Fig. 2

Left atrial measurement point diagram. a. In the oblique horizontal position for measuring the left atrial transverse diameter, the left atrial body between the bilateral pulmonary venous sinuses (dotted lines) is divided equally into four parts by lines c-e. Wall thickness is measured along these lines (c-e) in the oblique sagittal plane perpendicular to the transverse left atrial diameter. Figures c, d and e correspond to the lines in figure a. The arrows indicate the measurement points. Measurement point 4 is the midpoint of the posterior wall; measurement point 1 is located in the upper 1/3 of the line connecting measurement point 4 to the top line of the left room in figure c. Measurement points 2 and 3 are measured in the same way as measurement point 1; measurement point 7 is located in the lower 2/3 of the line connecting measurement point 4 to the bottom line of the left room in figure c. Measurement points 8 and 9 are measured in the same way as measurement point 7; the figures shown correspond to the positions of the measurement points shown in Fig. 1. Measurement point 1 = top right of the rear wall, measurement point 2 = top middle of the rear wall, measurement point 3 = top left of the rear wall, measurement point 4 = middle right of the rear wall, measurement point 5 = middle of the rear wall, measurement point 6 = middle left of the rear wall, measurement point 7 = bottom right of the rear wall, measurement point 8 = bottom middle of the rear wall, measurement point 9 = bottom left of the rear wall, comparison between top middle and bottom of the rear wall for 1, 2, 3; 4, 5, 6; 7, 8,9 The comparison between the three groups of data is 3, 6, 9; 2, 5, 8; 1, 4, 7 for the left-centre-right comparison of the rear wall