BACKGROUND Left atrial strain (LAS) analysis represents a newer non-invasive, sensitive and specific technique for assessing left atrial (LA) function and early detection of its deformation and dysfunction. However, its applicability in mitral regurgitation (MR) in pediatric population remains unexplored, raising pertinent questions regarding its potential role in evaluating the severity and progression of the disease. OBJECTIVE To investigate the impact of chronic MR in children and adolescents on LA remodeling and function. METHODS The study included 100 participants. Patients with primary and secondary chronic MR lasting at least 5 years fit our inclusion criteria. The exclusion criteria from the study were: patients with functional mitral regurgitation due to primary cardiomyopathies, patients with artificial mitral valve, patients with MR who had previously undergone surgery due to obstructive lesions of the left heart (aortic stenosis, coarctation of the aorta), patients with significant atrial rhythm disorders (atrial fibrillation, atrial flutter). The echocardiographic recordings were conducted by two different cardiologists. Outcome data was reported as mean and standard deviation (SD) or median and interquartile range (Q1-Q3). RESULTS The study included 100 participants, of whom 50 had MR and the remaining 50 were without MR. The average age of all participants was 15.8 ± 1.2 years, with a gender distribution of 37 males and 63 females. There was a significant difference in the values of LA volume index (LAVI), which were higher in patients with MR (p= 0.0001), S/D ratio (and parameters S and D; p= 0.001, p= 0.0001, p= 0.013), mitral annulus radius (p= 0.0001), E/A ratio (p= 0.0001), as well as septal e' (m/s), lateral e' (m/s), and average E/e' ratio, along with the values of TV peak gradient and LV global longitudinal strain (%). There was no significant difference in LA strain parameters, nor in LA stiffness index (LASI). CONCLUSION Our findings revealed significant differences in several echocardiographic parameters in pediatric patients with MR relative to those without MR, providing insight into the multifaceted cardiac structural and functional effects of MR in this vulnerable population.

BACKGROUND Left atrial stiffness index (LASI), defined as the ratio of early diastolic transmitral flow velocity/lateral mitral annulus myocardial velocity (E/e') to peak atrial strain, reflects reduced left atrial (LA) compliance and represents an emerging marker that can be used for noninvasive measurement of fibrosis of LA in patients with mitral regurgitation (MR). OBJECTIVE To investigate the impact of chronic MR in children and adolescents on the remodeling and function of the LA, quantified through strain parameters and diastolic function. METHODS The study included fifty patients (n= 50) diagnosed with primary and secondary chronic MR lasting at least 5 years. The echocardiographic recordings were performed by a third party, two cardiologists actively engaged in echocardiography on a daily basis. RESULTS Older participants had higher values of the LASI (r= 0.467, p= 0.001). Participants with higher LASI values had a smaller LA reservoir (r= 0.784, p= 0.0001) and smaller LA conduit values (r=-0.374, p= 0.00). Participants with higher LASI values had a larger LA diameter (r= 0.444, p-value= 0.001) and higher average E/e' ratio (r= 0.718, p= 0.0001). There was a significant difference (p= 0.04) in the LASI among participants based on the MR jet area (< 20.85 cm2/⩾ 20.85 cm2), LASI was higher in participants with an area greater than 20.85 cm2. Differences in other parameters such as LA reservoir, LA conduit, LA contractile were not statistically significant. CONCLUSION Increased LA stiffness is associated with diminished atrial compliance and reservoir capacity, and LASI has a potential to as an early marker for assessing disease severity and progression in pediatric MR.

Pediatric arrhythmology deals with studying of frequency and regularity of heart rhythm disorders in childhood. Rhythm disturbances (dysrhythmias, arrhythmias) occur as a result of disturbances in the creation or conduction of stimuli in the specific or working musculature of the heart. Simplifying the knowledge of everyday work on pediatric arrhythmias, they can originate from the atria of the heart when we speak about supraventricular arrhythmias or from the heart chambers when we talk about ventricular arrhythmias. There are currently three major problems that burden pediatric cardiologists and pediatric arrhythmologists, and which are the focus of interest in pediatrics as a whole. These are primarily sudden cardiac death in children (SCD), fetal arrhythmias (FA) and postoperative-incisional arrhythmias (IA). The development of pediatric arrhythmology is imperative in the development of pediatrics and pediatric cardiology.

BACKGROUND Left atrial (LA) strain analysis has emerged as a noninvasive technique for assessing LA function and early detection of myocardial deformation. Recently, its application has also shown promise in the pediatric population, spanning diverse cardiac conditions that demand accurate and sensitive diagnostic measures. OBJECTIVE This research endeavors to explore the role of LA strain parameters and contribute to the growing body of knowledge in pediatric cardiology, paving the way for more effective and tailored approaches to patient care. METHODS A comprehensive literature review was conducted to gather evidence from studies using echocardiographic strain imaging techniques across pediatric populations. RESULTS LA strain parameters exhibited greater sensitivity than conventional atrial function indicators, with early detection of diastolic dysfunction and LA remodeling in pediatric cardiomyopathy, children with multisystem inflammatory syndrome, rheumatic heart disease, as well as childhood renal insufficiency and obesity offering prognostic relevance as potential markers in these pediatric subpopulations. However, there remains a paucity of evidence concerning pediatric mitral valve pathology, justifying further exploration. CONCLUSION LA strain analysis carries crucial clinical and prognostic implications in pediatric cardiac conditions, with reliable accuracy and sensitivity to early functional changes.

