Aim. To study age-related electrocardiographic (ECG) dispersion mapping (DM) changes in adolescents with normal blood pressure (BP). ECG-DM makes it possible to assess the severity of myocardial electrophysiological abnormalities, which have not reached clinical manifestations with a standard ECG recording.

Material and methods. For the period of 2017-2020, the data of 1140 schoolchildren (590 boys and 550 girls) living in Magadan were analyzed. There were following inclusion criteria: age of 12-17 years, informed consent of parents, health status group 1-2, no prior chronic and acute diseases (vaccinations), and hypertension. Systolic (SBP) and diastolic blood pressure (DBP) were recorded 3 times on the A&D Company Ltd BP monitor (2017, Japan). ECG-DM parameters were obtained using the CardioVisor-06s system (2004, Russia, Moscow): Myocardium index (norm <15%), Rhythm index (norm <20%), right, left atrial (G1-G2) and right, left ventricular depolarization (G3-G4), right and left ventricular repolarization (G5-G6), ventricular depolarization symmetry (G7), intraventricular block (G8), ventricular hypertrophy (G9).

Results. In the period from 12 to 17 years old, an age-related increase in BP and a decrease in heart rate were determined (p<0,001). Significant rates of BP increase were observed in girls at the age of 12-13 years (p<0,01), while in boys, yearly differences regard only SBP from 12 years (p<0,05), except for 14-15 years. Sex differences were established at the age of 13 for DBP (p=0,026), from the age of 14 according to SBP, with higher values in boys (p<0,05). From 12 to 17 years old, age-related changes were observed only in the Rhythm index (p<0,001), while the predominance of average normal values was established from the age of 14 in boys (p=0,008) and from 15 years old in girls (p=0,022) relative to younger age. There was also an increase in the proportion of persons with normal values in boys from 28,7 to 50,0%, in girls from 29,4 to 61,7% (p<0,05). The Myocardium index at all ages approached the upper normal limit without dependence on age and sex. According to G1-G9 indicators, normal and borderline values prevailed. The greatest similarity was observed in G1-G2 in 45,6-40,8% of boys and 48,3-46,5% of girls, as well as in G9 — 35,1-39,6% (p>0,05), respectively.

The proportion of persons in G5-G6 was lower among boys (6,9 and 7,1%) compared with girls (14,2 and 13,1%) (p=0,002, p=0,010), while other indicators had no significant differences as follows: G3 (9,8 and 7,1%), G4 (4,9 and 4,0%), G7 (5,4 and 6,0%), G8 (1,4 and 1,1%) (p>0,05). Among boys according to G9, age differences were observed at 14-15 years old (p=0,026), while among girls — G1 at 16-17 years old (p=0,035).

Conclusion. ECG-DM allows monitoring early cardiac dispersion changes in children aged 12-17 years with a normal blood pressure level and identifying among them those adolescents who need further examination.

Aim. To study the factors associated with the intermediate probability of heart failure (HF) with preserved ejection fraction (HFpEF) according to the H₂FPEF score (Heavy; Hypertensive; Atrial Fibrillation; Pulmonary Hypertension; Elder; Filling Pressure) in asymptomatic patients in rotation work conditions in the Arctic.

Material and methods. In the polar village of Yamburg (68° 21’ 40” northern latitude), 100 men and 80 women with grade 1, 2 hypertension and normotensive persons were examined on the basis of the Medical Unit of OOO Gazprom Dobycha Yamburg. All patients underwent echocardiography using generally accepted methods of imaging and data processing, according to European Society of Echocardiography guidelines. To calculate the probability of HFpEF, the H₂FPEF score was used. The Bruce protocol treadmill test was performed. The SF-36 (Health Status Survey) questionnaire for assessment of life quality was used.

