Anatomy of the left atrium in the human heart: analyzis of anatomical interrelations

Objective - to identify and analyze the interrelations of the structure and local topography of the body of the left atrium (LA), left atrial appendage (LAA), and the main myocardial components of the LA. We studied 68 hearts of adults aged 35-89 years who died from non-cardiac causes. We measured the dimensions and local topography of the LA body and LAA at the specimens filled with polymerized silicone. At the dissected specimens, we determined the length and width of the myocardial components. We used the Mann - Whitney U-test, cluster and correlation analysis. The article presents the values of the length, width and thickness of the LA body and LAA. Correlations between the values of the LA body dimensions and the parameters of the LAA such as size, number of lobes, parameters of local topography were weak or absent. The LA volume and the size of the LAA as well as the values of some parameters of the LA local topography and the size of the orifice of the LAA exhibited moderate correlations. Long three-lobed LAAs were discovered to be common for large atriums with a parallelepiped-shaped body. The wider the body of that atrium, its LAA commonly had an oval-shaped orifice, the wider the anterior interatrial myocardial bundle and the longer the left lateral crest.