Requirements of carina ablation for PV isolation
The results of PV isolation by circumferential ablation are shown in
Figure 5. PV isolation was achieved by circumferential ablation alone in
5 of the 12 patients (42%) in the EC group, compared to 27 of 29
patients (93%) in the non-EC group (p < 0.003).
The ablation strategy after circumferential ablation was dependent on
the operator. In the first 5 of 7 patients in the EC group in whom PVs
were not isolated after circumferential ablation, repetitive
electroanatomical mapping revealed the earliest potential at the carina
region and we performed ablation at the carina resulting in PV
isolation. In the last two patients in the EC group, the earliest
activation area in the RA was mapped during pacing from the right
inferior PV prior to carina ablation, as shown in Figure 6. The earliest
area in the RA was broad, and extensive ablation to the area did not
result in PV isolation. Eventually, focal ablation at the carina was
required in both cases. In contrast, in 4 of the 29 patients (14%) in
the non-EC group in whom PV isolation was not achieved by
circumferential ablation, subsequent electroanatomical mapping revealed
an anterior gap in 2 patients (7%), and ablation of that gap isolated
the PVs. In the remaining 2 patients (7%), subsequent electroanatomical
mapping showed no gap in initial lesions and early activation at the
carina of the RPV. Additive ablation at the carina was performed and the
PVs were isolated.