Introduction. Hypertrophic cardiomyopathy (HCM) is characterized by clinical and genetic heterogeneity. Age of manifestation, clinical and anatomical phenotypes of HCM vary significantly. This study discusses genetic causes and reconstructive surgery results for patients with particular intracardiac phenotype - diffused generalized HCM (DG-HCM). Methods: personal and familial medical history, general examination, 12-lead resting ECG, 24-hour ECG Holter monitoring, transthoracic and transesophageal EchoCG, cardiac MRI with gadolinium enhancement. A ten-gene panel was sequenced by IonTorrent PGM. Mutational screening in patients with suspected multisystemic diseases was performed by Sanger sequencing. Results: 170 patients with obstructive HCM (oHCM) requesting genetic counseling and surgical correction of HCM were evaluated. We distinguished particular DG-HCM subtype of oHCM (diffuse hypertrophy of IVS, LV free walls, papillary muscles displaced towards the LV apex) in 34 patients; 31 out of 34 underwent open heart reconstructive surgery. Patients with DG-HCM were younger at the time of surgery, had higher risk of SCD, and connective tissue dysplasia of the mitral valve. Hemodynamics normalization was observed in 1, 3, and 5 years after surgery. Eighteen ICDs were implanted; five patients experienced appropriate shocks. The genetic spectrum was enriched up to 30% by multisystem disorders. Mutations in "sarcomeric" genes were detected in 15%. Conclusion: Intracardiac phenotype of HCM may correlate with genetic cause and long-term prognosis. DG-HCM phenotype accounts for 20% oHCM patients and indications for open-heart surgery. Extended myectomy with parietal resection of papillary muscles and correction of mitral valve insufficiency provides long-term benefits for DG-HCM patients. Multisystem disorders in patients with DG-HCM should be of special attention. Study was supported by research project FURG-2024-0004.

Aim. To study the clinical manifestations, incidence of life-threatening complications, and their possible mechanisms and outcomes of left ventricular non-compaction (LVNC) in adults.Material and methods. This study included 125 adult patients with LVNC, 74 men (59.2%) and 51 women (40.8%) aged 46.4±15.1 years. Echocardiography (EchoCG) (n=125), Holter monitoring (n=125), cardiac magnetic resonance imaging (MRI) (n=60), and contrast-enhanced multislice computed tomography (MSCT) of the heart (n=90), and, if indicated, coronary angiography (CAG) (n=33) and myocardial scintigraphy (n=27) were performed. The diagnosis of LVNC was confirmed in 74 cases using two methods, and in 21 cases, using three imaging methods. DNA diagnostics was performed in most patients. For most patients, the level of anticardiac antibodies and the genome of cardiotropic viruses were determined in the blood. Mean left ventricular (LV) ejection fraction (EF) was 38.6±14.0%; LV end-diastolic volume (EDV) was 158.1±67.8 ml; LV end-diastolic dimension (EDD) was 6.1±0.9 cm; and left atrial (LA) volume was 97.1±38.1 ml. The mean follow-up period was 14 months [4.0; 41.0]; from 1 month to 10 years.Results. Death rate was 14.4%; heart transplantation was performed in 5.6% of cases. Nonsustained ventricular tachycardia (VT) was detected in 45.6% of cases and sustained VT in 13.6%. The presence of VT was associated with poor R-wave progression in the precordial ECG leads, low QRS voltage, QRS duration >105 ms, NYHA chronic heart failure functional class (CHF FC) ≥2-3, LV EF <40%; LV EDD >6.1 cm, the presence of myocarditis, and higher death rate. Cardioverter defibrillators, including cardiac resynchronization therapy defibrillators (CRTD), were implanted in 38 patients. Appropriate defibrillator shocks were associated with frequent premature ventricular contractions (PVCs). The incidence of thrombosis and embolism was 22.4%. Their predictors included CHF FC ≥2-3, RV anteroposterior dimension >3.1 cm, LA volume >98 ml, E/A >1.65, LV EDD >6.3 cm, LV EDV >153 ml, LV EF <35%, and myocardial necrosis of unknown origin (in patients without coronary atherosclerosis). The incidence of myocardial necrosis in LVNC was 16.0%. The mechanisms identified, in addition to coronary atherosclerosis, were embolism in unchanged coronary arteries, secondary myocarditis, and the presence of genetically determined thrombophilia.Conclusion. LVNC is associated with a high risk of life-threatening conditions, such as ventricular arrhythmias, thrombosis and embolism, and myocardial necrosis, that are typical complications of LVNC in adults. Reassessing the predictors for the risk of thromboembolic and arrhythmic events, specifying the indications for implantable cardioverter defibrillator and anticoagulants, and actively identifying and treating concomitant myocarditis are essential.

