Anatomical characteristics of mitral isthmus and its spatial relationship with the esophagus in patients undergoing atrial fibrillation ablation using CT angiography

Figures

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  Figure 1. Linear and curved MI: (A) On the left is an illustration of a linear-shaped MI, whereas (B) on the right is a depiction of a curved-shaped MI. The annotations are as follows: Ao, aorta; LA, left atrium; LIPV, left inferior pulmonary vein; S, spine; red curve, distance of MI; black straight line, length of MI; blue straight line, depth of MI.

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  Figure 2. Ridge-shaped and pouch-shaped MI: (A) The left image depicts a ridge-shaped MI, whereas (B) the right image illustrates a pouch-shaped MI. The annotations are as follows: Ao, aorta; LA, left atrium; LIPV, left inferior pulmonary vein; S, spine; red curve, distance of MI.

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  Figure 3. Spatial measurements of MI and its proximity to the esophagus. The measurements were taken at three key locations: Level 1 (intersection of the upper end of MI and LIPV) in image D, Level 2 (midpoint of MI) in image C, and Level 3 (level of the mitral annulus) in image B. The annotations are as follows: Ao, aorta; LA, left atrium; LIPV, left inferior pulmonary vein; RIPV, right inferior pulmonary vein; S, spine; black solid line, MI distance measurement; yellow solid line, distance from the three levels to the esophagus.

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  Figure 4. Spatial relationship between MI and esophagus. The cross-sectional (A) and sagittal (B) images show direct contact between the bottom of the left lower pulmonary vein and the esophagus (indicated by red lines). Right image: As the esophagus descends, the spatial distance between it and MI gradually increases. Ao, Aorta; LA, left atrium; LIPV, Left lower pulmonary vein; LSPV, Left superior pulmonary vein; S, spine.