EP Study and Ablation Procedure
All procedures were performed in the fasting state under general
anesthesia with mechanical ventilation through a laryngeal mask airway.
After introducing the vascular access, intravenous heparin was initiated
to maintain the activated coagulation time over 300 seconds throughout
the procedure.
A duodecapolar catheter (BeeATâ„¢, Japan Lifeline Co., Tokyo, Japan) was
placed in the coronary sinus (CS) through the right internal jugular
vein. The proximal eight electrodes of this catheter covered the septum
of the right atrium (RA) and superior vena cava (SVC). We performed
transseptal puncture with the guidance of the intracardiac ultrasound.
After the puncture, a single 8.5 Fr steerable catheter (Agilis, St. Jude
Medical, St. Paul, MN, USA) and two pre-shaped catheters (8Fr SL0, St.
Jude Medical, St. Paul, MN, USA) were inserted into the left atrium
(LA). Three-dimensional electroanatomic mapping system (EnSite NavX, St.
Jude Medical, St. Paul, MN, USA and Carto 3, Biosense Webster, Irvine,
CA, USA) were used in all patients.
All patients underwent PV isolation with or without posterior wall
isolation (i.e., BOX isolation). We preferentially performed BOX
isolation; however, considering the type of AF (paroxysmal or
non-paroxysmal) and the spatial relationship between the esophagus and
the LA posterior wall, a standard PV isolation was adopted in some
patients. The ablation catheter and double Lasso mapping catheters were
each advanced into the LA. Radiofrequency (RF) ablation was applied via
an irrigated tip catheter to encompass the left and right PVs for PV
isolation and encompass all PVs together with the posterior wall for BOX
isolation. The endpoint of the PVI and BOX isolation was a bidirectional
conduction block between the LA and each isolation area.
SVC isolation was also performed in patients who has long SVC myocardial
sleeve (> 2 cm). The endpoint of SVC isolation was a
bidirectional conduction block between RA and SVC. To prevent
diaphragmatic paralysis, we performed pace mapping to identify the site
with diaphragmatic capture. RF ablation was applied in a point-by-point
manner at the earliest activation site of SVC potentials during sinus
rhythm.
Cavotricuspid isthmus (CTI) ablation was performed in all patients
except for the patients who underwent a prior ablation procedure for AF.
The endpoint of CTI ablation was a bidirectional conduction block across
the CTI.
The other ablation strategies such as linear ablation, ablation
targeting complex atrial fractionated electrocardiogram (CFAE), or low
voltage area were at the operator’s discretion.