac Arrhythmia
Training Course
( 中華民國心律醫學會 )
謝敏雄 醫師
台北醫學大學醫學系副教授
萬芳醫院心臟內科主任
April 15, 2012 於台北國賓飯店

2. Supraventricular tachycardia (SVT)
• Etiology: ( 臺北榮總十三年經驗 )
1. AVNRT (n=1452): 50%
Typical (slow-fast) 90%
Atypical (fast-slow) 7%
Variant (intermediate) 9%
2. AVRT (n=1221): 42%
orthodromic (fast AP 90% or
slow AP 10%)
3. AT (n=245): 8%

3. 12-lead ECG for
differential diagnosis
of SVTs (important!)

4. Retrograde P wave in SVT
(Tai CT et al. JACC 1997)

5. Short RP SVT
1. Slow-Fast AVNRT:
No apparent retrograde P wave: 50%
Pseudo R’ in V1 or pseudo-S in inferior
leads: 50% (RP<70 ms)
• Orthodromic AVRT: 70 ms<RP<PR
The presence of delta wave in NSR.
6. AT with PR prolongation: the presence of
AV block favors AT.

6. S-F AVNRT
Pseudo-R’
Pseudo-S

7. Orthodromic AVRT
RP>70 ms, electrical alternans

8. SVT with Electrical Alternans
• Electrical (QRS) alternans during narrow
QRS tachycardias is a rate-related
phenomenon.
• It depends on an abrupt increase to a
critical rate.
• It is independent of the tachycardia
mechanism.
(Morady F et al. JACC 1987)

9. Long RP SVT
1. Fast-Slow AVNRT:
Positive p wave in V1 and negative p
wave in inferior leads.
• Are the P waves of SF and FS AVNRT
different?
4. Orthodromic AVRT using decremental
(slow) APs.
3. AT with normal PR interval.

10. FS AVNRT

11. PJRT (slow AP)

12. PJRT
• The arrhythmia was permanent or incessant in
23/49 cases (47%) and paroxysmal in 26/49
(53%).
• Eight patients (16%) presented with tachycardia-
induced cardiomyopathy (TIC).
• The accessory pathway (AP) was located in the
right posteroseptal region in 37 cases (76%) and
in atypical sites in 12 cases (24%).
• Regression of TIC was observed in all cases
(8/8) after catheter ablation.
(Meiltz A et al. Europace 2006)

13. AT (with AV block)

14. EP study for
differential diagnosis
of SVTs

15. Favors AVNRT
1. The presence of dual AVN physiology:
upper or lower common pathway.
2. The critical prolongation (jump) of AH
interval during the initiation of SVT.
3. The concentric atrial activation:
especially a straight line from ECG-A-V
or A before V (SF AVNRT)

16. AVNRT
• Antegrade SAVN: AH jump > 50 ms
• Continuous curve AVNRT
• V induced SF AVNRT
• AVNRT with retrograde eccentric activation
• Clinically documented, non-inducible AVNRT
(Lee SH, et al. AJC 1997)
• During 23+/-13 months of follow-up, none of the
16 patients with slow-pathway ablation had
recurrence of PSVT.
• However, 7 of the 11 patients without ablation
had PSVT recurrence at 13+/-14 months of
follow-up. (Lin JL et al. JACC 1998)

17. Definitions
• Retrograde FAVN: short VA, HIS earliest-A
and no decremental conduction.
• Retrograde SAVN: long VA, CSO earliest-A
and decremental conduction.
• V pacing: long VA interval with jump (>50 ms); A
sequence changes from HIS to CSO earliest
2. SVT: AH<HA, CSO earliest-A
• Retrograde intermediate AVN:
Intermediate VA interval, HIS and CSO-A
simultaneously, minimal decremental conduction
• S-I (AH>HA) or F-I (AH<HA)
(Tai CT et al. AJC 1996)

18. Continuous curve SF AVNRT
Induction of AVNRT Induction of AVNRT
18
(Tai CT et al. Circulation 1997)

19. V Pacing Induced SF AVNRT
Retrograde fast
Antegrade slow
19
Lee PC et al. J Interv Card Electrophysiol. 2005

20. SF AVNRT with eccentric A activation
20
(Ong M. et al. IJC 2007)

21. Favors AVRT
1. No decremental conduction during
pacing (except slow AP).
2. The eccentric atrial activation with short
VA interval (>70 ms)
4. VA interval increases >30 ms with
functional BBB.

