Морфометрическая характеристика и гистотопография стенок левого предсердия

Abstract

Background. Knowledge of the anatomical features of the left atrium walls will minimize complications during the “Cox-Maze” surgery. Aim. To clarify common features and local anatomical specificities of the anterosuperior, lateral and inferior walls of the left atrial body of the heart of an adult. Material and methods. From 60 preparations of the hearts of men and women aged 35-89 years who died from non-cardiac causes, 61 histotopograms and 180 anatomical sections of the left atrium walls were made. A stereoscopic microscope (×4.7-15 magnification), a histological microscope (×40 magnification), and an image recognition program were used. Nonparametric dispersion, correlation, one-way regression analysis were applied. The significance of differences was assessed by the Mann-Whitney U-test. The results were presented as medians. Results. Anatomical markers of the anterosuperior wall were a compact group of transverse myocardial fibers (anterior interatrial Bachmann bundle) and a thinned section of the lower third of the medial half of the wall. A feature of the lateral wall was a group of oblique myocardial fibers (left lateral ridge). The inferior wall was characterized by well-developed subepicardial tissue. Anteroposterior wall in the medial area (5130 µm) and lateral wall (5243 µm) were thin. The epicardium with subepicardial tissue in the medial part of the inferior wall was thicker (4750 µm) than in the lateral (2651 µm) and anterosuperior (2535 µm) walls. The myocardium of the anteroposterior wall (2714 µm) was thicker than the myocardium of both the lateral (2213 µm) and inferior wall in its central (1947 µm) and lateral (1913 µm) sections. The median thickness of the endocardium of different walls varied from 335 to 426 µm. The wall thickness in the upper third mostly depended primarily on the myocardium thickness, and in the inferior third on the epicardium and subepicardial tissue thickness. Conclusion. For the walls of the left atrium, their thickening towards the coronary sulcus was common due to the subepicardial adipose tissue. The peculiarities were the differences of the left atrium walls in thickness and their unique pattern of myocardial anatomy. © Eco-Vector, 2022. All rights reserved.