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Figure 1 The measurement of the atrial wall thickness in our representative case. A, B) Axial, C, D) coronal and E, F) sagittal views of the atria from one representative subject overlaid, in the bottom row, with the performed manual segmentations. Ao, aorta; LA, left atrium; LAA, left atrial appendage; PA, pulmonary artery; LV, left ventricle; RA, right atrium.
Figure 2 The mean AWT in each segment of the whole left atrium (A) and mean AWT in the NPAs and PAs in lesser LGE and all LGE areas (B). AWT, atrial wall thickness; LAA, left atrial appendage; LGE, late gadolinium enhancement; NPA, non-passively activated area; PA, passively activated area. PV, pulmonary vein.
Figure 3 The distribution of the NPAs and PAs according to the AWT and LGE-volume ratio. The NPAs (red) and PAs (blue). The AWT correlated negatively with the LGE-volume ratio in the total areas (A). This correlation was stronger in the NPAs (B) than PAs (C). AWT, atrial wall thickness; LGE, late gadolinium enhancement; NPA, non-passively activated area; PA, passively activated area.
Figure 4 Representative case in our study. ExTRa Mapping with the NavX system in the AP (A) and PA (B) views. The red, yellow, green, and light blue circles indicate the NPAs with a high %NP of 73, 59, 57, and 55%, respectively. The 3D LGE-MRI of the LA in the AP (C) and PA (D) views. The red, yellow, green, and light blue circles correspond to those in panel A. Despite the low value of the LGE-volume ratio, these 5 areas were determined to be NPAs and their AWT was thick.
AP, anterior-posterior; AWT, atrial wall thickness; LA, left atrium.
LGE-MRI, late-gadolinium enhancement magnetic resonance imaging; LSI, lesion size index; NPA, non-passively activated area; PA, posterior-anterior; %NP, non-passively activated ratio.
Figure 5 The proportion of MRs and MWs in the %NP of NPAs in lesser LGE and heterogenous LGE areas. LGE, late gadolinium enhancement; MR, meandering rotors; MW, multiple wavelets; NPA, non-passively activated area; %NP, non-passively activated ratio.