Knowledge in interrelations between gross anatomy of the left atrial appendage (LAA) and thickness of the walls of LAA and periauricular area enables decreasing operational risks in LAA ostium occluding and «Cox-Maze» surgery for atrial fibrillation. The aim of the study was to identify significant interrelations between the macroscopic characteristics of the LAA (size, shape, number of lobes) and the parameters of the wall thickness of the LAA and its isthmus. Material and methods. The study includes 50 heart specimens of patients died from non-cardiac diseases. We examined 60 anatomical sections from 30 hearts by means Olympus SZX2-ZB10 microscope, and histological slices from 20 hearts. Results. The layers of the LAA wall were thinner than those in the isthmus. The thickness of LAA walls did not show direct correlation with the external dimensions of LAA. We found inverse correlation (Rs = – 0.4, p < 0,05) between the thickness of the myocardium, endocardium and some external sizes of LAA. The wall thickness of «chicken wing», «cauliflower» and «arrowhead» was the same. The wall of single-lobe LAA was thinner than that of two-lobed LAA (p = 0.036). The LAA isthmus wall was thinner (p = 0.03) in hearts with «cauliflower» LAA compared to hearts with LAA resembled a «chicken wing». Differences in wall thickness in LAA of various shapes were due to the degree of subepicardial fatty tissue development. Intracardiac operations should be done with the utmost care in patients with «cauliflower» LAA and single-lobe LAA to avoid damage of the LAA and periauricular area. Conclusions. The research found clinically significant interrelations between the LAA wall thickness and the number of its lobes as well as between the LAA isthmus wall thickness and LAA shape variants.

Знание топографии левого ушка сердца важно при операциях по поводу наджелудочковых аритмий и при герметизации устья ушка с целью профилактики тромбоэмболий при криптогенных инсультах. Цель работы -по результатам морфометрического изучения секционного материала дать характеристику типичному положению и вариантам локальной топографии левого ушка сердца взрослого человека. Материал и методы. На 54 препаратах сердца массой 200-400 г, заполненных силиконом, штангенциркулем измеряли расстояния от основания левого ушка сердца до верхушки сердца, до структур предсердного комплекса, присердечных сосудов и левой венечной артерии. Результаты и их обсуждение. Основание левого ушка сердца находилось на расстоянии 87,0 ± 13,1 мм от верхушки сердца, 49,7 ± 7,0 мм -от основания правого ушка сердца. Расстояние от левого ушка сердца до устья верхней полой вены (36,4 ± 8,1 мм) было на 16 % больше расстояния до восходящей части аорты (30,4 ± 6,4 мм), в 1,25 раза меньше расстояния до овальной ямки (45,2 ± 6,0 мм), в 1,5 раза меньше расстояния до устья нижней полой вены (55,5 ± 8,7 мм). Наименьшее медианное значение (9,6 мм) и наибольшая вариация (1,4-15,2 мм) были отмечены для расстояния до легочного ствола. Устья четырех легочных вен находились на разном расстоянии от устья ушка, ближе всего была левая верхняя легочная вена, в 59,6 % случаев она непосредственно примыкала сверху к ушку. Ее устье в 43 % случаев было выше устья ушка и в 57 % -на одном уровне с ним (р = 0,07). Левая венечная артерия находилась в 2,63-18,74 мм снизу от основания ушка. Прямые корреляционные связи выявлены для параметров предсердного комплекса. Длина желудочкового комплекса не являлась значимым предиктором для определения взаимного положения левого ушка сердца и соседних с ним структур. Заключение. Установленные значения морфометрических параметров и их взаимосвязи можно использовать как критерии нормального строения предсердного комплекса сердца.

The aim of the study was a morphometric characteristic of the left atrial appendage of a conditionally normal adult heart with a different number of lobes of this structure. We studied 52 preparations of the heart weighing 250-400 grams of people aged 36-89 who died from causes not related to diseases of the heart, blood vessels, muscle or connective tissue. The left atrium of the heart was filled with liquid silicone with a hardener. During the silicone hardening, the preparations were suspended so that the its lower wall was raised above the table plane by 10–15º. After the silicone hardened, the overall dimensions of the heart, left atrial appendage, and its lobes were measured with a caliper. The number of lobes and edges of the atrial appendage was determined. Nonparametric tests were used for statistical analysis of differences. It was established that in 71,1% of cases the left atrial appendages had two lobes, in 21,2% three lobes, in 7,7% it was single-lobed. The proximal lobes of the three-lobed left atrial appendages could be short or long. Three-lobed left atrial appendages were longer than two-lobed ones (U=106,5; p=0,018). The values of the width of the left atrial appendage of the heart did not depend on the number of its lobes (H=0,95; p=0,62). In 98,1% of cases, the atrial appendage had an edge directed towards the pulmonary artery, in 96,1% of cases they had an edge facing the diaphragmatic surface of the heart, in 94,2% of the preparations there was an edge facing the apex of the heart, in 25% of cases there was a left atrial edge directed back and up. Most often, in 65,4% of cases, the left appendage of the heart had three edges: pulmonary, apical and diaphragmatic. Thus, it was established that the left atrial appendage of the heart is characterized by a pronounced anatomical variability in shape. A different number of lobes, edges of the left atrial appendage, a different combination of these features and the ratio of the length and width of the lobes of the atrial appendage and the atrial appendage as a whole are proposed to be considered as criteria for distinguishing anatomical types and structural variants of the human left atrial appendage.