22. LT AP with LBBB
(Josephson ME. P237)

23. Single VPC reset SVT

24. His refractory VPC
• 35-55 ms before the His deflection.
• Advance the following A: AVRT
• VPC terminate the SVT without
conducting to the atrium: rule out AT,
favors AVRT.
• VPC from the sites other than RVA:
LV: for left side APs
RVOT: for septal APs

25. VPC reset SVT (FS AVNRT)
No advance A
VA= 140 ms VA= 250 ms
Lower common pathway
Same retrograde A sequence

26. VPC reset SVT (AVRT)
Advance A
342 342 323 378
His refractory VPC

27. VPC terminates SVT (AVRT)
Without conduction to atrium, R/O AT
His refractory VPC, R/O AVNRT

28. Ventricular Overdrive
Pacing (VOP) (10-40 ms
shorter than tachycardia)
during SVT

29. VOP entrains the SVT
• VOP could not entrain SVT: AT
• The same atrial activation sequence:
AVNRT or AVRT
The different atrial activation sequence: AT
• The presence of lower common pathway:
AVNRT is more likely.
• The presence of V-A-A-V response: AT
• The presence of V-A-V response: favors
AVNRT or AVRT.

30. VOP during SVT (FS AVNRT)
A
V V
V A V AV AV A
Same retrograde A sequence
Lower common pathway

31. VOP during SVT (AT)
A A
V
V
1. The retrograde A sequence is different during tachycardia and VOP
2. The presence of V-A-A-V response during VOP
(Veenhuyzen G. et al. PACE 2011)

32. (Veenhuyzen G. et al. PACE 2011)

33. Ablation Strategy of AVNRT
• Make a correct diagnosis!!!
• Ablation of antegrade or retrograde slow AVN
• Anatomic approach: PMA
• Electrogram approach: 小 A, 大 V (slow
potential)
• Junctional tachycardia during RF
• Mapping during V pacing but ablation during SR
(for retrograde SAVN only): ABL-earliest A
• How to avoid AV block?
• Ablation during A pacing
• Avoid ablation during SVT or V pacing.
• Quick hand! Quick leg! Quick brain! (You have

34. Slow Potential
34

35. JT during ablation
True
Junctional
rhythm
H H
CS junctional rhythm
35

36. Transient complete AVB
Complete AVB
One second
36

37. Transient complete AVB
Complete AVB for more than 10 seconds
37

38. SAVN Ablation Site
RAO 30 degree LAO 60 degree
38

39. Ablation site
RAO 30 degree LAO 60 degree
Retrograde
Slow AVN
Antegrade
Slow AVN

40. Ablation Strategy of AVRT
• Make a correct diagnosis!!!
• Localization of the APs: 12-lead ECG
algorithm and intracardiac recordings.
• A-V or V-A fusion or earliest
• Antegrade approach: for RT AP
• Retrograde approach: for LT AP
6. V site (subvalvular): small A, large V, stable
ablation catheter
7. A site (ante- or retro-grade): larger A, unstable
ablation catheter

41. Delta Wave in NSR
(Chiang CE et al. AJC 1996)

42. Cases Discussion

43. Case 1: 12 lead ECG
Long RP tachycardia

44. RAS1S2 induced PSVT
A H A
CSO-A earliest
FS AVNRT? Orthodromic AVRT? Or AT

45. VPC reset SVT
No advance the following A
The same retrograde A sequence
Increased the VA interval

46. VOP during SVT:
A A
V V
1. The same atrial activation sequence
2. Progressive prolongation of VA interval
3. The presence of V-A-A-V response

47. VOP changes SVT
FS AVNRT SF AVNRT

48. Another SVT
SF AVNRT

49. Successful ablation site

50. JT during RF

51. PR prolongation during RF

52. VA dissociation after Ablation

53. Successful ablation site

54. Case 2: 12 lead ECG
RP>70 ms

55. RVS1S1 350 ms
His-A earliest
CS ostium at 5,6?

56. RAS1S1 550 ms

57. RAS1S1+isuprel induced PSVT
A H A
CS9,10-A earliest AH~=HA

58. PSVT

59. VPC terminates SVT
AT is not likely

60. RVS1S1 350 ms+ isuprel
Increased VA interval Fusion FAVN

61. VPC Reset SVT
No advance A

62. VOP during SVT
No decremental conduction

63. VPC reset SVT
VPC advance A

64. Successful ablation site

65. Successful ablation

66. Successful ablation site
RAO LAO

67. Unknown Tracings

68. Small & narrow P waveRA & LA depolarization simultaneously
Test 1 A P wave in the midpoint between the two QRS beats
Diagnosis: SF AVNRT with 2:1 AV block

69. Test 1
AT with 2:1 AV block?
What’s the next step?

70. Test 1: VOP 2:1 to 1:1 conduction

71. Test 2
A 57 Y/O male patient had an arrhythmic attack during hospitalization.
PSVT with (RBBB) cycle length alternans and a fixed short RP interval
Cycle length alternans due to one longer and another shorter PR interval
Diagnosis: Orthodromic AVRT with dual AVN physiology
Initiation?

72. Test 2:RAS1S2 500/380 ms
One P with three Q
1. FAVN
2. SAVN
3. AVRT echo

73. Test 2: Spontaneous Initiation of SVT
One P with Two Q
Orthodromic AVRT with antegrade FAVN and retrograde LL AP

74. 謝謝聆聽
敬請指教