Results. Group 1 included 95 male and female patients with a low probability of HF (H₂FPEF score — 0-1), group 2 — 85 patients of both sexes with an intermediate probability of HF (H₂FPEF score — 2-5). Group 2 patients were older (p=0,038), worked longer on a shift (p=0,0143), and had higher ambulatory systolic (p=0,0001) and diastolic blood pressure (p=0,0013) with a higher body mass index (BMI) (p=0,0001). Based on the odds ratio (OR) analysis, the factor most strongly influencing the intermediate probability of HFpEF was BMI (OR=1,261, 95% confidence interval (CI): 1,140-1,393). SF-36 questionnaire revealed intergroup differences only on the role functioning scale (p=0,013) with lower values in group 2. In the logistic regression model, dyspnea during the treadmill test occupied a leading position as follows: OR=8,952; 95% CI: 3,454-15,197 (p<0,0001). The second place was taken by inotropic reserve value (OR=1,020; 95% CI: 1,006-1,035 (p=0,005), which was higher in group 2 and was regarded as one of the compensatory mechanisms for adapting to stress. In the group 2, echocardiography revealed significant differences in terms of left ventricular (LV) myocardial mass (p=0,0002), LV internal area (p=0,0002), isovolumic relaxation time (p=0,003), and ratio of transmitral diastolic flow rate to mean mitral annulus velocity (p=0,0001), which indirectly indicates the presence of LV diastolic dysfunction.

Conclusion. There are following factors associated with H₂FPEF intermediate probability of HFpEF in asymptomatic patients on shift in the Arctic: BMI, length of shift, dyspnea and an increase in inotropic reserve during exercise due to a decrease in adaptive potential, impaired LV diastolic function. Initiating management strategies that target identified factors in patients with asymptomatic HF may slow symptomatic disease progression in shift workers in the Arctic region.

Aim. To study the associations of hypoxia-inducible factor-1 alpha (HIF-1α) gene polymorphism (rs11549465) with the clinical course of heart failure (HF) with reserved ejection fraction (HFpEF) in patients with obesity and moderate and severe obstructive sleep apnea (OSA).

Material and methods. The study included 76 men with HFpEF and OSAS. Patients underwent a polysomnography, echocardiography, and a 6-minute walk test. In addition, apnea/hypopnea index was calculated, and the level of N-terminal pro-brain natriuretic peptide (NT-proBNP) was assessed. HIF1A gene polymorphisms (rs11549465) were analyzed using polymerase chain reaction. After 12-month follow-up, the clinical course of HF was assessed.

Results. The T/T genotype of the HIF1A gene was associated with a high risk of HF progression (p=0,004), development of supraventricular premature beats (p=0,004) and atrial fibrillation (p=0,039). Carrying the T/T genotype was associated with severe OSA (p=0,006) and increased NT-proBNP (p=0,044), and also correlated with certain echocardiographic characteristics of myocardial remodeling.

Conclusion. T/T genotype of the HIF1A gene is associated with OSA severity and increased NT-proBNP, as well as with the severity of left and right heart remodeling. The carriage of this genotype was associated with an unfavorable course of HF and an increased risk of atrial fibrillation in patients with HFpEF and OSA.

Aim. To identify the incidence of deep vein thrombosis (DVT) as determined by compressive duplex ultrasound in primary health care facilities before and during the pandemic of a coronavirus disease 2019 (COVID-19).

Material and methods. This retrospective analysis of 1492 duplex ultrasound examinations in 2018 and 1710 examinations in 2020-2021 in patients with suspected lower limb DVT was performed. The studies were carried out in 4 primary health care institutions in different cities of the Republic of Uzbekistan. Each patient underwent duplex ultrasound of lower limb deep veins. Most patients had complaints (swelling, leg pain) (symptomatic patients), while some individuals underwent preventive screening before various surgical interventions and had no complaints (asymptomatic patients).

Results. According to the data obtained, the prevalence of DVT increased significantly during the pandemic — from 3,9 to 15,1% (χ²=113,23, p<0,001). During the pandemic, there was a trend towards a relative increase in lower limb DVT among the elderly and young people — by 8,7 and 3,8%, respectively (χ²=1,66, p=0,19 and χ²=0,64, p=0,42, respectively). No dependence of the prevalence of lower limb DVT on the sex was found (χ²=0,02, r=0,9).

Conclusion. The study results showed an increase in the prevalence of lower limb DVT during the COVID-19 pandemic. Further clinical studies are needed to analyze the lower limb DVT during this period.

Aim. To study the features of deceleration capacity (DC) and acceleration capacity (AC) in patients with hypertrophic cardiomyopathy (HCM) and assess the correlation of these indicators with known complications and risk factors for sudden cardiac death (SCD).

Material and methods. A total of 50 patients with HCM were examined. Comparable by sex and age, the control group included 50 individuals without cardiovascular diseases. All patients underwent 24-hour electrocardiographic monitoring with the determination of DC and AC. The follow-up period lasted 5 years. Lethal outcomes were recorded in 6%, including SCD — 4%.

