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.