Aim. To study the prevalence of RBM20 gene polymorphisms and their relationship with the structural and functional left atrial (LA) characteristics in patients with coronary artery disease and heart failure with reduced ejection fraction (HFrEF).

Material and methods. The study included 138 men aged 55,8±6,6 years with prior myocardial infarction ³12 months ago and HFrEF (class II-IV heart failure, left ventricular ejection fraction (Simpson’s methods), 25,1±7,2%). The control group consisted of 384 healthy donors. Genotyping of two RBM20 polymorphic variants (rs942077 and rs35141404) was performed by real-time polymerase chain reaction.

Results. The prevalence of RBM20 polymorphisms did not differ in the HFrEF cohort and the control group. The GA rs35141404 genotype was more common among patients with a less pronounced increase in LA volume index (LAVI) (p=0,034). The minor A allele rs35141404 was associated with a protective effect on severe LA remodeling. However, this association did not reach the level of significance.

Conclusion. For the rs942077 and rs35141404 polymorphic variants of the RBM20 gene, no significant associations were found with the LA size and atrial fibrillation presence in patients with HFrEF and old myocardial infarction. There was a tendency towards the association of the A allele and the GA rs35141404 genotype with a protective effect on LA remodeling. The data obtained confirm the need for further search for genotype-phenotype relationships of a wider population of patients with heart failure and coronary artery disease.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a hereditary myocardial disease with a high risk of sudden cardiac death. The most common genetic forms of the disease are associated with desmosomal gene mutations.

Aim. To study the prevalence of desmosomal forms of ARVC and to analyze variations in the PKP2, DSG2, DSP, DSC2 and JUP genes in a sample of Russian patients with ARVC.

Material and methods. Included patients with ARVC underwent resting electrocardiography (ECG), 24-hour Holter ECG monitoring, echocardiography, chest x-ray, myocardial biopsy (if indicated), contrast-enhanced cardiac magnetic resonance imaging. All patients underwent medical genetic counseling. Mutations in the PKP2, DSG2, DSP, DSC2, and JUP genes was detected using highthroughput sequencing on the IonTorrent platform, followed by Sanger sequencing of uncovered gene regions. The pathogenicity of identified genetic variations was assessed according to modern guidelines.

Results. ARVC was established in 80 Russian unrelated patients. More than half of the probands (57%) in the study sample had definite diagnosis of ARVC, while 30% and 13% — borderline and possible ARVC, respectively. A positive family history of heart disease and/or SCD was noted in 30%. Genetic variants of pathogenicity class IV-V were detected in 15 (18,75%) probands in the PKP2, DSG2, DSP genes. The detection of genetic variants of pathogenicity class IV-V was different in the subgroups of patients with varying degrees of diagnosis reliability: 13 probands (28,3%) in the subgroup with definite ARVC and 2 probands (8,3%) in the subgroup with borderline ARVC. No genotype-positive probands were found in the subgroup with possible ARVC. Variations of unknown clinical significance were found in 13 (16,25%) probands.

Conclusion. The diagnostic yield of the desmosomal genes PKP2, DSG2, DSP, DSC2, and JUP was 19% with initial diagnosis of ARVC. The detection of mutations was significantly higher in patients with definite ARVC and severe disease manifestations.

Aim. To study the associations of angiotensinogen (AGT) (s4762(С521Т), rs699(Т704C)) and angiotensin II receptor type I (AGTR1) (rs5186(A1166C)) genetic polymorphisms with serum levels of insulin, glucagon, C-peptide, leptin, as well as with dyslipidemia and glycemic levels in Dagestan residents with combination of type 2 diabetes (T2D) and hypertension (HTN), as well as with isolated T2D/HTN.

Material and methods. We examined 16 patients with isolated T2D, 59 patients with T2D+HTN and 51 patients with isolated HTN from Dagestan. Genetic polymorphisms of the AGT and AGTR1 genes were studied. The levels of insulin, glucagon, C-peptide, and leptin were studied by enzyme-linked immunosorbent assay (ELISA), while lipid and carbohydrate metabolism — by biochemical methods.

