Anatomy of the shape of the cavity and the internal relief of the walls of the left atrial appendage
Abstract
Introduction. The evaluation of the shape of the left atrial appendage into interconnection with the internal relief of its wall is of an importance for discovering anatomical patterns of the left atrium, which appears to be the most thrombogenic and are associated with a high thromboembolic risk from this chamber.The objective was to study features of the internal relief of the walls of the left atrial appendage of the adult heart and to find the dependence of these features on the size and shape of the appendage.Methods and material. We studied 68 left atrial silicone casts prepared from the hearts of 35–89 years men and women died from non-cardiac causes. By means a caliper, we measured the length and width of the cavity of the left atrial appendage, determined the shape, the number of lobes and intertrabecular spaces. With Image J program, we estimated the proportion of the area occupied by these spaces and pectinate muscles in pixels from photographs of the anterosuperior surface of the appendage. We used correlation analysis, Mann–Whitney U-test.Results. We found two-lobed appendages commonly than single-lobed and three-lobed. The number of intertrabecular spaces was 4–41 (median 21), with one-lobed appendages having fewer than twoand three-lobed. The same parameter was higher in the «chicken wing» than in the «arrowhead» specimens (23 vs 18, p=0.004). The proportion of the area occupied by the pectinate muscles and intertrabecular spaces in the left atrial appendage was 47 % (16–83 %) and showed none association with the shape of the cavity and the number of lobes.Conclusion. The number of intertrabecular spaces in the walls of the left atrial appendage correlated with its length and width and was the smallest in single-lobed specimens and in the appendages of the «arrowhead» shape. The abundant intertrabecular spaces were common for «chicken wing» variant of the left atrial appendage.
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