PVI
PVI was performed by two electrophysiologists (MH and MK) with more than
500 case experiences of AF ablation before the study. RF energy was
applied in a point-by-point manner using an open-irrigated catheter
equipped with a CF sensor (Thermocool Smarttouch® SF, STSF, Biosense
Webster, Diamond Bar, CA, USA).
Before AI technology was introduced to our facility, AI-blinded
retrospective analysis was performed by the medical device manufacturer
(Biosense Webster) to estimate optimal AI for a first-pass isolation in
standard PVI (n=5 in each operator).
Target CF was10-30g (irrigation flow rate: 8 ml/min for ≤30W, 15 ml/min
for >30W, power control mode). Contiguous RF region was
ensured by targeting an inter-lesion distance ≤6 mm.4The ablation lesion sets encircling the PV antra were created
>5 mm outside the PV ostia, where the local electrograms
did not show near-field PV signals. For the anterior segment in the
left-PV (the left lateral ridge), RF delivery was applied only to the
inside (<5 mm) of the left-PV ostium. The RF ablation on the
inter-PV carina was not performed as a part of initial lesion set,
unless it was needed to achieve PVI. No additional linear ablation in
the LA was performed, and only cavotricuspid isthmus ablation was
permitted for documented typical atrial flutter. RF energy was delivered
at 30-40W in power-controlled mode but was decreased to 20-30W at the
posterior/bottom segments if esophageal temperature exceeded 39℃
(irrigation flow rate: 8 ml/min for ≤30W, 15 ml/min for
>30W). The LASSO NAV catheter was placed inside the
ablation line of PVI. The success of first-pass isolation was defined as
the electrical isolation of ipsilateral PV which occurred either before
or at completion of the RF lesion sets without the ablation of the
inter-PV carina. After the circular RF application, electro-anatomical
mapping was performed using the PENTARAY catheter. If residual PV
potentials and/or conduction gaps within the isolated area were
observed, additional RF ablation was performed to eradicate them.
Conduction block from the PV to the LA was confirmed by high-output
pacing (20 V output, 1 msec pulse) from the isolated PV area at the both
sides. After a 20-minute waiting period, boluses of isoproterenol (2-4
μg) and adenosine triphosphate (20 mg) was administered. If spontaneous
PV reconnection and/or drug-evoked dormant conduction were observed, an
additional RF application was done to eliminate it.