Results. In patients with T2D, the association of CC genotype of AGT gene rs4762(С521Т) polymorphism with a leptin decrease was determined, while its CT genotype was associated with an increase in serum level of triglycerides. The TC genotype of AGT gene rs699(Т704C) polymorphism was associated with an increase in leptin, triglyceride and glucose levels. The AA genotype of AGTR1 gene rs5186(A1166C) polymorphism was associated with an increase in insulin and glucose levels, as well as a decrease in leptin level. In patients with a combination of T2D and HTN, CC and CT genotypes of AGT gene rs4762(С521Т) polymorphism was associated with a decrease in glucagon level. The TT genotype of AGT gene rs699(Т704C) polymorphism was associated with an increase in insulin, triglyceride, glucose and body mass index (BMI) levels. In isolated HTN, the CC and CT genotypes of AGT gene rs4762(С521Т) polymorphism were associated ith a decrease in glucagon level. The TT genotype of AGT gene rs699(Т704C) polymorphism was associated with increased levels of insulin, low density lipoproteins, and BMI.

Conclusion. Associations of AGT (s4762(С521Т), rs699(Т704C)) and AGTR1 (rs5186(A1166C)) genetic polymorphisms with carbohydrate and lipid metabolism changes are an important pathogenetic link of T2D and HTN, which allows developing an individual prognosis of these diseases in Dagestan residents.

Aim. To investigate the application of the Oxford Nanopore Technologies’ third generation sequencing for the genetic testing of hypertrophic cardiomyopathy.

Material and methods. The study involved 12 patients with hypertrophic cardiomyopathy aged 18 to 67 years (women, 9; men, 3). Using the PCR barcoding amplicons (SQK-LSK109) protocol, DNA libraries were created which contained long-range PCR fragments of the MYH7, MYBPC3, TNNT2, TNNI3 and TPM1 genes. The sequencing was performed using the MinION system by Oxford Nanopore Technologies (UK). Bioinformatic algorithms for data analysis included Guppy v.5.0.7, Nanopolish and Clairvoyante. The identified genetic variants were confirmed by Sanger sequencing.

Results. Data on the complete sequence of the five major sarcomeric genes for hypertrophic cardiomyopathy were obtained. We found eight potentially disease-causing sequence variants in MYH7, MYBPC3 and TNNT2 genes by monomolecular sequencing. However, only three mutations p.Arg243Cys, p.Tyr609Asn, p.Arg870His in the MYH7 gene, and one mutation p.Lys985Asn in the MYBPC3 were confirmed by Sanger sequencing. Cascade screening of pathogenic variant p.Arg870His in the MYH7 gene was performed. We found one asymptomatic carrier.

Conclusion. It appears that monomolecular sequencing technology is a feasible approach to identify mutations in patients with hypertrophic cardiomyopathy. Although improvement in accuracy of DNA sequencing, as well as optimization and simplification of bioinformatic algorithms for identification of the genetic variants are needed.

Aim. To determine the spectrum of mutations in the genes responsible for the long QT syndrome (LQTS) and study their phenotypic manifestations in patients with LQTS in different age groups.

Materials and methods. The study included 35 unrelated probands with a clinical diagnosis of LQTS: 23 adults (8 men) and 12 children (9 boys). There were following clinical features: syncope — 54%, positive family history for SCD — 29%, implanted cardioverter defibrillator (ICD) — 46%. All participants underwent 12-lead electrocardiography (ECG), 24-hour Holter monitoring, genealogical analysis, echocardiography and cardiac MRI. The genetic study was performed by nextgeneration sequencing (NGS) using the MiSeq system (Illumina). The quantitative comparison of two unrelated groups was carried out using the nonparametric MannWhitney U-test. The differences were considered significant at p<0,05.

