Regularities in the distribution of myocardial bridges over the branches of the coronary arteries

Abstract

The article highlights peculiarities of localization of myocardial bridges. It is believed that the coronary arteries and their branches are located in the subepicardial tissue. However, some researchers describe cases of intramural localization of their sections. Myocardial bridges – a set of fibers of the ventricular myocardium located over a certain area of the subepicardial branch of the coronary artery - represent variants of such localization.The aim of the study was to establish the patterns of macroscopic anatomy and topography of myocardial bridges investigating anatomical sections of the human heart in the adult and elderly people. Material and methods. The study involved 65 formalin-fixed sample preparations of the human heart of the adult and elderly people who died of conditions that were not associated with heart diseases. The authors measured transverse and longitudinal dimensions of the ventricular complex of the heart, and calculated the transverse-longitudinal index. Subepicardial vessels were prepared without prior injection. The number of myocardial bridges over the main branches of the coronary arteries was counted and their length was measured. The type of blood supply to the heart was determined according to a three-member classification, depending on the source of discharge of the posterior interventricular branch. Results. Myocardial bridges were observed on 44 (67.6%) sample preparations. As a rule, they were located over the branches of the left coronary artery (91.5%). They were typically located in the proximal half of the anterior interventricular sulcus. The length of the bridges ranged from 2.5 to 64 mm (Me = 13 mm). A direct positive correlation was found between the length of the ventricular complex of the heart and the length of the bridges. The relationship between the type of blood supply to the heart and the presence of bridges was not revealed. In 26 preparations, a cone artery departed from the right coronary sinus of the aorta, in addition to the right coronary artery, and bridges were observed in 17 sample preparations. Conclusion. Myocardial bridges are more typical for the branches of the left coronary artery compared to the right. They are typically localized in the proximal third of the anterior interventricular sulcus. There is a dependence between the length of the bridges and the length of the ventricular complex of the heart. The distribution and number of myocardial bridges does not depend on the type of blood supply to the heart, but is associated with the independent discharge of the cone artery from the aorta.