The analysis of literature data has studied the pathogenetic mechanisms of heart rate variability (HRV) disorders in patients with congenital heart defects (CHD). The findings demonstrate that HRV alterations begin in utero and are determined by both the type of defect and associated hemodynamic disturbances. In the preoperative period, HRV is influenced by the severity of the defect, patient age at the time of surgical intervention, psychological state, and genetic factors. Surgical correction, particularly under cardiopulmonary bypass conditions, leads to further reduction in HRV due to autonomic nerve fiber damage, systemic inflammatory response, and scar tissue formation. The type of surgery significantly affects the degree of impairment, with more pronounced changes observed in open surgical interventions compared to endovascular methods. In the postoperative period, the pattern of HRV recovery depends on the type of correction and the initial defect. Notably, even in the long-term postoperative period, autonomic regulation imbalance often persists with predominant sympathetic influences. This may be attributed to both residual structural changes and long-term consequences of surgical damage to autonomic innervation. Understanding the mechanisms of HRV disorders is crucial for developing strategies to improve long-term outcomes in CHD patients; however, further research is needed to clarify the role of specific pathogenetic mechanisms and find ways to correct autonomic dysfunction.

Traditionally, stress tests in medicine have been used to diagnose coronary artery disease. However, this article explores their potential far more broadly, demonstrating that these tests can provide crucial information in the evaluation of patients with ventricular arrhythmias. The paper offers a detailed examination of the pathophysiological mechanisms underlying these arrhythmias, identifying autonomic nervous system imbalance as a key factor — specifically, reduced vagal reactivity against a backdrop of persistent elevated sympathetic activity.
The significance of a thorough assessment is emphasized, extending beyond the exercise phase itself to include the recovery period, which is usefully divided into an early phase (up to three minutes) and a late phase (after four minutes). A minute-by-minute analysis of ventricular arrhythmias recorded during post-exercise recovery enables the identification of specific early recovery phase arrhythmias (termed “sympathetic-driven”), which carry an unfavorable prognosis. These arrhythmias prove to be more significant predictors of cardiovascular complications than those occurring solely at peak exercise and often serve as markers of concealed structural heart disease.
The article underscores that the primary objective for the clinician must be the timely identification of the underlying pathology manifesting as these arrhythmias. Differentiated approaches to antiarrhythmic treatment, tailored to the nature of the rhythm disturbances, are also discussed. The early detection of patients with such arrhythmias will help prevent cases of sudden cardiac death, particularly among young individuals engaged in sports. Thus, the presented research highlights the pressing need for further in-depth study and systematization of ventricular arrhythmias during the recovery period to enhance the effectiveness of diagnostics and prevention in cardiovascular disease.

Background. Heart valve biopstheses are widely used in the surgical treatment of acquired heart valve defects. However, their main drawback remains progressive structural dysfunction, which requires replacement of up to 50 % of implants after 10–15 years. Modern diagnostic methods are needed to analyze the causes of dysfunction. One of the most promising methods is computed tomography (CT) with subsequent three-dimensional reconstruction of DICOM images, which allows for detailed visualization of the entire prosthesis as a whole, rather than just its individual fragments. Objective. To develop a method for non-destructive analysis of the calcification of biological heart valve prostheses based on computed tomography data. Materials and Methods. Two domestic “UniLine” bioprostheses with similar service lives (4 years 6 months and 5 years 9 months), but different degrees of calcification, were studied. Both prostheses were scanned using a clinical LightSpeed VCT CT scanner. The obtained DICOM images were processed using specially developed algorithms to construct three-dimensional models and calculate the volume of calcifications. Results. The first prosthesis, explanted earlier (after 4 years and 6 months), was significantly more calcified. Its total volume of calcification together with the metal frame was 129.53 mm³. In the second sample (service life 5 years 9 months), a lower calcification volume was recorded — 68.95 mm³ (the volume of the frame itself) — confirming a minimal degree of calcium deposition. Conclusion. The developed CT analysis method has proven effective for non-destructive research into the structural changes of bioprostheses. Nevertheless, there are certain limitations due to the equipment’s resolution and the difficulty of differentiating metal components from calcium deposits. This approach requires further improvement but already represents a valuable tool for the objective assessment of the condition of implanted devices.