Hypertrophic cardiomyopathy (HCM), caused by mutations in thin filament proteins, manifests as moderate cardiac hypertrophy and is associated with sudden cardiac death (SCD). We identified a new de novo variant, c.656A>T (p.D219V), in the TPM1 gene encoding cardiac tropomyosin 1.1 (Tpm) in a young SCD victim with post-mortem-diagnosed HCM. We produced recombinant D219V Tpm1.1 and studied its structural and functional properties using various biochemical and biophysical methods. The D219V mutation did not affect the Tpm affinity for F-actin but increased the thermal stability of the Tpm molecule and Tpm-F-actin complex. The D219V mutation significantly increased the Ca2+ sensitivity of the sliding velocity of thin filaments over cardiac myosin in an in vitro motility assay and impaired the inhibition of the filament sliding at low Ca2+ concentration. The molecular dynamics (MD) simulation provided insight into a possible molecular mechanism of the effect of the mutation that is most likely a cause of the weakening of the Tpm interaction with actin in the "closed" state and so makes it an easier transition to the “open” state. The changes in the Ca2+ regulation of the actin-myosin interaction characteristic of genetic HCM suggest that the mutation is likely pathogenic.

The same variants in sarcomeric genes can lead to different cardiomyopathies within the same family. This gave rise to the concept of a continuum of sarcomeric cardiomyopathies. However, the manifestations and evolution of these cardiomyopathies in pathogenic variant carriers, including members of the same family, remains poorly understood. We present a case of familial sarcomeric cardiomyopathy caused by heterozygous truncating pathogenic variant p.Q1233* in cardiac myosin-binding protein C (MyBPC3) gene. The proband was first diagnosed with restrictive cardiomyopathy combined with left ventricular noncompaction (LVNC) and sarcoidosis at the age of 64. The predominantly restrictive phenotype of cardiomyopathy is considered to be a result of interaction between LVNC and sarcoid myocarditis. His 39-year-old son and 35-year-old daughter have identical non-obstructive asymmetric hypertrophic cardiomyopathy. The risk of sudden cardiac death in the son is high due to myocardial fibrosis, ischemia and nonsustained VT. We assume that both phenotypes in the family may have originally been different or there may have been a gradual transformation of the hypertrophic phenotype into LVNC. Myocarditis is regarded as an important epigenomic modifier of sarcomeric cardiomyopathy. In the proband and his son, cardioverter-defibrillators were implanted, and the proband experienced appropriate shocks due to ventricular tachycardia/fibrillation. The proband was also treated with corticosteroids. His death at the age of 69 years occurred due to acute gastric hemorrhage accompanied by progressive heart failure. This report confirms the concept of the phenotypic continuum of sarcomeric cardiomyopathies and describes possible phenotypic patterns and their transformation over time.

