Distribution and EGM Characteristics of AEPVR
Distal Insertion sites of AEPVR were found 12.8±3.6mm distant from the
linear lesion (Right PVs: 12.6±3.5mm, Left PVs: 13.3±4.2mm). They were
most frequently located at the posterior PV antrum between the
ipsilateral PVs (17/32), including 9 from left and 8 from the right PVs,
followed by the anterior (12/32) carina of right PVs. In addition, 2
patients showed epicardial connection at anterior and posterior roof in
right PV, respectively. The other one demonstrated acute reconnection to
the left PVs through the vein of Marshall (Figure 3). Localized distal
activation patten was seen in 25/32 (78.1%) patients, followed by
widely spread pattern in the others. In 19/32 (59.4%) cases, activation
due to AEPVR propagated into both upper and lower PVs during sinus
rhythm. In the rest patients, residual potentials could only be observed
in a single PV.
Pace mapping discovered 2 major reconnection patterns. AEPVRs found at
the posterior PV antrum were connected to the posterior wall of the left
atrium. The connections traversed the ablation line generally in an
oblique direction. The connections to right anterior carina showed
proximal ends at posterior right atrium presumably through the
intercaval bundle (ICB). Different from posterior AEPVR, those
connections did not pass the prior ablation line (Supplementary Figure
1). Proximal insertion sites could also demonstrate localized or diffuse
patterns (Figure 4).
The EGMs at distal insertion sites of AEPVR showed an amplitude of
0.48±0.38 mV and duration of 26.3±10.0ms without fractionation. The mean
slope of major deflection was 0.10±0.09mV/ms. AEPVRs at the anterior
carina and posterior PV antrum were similar in amplitude (0.55±0.48mV
vs. 0.43±0.28mV, P =0.346) and slope (0.12±0.11mV/ms vs.
0.10±0.09mV/ms, P =0.524). Those distribution and EGM
characteristics of AEPVRs did not show difference from the delayed
epicardial connection in the repeated ablation procedures (Table 2,
Figure 3). In contrast, reconnection owing to endocardial gap conduction
was distributed in a wide area along the circular lesion including the
left atrial roof, floor and ridge. Most of the EGMs at the reconnection
sites involved highly fractionated deflections (Figure 1&3).