Coronary heart disease remains one of the leading causes of death worldwide. Myocardial ischaemia-reperfusion injury, the underlying cause of сoronary heart disease, involves the excessive formation of reactive oxygen species, which leads to myocardial oxidative damage. The most logical way to combat excess ROS is to use antioxidants, which have been shown to be effective in experimental studies. However, appropriate targeting delivery methods are needed for the systemic use of antioxidant-based drugs in a clinical setting. This review discusses the mechanisms of ROS generation and action in cardiac сoronary heart disease, as well as the consequences of oxidative damage. The authors present the principles of targeted antioxidant delivery using both passive and active methods involving ligands that are specific to ischaemic tissue, such as targeted homing peptides. Analysis of the results of the various studies presented in this review shows that delivery using such specific ligands may increase the bioavailability of antioxidants and the cardioprotective efficacy of drugs based on them. In the future, the use of artificial intelligence to design high-affinity targeted peptides may open new possibilities for personalized therapy for coronary heart disease. Thus, the development of targeted drug delivery systems represents one of the most promising strategies for improving the effectiveness of treatment for myocardial ischemia-reperfusion injury.

The hematopoietic stem cell (HSC) niche is a specific microenvironment in the bone marrow that maintains the ability of HSCs to differentiate and self-renew. It comprises two interconnected sub-niches: the vascular and the intraosseous. This distinction is particularly relevant in the context of homing, as hematopoietic stem cells sequentially interact with both niches during the engraftment process. The components of the bone marrow niche are divided into cellular and extracellular elements. All of them are crucial for maintaining niche homeostasis and, consequently, are essential for the success of HSC transplantation and subsequent engraftment.
Homing is the process of active migration of hematopoietic stem cells into the bone marrow, which occurs during bone marrow transplantation — a common treatment for hematopoietic tissue tumors. However, a significant proportion of the transplanted cells fail to reach their niche, leading to various side effects and complications of this procedure. Currently, there is active research focused on improving the efficacy of HSC transplantation. The approaches under investigation include both methods to directly enhance cell migration and strategies to preemptively increase the number of transplantable hematopoietic stem cells. Homing itself is a key target for new technologies, as improving its efficiency can reduce the time required for blood cell recovery after transplantation. Advancements in this field have the potential to transform current HSC transplantation practices and significantly increase patient survival rates following the procedure.

Non-traumatic subdural hematomas (NSDH) represent a rare but clinically significant pathology in the practice of neurologists and neurosurgeons. Establishing their non-traumatic origin often poses a challenge, especially in the absence of obvious risk factors, among which the leading ones are the use of antithrombotic therapy and advanced age of patients. Less common etiological factors include rupture of aneurysms, arteriovenous malformations and fistulas, as well as dural venous sinus thrombosis. Currently, there are no large case series dedicated to the management strategies of NSDH patients; therefore, indications for surgical treatment are based on recommendations for traumatic subdural hematomas. This article presents a literature review covering the period from 2000 to 2024, based on the Elibrary and PubMed databases, focusing on NSDH cases. Of the 119 publications screened, 36 met the inclusion criteria (strictly non-traumatic origin). The analysis allowed for the systematization of current data on the etiology, diagnosis, and treatment approaches for NSDH, emphasizing the importance of thorough angiographic examination to detect vascular anomalies, especially in young patients, and the necessity of correcting hemostatic disorders in the perioperative period. Furthermore, three original clinical cases are presented illustrating the course and outcomes of this condition in patients receiving dual antithrombotic therapy, where despite successful hematoma evacuation, a high risk of somatic complications was observed. Thus, the article summarizes contemporary understanding of the complex issue of NSDH, which holds significant practical value for improving diagnosis and treatment of this pathology.