Aim. To study the place of NCM in the structure of DCM, its clinical features and influence on prognosis in comparison with other forms of DCM syndrome.Methods. The NCM registry includes 125 patients, mean age 46.4±15.1 years, 74 men and 51 women, median follow-up 14 [4.0; 41.0] months. The DCM registry included 365 patients, mean age 46.4±15.1 years, 253 men and 112 women, median follow-up 14 [5; 43.75] months. The examination included electrocardiography (ECG), ECG Holter monitoring, echocardiography, blood anti-heart antibody level evaluation, and additionally cardiac computed tomography, magnetic resonance imaging, DNA diagnostics (in the MYH7, MYBPC3, TPM1, TNNI3, TNNT2, ACTC1, TAZ, ZASP (LDB3), MYL2, MYL3, DES, LMNA, EMD, TTR gene panel), coronary angiography, right ventricular endomyocardial biopsy.Results. The proportion of patients with DCM phenotype in the NCM registry was 40% (n=49), another 11% (n=15) had NCM diagnosed simultaneously with acute/subacute myocarditis. Lethality in these subgroups was 12.2% and 33.3%, respectively, and was significantly higher than in asymptomatic, ischemic and arrhythmic variants of NCM. In the DCM registry, the proportion of patients with NСM was 21% (n=78), and increased left ventricular (LV) trabecularity was detected in another 18% (n=64). DCM patients with and without NСM did not differ by baseline echocardiographic parameters, heart failure class, and cardiotropic therapy. Pathogenic mutations were detected in 14% of DCM patients with NCM and only 3% of other patients with DCM (p<0.001). Only in patients without NCM the presence of mutations had a significant effect on lethality. The patients with NCM compared with the others DCM patients showed significantly lower increase in EF in early and late period (from 31.0±10.2 to 34.8±11.0 and 37.1±10.9% [р<0.05] vs from 31.8±9.7 to 38.8±11.3 and 42.3±12.4% [р<0.01] respectively), a greater incidence of premature ventricular beats (1568 [105;7000] vs 543.5 [77.75; 3194], p<0.05), appropriate defibrillator shocks and sudden deaths (17.9 vs 5.9%, p<0.001), intracardiac thrombosis (21.8 vs 13.5%, p=0.069) despite a greater frequency of anticoagulants (73.1 vs 57.4%, p<0<05). There were no significant differences in death (19.2 vs 18.5%) and transplantation (7.7 vs 3.8%) between patients with and without NCM. There were no cases of NCM regression.Conclusion. NCM is an independent form of DCM syndrome, which is characterized by higher frequency of pathogenic mutations, arrhythmic events, worse response to cardiotropic therapy, higher frequency of intracardiac thrombosis. The absence of mortality differences can be explained by the higher frequency of preventive interventions in this category of patients with DCM (prescription of anticoagulants, defibrillator implantation, heart transplantation).

It has now been shown that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing a new COVID-19 infection, can penetrate the myocardium and have both direct damaging and toxic effects. The main cardiac manifestations of this disease are fulminant myocarditis, atrial and ventricular arrhythmias, and heart failure. Cardiac arrhythmias are common complication not only in adult patients, but also in children. In this paper, we present a clinical case of the young female patient who successfully underwent operation because of a submitral (diffuse-generalized) form of HCM, with a long event-free postoperative course, and with the rapid cardiac dysfunction, syncopes and cardiac arrhythmias after COVID-19 infection. Syncopes were caused by self-terminating short runs of ventricular tachycardia that did not trigger ICD shock. After the medical treatment of myocarditis, she has a clinical improvement and further favorable postoperative period.

BACKGROUND:The KCNJ2 gene encodes inward rectifier Kir2.1 channels, maintaining resting potential and cell excitability. Presumably, clinical phenotypes of mutation carriers correlate with ion permeability defects. Loss-of-function mutations lead to QTc prolongation with variable dysmorphic features, whereas gain-of-function mutations cause short QT syndrome and/or atrial fibrillation.METHODS:We screened 210 probands with Long QT syndrome for mutations in the KCNJ2 gene. The electrophysiological study was performed for the p.Val93Ile variant in the transfected CHO-K1 cells.RESULTS:We found three rare genetic variants, p.Arg67Trp, p.Val93Ile, and p.R218Q, in three unrelated LQTS probands. Probands with p.Arg67Trp and p.R218Q had a phenotype typical for Andersen-Tawil (ATS), and the p.Val93Ile carrier had lone QTc prolongation. Variant p.Val93Ile was initially described as a gain-of-function pathogenic mutation causing familial atrial fibrillation. We validated electrophysiological features of this variant in CHO-K1 cells, but no family members of these patients had atrial fibrillation. Using ACMG (2015) criteria, we re-assessed this variant as a variant of unknown significance (class III).CONCLUSIONS:LQT7 is a rare form of LQTS in Russia, and accounts for 1% of the LQTS cohort. Variant p.Val93Ile leads to a gain-of-function effect in the different cell lines, but its clinical appearance is not so consistent. The clinical significance of this variant might be overestimated.

