This document presents a case study of a 51-year-old female patient who suffered from chest pain, palpitations, and dizziness. She was previously diagnosed with paroxysmal supraventricular tachycardia. An electrophysiology study revealed dual atrioventricular nodal pathways. Radiofrequency ablation was performed and initially failed to eliminate the tachycardia. After further ablation attempts, junctional rhythm occurred and ablation was stopped. This resulted in second-degree atrioventricular block. Follow-up EKGs showed first-degree AV block initially and normal sinus rhythm later. The document discusses endpoints for successful radiofrequency ablation and techniques for preventing AV block.

1. CASE PRESENTATAION
AND
DISCUSSION
馬偕紀念醫院
心臟內科
A2 祁栢慶

2. CASE 1
 51 y/o female
 suffered from retrosternal pain, palpitation, and
dizziness for 1 hour and she visited 中興 hospital
five months ago,
 PSVT was diagnosed (with HR 180/min) and
corrected after adenosine injection. She then visited
our CV clinic. Thyroid function tests were normal.

3.  Holter EKG: infrequent PVCs
 Heart echo: mild TR
 EP study on 101/2/24

4. BASELINE EKG

5. RETROGRADE STUDY
 Retragrade: dual AVN pathways
 RV S1S2 induced echo beat (AVNRE)

6. A2H2=160ms
ANTEGRADE STUDY
 Dual AVN pathways
 RAS1S2:
 FPERP:380/500 ,
 Jump to slow at 370/500 A2H2=237ms
>50ms
Dual AVN pathways

7. RAPID RA PACING INDUCED PSVT
 RA S1S1 at 260ms with isoprotenerol infusion
 Tachycardia cycle length: 282ms; VA 33ms

8. ENTRAINMENT STUDY
 TCL: 282ms, PCL: 280ms,
∆ VA>85ms
 Post pacing interval= 408ms
 PPI- TCL: 408-282 = 126ms

9. ENTRAINMENT STUDY
 TCL: 291ms, PCL: 270ms,
 Post pacing interval= 408ms;
 PPI- TCL: 441-291= 150ms
 Rapid RV pacing can terminate the tachycardia

10. ABLATION SITE

11. ABLATION SITE
 Amplitude A:V = 1:5
 (Small A and big V)
 Each ablation: 10 to 20 seconds

12. JUNCTIONAL RHYTHM DURING ABLATION
 Setting: 50W 55⁰C 60s ;
 Could only reach 47 ⁰C

13. AFTER ABLATION
 AH prolonged to 117-162ms

14. AFTER ABLATION
 AVN WCL: 490ms

15. AFTER ABLATION
 AH interval 213ms
 CS S1S1 620ms , AH interval 369ms (slow)

16. POST ABLATION STUDY
 Without isoprotenerol: VA dissociation
VA dissociation ~~~

17. POST ABLATION STUDY
 With isoprotenerol: AH came back.
 AVNERP: 230/500

18. AFTER ABLATION
 With isoprotenerol, VA conduction present
 Retrograde fast pathway

19. AFTER ABLATION-
 With isoprotenerol infusion
 CS pacing: AVNRT with longer cycle length

20. FINAL ABLATION SITE
 One last shot…

21. FINAL ABLATION- ONE LAST SHOT
 JR occurred then ablation stopped immediately
 (in 5.8seconds)

22. FINAL ABLATION- ONE LAST SHOT
 Second degree AV block,
 Mobiz type 1.

23. AFTER FINAL ABLATION
 PR interval 288ms
 First Degree AV block

24. AFTER FINAL ABLATION-
 With isoprotenerol infusion
 Still AVNRT (slow-fast)

25. EKG AFTER ABLATION-
Day 0

26. EKG AFTER ABLATION- DAY 7
Day 7

27. EKG AFTER ABLATION--1MONTH
Day 30

28. DISCUSSION

30. ABLATION SITE
 Each ablation: 10 to 20 seconds
 Amplitude A:V = 1:5
 (Small A and big V)

31. END POINTS FOR RADIOFREQUENCY
DELIVERY
 Tachycardia rendered noninducible with and without
isoproterenol challenge
 Elimination or modification of slow pathway function
 Elimination of atrium–His bundle (AH) interval jumps
 Elimination of 1:1 antegrade conduction over the slow
atrioventricular (AV) nodal pathway
 Retrograde ventricular-atrial block through the slow AV nodal
pathway (fast-slow and slow-slow)
 AH interval jump with single echoes only (previously
inducible)
 Fast pathway injury
 PR interval prolongation (persistent)
 Transient antegrade AV block after radiofrequency
(caution warranted for further ablation)

32. PREVENTING ATRIOVENTRICULAR BLOCK
Method Description Comment
Ablation sites below triangle of Koch Inferior to level of CS roof Standard practice
Discontinue RF for loss of 1:1 retrograde
Monitor retrograde junctional conduction Standard practice
conduction
Discontinue RF for junctional rhythm <
Monitor for rapid junctional rhythm[87] Not prospectively tested
350msec
Difference timing between AEGM His and
Δ A-A timing His and ablation recordings[112] Not prospectively tested
AEGM ablation site > 20msec
Identify site on septum producing shortest
Pace mapping triangle of Koch[113] Not prospectively tested
stimulus to His time and avoid ablation there
Pace atrium faster than junctional rate to
Overdrive atrial pacing Not prospectively tested
monitor antegrade conduction
Start at 5W and increase power by 5W
Gradual power titration[114] every 5sec until junctional rhythm, then Not prospectively tested
increase power by 10W for total RF 120sec
Cryoablation 6 or 4mm tip

33.  Thank You Very Much