Introduction. Obesity in adolescents is a highly prevalent and clinically heterogeneous disorder. Objective. To study the clinical diversity of the most significant obesity-related complications in adolescent boys. Materials and Methods. The study included 104 adolescents aged 14–17 years with obesity (ICD-10 code E66.0). A comprehensive examination was conducted, which included assessment of medical history, anthropometry, hormonal profile (LH, FSH, testosterone, kisspeptin, etc.), blood biochemical parameters (lipids, glucose), echocardiography and abdominal ultrasound, and blood pressure measurement. Data analysis was performed using descriptive statistics and Rasch mixture modeling. Results. Three distinct clinical phenotypes with heterogeneous propensities for developing complications were identified. Patients in the first phenotype had the highest likelihood of developing disorders of glucose metabolism and cardiovascular complications. The second phenotype was characterized by a prominent degree of insulin resistance and, to a lesser extent, dyslipidemia, while the probability of arterial hypertension was minimal. The third phenotype was defined by the highest risk of dyslipidemia and non-alcoholic fatty liver disease, with a minimal risk of glucose metabolism disorders. The overall potential for developing the full spectrum of complications was highest in the first clinical phenotype, significantly exceeding the levels observed in the second and third. A strong association was found between a high propensity for arterial hypertension and more advanced stages of pubertal development according to the Tanner scale. Conclusions. Adolescent boys with obesity exhibit varying predispositions to specific types of complications. Arterial hypertension shows a tendency to associate with insulin resistance, while dyslipidemia is linked to non-alcoholic fatty liver disease. Testosterone levels and pubertal stage have prognostic value for identifying the clinical phenotype characterized by an increased susceptibility to arterial hypertension.

Introduction. Chronic systemic inflammation (CSI) is a pathologic process that significantly worsens the life prognosis of patients. The need for a detailed study of the pathogenesis of this condition and testing new approaches to its treatment requires the creation of reproducible experimental models. The aim of the study was to develop a representative experimental model of CSI in rats using repeated subcutaneous administration of complete Freund’s adjuvant (CFA). Materials and Methods. Twenty male Wistar stock rats divided into CFA (n = 10) and control (n = 10) groups and were used in the experiment. Animals of the experimental group were injected with CFA subcutaneously in the interscapular region twice with an interval of 2 weeks (0.1 ml/kg). The control group was injected with saline solution according to the same protocol. Body weight was assessed weekly. Clinical blood analysis was performed before modeling and on days 7 and 21. At the end of the study, spleen mass index (SMI) was detected and tissue histologic picture was evaluated. Results. A decrease in the rate of body weight gain was observed in animals from the CFA group. In the same group, a statistically significant increase in the total number of leukocytes, lymphocytes and IMC (p < 0.05), a decrease in the level of erythrocytes and hemoglobin, as well as histological signs of inflammatory infiltration in the lungs and hyperplasia of the lymphoid tissue of the spleen were revealed. Conclusions. Repeated subcutaneous administration of CFA induces mild but stable systemic immune activation without pronounced local damage. The obtained model of CSF is reproducible and can be used in preclinical studies of chronic inflammation.

The study aims to assess the quality of life among older adults in the context of the pandemic and its aftermath. In recent years, there has been an increase in the aging population in modern Russia, and a paradigm shift is necessary regarding the older generation. This includes changes in their socialization, medical care, and health maintenance, which are directly linked to quality of life.
The study of quality of life will be combined with the analysis of laboratory data, instrumental studies, genetic tests, and indicators of post-infection immunity. This will help optimize the medical monitoring of patients aged 65 and over with chronic noncommunicable diseases during shock events like pandemics.
The goal is to create an optimal follow-up plan for these patients through the introduction of physical, occupational, and psychological therapies. Secondary prevention measures will also be implemented to help these individuals maintain their health and quality of life during and after the pandemic.