Abstract Introduction Noncompact myocardium (NCM) is a cardiomyopathy with various genetic causes and clinical manifestations; its relationship with other forms of dilated cardiomyopathy (DCM) and its impact on prognosis are unclear. Objective To study the place of NCM in the structure of DCM, its clinical features and influence on prognosis in comparison with other forms of DCM syndrome. Methods The NCM registry includes 125 patients, mean age 46.4±15.1 years, 74 men and 51 women, mean follow-up 14 [4.0; 41.0] months. The DCM registry included 365 patients, mean age 46.4±15.1 years, 253 men and 112 women, mean follow-up 14 [5; 43.75] months. The examination included ECG, ECG Holter monitoring, echocardiography, blood anti-heart antibody level evaluation, and additionally cardiac CT, MRI, DNA diagnostics (in the MYH7, MYBPC3, TPM1, TNNI3, TNNT2, ACTC1, TAZ, ZASP (LDB3), MYL2, MYL3, DES, LMNA, EMD, TTR gene panel), coronary angiography, right ventricular endomyocardial biopsy. Results The proportion of patients with DCM phenotype in the NCM registry was 40% (n=49), another 11% (n=15) had DCM syndrome diagnosed simultaneously with acute/subacute myocarditis. Lethality in these subgroups was 12.2% and 33.3%, respectively, and was significantly higher than in asymptomatic, ischemic and arrhythmic variants of DCM. In the DCM registry, the proportion of patients with NCM was 21% (n=78), and increased left ventricular (LV) trabecularity was detected in another 18% (n=64). DCM patients with and without NCM did not differ by baseline echocardiographic parameters, heart failure class, and cardiotropic therapy. Pathogenic mutations were detected in 14% of DCM patients with NCM and only 3% of other patients with DCM (p<0.001). Only in patients without NCM the presence of mutations had a significant effect on lethality. The patients with NCM compared with the others DCM patients showed significantly lower increase in EF in early and late period (from 31.0±10.2 to 34.8±11.0 and 37.1±10.9% vs from 31.8±9.7 to 38.8±11.3 and 42.3±12.4%, p<0.05 vs 05 and <0.01, respectively), a greater incidence of PVBs (1568 [105; 7000] vs 543.5 [77.75; 3194], p<0.05), appropriate defibrillator shocks and sudden deaths (17.9 vs 5.9%, p<0.001), intracardiac thrombosis (21.8 vs 13.5%, p=0.069) despite a greater frequency of anticoagulants (73.1 vs 57.4%, p<0<05). There were no significant differences in death (19.2 vs 18.5%) and transplantation (7.7 vs 3.8%) between patients with and without NCM. There were no cases of NCM regression. Conclusion NCM is an independent form of DCM syndrome, which is characterized by higher frequency of pathogenic mutations, arrhythmic events, worse response to cardiotropic therapy, higher frequency of intracardiac thrombosis. The absence of mortality differences can be explained by the higher frequency of preventive interventions in this category of patients with DCM (prescription of anticoagulants, defibrillator implantation, heart transplantation). Funding Acknowledgement Type of funding sources: None.

Background. A few cases of combination of arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVC) with left ventricular noncompaction (LVNC) have been described. Aims to study the genetics, diagnostical features and clinical course of the combination of ARVC with LVNC. Methods. 58 patients with ARVC diagnosis (26 men; mean age 39.1 14.2 years; mean follow-up period 21.5 [6; 60] months) and 125 patients with LVNC (74 men; mean age 46.4 15.1 years; mean follow-up period 14 [3; 40] months). All patients underwent electrocardiogram (ECG), echocardiography, 24-h ECG monitoring. Heart MRI was performed in 53 (91.4%) patients with ARVC and 60 (48%) with LVNC, heart CT in 18 (31%) patients with ARVC and 89 (71.2%) with LVNC. For all patients with combination of ARVC and LVNC DNA-diagnostic was performed using both ARVC (PKP2, DSG2, DSP, DSC2, JUP, TMEM43, TGFB3, PLN, LMNA, DES, CTTNA3, EMD, SCN5A, LDB3, CRYAB, FLNC) and LVNC (MYH7, MYBPC3, TAZ, TPM1, LDB3, MYL2, MYL3, ACTC1, TNNT2, TNI3) gene panels. Results. Combination of ARVC and LVNC was found in 9 patients (15.5% of patients form ARVC cohort and 7.2% from LVNC cohort). These patients were distinguished from patients with isolated ARVC or LVNC by aggressive ventricular arrhythmias (frequent premature ventricular beats, sustained ventricular tachycardia, significantly worse antiarrhythmic therapy effect, appropriate shocks of implanted cardioverter-defibrillators (ICD) in all patients with ICD). Patients with combination of ARVC + LVNC were also distinguished from patients with isolated LVNC by the dilatation of RV, low QRS voltage on ECG, presence of AV block, absence of signs of LV hypertrophy on ECG. LV dilatation with reduction of its ejection fraction distinguished patients with mixed cardiomyopathy from patients with isolated ARVC. Potentially pathogenic variants (IVV classes of pathogenicity) and variants of unclear clinical significance (III class of pathogenicity) were found in both desmosomal and non-desmosomal genes in 78% of patients, including 3 (33%) in DSP gene. Conclusions. The combination of ARVC and LVNC can be caused by mutations in both desmosomal and non-desmosomal genes and has typical features: aggressive, resistant ventricular rhythm abnormalities leading to appropriate ICD shocks and a high risk of sudden cardiac death.