The aim of this study was to explore the anatomy and morphometry of the coronary sinus in hearts of adult humans, clarify position of the sinus to left atrium, left fibrous ring and adjacent arteries and describe topographic variants for adjacent anatomy of the coronary sinus in hearts of various types of coronary dominance. We studied 40 hearts weighing 200-420 g, obtained from patients who died from non-cardiac causes. We dissected 30 non-injected macroscopic specimens preserved into 4% PBS formalin to reveal and measure coronary sinus and neighboring coronary arteries. The rest 10 hearts we used for preparing histological slices from the points of the beginning of the sinus, in the middle, and near the “crux cordis”. We measured large and small diameters, circumference, wall thickness of the coronary sinus, as well as explored relative position of the coronary sinus, adjacent arteries, left atrium and left fibrous ring. The reference range of coronary sinus length was 33.76-48.4 mm. The median (Me) of the circumference of the coronary sinus increased from 13.87 mm at the beginning of the sinus to 23.99 mm at the “crux cordis”. In some specimens, the cross section of the sinus looked flattened in the anteroposterior direction; in others, it appeared to be flattened basoapically. We distinguished two anatomical patterns of the coronary sinus: subepicardial and intramyocardial. The first we proposed to term myocardialless or, simply, “naked”, and the second type we named muscularized. We proposed to divide the latter into partially and completely muscularized. Lack of adventitia between the myocardial sheet and tunica media of the coronary sinus allowed us to consider myocardial sleeves as an integral structure of the intramyocardial sinus wall. The wall thickness value of the coronary sinus at the point of origin, in the middle, and at the point of its turning anterosuperiorly toward the right atrium had no differences, but significantly depended on the myocardial cover and on the position of the coronary sinus in the left atrioventricular sulcus. The distance from the sinus to the posterior wall of the left atrium was 0.15-7.66 mm (Me 0.91 mm); the distance to the left fibrous ring was 2.9-13.7 mm (Me 7.9 mm). We found four variants of topographic and anatomical relations of the sinus and its adjacent arteries. Commonly, arteries were located below the coronary sinus. The ranges of variability of morphometric values of the coronary sinus and neighboring structures may be considered as reference values of the anatomy of the coronary sinus in the normal human adult heart.

Aim. To determine the left atrial dimensions, their ratios and relationships that characterize anatomy for left atrium structure in the normal human adult using the model of the atrial end-diastolic phase. Methods. We studied 54 heart specimens of subjects aged 3588 years who died from non-cardiac causes. The atrial end-diastolic phase was modeled by filling a specimen fixed in 1% formalin with liquid silicone. After silicone hardened, we performed morphometric measurements by a caliper. The data were processed by using a cluster, correlation and variance analysis. For pairwise comparison, we used the MannWhitney U-test or a two-sided t-test. Results. The article presents mean, standard deviation, median, 25th percentile and 75th percentile and coefficients of variation for the length, width and sagittal size of the left atrium, as well as the values of the distances between the pulmonary vein orifices, which characterize the dimensions of the left atrium posterior wall. Based on the left atrial size differences and their ratios, the specimens were divided into three clusters. The first (n1=23) and second clusters (n2=10) were represented by hearts with a cubic atrium; the second group differed from the first in the larger size of the left atrium. The third cluster (n3=21) included the hearts in which the largest left atrium size was the width, so the shape of the atria resembled a parallelepiped. The typical number of the pulmonary vein ostia we found in 91% of the specimens. The posterior wall of the left atrium, with a common number and topography of the ostia, were rectangle or an unequal trapezium in shape. We analyzed correlations between the sizes of the heart, left atrium and its posterior wall. We concretized the conceptual apparatus concerning the nomenclature and terminology of the left atrium anatomical structures. Conclusion. Based on the size ratio, two shape variations of the left atrium body can be identified: cubic or parallelepiped; cubic atria can be divided into large and small; the co-directional dimensions of the left atrial body and its posterior wall showed the strongest correlations.