Results. In the examined group of 35 probands, 23 genetic variants of pathogenicity class IV and V (hereinafter referred to as) were identified. The molecular genetic variant of the disease was verified in 66% of probands. At the same time, the detection of mutations in the group with early manifestation (children) was significantly higher: 83% (10 out of 12 children) vs 57% in adults (13 out of 23). Rare genetic variants of uncertain significance (VUS, class III pathogenicity) were detected in 4 probands (11%). In the groups of children and adults with LQT1, LQT2 and LQT3, the sex distribution deviated from the 1:1 ratio. Among children, two-thirds were boys, among adults — the same proportion was represented by women. Disease manifestation time, QTc duration and adverse events risk depended on the genetic type of LQTS, intragenic localization of mutations and sex. In children, all 4 missense mutations in the KCNQ1 gene were located in transmembrane domain, and in adults, 4 mutations were in the transmembrane domain and three — in the C-terminal domain of the protein. LQT1 in boys was characterized by early manifestation, while QTc did not exceed 500 ms and there were no adverse outcomes. Two women out of 7 adults with LQT1 with mutations in the transmembrane domain had na ICD (QTc >520 ms). All patients with LQT2 (4 children, 4 adults) had QTc >500 ms. At the same time, 2 children and 3 women had an ICD. LQT3 was diagnosed only in the children subgroup (2 boys, with QTc of 510 ms and QTc of 610 ms); one of them died suddenly despite beta-blocker therapy. Four adult patients, carriers of class III pathogenicity variants, had QTc <500 ms and delayed disease manifestation (after 30 years). Three of them had episodes of clinical death with subsequent resuscitation and implantation of cardioverter defibrillator.

Conclusion. The average diagnostic efficiency of mutation identification using NGS in patients with clinically manifest LQTS was 66%. At the same time, mutations were more common in the children’s group. In genotype-positive probands, the risk of adverse outcomes correlated with sex, age and the genetic variant of disease. The greatest number of adverse outcomes was observed in carriers of mutations in both KCNH2 (LQT2) and SCN5A (LQT3) genes. Variants with unknown clinical significance were identified in 4 probands (11%), which potentially allowed to confirm the diagnosis after functional tests.

Aim. To identify the proportion of restrictive cardiomyopathy (RCM), as well as cardiomyopathy (CMP) with a restrictive type of hemodynamics among all cases of genetic CMP and to determine the relative frequencies and spectrum of nucleotide variants in Russian children with RCM, as well as to search for phenogenotypic correlations.

Material and methods. The study included 689 children with CMPs. All children underwent a molecular genetic testing of the target regions of 419 genes responsible for various cardiomyopathies and channelopathies using the method of massively parallel sequencing (MPS).

Results. In 668 (97,0%) children, pathogenic, likely pathogenic nucleotide variants, as well as nucleotide variants with unknown clinical significance, were identified. Of these, 45 (6,7%) patients were selected to determine the molecular genetic characteristics of RCM, 20 of whom had clinical symptoms and morphofunctional structure of RCMP (3,0%), while the remaining 25 (3,7%) children were diagnosed with another CMP type with a restrictive type of hemodynamics. In total, these patients had 41 nucleotide variants in 15 different genes, while 19 (46,3%) variants were pathogenic, 12 (29,3%) — likely pathogenic, 10 (24,4%) — uncertain clinical significance. Pathogenic and likely pathogenic variants were identified in a total of 38 (84,4%) patients, while in 19 (42,2%) patients, the pathogenic variants described earlier were found. The most common genetic marker of RCM in Russian children was TNNI3 gene mutations. In total, they were identified in 12 (25%) children: with RCP — 8 (40%) patients; with CMP with a restrictive type of hemodynamics — 4 (16%) patients. At the same time, the most common mutation of the TNNI3 gene was the nucleotide variant c.575G>A, leading to the amino acid variant p.R192H, described earlier in patients with RCM and identified by us in three (15%) unrelated children with RCM. In addition, a significant difference was found between the averaged values of N-terminal pro-brain natriuretic peptide in patients with mutations in the MYH7 and TNNI3 genes (0,0039, p<0,05), as well as between the peak flow gradient values in children with mutations in TNNI3 and FLNC genes (0,0016, p<0,05), TNNI3 and MYH7 genes (0,039, p<0,05).

Conclusion. The results of this study indicate a significant genetic heterogeneity of RCM in Russian children and the need for further research aimed at finding genotype-phenotype associations in order to predict the course of the disease and select the proper therapy.