Andersen-Tawil syndrome (ATS) is a rare channelopathy, sometimes referred to as long QT syndrome type 7. ATS is an autosomal dominant disease predominantly caused by mutations in the KCNJ2 gene. Patients with ATS present with episodes of muscle weakness, arrythmias, including prolonged QT intervals, and various skeletal abnormalities. Unlike other channelopathies, ATS has a relatively mild clinical course and low risk of sudden cardiac death. In this study, we describe a female patient with typical symptoms of ATS with the addition of unusually severe arrhythmias. Extensive DNA testing was performed to find the possible cause of this unique presentation. In addition to a known mutation in KCNJ2, the patient carried a variant in KCNH2 The combination of genetic variants may lead to the severe clinical manifestation of ATS. Additional genetic information allowed accurate genetic counselling to be provided to the patient.

Abstract Background Inherited deficiency of the antithrombin (hereditary antithrombin deficiency, AT deficiency, OMIM #613118) is a relatively rare (1:2000–3000) autosomal-dominant disorder with high risk of venous thromboembolism. Mutations in the serpin family C member 1 gene (SERPINC1) can lead to Quantitative (type I) and Qualitative (type II) types of antithrombin deficiency. We describe a new genetic variant in the SERPINC1 gene and our approach to variant interpretation. Case presentation We observed a 29 y.o. female proband with the episode of venous thrombosis at the age of 18 and family history of thrombosis. The antithrombin level in our patient was low, 44–48% (AT deficiency type I). A new genetic variant c.662G > C (p.W221S) in the SERPINC1 gene was detected in proband and affected father but was absent in healthy sister. We used in silico tools to evaluate the possible impact of p.W221S variant on protein structure and function. In mutated SERPINC1 protein a new N-linked glycosylation site is formed, however, it is unclear if the glycosylation at 219–221 site is possible. Conclusion The proband was provided with appropriate genetic counseling and referred to a hematologist. Based on all the evidence we classify the p.W221S variant as variant of unknown clinical significance. In this paper we discuss some aspects of genetic counseling, variant interpretation and thromboembolic prophilaxis.

Aim. To study the nosological spectrum in the syndrome of primary left ventricle hypertrophy (PLVH) using morphological and genetic diagnostics and to compare the clinical course of true hypertrophic cardiomyopathy (HCM) and its phenocopy.Material and methods. Fifty five adult patients (29 men, 48.2±17.0 years) with PLVH (12 mm and more) were included. The exclusion criteria were athletic heart, hypertensive heart disease, severe valvular disease and other causes of secondary left ventricle (LV) hypertrophy. We performed 11 endomyocardial biopsy, 8 intraoperative biopsy, 1 study of explanted heart, 1 autopsy with virus investigation (real-time polymerase chain reaction) of the blood and myocardium. Mutational screening had included simultaneous sequencing of the MYBPC3, TAZ, TPM1, LDB3, MYL2, ACTC1, MYL3, MYH7, TNNI3 and TNNT2 genes based on NGS technology (Ion Torrent PGMTM) with following Sanger resequencing of potentially significant genetic variants. For patients with a phenotype of particular genetic syndrome the Sanger sequencing of target gene(s) for performed first. Clinical examination had included electrocardiography, Holter monitoring, echocardiography, coronary angiography, computer tomography/magnetic resonance imaging (by indication). The mean follow-up was 8 [3;32] month.Results. Isolated HCM was found in 28 patients, and 10 have a combination of HCM and noncompaction myocardium (NCM). Mutations in the MYH7 and MYBPC3 genes were detected in six cases. In 17 cases (30.9%) the non-sarcomeric causes of LVHS were detected. Three patients had Fabry disease, 2 ‒ had Danon disease, in 10patients we found amyloidoses, in 1 – Friedreich ataxia, and 1 patient was diagnosed with LEOPARD syndrome (all cases were confirmed by DNA diagnostics). Genotype-positive diagnosis was established in 23.6% of patients. In patients with HCM were significantly more frequent asymmetric septal hypertrophy with obstruction and muscle bridges, in other forms of primary hypertrophy – right ventricular hypertrophy, low QRS voltage, QS complexes and increasing of ejection fraction (EF) (55.7±12.5% vs 62.5±10.1% in HCM, p=0.08). The morphologic signs of myocarditis were in 46.7% of patients with HCM detected: in 3 patients with NCM and in 4 patients with isolated HCM. The viral genome in the myocardium was in 11 patients with HCM (73.3%) detected, previously human herpes virus type 6 (it was correlation with myocarditis) and parvovirus B19. Eleven patients died due to a stroke/heart failure without no significant differences between patients with HCM and phenocopy.Conclusion. The spectrum of causes of the primary left ventricular hypertrophy is very wide. The frequency of myocarditis associated with sarcomeric HCM was 46.7%. When lower EF and heart failure in patients with HCM can be result of myocarditis, in patients with storage disease they are the result of disease itself.

