Mapping and Ablation of AEPVR and Endocardial Gap-related PVR
All PVs should be isolated before the observation of PVR. Additional
ablation was given if first-pass isolation was not achieved after
circumferential ablation. Thereafter, PV potentials was continuously
monitored. Acute PVR was defined as recovery of conduction between any
PV and extra-PV structures after 5 minutes counted from the time of
isolation. For the first isolated ipsilateral PVs, PentaRay catheter was
remained in the veins until ½ of the second ablation circle was
completed. It was then placed into the contralateral PVs to guide
ablation. A minimum of 40-minute waiting period, counted from the
isolation time were thereafter arranged for each PV to monitor acute PVR
with PentaRay and ablation catheter.
Once acute PVR was observed, activation mapping was performed to
distinguish AEPVR from endocardial gap conduction using the standard
described previously[10]. AEPVR was defined as
acute PVR with the earliest activation site within ablation circle
>5mm distant from the lesion, plus the absence of
near-field EGMs along the circle. In contrast, endocardial conduction
gap was characterized by the earliest activation site at the ablation
line (Figure 1). Pace mapping from within the circle was helpful to
differentiate AEPVR and far-field potentials[13],
and to localize the proximal insertion sites. For patients with
suspected AEPVR but in AF rhythm after PV isolation, direct current
cardioversion was attempted after additional ablation performed at the
discretion of operators, followed by mapping of AEPVRs. Ablation could
be performed by targeting the distal insertions of AEPVRs during sinus
rhythm or their proximal insertions during PV pacing.
The time from PV isolation to the observation of each AEPVR was
recorded. EGMs were measured by two electrophysiologists with average
value as the results. The clinical variables, electrophysiologic
characteristics and lesion set parameters were analyzed and compared
between patients with and without PVR (Control group), so were they
compared between patients showing the 2 types of PVR i.e., AEPVR (AEPVR
group) and endocardial conduction gap (Gap group). Furthermore, AEPVRs
were compared with a group of epicardial PVR confirmed in repeat AF
ablation procedures during the same period, which were not present in
the index procedure.