Delineation of conduction gaps of linear lesions during atrial fibrillation ablation using ultra-high-density mapping

Figure 1. Flowchart of the patients. AF, atrial fibrillation; box isolation, simultaneous electrical isolation of all four PVs; PV, pulmonary vein.

Figure 2. Bidirectional activation maps of the electrical conduction gap. (A, B) Example of a short gap length at the bottom lesion. (C, D) Example of a long gap length at the roof lesion. CS, coronary sinus; PV, pulmonary vein.

Figure 3. Regional distribution of the entrances and exits and their gap lengths. (A) The gap length is longer at the roof lesion than at the bottom lesion in the box group (26.8 ± 11.8 and 14.6 ± 9.8 mm, respectively; P = 0.022). (B) The gap length tends to be longer around the right PV than around the left PV, although there is no significant difference (28.0 ± 15.3 vs. 16.8 ± 8.0 mm, P = 0.201). (C, D) The conduction gaps are located at the roof lesion in nine cases and at the bottom lesion in 12 cases in the box group and around the right PV in nine cases and around the left PV in four cases in the PVI group. ▪ and ● indicate exit and entrance, respectively. The linear length between the entrance and exit correlates with the actual gap length. PV, pulmonary vein; LIPV, left inferior pulmonary vein; RIPV, right inferior pulmonary vein; LSPV, left superior pulmonary vein; RSPV, right superior pulmonary vein.

Figure 4. Three-dimensional map showing the anisotropic property of the electrical activation speed at the left atrial posterior wall. (A, B) The endocardial activation speeds in the vertical direction are faster than those in the horizontal direction, whereas the endocardial activation speeds in the horizontal direction did not differ between the rightward and leftward directions. (C) The endocardial activation speed at the entrance into the box lesion is 2.3 ± 1.1 m/s in the vertical direction and 0.8 ± 0.4 m/s in the horizontal direction (P < 0.001). (D) The endocardial activation speed at the exit from the box lesion is 1.7 ± 0.9 m/s in the vertical direction and 1.4 ± 0.6 m/s in the horizontal direction (P = 0.100). (E) The activation speed ratios between the vertical and horizontal directions are 3.1 ± 1.6 at the entrance and 1.4 ± 0.6 at the exit (P < 0.001). CS, coronary sinus.

Figure 5. Representative case of epicardial conduction visualization during coronary sinus pacing. The entrance identified by the standard algorithm is at the centre of the box lesion. In the LUMIPOINT activation algorithm, electrical activation conducts linearly, from the roof line to the entrance, and centrifugally. The electrograms highlighted by the LUMIPOINT activation algorithm and the Skyline histogram are also shown. CS, coronary sinus.

Figure 6. Representative case of epicardial conduction visualization during pulmonary vein pacing. The exit identified by the standard algorithm is located away from the roof ablation line. In the LUMIPOINT activation algorithm, electrical activation is conducted continuously from the roof line to the exit and is then conducted centrifugally. The electrograms highlighted by the LUMIPOINT activation algorithm and the Skyline histogram are also shown. PV, pulmonary vein.