Results.
A total of 76 consecutive patients with symptomatic, drug refractory
paroxysmal AF were enrolled. The study group included 34 patients
undergoing WACA and 32 patients undergoing WACA+. Finally, 10 patients
underwent a staged procedure of WACA that was followed by WACA+ in case
of lack of first pass isolation with WACA only (Table 1). Procedural
time, dwell time, fluoroscopy time and radiofrequency time were not
different between the study (WACA and WACA+) groups (Table 2).
In contrast to a WACA only approach, the WACA+ approach (of
systematically performing ablation of the carina in addition to WACA)
increased the odds of achieving PV isolation from 65% (22 of 34 in the
WACA group) to 91% (29 of 32 in the WACA+ group, p=0.012). Analysis of
patients not achieving first pass PV isolation further demonstrated the
crucial role of the carina. In the WACA-only group, first pass isolation
was not achieved in 12 patients: in 7 patients (representing 20% of the
WACA group and 58% of the WACA not achieving first pass PV isolation),
the right carina had to be ablated to achieve right sided veins
isolation; in 3 patients, the left carina had to be ablated to achieve
left sided veins isolation; finally, in 2 (6.7 %) patients both carinas
had to be ablated to achieve pulmonary veins isolation.
In the WACA+ group, first pass isolation confirmed with circular mapping
catheter was achieved in 29 (91%) of patients. Two patients (9%)
required additional ablations to achieve isolation. In the first, this
was delivered at the anterior ridge where the previous ablation reached
an ablation index value of 480, while in the second additional ablation
was required at the anterior carina.
Based on the results of the study group (WACA and WACA+ groups) pointing
out at the carina as a critical site that needs to be ablated to achieve
complete PV isolation, we added a small third group of 10 patients who
underwent a step-by-step ablation of WACA and carina. In group 3, before
the carina was ablated, first pass isolation was achieved in 2 patients
(20%) patients only. In all patients the lack of isolation and its
location demonstrated with the ablation catheter was confirmed with the
circular mapping catheter. In the remaining 8 patients, the left carina,
the right carina and both carina areas, had to be ablated to achieve PV
isolation in 4 (40%), 2 (20%) and 2 (20%) patients, respectively.
Adenosine challenge revealed dormant PV-LA connections in 5/34 (14.7%)
in the WACA group, 4/32 (12.5%) in the WACA+ patients and 1/10 (10%)
in group 3 (p=NS). In 4 of 5 patients with dormant PV-LA connection
revealed by adenosine in group 1, the dormant connection was detected in
the 3 at the left carina, in 1 in the right carina and in 1 at the
anterior ridge. In group 2, the dormant connections were detected at the
left carina and the right carina in 2 patients each. In group 3 dormant
connection was detected at the left carina.
At the procedure termination, acute pulmonary vein isolation was
achieved in 100% of pulmonary veins ablated in the three groups.
No major complications occurred in any of the patients enrolled.
At a mean follow up of 18 months [IQR 15.2-20.8], freedom from
atrial fibrillation was 84% for the entire cohort. In group 1 the
success rate was 76.5% (26/34). In group 2 the success rate was 87.5%
(28/32), (p=0.342). In group 3 the success rate was 90% (9/10). In view
of the small number of patients, the success rate of group 3 was not
compared to that of group 1 and 2.