Aim. To study the diagnostic significance of genetic testing in patients with dilated cardiomyopathy (DCM), identify predictors of life-threatening ventricular tachyarrhythmias (VTAs) and assess adverse clinical outcomes in different genetic groups.

Material and methods. The study included 126 unrelated patients with verified DCM as follows: 70 (55,6%) probands with criteria for familial DCM and 56 (44,4%) individuals with a probable hereditary component. All patients (age, 43,1±11,3 years; men, 92 (73%); left ventricular ejection fraction, 30,6±8,43%; left ventricular enddiastolic diameter, 68,3±8,36 mm; follow-up period — median, 49 months) receive a complex of diagnostic investigations, including genetic screening using nextgeneration sequencing, followed by verification of variants by the Sanger method.

Results. Pathogenic and likely pathogenic genetic variants were found in 61 (48,4%) of 126 patients with DCM. The dominant mutations were titin-truncating variants (TTNtvs), identified in 16 individuals (12,7%), and variants of lamin A/C (LMNA), identified in 13 probands (10,3%). Mutations in the other 19 genes were found in 32 (25,4%) patients. The following primary endpoints were assessed: sudden cardiac death (SCD), episodes of VTA (sustained ventricular tachycardia/ventricular fibrillation) and appropriate shocks of implanted cardiac resynchronization therapy (CRT)/cardioverter defibrillators (CVD) devices. As a result of ROC analysis, the following independent risk factors for SCD were identified: mutations in the LMNA gene (AUC, 0,760; p=0,0001) and non-sustained ventricular tachycardia (cut-off heart rate ≥161 bpm: AUC, 0,788; p=0,0001). When comparing the phenotypes and genotypes of DCM, TTNtv genotype was associated with a lower prevalence of complete left bundle branch block (χ²=7,46; p=0,024), a lower need for CRT/CVD implantation (χ²=5,70; p=0,017) and more rare episodes of sustained ventricular tachycardia/ventricular fibrillation (χ²=30,1; p=0,0001) compared with LMNA carriers. Kaplan-Meier analysis showed the worst prognosis in carriers of LMNA mutations both in relation to life-threatening VTA (log rang χ²=88,5; p=0,0001) and in achieving all unfavorable outcomes (χ²=27,8; p=0,0001) compared with groups of genenegative individuals, carriers of TTNtv and other genotypes.

Conclusion. The phenotypes of DCM with TTNtv did not significantly differ in the incidence of VTAs and adverse outcomes compared with the gene-negative group and other genotypes (with the exception of LMNA). The contribution of the associations of LMNA mutations with VTAs on prognosis was confirmed, which shows the important role of LMNA genotype diagnosis for SCD risk stratification in patients with DCM.

Left ventricular non-compaction is a heterogeneous heart disease with various phenotypic and clinical manifestations. The article presents the results of clinical, instrumental and molecular genetic investigations of a family with diagnosed left ventricular non-compaction (LVNC) with different clinical and phenotypic manifestations. As a result of a molecular genetic testing, all family members with the LVNC phenotype were found to have a likely pathogenic variant in the FLNC gene. Variants in this gene are associated with a number of cardiomyopathies: dilated, hypertrophic, and restrictive. In the international scientific literature, isolated clinical cases of LVNC development with variants of the FLNC gene nucleotide sequence are presented. In our work, we present a case report of LVNC with a variety of clinical manifestations within the same family.

Aim. To study the clinical course specifics of coronavirus disease 2019 (COVID-19) and comorbid conditions in COVID-19 survivors 3, 6, 12 months after recovery in the Eurasian region according to the AKTIV register.