Aim Compare the efficacy of nebulized hypertonic saline and normal saline in the treatment of infants hospitalized for bronchiolitis. Methods This retrospective study was conducted at the Department of Pulmonology, Paediatric Clinic, Clinical Centre University of Sarajevo, covering the period from January 2015 to December 2019 and comprising 380 children aged between 1 and 12 months having bronchiolitis. One group received nebulized hypertonic saline (NHS, 3% NaCl)), and another group received nebulized normal saline (NNS, 0.9% NaCl). The control group did not receive any of these treatment options. Results There was no statistically significant difference between the treatment groups regarding length of hospital stay (LOS) and Clinical Severity Score (CSS) at admission and discharge as well as in oxygen therapy duration and antibiotic use, the duration of symptoms before hospital admission, frequency of nasal discharge, elevated temperature, dyspnoea, cough and dehydration. Conclusion The results of this study are consistent with several recent studies or meta-analyses and support the evidence against the use of NHS in hospitalized infants with mild or moderate bronchiolitis.

Aim To analyse the association of human leukocyte antigen B27 with clinical and laboratory parameters in patients with juvenile idiopathic arthritis (JIA) at the disease onset. Methods A retrospective review of medical records of 25 HLAB27 positive and 25 HLA-B27 negative JIA patients was performed. The diagnosis of JIA was based on the 1997-2001 International League Against Rheumatism (ILAR) criteria. Collected data: age, sex, HLA- B27 antigen presence, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), rheumatoid-factor (RF), antinuclear antibody (ANA), fever, rash, uveitis, enthesitis, inflamed joints and subtype of JIA. Results HLA- B27 positive study group had more boys (p=0.01), higher erythrocyte sedimentation rate (p=0.038), higher presence of fever (p= 0.025) and enthesitis (p=0.024). Any significant difference in age of the disease onset, CRP, ANA, RF, rash, uveitis, inflamed joint and dactylitis was not noticed. The most common subtype of JIA in the HLA-B27 positive patients was ERA (60%). Conclusion This study showed that the presence of HLA- B27 antigen plays a significant role in determining the presenting clinical and laboratory characteristics in JIA patients.

Abstract Aim: The study aimed to evaluate the acute effect of ultrafiltration on the mechanical properties of the aorta using brachial-ankle pulse wave velocity (PWV) before and after hemodialysis (HD). Patients and Methods: This study included 80 patients who were on a long-term HD program. The input variables were anamnestic data, body composition monitor (BCM) parameters, and echocardiography findings. The assessment of hydration status was determined by BCM, whose work is based on the principle of multifrequency bioimpedance spectroscopy. Another diagnostic procedure was the use of an arteriograph apparatus to assess PWV and Augmentation Index (AIx). All measurements were performed before and after dialysis on the middle dialysis day of the week. Results: The participants were divided into two groups based on hydration status: the experimental group consisted of 40 overhydrated participants and the control group consisted of 40 normovolemic participants. Statistically, the following BCM parameters correlated significantly positively with PWV: total body fat (r = 0.222; P < 0.05), overhydration (r = 0.290; P < 0.001), and relative overhydration (r = 0.290; P < 0.001). From echocardiography findings, only left atrial diameter correlated statistically significantly positively with PWV (r = 0.359; P < 0.001). Comparison of the mean PWV values within the experimental group before and after HD showed a statistically significant decrease from 14.32 ± 2.34 m/s to 8.72 ± 1.52 m/s (Z = 3.254; P = 0.0001). Mean PWV values within the control group did not decrease significantly from 13.39 ± 1.32 m/s to 10.39 ± 1.18 m/s (Z = 0.524; P = 0.742). If we compare the mean values of PWV between groups, then before HD treatment, there was no statistically significant difference between groups with PWV values in the experimental group of 14.32 ± 2.34 m/s and the control group of 13.39 ± 1.32 m/s (Z = 0.762; P = 0.852). According to the results of univariate regression analysis before and after HD treatment, only overhydration showed an absolute effect on PWV before and after HD. Conclusion: Overhydration showed an effect on brachial-ankle PWV before and after HD, and brachial-ankle PWV should be followed in HD patients.

The emergence of blockchain technologies, including smart contracts, enables the decentralization of applications that were previously controlled by a single entity. In many cases, however, smart contracts still need to distinguish between different user roles according to their assigned duties. To ensure security, smart contracts often apply a simple form of role-based access control (RBAC), where a dedicated administrator assigns users to roles that are authorized to invoke specific smart contract functions. As this solution contradicts the blockchain principles of decentralization and democratic decision making, smart contracts may also form decentralized autonomous organizations where governance decisions are based on voting by all participants. Many applications would benefit from a hybrid approach that involves roles with different permissions while still allowing for collaborative management. Therefore, we propose a novel mechanism for RBAC administration in smart contracts based on hierarchical roles and configurable administration rules for each role. Any change in the user-role relation requires joint approval by members of selected roles according to the associated rule. This enables decentralized organizational charts with flexible administration constraints, where each role corresponds to specific permissions in the decentralized application and any change is transparently and securely recorded on the blockchain. The practical feasibility of the approach is demonstrated by means of a prototypical implementation for the Ethereum blockchain. Several benchmarks are performed to analyze the potential overhead of different solution variants.