HISTOLOGICAL SIGNS OF DAMAGE TO THE CONDUCTION SYSTEM OF THE HEART

Abstract

This paper presents an analysis of the available medical literature on the conducting system of the heart and its pathologies.

Full Text

Relevance: Pathology of the conducting system leads to severe cardiac arrhythmias and death of the patient.
The purpose of the study: To study the information in the available literature.
Materials and methods: Analysis of available medical literature.
Results:
The conducting system of the heart ensures the coordinated work of different parts of the heart. The pathology of the conducting system is reduced to the syndrome of weakness of the sinus node, pathological additional conducting pathways between the atria and ventricles, heart block. The conduction system of the heart includes a complex of nodes, bundles and fibers and consists of atypical muscle fibers (they are not neurons). Muscle fibers in the sinus node resemble cardiac myocytes, but they are thinner, have a wavy shape and are less intensively stained with hematoxylin-eosin. Two nodes are recognized by areas enveloped in collagen tissue, which is full of capillaries and autonomic nerves. The three branches of the Gis bundle are colored rather pale due to the high content of glycogen granules and mitochondria in them. Purkinje fibers also contain a central area that is colored pale. Cardiopulmonary cells are connected strictly only through desmosomes and slit junctions. They also don't have a T-duct system. [1]
The main morphological signs of damage to the conductive system of the heart are general pathological changes in the heart, such as the diffuse nature of the pathological process of the left ventricular wall caused by a violation of the blood supply to the myocardium and the conductive tissue due to severe atherosclerotic stenosis and / or thrombotic occlusion of the main branches of the "coronary tree". This conclusion is confirmed by the involvement of elements of the conducting system in the area of ischemia, subendocardial or transmural infarction.[2]
The main histopathological signs of damage to the conducting system can be divided into acute, necrotic and scarring disorders.
Acute, probably reversible lesions include such as intracellular and extracellular edema, turbid edema and vacuolization of cells with preserved myofibrils and nuclei, leukocyte infiltration and an increase in the number of red blood cells throughout the branch of the conductive bundle. [3, 4]
Necrotic, irreversible, changes are characterized by cell homogenization with loss of nuclei from coagulation necrosis, coarse vacuolization of fibers with loss of myofibrils and nuclei.[3, 4]
The resulting scarring disorders are represented by atrioventricular node fibrosis, atrophy and replacement fibrosis of individual fibers, sclerotic replacement of the Gis bundle [3, 4]. These disorders are noted against the background of emerging myocardial fibrosis or scarring from septal infarction, destroying the left branch of the bundle.
Conclusions.
The conduction system of the heart includes a complex of nodes, bundles and fibers and consists of atypical muscle fibers. These muscle fibers resemble heart myocytes, but they are thinner, have a wavy shape and are less intensively stained with hematoxylin-eosin. Cardiopulmonary cells connect only through desmosomes and slit junctions. They don't have a T-duct system.
The main morphological signs of damage to the conduction system of the heart are general pathological changes in the heart.
Acute histopathological signs of damage to the conducting system include edema and vacuolization of cells with preserved myofibrils and nuclei, leukocyte infiltration and infiltration of erythrocytes. Necrotic changes are characterized by cell homogenization, loss of nuclei, vacuolization of fibers with loss of myofibrils. Scarring disorders are represented by fibrosis atrophy, sclerosis.