Characteristics of LAA in children
The LAA is the remnant of the original embryonic left atrium that develops during the third week of gestation8, so it is a structure anatomically appended to the main body of the LA, which locate between the left upper pulmonary vein and the left ventricle. The LAA has a wide perimeter that interfaces with the atrial musculature4. In the LAA, thick cords of pectinate muscle intervene with thin-walled tissue8. The anisotropic junctional tissue, with a complex fiber orientation, results in electrophysiological properties that may predispose this region to be the source of the arrhythmia3.
In children, left atrium in size is small, and increase as ages. The LAA lies within the confines of the pericardium, and thus its emptying and filling may be affected by left ventricular function.