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.
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.
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)
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.
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
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)
33. Ablation Strategy of AVNRT
• Make a correct diagnosis!!!
• Ablation of antegrade or retrograde slow AVN
• Anatomic approach: PMA
• 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
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
68. Small & narrow P waveRA & LA depolarization simultaneously
Test 1 A P wave in the midpoint between the two QRS beats
Diagnosis: SF AVNRT with 2:1 AV block
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?