Catheter Ablation -> Atrial Fibrillation & Atrial Flutter: -> Ablation Techniques D-PO03 - Poster Session III (ID 48) Poster

D-PO03-123 - Safety And Effectiveness Of The Superior Vena Cava Isolation In Atrial Fibrillation Using Ablation Index-guide Radiofrequency (ID 1110)


Background: Superior vena cava (SVC) is one of the non-pulmonary vein (PV) trigger sites in atrial fibrillation (AF). Although SVC isolation has been shown to be effective, it may cause phrenic nerve (PN) injury. Ablation index (AI) is a quantitative lesion formation marker in radiofrequency ablation, but its safety and effectiveness in SVC isolation remains to be determined.
Objective: To identify the safety and effectiveness of AI-guide SVC-isolation for AF.
Methods: Of the 469 consecutive patients undergoing AF ablation from June 2018 to February 2019, 132 undergoing first AF ablation and SVC isolation were studied (mean age, 65±11 years; paroxysmal AF in 104 patients). SVC isolation was done when non-PV trigger was detected in SVC or myocardial sleeve >2 cm in SVC was present. After completing PV isolation, sinus node was identified during sinus rhythm by CARTO mapping. PN location in the SVC was identified by pacing at 10 volts while observing if diaphragm twitching was induced. Under monitoring the SVC potentials by 20-pole electrode catheter, SVC isolation was started at a site one cm above the sinus node and just adjacent to PN site with radiofrequency power at 25W and AI at 260. Circumferential, point-by-point ablation was successively done in the leftward direction until all SVC potentials disappeared. When abating on PN site, the diaphragm movement was periodically observed by fluoroscopy. SVC isolation was divided into two types: Isolation completed without ablating on PN site (Type 1) and isolation requiring ablation on PN site (Type 2).
Results: SVC isolation was completed in all patients. Types 1 and 2 were observed in 96 (73%) and 36 patients (27%), respectively (p<0.001). Mild to moderate PN injury judged by Chest X-ray occurred in 1/96 Type 1 (1%) and 5/36 Type 2 patients (14%) (p=0.006). No symptom was noted and PN injury recovered spontaneously in all patients. There was no difference in the AF recurrence rate between the two types (7/96 versus 3/36, p=0.547) during a mean follow-up period of 6 months.
Conclusion: SVC isolation under AI guidance using a power of 25W and AI value at 260 can be achieved without ablating on PN site in many patients (73%). There is an increased risk of PN injury when ablation on PN site is performed.