Cryoballoon Ablation Procedure:
All procedures were performed under general anesthesia. Briefly,
utilizing a femoral venous approach, two sheaths (7Fr and 9Fr) were
placed in the left femoral vein. Via these sheaths, a Livewire decapolar
catheter and an Intracardiac Echocardiography (ICE) catheter (both St.
Jude Medical, St. Paul, MN) were advanced into the right atrium (RA) and
subsequently positioned under fluoroscopic guidance in the coronary
sinus and RA, respectively. A transseptal sheath was placed in the right
femoral vein. Using ICE and fluoroscopy guidance, trans-septal access to
the LA was obtained. A heparin bolus was given prior to trans-septal
puncture and then as needed to maintain the activated clotting time
(ACT) greater than 300 seconds during the procedure. The transseptal
sheath was then exchanged for a 12 Fr Flexcath sheath through which a 28
mm Artic Front Advance Cryoballoon ablation catheter (both Medtronic,
Inc., Minneapolis, MN) along with an inner lumen Achieve spiral mapping
catheter (Medtronic, Inc.) were placed in the LA. Using the St. Jude
Medical Ensite Velocity NAVX software, guided by a three dimensional CT
recreation of the LA, electroanatomic mapping was performed in the LA to
identify all the PVs. Each of the PVs were then sequentially isolated
using cryoballoon insufflations after ensuring tight contact with their
respective antrums. During cryoablation of the right-sided PVs, the
livewire catheter was used to stimulate the phrenic nerve from the SVC
to monitor for phrenic nerve injury. Following cryoablation, a
bidirectional conduction block was demonstrated from all veins, and a
post-ablation voltage map was created using the NAVX software. For areas
noted to have incomplete PV isolation with electrical gaps, additional
touch up freezes with the cryoablation catheter or, if necessary, a RF
ablation catheter was performed. For LCPVs with large ostiums, a
segmental approach was utilized with multiple cryoablation applications
delivered around the circumference of the PV antrum in order to achieve
antral isolation of the common vein. Additional cryoablation
applications or additional RF ablation was performed as needed until
complete PV isolation was achieved from all veins.