Material and methods.The AKTIV register was created at the initiative of the Eurasian Association of Therapists. The AKTIV register is divided into 2 parts: AKTIV 1 and AKTIV 2. The AKTIV 1 register currently includes 6300 patients, while in AKTIV 2 — 2770. Patients diagnosed with COVID-19 receiving in- and outpatient treatment have been anonymously included on the registry. The following 7 countries participated in the register: Russian Federation, Republic of Armenia, Republic of Belarus, Republic of Kazakhstan, Kyrgyz Republic, Republic of Moldova, Republic of Uzbekistan. This closed multicenter register with two nonoverlapping branches (in- and outpatient branch) provides 6 visits: 3 in-person visits during the acute period and 3 telephone calls after 3, 6, 12 months. Subject recruitment lasted from June 29, 2020 to October 29, 2020. Register will end on October 29, 2022. A total of 9 fragmentary analyzes of the registry data are planned. This fragment of the study presents the results of the post-hospitalization period in COVID-19 survivors after 3 and 6 months.

Results. According to the AKTIV register, patients after COVID-19 are characterized by long-term persistent symptoms and frequent seeking for unscheduled medical care, including rehospitalizations. The most common causes of unplanned medical care are uncontrolled hypertension (HTN) and chronic coronary artery disease (CAD) and/or decompensated type 2 diabetes (T2D). During 3- and 6-month follow-up after hospitalization, 5,6% and 6,4% of patients were diagnosed with other diseases, which were more often presented by HTN, T2D, and CAD. The mortality rate of patients in the post-hospitalization period was 1,9% in the first 3 months and 0,2% for 4-6 months. The highest mortality rate was observed in the first 3 months in the group of patients with class II-IV heart failure, as well as in patients with cardiovascular diseases and cancer. In the pattern of death causes in the post-hospitalization period, following cardiovascular causes prevailed (31,8%): acute coronary syndrome, stroke, acute heart failure.

Conclusion. According to the AKTIV register, the health status of patients after COVID-19 in a serious challenge for healthcare system, which requires planning adequate health system capacity to provide care to patients with COVID-19 in both acute and post-hospitalization period.

Aim. To analyze thromboembolic risk factors and identify additional predictors of left atrial appendage (LAA) thrombosis, which are not included in the CHA2DS2VASc scale, in long-term Far North residents with nonvalvular atrial fibrillation (AF).

Material and methods. The study included 162 patients (men, 108; women, 54; mean age, 55,3±8,7 years) with non-valvular AF, living in the Far North, and 684 patients (men, 408; women, 276; mean age, 56,9±9,3 years), living in the temperate latitudes, hospitalized for catheter ablation. All patients underwent transthoracic and transesophageal echocardiography. According to transesophageal echocardiography, Far North patients were divided into two groups: group 1 — 21 patients with LAA thrombosis, group 2 — 141 patients without LAA thrombosis.

Results. Compared to patients living in the temperate latitudes, Far North patients were younger (p=0,021) and were more likely to have type 2 diabetes (14,2% vs 8,3%, p=0,022), class ³II obesity (29,6% vs 21,1%, p=0,019), persistent AF(47,5% vs 33,2%, p=0,0019), LAA thrombosis (13% vs 6,6%, p=0,006), and severe structural and functional cardiac abnormalities (biatrial and right ventricular enlargement, lower left ventricular ejection fraction). In Far North patients, using logistic regression, independent predictors of LAA thrombosis were identified: an increase in left ventricular mass index (odds ratio (OR), 1,029; 95% confidence interval (CI), 1,011-1,048; p=0,001), persistent AF (OR, 3,521; 95% CI, 1,050-11,800; p=0,041).

Conclusion. In Far North patients with nonvalvular AF, scheduled for catheter ablation, compared with patients from temperate latitudes, with a similar profile of cardiovascular diseases at a younger age, type 2 diabetes, grade ³II obesity, persistent AF, and LAA thrombosis were more common. The presence of persistent AF and an increase in left ventricular mass index are independent predictors of LAA thrombosis in Far North patients with nonvalvular AF.

Aim. To determine the early predictive factors of cardiovascular changes in professional athletes, depending on the type and intensity of physical activity.