Mutations in the MYH7 gene are the source of an allelic series of diseases, including various cardiomyopathies and skeletal myopathies that usually manifest in adulthood. We observed a 1.5 y.o. male patient with congenital weaknesses of the axial muscles, "dropped head" syndrome, and dilated cardiomyopathy. The clinical evaluation included medical history, an echocardiogram, electromyography, and a histopathological study. The genetic evaluation included whole exome sequencing. Muscle biopsy samples from the proband were used for mRNA extraction. We revealed a novel genetic variant c.5655 + 5G > C in the MYH7 gene. The analysis of the cDNA showed an in-frame skipping of exon 38 (p.1854_1885del). This variant and two previously published mutations (c.5655G > A and c.5655 + 1G > A), also presumably leading to exon 38 skipping, were studied by expression analysis in the HEK293T cell line transfected with 4 plasmids containing the MYH7 minigene (wt, c.5655G > C, c.5655 + 1G > A and c.5655 + 5G > A). A quantitative difference in expression was shown for cell lines with each of the three mutant plasmids. All mutation carriers had a similar phenotype and included congenital axial myopathy and variable cardiac involvement. Prominent dropped head syndrome was mentioned in all patients. Early-onset axial myopathy with a dropped head syndrome is a distinct clinical entity within MYH7-related disorders. We suggest that mutations in the MYH7 gene affecting the C-terminal domain of beta-myosin heavy chain should also be considered as a possible cause in cases of early-onset myopathy with "dropped head" syndrome.

Aim. To study clinical forms of noncompact myocardium (NCM) in adults, the features of their manifestation, course and progression.Material and methods. The study included 116 adult patients with NCM of the left ventricle (LV) (67 men, mean age 46,3±15,1 years) and 42 patients with increased LV trabecularity (24 men, mean age 43,5±15,2 years). The mean LV end-diastolic diameter was 6,0±0,8 and 5,9±1,1 cm, LV ejection fraction was 38,6±14,0% and 44,6±18,3%, respectively. NCM was diagnosed using echocardiography, multispiral computed tomography (n=77) and magnetic resonance imaging (n=51), increased LV trabecularity was diagnosed according to echocardiography, multispiral computed tomography (n=11), multispiral computed tomography (n=24). DNA diagnostics was carried out according to the NGS method, followed by Sanger sequencing. The examination included the determination of anticardial antibodies, the genome of cardiotropic viruses by PCR, coronary angiography (n=29/2), scintigraphy (n=27/4). A morphological study of the myocardium was performed on 22/6 patients with NCM/increased LV trabecularity (14/6 endomyocardial biopsy, 1 intraoperative biopsy, 3 explanted heart studies, 6 autopsies).Results. Pathogenic mutations were found in 12 (10,3%) patients (MYH7, MyBPC3, LAMP2, DES, DSP, TTNgenes), variants of uncertain clinical significance (VUCS) — in other 5 (4,3%) patients; we detected VUCS in 1 patient with increased LV trabecularity. Familial cardiomyopathy may be diagnosed in 24 patients (22%). The combination of NCM with congenital heart defects was diagnosed in 11 (9,5%) patients. We identified six clinical variants of NCM: asymptomatic (2%), arrhythmic (15%), ischemic (7%), NCM in patients with dilated cardiomyopathy (42%), NCM in patients with acute/subacute myocarditis (12%) and in combination with other primary cardiomyopathies (22%) — hypertrophic cardiomyopathy, arrhythmogenic right ventricular dysplasia, restrictive cardiomyopathy, primary myodystrophy, cardiac sarcoidosis, Danon disease. Myocarditis was diagnosed in 51,7% of patients with various forms of NCM and in 59,5% of patients with increased LV trabecularity. The frequency of the main clinical manifestations of NCM (chronic heart failure, various cardiac arrhythmias, thromboembolic complications) and outcomes varied in groups of patients with different variants of the NCM course. In patients with increased LV trabecularity, similar clinical variants were noted with a less severe myocardial dysfunction, rare arrhythmias and embolism. A significant improvement in dynamics of EF and LV end-diastolic diameter was noted only in the group of patients with acute/subacute, most of which received basic myocarditis therapy. In other groups, there was an unreliable improvement.Conclusion. NCM can be detected in a patient of any age with a previously diagnosed heart disease (coronary heart disease, arterial hypertension, congenital heart defects, cardiomyopathy, myocarditis, etc.), and in the absence of any symptoms. Stable clinical forms are characterized by stability over time with a tendency to improvement against the background of complex medical therapy.

