Ablation procedure
Deep sedation was performed with a continuous infusion of propofol and
fentanyl. A 9-French (Fr) long sheath, a 7-Fr long sheath, and an 8.5-Fr
long sheath (SL-1) were introduced through the right femoral vein.
Intracardiac echocardiography (ICE; ViewFlex™, Abbott, Inc., USA) was
used to identify the absence of thrombi in the left atrium (LA) or LA
appendage before transseptal puncture and to guide the appropriate
transseptal puncture for CBA in all patients. After a single transseptal
puncture, the SL-1 sheath was exchanged with a 15-Fr steerable sheath
(FlexCath™, Medtronic, USA). The cryoballoon (CB) catheter (CB2; Arctic
Front AdvanceTM, Medtronic), assembled with an intraluminal mapping
catheter (20 mm, Achieve™, Medtronic), was gently advanced through the
steerable sheath until it reached the distal CB shaft marker to the
entrance of the steerable sheath. The CB catheter was advanced over the
intraluminal mapping catheter inserted into each PV and inflated. After
advancing the inflated CB to each PV antrum, Doppler ICE imaging was
used to identify the complete occlusion of each PV. With best-fit
occlusion, the mapping catheter was used to obtain PV potential
recordings for real-time monitoring of PVI. The dosing regimen was
different depending on the time to isolation (TTI, time from freeze
initiation until loss of PV potentials). An initial freeze was delivered
for 3 min if the TTI was ≤30 s. Otherwise, the initial freeze was
delivered for 4 min. The freeze stopped and reposition of the CB
catheter was performed if the TTI was not achieved or the temperature
did not reach –40℃ for 60-s freezing. After PVI, a bonus freeze was
applied for 2 min at the more antral side of each PV to create a wide
antral circumferential ablation. To avoid phrenic nerve palsy,
diaphragmatic stimulation was achieved by pacing the ipsilateral phrenic
nerve with a 900 ms cycle and a 20 mA output during right-sided CBA. A
fisherman’s knot suture closure without protamine injection was
performed to obtain femoral venous hemostasis following sheath removal.
After 6 h of immobilization, puncture sites were inspected. NOAC was
taken at the scheduled time on the day of the procedure after confirming
complete hemostasis or the absence of bleeding complications.