Material and methods. A total of 136 male athletes were examined. Of these, 116 were professional athletes (age, 22,07±4,1 years) as follows: freestyle wrestling, judo (n=30), cross-country skiing, biathlon (n=27), powerlifting (n=33), volleyball (n=26). Control group included 20 athletes (age, 17,95±1,5 years) with a history of training less than 3 years. All participants underwent electrocardiography (ECG), echocardiography, cycle ergometry (CE) with assessment of physical performance at a heart rate of 170 bpm (PWC170) and maximum oxygen consumption (MOC). When creating predictive models of early cardiovascular changes, we used logistic regression, stepwise regression and Wald statistics. Differences were considered significant at p<0,05.

Results. Predictive models of logistic regression using ROC analysis showed high sensitivity and specificity, a high percentage of correct predictions using data from echocardiography — 86,8%, CE — 80,9%, ECG and other indicators — 83,1%. A stepwise algorithm was used to select prognostic factors determining early cardiovascular changes in young athletes, depending on the stage of sports training, the intensity and type of dynamic and/or static exercise: left ventricular posterior wall thickness (p=0,008), left ventricular mass (p=0,001), stroke volume (p=0,002), end-systolic volume (p=0,001), PWC170 (p=0,025), MOC (p=0,003), recovery time of heart rate (HR) (p=0,029) and blood pressure (p=0,032) after submaximal exercise on a cycle ergometer, body mass index (p=0,029), heart rate (p=0,034), office systolic blood pressure (p=0,009), intraventricular (bundle) block (p=0,046), left ventricular repolarization abnormalities (p=0,010), mild cardiac connective tissue anomalies (p=0,035).

Conclusion. The early prognostic factors established by the logistic regression affect the characteristics and risk of cardiovascular changes in each group of young athletes. This demonstrates the need to develop individual medical support programs, further monitoring, evaluation, correction and prevention of identified disorders, taking into account the type of sports, intensity and exercise.

This review considers the clinical and epidemiological significance of hospitalizations for decompensated heart failure, as well as using it as an indicator of therapy effectiveness. The data on the frequency of using medications that reduce the hospitalization risk in randomized clinical trials and in real practice are presented. The reasons for inadequate prescription of drugs for the treatment of heart failure with reduced ejection fraction and their use in insufficient doses, which include therapeutic inertness and physiological limitations, as well as the need to introduce drugs with alternative mechanisms of action into clinical practice, are iscussed.

To date, a sufficient volume of clinical studies has been accumulated that have demonstrated a reduced antiplatelet effect of enteric-coated (EC) lowdose acetylsalicylic acid (ASA). Delayed and incomplete absorption from the intestinal alkaline medium, which significantly reduces the bioavailability of drug, is considered the main reason for laboratory aspirin resistance (pseudoresistance) to EC ASA. This phenomenon is of particular importance for patients with acute coronary syndrome, when a quick effect is required, as well as for patients with diabetes and obesity due to additional causes of increased platelet activity, on the one hand, and reduced bioavailability of ASA, on the other. Given the issue of efficacy, the dubious gastroprotective effect and the more pronounced damaging effect on the mucous membrane of small intestine, the use of EC ASA should be avoided, especially in patients with a multifactorial risk of insufficient response to therapy. A good alternative is buffered ASA, which quickly dissolves and is partially absorbed directly in the stomach, having antiplatelet activity comparable to simple ASA and a similar aspirin resistance, is associated with a lower risk of aspirin-induced enteropathy in comparison with ES ASA. In addition, according to a number of small studies and retrospective analyzes, buffered ASA is less likely to cause damage to gastric mucosa compared to EC ASA.

The search and study of endogenous heart repair remains an urgent issue in modern regenerative medicine. It is generally accepted that the human heart has a limited regenerative potential, but recent studies show that functionally significant regeneration is possible. However, the mechanisms underlying these processes remain poorly understood. In the heart, there are populations of resident mesenchymal cells that have some properties of stem cells that carry certain markers, such as c-kit⁺, Sca-1, etc. The ability of these cells to differentiate directly into cardiomyocytes remains controversial, but their use in clinical trials has shown improved cardiac function in patients with myocardial infarction. Currently, approaches are being developed to use, mainly, induced pluripotent stem cells as a promising regenerative therapy, but the cardioprotective role of cardiac mesenchymal cells remains the subject of active study due to their paracrine signaling.