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Figure legends
Figure 1. Determination and relative location of the EC site and the ablation line
Coherent mapping of three EC-positive groups: On-the-line group, the EC located on PVI line; Inside-line group, the EC located on PV side; Outside-line group, the EC located on LA side. Star symbol with dashed line shows the earliest activation point in the EC site. Bachman bundle was shown in earlier activation site in the anterior wall of LA (square symbol). EC, epicardial connection; LA, left atrium; PV, pulmonary vein
Figure 2. Grouping of patients
Patients were divided into two groups according to the presence or absence of the EC (EC-positive group and EC-negative group). Patients in the EC-positive group were further divided into two groups according to the relative location of the EC. EC, epicardial connection; PV, pulmonary vein; RA, right atrium.
Figure 3. First-pass isolation
In EC-positive group, the success rate of first-pass isolation in the On-the-line group was significantly higher than that in the inside-line group (10/11, 91% vs. 2/10, 20%; p=0.0019).
Figure 4. Speculative schema of association of epicardial connection and ablation site
A. The green line indicates the EC between right-sided PV and RA. The EC transverses the epicardial fat of the interatrial groove.
B. a.) Since the ablation lesion is close to the attachment site, the EC can be eliminated. b.) Since the EC runs farther from the endocardium, the ablation lesion cannot sufficiently reach the EC. c.) Since the EC site is on the LA side of the isolation line, it does not affect the pulmonary vein isolation.
LA, left atrium; EC, epicardial connection; PV, pulmonary vein; RA, right atrium
Table 1. Patients characteristics