Case report
A 65-year-old man complained of palpitation, prompting a visit to our hospital. He had a history of pulmonary vein isolation (PVI) for paroxysmal AF and underwent additional SVC isolation procedures for AF arising from the SVC. He experienced AF recurrence 7 months after the first procedure and underwent the second procedure. The reconduction between the SVC and the RA along the path of the PN and SVC firing was detected. Point-by-point radio frequency (RF) applications were performed at 15 W/30 seconds on the PN and SVC isolation was achieved. However, he had AF recurrence again 5 months following the second procedure. Written informed consent was obtained from the patient. He underwent the third procedure for recurrent paroxysmal AF.
The SVC-RA map during sinus rhythm using a three-dimensional (3D) mapping system (CARTO 3 system version 6; Biosense Webster, Diamond Bar, CA, USA) and a 20-electrode mapping catheter (Pentaray; Biosense Webster) revealed the reconduction between the SVC and the RA (Figure 1, Supplement 1). The PN site was identified by pacing at 20 mA/2.0 ms and 5 mA/2.0 ms using the contact force-sensing irrigated ablation catheter (Thermo-Cool Smart touch SF, Biosense Webster). The circumferential conduction block line was detected by the lower threshold function in the CARTO 3 system version 6 (lower threshold at 20%, total local activation time of 155 ms) except for the course of the PN. Therefore, we attempted SVC isolation by making longitudinal lines on both sides of the course of PN(RF applications; 30W/30 seconds). The course of the PN identified at high output pacing (20 mA/2.0 ms) was wide, so we performed catheter ablation along the path of the PN site except for where low-output pacing (5 mA/2.0 ms) captured (Figure 1).We performed PN pacing at the right subclavian vein and confirmed compound muscle action potential (CMAP) to detect PN injury. Eventually, the SVC was successfully isolated without PN injury by making longitudinal lines on both sides of the PN in a cranial direction (Figures 1, 2). We confirmed the bi-directional block with SVC using isoproterenol infusion and adenosine triphosphate (40 mg). Postoperatively, the patient maintained sinus rhythm without antiarrhythmic drugs during a 14-month follow-up period.