Aim. To evaluate the prevalence of myocarditis in adult patients with non-compaction myocardium (NCM) of the left ventricle (LV), and its influence on the disease course, results of treatment and outcomes.Material and methods. To the study, 103 adult patients included, with NCM, 61 males, mean age 45,6±14,9 y. o. (from 18 to 78). Mean end diastolic LV size was 6,0±0,8 сm, EF LV 38,8±14,5%. Diagnosis of NCM had been done by echocardiography, multispiral computed tomography (n=81) and magnetic resonance tomography (n=39). DNA-diagnostics was performed by NGS method with further Senger sequencing. Pathogenic mutations were found in 9% of patients in the genes MYH7, MyBPC3, LAMP2, DES, DSP, TTN. The investigation also included anticardiac antibodies, genome of cardiotropic viruses by PCR, coronary arteriography (n=26), scintigraphy (n=25). Morphological assessment of the myocardium was done in 19 patients (12 endomyocardial biopsies), 1 intraoperation biopsy, 3 explanted hearts, incl. 2 after biopsy, and 5 autopsies. Mean follow-up 12 [2; 32] months.Results. Myocarditis was found in 53,4%, incl. virus-positive in 32,7% of those, with morphology done for 19 patients (active myocarditis in 10, borderline in 6; with minimal signs of activeness in 3). Viral genome in myocardium found in 8 patients (42,1%). The prevalence of myocarditis 44,4% in an arrhythmic variant of NCM, 12,5% in chronic ischemic, 57,5% in dilation cardiomyopathy, 50,0% in NCM patients with other cardiomyopathies. Special cases were acute/subacute myocarditis in NCM (10,7% of all), acute necrosis (infarction) in 4,9%. Comorbidity with myocarditis in NCM led to significantly more severe LV dysfunction (CHF FC 2 [1; 3] v 1,75 [0; 2], p<0,01, EF 33,8±13,5 v 44,7±13,6%, p<0,001), more prevalent non-sustained ventricular tachycardia (67,3% v 29,3%, p<0,01), proper shocks (38,9% v 0, p<0,05), deaths (16,4 and 4,2%, OR 5,75, 95% CI 1,21-27,43, p<0,05) and transplantation (7,3% v 2,1%, p>0,05). Only in myocarditis patients, as a result of basis (antiviral, immune suppression) and cardiotropic therapy there was significant increase of EF (in acute myocarditis from 25,4±7,9 to 38,6±9,5%, p<0,01), decrease of LV size and pulmonary systolic pressure.Conclusion. Myocarditis is typical phenomenon developing in patients with the primary, i. e. genetically verified NCM. The nature of myocarditis in NCM varies (primary infectious-autoimmune, secondary as a response on genetic/ischemic damage of cardiomyocytes), however regardless of this, it leads to significant worsening of structural and functional parameters, increase of the life-threatening arrhythmias rate, and outcomes (death + transplantation, proper shocks), demanding for active basic therapy.