Results. Patients with HCM were characterized by significantly lower mean DC — 5,5 [3,7; 7,4] vs 7,8 [7,1; 8,5] ms (p=0,0001) and significantly higher AC– -7,4 [-8,9; -5,8] vs -9,3 [-10,0; -8,6] ms (p=0,001) compared with the control group. In 36% of patients with HCM, pathological values of DC ≤4,5 ms were detected, while in all individuals in the control group, DC corresponded to a favorable prognosis (p=0,001). In patients with and without nonsustained ventricular tachycardia (NSVT), a decrease in DC was detected in 56% and 25,5% (p=0,043), respectively, while with and without heart failure (HF) — in 78% and 27% (p=0,016), respectively. In patients with HF (p=0,003) and paroxysmal atrial fibrillation (p=0,023), mean DC values were significantly lower than in patients without these complications. HF was an independent predictor of DC reduction. DC decrease was not associated with an increase in SCD risk estimated using the HCM Risk-SCD calculator.

Conclusion. Patients with HCM compared with healthy individuals are characterized by lower DC and higher AC values. Among patients with HCM, a decrease in DC is typical for patients with a more severe disease course (HF, AF, NSVT). However, the rationale for using this indicator in SCD risk stratification needs to be clarified.

Aim. To establish the prevalence of myocarditis and primary (genetic) cardiomyopathies (CMP) among patients in a cardiology hospital.

Material and methods. Medical records of 671 patients of the cardiology department were analyzed. The diagnosis at admission and at discharge was recorded. The diagnoses were divided into 7 following categories: hypertension, coronary artery disease, heart disease, idiopathic arrhythmias, cardiomyopathy, myocarditis and others. Types of myocarditis and cardiomyopathy, the presence of arrhythmias and heart failure were also recorded.

Results. Myocarditis was diagnosed in 194 (28,9%) patients, cardiomyopathy — in 76 (11,3%) patients, combination of cardiomyopathy and myocarditis — in 26 (3,9%) patients. Myocarditis with the development of arrhythmia and heart dilatation prevailed as follows: 47,4 and 41,2%, respectively. The most numerous CMPs were left ventricular noncompaction (n=30), non-inflammatory dilated CMP (n=13), hypertrophic CMP (n=10) and arrhythmogenic CMP of the right ventricle (n=9). In the group with idiopathic arrhythmias, 64,3% of patients were diagnosed with myocarditis, and 19,4% — with cardiomyopathy.

Conclusion. The prevalence of non-coronary myocardial diseases among patients in a cardiology hospital is high and amounts to 40,2%. The presence of arrhythmias, heart failure or dilated cardiomyopathy may be a manifestation of non-coronary myocardial diseases, and requires a comprehensive examination aimed, in particular, at ruling out or verifying the diagnosis of myocarditis.

Aim. To study the lipid-lowering and pleiotropic vasoprotective effects of atorvastatin depending on the achievement of the target low-density lipoprotein cholesterol (LDL-C) level in patients after ST-segment elevation myocardial infarction (STEMI) within 48-week follow-up period.

Material and methods. A total of 125 patients with STEMI, randomized to receive atorvastatin 40 or 80 mg per day for 48 weeks, were examined. On days 7-9, after 24, 48 weeks, we performed biochemical blood tests, echocardiography, as well as assessed the carotid arteries and endothelial function. The subjects were divided into the following groups: high-efficiency therapy (HET) — 41 patients who reached target LDL-C at control visits; moderate-efficiency therapy (MET) — 35 patients who achieved target LDL-C at one visit; low-efficiency therapy effective (LET) — 49 people who did not reach the target LDL-C. Differences were considered significant at p<0,05.

Results. A decrease in detection rate of an elevated brain natriuretic peptide was found in HET group from 41,5 to 17% (p<0,01) and in MET group from 48,6 to 23% (p<0,01), while no changes in the LET were revealed. The glomerular filtration rate in the LET group decreased by 8% (p<0,01). In the HET group, a decrease in arterial elastance by 9,4%, intima-media thickness by 9,9%, a decrease in the frequency of a negative response and an increase in a positive response (p<0,05) were revealed.

Conclusion. The results demonstrate the importance of achieving target LDL-C for the most favorable dynamics of brain natriuretic peptide, structural and functional characteristics of the arterial system.

