Catheter ablation procedure
All antiarrhythmic drugs were discontinued for at least 5 half-lives
before the procedures. The ablation procedures were performed under deep
sedation with boluses of hydroxyzine, pentazocine, and propofol followed
by a continuous infusion of propofol and dexmedetomidine. The patients
received respiration control with adaptive servo ventilation (ASV). An
esophageal temperature monitoring catheter was inserted via the nose. A
duo-decapolar catheter (BeeAT; Japan Lifeline, Tokyo, Japan) was placed
in the coronary sinus (CS) though the right internal jugular vein or
right subclavian vein. A Brockenbrough puncture using an RF needle
(Japan Lifeline) was performed under guidance of the Soundstar 3D
Ultrasound Catheter (Biosense Webster). After the Brockenbrough
puncture, 2 or 3 long sheaths (SL0; Abbott, Chicago, IL, USA) were
inserted into the LA. An initial intravenous bolus of heparin (100IU/kg
body weight) was administered followed by a continuous infusion of
heparin to maintain the activated clotting time at 300-350 seconds. One
or two circular mapping catheters were placed in the superior and
inferior pulmonary veins (PVs), and the ipsilateral PVs were
circumferentially ablated guided by the CARTO3 mapping system. All PVI
was performed with the CF-sensing open-irrigated-tip ablation catheter.
The endpoint of the PVI was the achievement of bidirectional conduction
block between the LA and PVs. After the achievement of the PVI,
isoproterenol (20-300μg/h) and 40mg adenosine triphosphate (ATP) were
infused to examine any dormant PV reconnections and non-PV AF triggers.
A non-PV trigger ablation was strongly encouraged. Cavo-tricuspid
isthmus (CTI) block was created in almost all patients.
Ablation procedures performed between September 2014 and July 2018 were
CF-guided, whereas those between August 2018 and August 2019 were
AI-guided. In the CF-guided ablation, lesion creation was guided by CF
targets of 5-40g. Each radiofrequency application was delivered for 25
seconds with a power of up to 30W. In AI-guided ablation, the procedure
was guided by AI target values for each lesion as follows: 450 for the
anterior/roof segments and 400 for the posterior/inferior segments of
the LA. In both groups, the esophageal temperature was monitored
continuously during the ablation procedure to avoid any thermal injury,
and the radiofrequency delivery was terminated immediately when the
esophageal temperature reached > 40℃.