Figure legends
Figure 1 Representative measurements of the roof (left panel) and floor line (right panel) on 3-dimentional computed tomography (3DCT) images in a case in which a gap was detected at the center of the roof line. Coronal plane images are used for measurement of the roof line, and horizonal plane images for measurement of the floor line. Each line is divided into 3 segments; right, center, and left segments (red lines). Ao = aorta; LA = left atrium; LIPV = left inferior pulmonary vein; LSPV = left superior pulmonary vein; LV = left ventricle; RIPV = right inferior pulmonary vein; RSPV = right superior pulmonary vein.
Figure 2 Representative left atrial bipolar voltage map from a case in which a gap was detected at the center of the roof line. Purple areas on the map are high voltage zones (≥ 2.64 mV), and blue, green, yellow, orange, and red areas are those of lower voltage (< 2.64 mV). LIPV = left inferior pulmonary vein; LSPV = left superior pulmonary vein; RIPV = right inferior pulmonary vein; RSPV = right superior pulmonary vein.
Figure 3 Histograms showing average bipolar voltage (upper panel) at each of the 6 segments in which voltage was measured and left atrial posterior wall (LAPW) thickness (lower panel) at each of the same 6 segments. Open circles below the upper histogram indicate failed first-pass LAPW isolation (LAPWI), solid circles indicate acute LAPW reconnections.
Figure 4 Scatter plot and regression line showing the relation between left atrial bipolar voltage and left atrial posterior wall (LAPW) thickness.
Figure 5 Three-dimensional computed tomography image (3DCT) and LA bipolar voltage map obtained in a case in which first-pass left atrial posterior wall isolation (LAPWI) was unsuccessful due to a gap in the center of the roof line. As seen, the LA wall (A) is 5.41 mm thick, and the LA bipolar voltage (B) is 3.63 mV. LA = left atrium; LIPV = left inferior pulmonary vein; LSPV = left superior pulmonary vein; LV = left ventricle; PA = pulmonary artery; RIPV = right inferior pulmonary vein; RSPV = right superior pulmonary vein.
Figure 6 Receiver-operating characteristic curves for prediction of a gap after an initial attempt at left atrial posterior wall isolation (LAPWI). The modified AI, the bipolar voltage and wall thickness on the LAPWI line provide significantly better predictive value than the AI (P < 0.01, respectively). AI = ablation index.