Left Margin of LVS – mitral margin.
The left circumflex coronary artery, together with the accompanying left lateral cardiac nerve, forms the mitral (or inferior) boundary of the LVS. In the distal sector of the mitral margin, the small section of the great cardiac vein is also present (Figure 1) [25]. In some cases, the circumflex coronary artery is accompanied by the conus vein, which trespasses under the trunk of the left coronary artery (Figure 2A,B). The length of the mitral margin is equal to the length of the septal margin. This margin neighbors close to the mitral annulus (thus the name of the margin), left fibrous trigon, left atrium and the left atrial appendage base [19]. The left atrial appendage overlaps the mitral margin, most commonly covering around 80% of its length, but this may vary depending on the left atrial appendage body type (shape) [26].