Aim. To assess the changes of heart rate (HR), exercise tolerance and quality of life in patients after coronavirus disease 2019 (COVID-19) during treatment with ivabradine monotherapy or in combination with beta-blockers (BB) compared with BB monotherapy.

Material and methods. This randomized comparative study included 90 patients discharged from a university hospital after an acute COVID-19. The main group (n=60) received, in addition to standard therapy, ivabradine monotherapy or in combination with BB, while the control one (n=30) — standard therapy in combination with BB. The follow-up period lasted 24 weeks. Statistical processing was performed using the STATISTICA 8.0 program. The level of statistical significance was p<0,05.

Results. There was a significant decrease in heart rate, an increase in physical activity, as well as an improvement in the quality of life in both groups. In the ivabradine group, significantly lower heart rates (71,2±4,1 vs 73,9±5,1 bpm (p=0,015)), significantly higher increase in physical activity (80 (60; 135) vs 65 m (40; 100) (p=0,017)) and quality of life (35 (27; 45) vs 30 (26; 36) points (p=0,03)) was revealed.

Conclusion. It has been shown that ivabradine and beta-blockers can be used in post-COVID-19 tachycardia. Ivabradine monotherapy or in combination with beta-blockers causes a more pronounced decrease in heart rate compared to beta-blocker monotherapy, accompanied by a significant improvement in exercise tolerance and quality of life in this category of patients.

Aim. Comparative analysis of mathematical models obtained using multivariate logistic regression (MLR) with stepwise inclusion of predictors and machine learning (ML) for assessing the probability of subclinical carotid atherosclerosis in normotensive overweight and obese patients without cardiovascular diseases and/or diabetes.

Material and methods. We received data on patients from the Webiomed platform database. The inclusion criteria were age ≥18 years, body mass index ≥25 kg/m2, extracranial artery ultrasound results, while the exclusion criteria included diabetes and/or cardiovascular disease. MLR analysis was carried out with stepwise inclusion of predictors. ML algorithms were used to create an alternative model.

Results. The overall percentage of true results for MLR model was 73,2%, while the proportion of true negative and positive predictions was 80,1% and 63,4%, respectively. Mathematical models created using ML methods are characterized by a predictive value from 75 to 97% with a sensitivity of 77 to 92% and a specificity of 80 to 98%.

Conclusion. A significant superiority of ML models was revealed in the study of available clinical and paraclinical parameters. Integration of ML mathematical models into a diagnostic algorithm for making a decision to refer a low-risk patient for extracranial artery ultrasound will significantly improve its accuracy and cost efficiency.

The coronavirus disease 2019 (COVID-19) pandemic remains one of the most urgent problems for healthcare professionals due to the variety of non-pulmonary manifestations. Along with the respiratory syndrome in a significant proportion of patients, the disease course is accompanied by pronounced systemic inflammatory response and hemostasis changes. This is associated with a high risk of complications, especially in patients with concomitant cardiovascular pathology. The aim of the study was to analyze and systematize the literature data on the pathogenesis, clinical course, and outcomes of myocardial infarction (MI) in patients with COVID-19. For review, publications indexed in the PubMed, Google Scholar, Web of Science, and Cyberleninka databases were used. The search depth was 2 years, starting from 2020. The review is based on summarized data from the most relevant clinical studies, reports and systematic reviews. The literature analysis made it possible to conclude that the published data on MI in patients with COVID-19 are currently contradictory. Multiple thrombosis, sepsis, macrophage activation, increasing hypoxemia, imbalance between myocardial oxygen supply and demand in patients with severe COVID-19 have led to a high incidence of type 1 and type 2 MI. It should be especially noted that in a number of cases, MI with COVID-19 occurs in patients with intact coronary arteries, and its course is associated with a high incidence of complications, which, in turn, leads to a significant increase in short- and mid-term mortality.

Chronic mesenteric ischemia (CMI) is an urgent public health problem. The long asymptomatic course of the disease, sudden onset and an unfavorable prognosis in the absence of treatment make it necessary to pay closer attention to this pathology. There are currently two competitive treatments for CMI: surgical and endovascular revascularization. Despite numerous studies comparing these methods, the question of which one is more effective and reliable remains open. The review includes current data from clinical trials and meta-analyses demonstrating the advantages and disadvantages of both methods.