The morphology of the elements of the myocardial contractile apparatus question and research prospects

Background. Over the past 50 years, specific methods for studying the ultrastructure of the heart have been rapidly developed. The complex interaction of various research methods makes it possible to more accurately form a representation of the spatial structure of the components of the myocardial contractile apparatus. Objective. To conduct a content analysis of the results of the study of the composition of the myocardial contractile apparatus. Conduct a broad analysis of literary references and form an understanding of the spatial structure of the components of the myocardial contractile apparatus in the prospect of research at different levels of cell organization. Methods. Processing of information sources was carried out by the method of complex meta-analysis of data analysis. Results. The morphological characteristics of the myocardial contractile apparatus include a number of broad profile elements. The system of composite elements of the contractile apparatus of cardiomyocytes is the most formed and developed in the structure of the cytoplasmic complex of organelles in the group of contractile cardiomyocytes. The complex of the contractile apparatus is represented by myofibrils, each of which consists of thousands of sarcomeres telophragm connected in series, containing actin (thin) and myosin (thick) myofilaments. The main methods for studying the contractile apparatus of the myocardium include how immunohistochemistry and transmission electron microscopy provide an understanding of the structure of components at various levels of organization of histoarchitectonics and ultrastructure of organelles.. The contractile apparatus of the myocardium includes species-specific organelles, which basically belong to a number of basic hardware systems of cardiomyocytes. Conclusion. Immunohistochemical methods should clearly show the localization of individual tipes of elements in the protein structure of the contractile apparatus of the myocardium, and therefore should include in the study methods the use of the following immunohistochemical markers that can show the configuration of thin and thick myofilaments. The results of analytical review and analysis of information sources on the characteristics of the components of the myofibrillar complex gives a choice of specific research methods and forms a more detailed understanding of the spatial organization of the morphology of the myocardial contractile apparatus.

Are HFpEF and HFmrEF So Different? The Need to Understand Distinct Phenotypes

Traditionally, patients with heart failure (HF) are divided according to ejection fraction (EF) threshold more or <50%. In 2016, the ESC guidelines introduced a new subgroup of HF patients including those subjects with EF ranging between 40 and 49% called heart failure with midrange EF (HFmrEF). This group is poorly represented in clinical trials, and it includes both patients with previous HFrEF having a good response to therapy and subjects with initial preserved EF appearance in which systolic function has been impaired. The categorization according to EF has recently been questioned because this variable is not really a representative of the myocardial contractile function and it could vary in relation to different hemodynamic conditions. Therefore, EF could significantly change over a short-term period and its measurement depends on the scan time course. Finally, although EF is widely recognized and measured worldwide, it has significant interobserver variability even in the most accredited echo laboratories. These assumptions imply that the same patient evaluated in different periods or by different physicians could be classified as HFmrEF or HFpEF. Thus, the two HF subtypes probably subtend different responses to the underlying pathophysiological mechanisms. Similarly, the adaptation to hemodynamic stimuli and to metabolic alterations could be different for different HF stages and periods. In this review, we analyze similarities and dissimilarities and we hypothesize that clinical and morphological characteristics of the two syndromes are not so discordant.

CHARACTERISTICS OF INDICATORS OF CENTRAL HEMODYNAMICS OF CADETS OF MARINE UNIVERSITY IN THE PERIOD OF LONG SWIMMING

Goal. To reveal the peculiarities of central hemodynamics of cadets of a marine university in the conditions of a five-month sailing.Materials and methods. A survey of 70 cadets on board of a sailing training vessel was carried out in the dynamics of a five-month voyage (165 days). Hemodynamic indicators were monitored before entry on duty. For the statistical processing of the results, the SPSS software, v 17.0 (IBM) was used.Results and its discussion. The first two months are characterized by stable indicators of myocardial contractile function, which begins to change from the third month. In the third month, signs of mobilization of the circulatory function appear, which is expressed in an increase in blood pressure (p<0.05) and blood pressure (p<0,05) (by 6.6% and 14%, respectively).The fourth and fifth months are characterized by a further activation of the compensatory-adaptive mechanisms of hemodynamics: an increase in blood pressure (p<0,05), blood pressure (p<0,001), as well as MVC (p<0,05) due to an increase in heart rate (p<0,001), which indirectly indicates a decrease in efficiency in the work of the cardiovascular system.