Aim. To assess the prevalence of the left ventricle involvement and the features of the biventricular phenotype of arrhythmogenic cardiomyopathy in patients with pathogenic mutations in the PKP2 and DSP genes. Material and methods. Three unrelated probands underwent a comprehensive molecular-genetic, clinical and instrumental examination, which included a 12-lead ECG, 24-hour ECG monitoring, transthoracic echocardiography, and cardiac magnetic resonance imaging with late gadolinium enhancement. Results. The results of our clinical observations showed that in three studied patients with arrhythmogenic cardiomyopathy left ventricle involvement of various degree was found. The left ventricle damage was characterized by fibrous or fibro-fatty infiltration of the myocardium, as well as regional or global systolic dysfunction of different severity. The patients had pathogenic mutations c.1912C > T (p.Gln638*, rs397517012, rs397517012); c.1237C > T (p.Arg413*, rs372827156) in the PKP2 gene and a new probably pathogenic variant in the form of a c.3494delA deletion in the DSP gene. It was found that the mutation in the DSP gene was associated with a more pronounced systolic dysfunction and a greater percentage of fibrous replacement of the left ventricular myocardium compared with carriers of mutations in the PKP2 gene. All patients had life-threatening ventricular arrhythmias with the need for implantation of a cardioverter-defibrillator. Conclusion. Our clinical observations have shown that in patients with biventricular arrhythmogenic cardiomyopathy, the detection of a mutation in the DSP gene is associated with a more pronounced systolic dysfunction and a higher percentage of fibrous replacement of the left ventricle myocardium compared with carriers of mutations in the PKP2 gene.

Инфекция COVID-19 представляет потенциальные риски для пациентов с каналопатиями. Сочетание многих проаритмогенных факторов, включая гипертермию, стресс, гипоксию, электролитные нарушения, диарею, а также применяемые в настоящее время лекарственные средства (ЛС) для лечения инфекции могут являться потенциальной причиной удлинения интервала QTc и приводить к возникновению угрожающих жизни аритмий. Поэтому пациентам с LQTS следует проявлять особую осторожность и при инфицировании COVID-19 желательна их госпитализация в стационар для адекватного мониторирования интервала QTc. Особые трудности диагностики вызывают пациенты с предрасположенностью к удлинению интервала QT и наличием преходящего или латентного удлинения интервала QTc. Авторы представляют клинический случай 29-летней пациентки, у которой на фоне гипертермии, диареи и рвоты, обусловленных инфекцией COVID-19, появились рецидивирующие пресинкопальные состояния и сердцебиения. Диагноз преходящего LQTS пациентке был установлен на основании эпизодов удлинения QTc до 609 мс при мануальной оценке ХМ ЭКГ на фоне тахикардии более 120 уд/мин. Оценка вероятности LQTS по шкале Шварца составила 4,0 балла. При молекулярно-генетическом исследовании обнаружено сочетание нескольких редких генетических вариантов с неопределенной значимостью в генах KCNE1, HCN4 и ANK2, кодирующих ионные каналы и ассоциированных с каналопатиями и нарушениями сердечного ритма. Комбинация нескольких генетических вариантов могла играть существенную роль как в вариабельности экспрессии фенотипа заболевания, так и в разнообразии ответов на различные провоцирующие факторы, обусловленные инфекцией COVID-19. COVID-19 presents potential risks for patients with channelopathies. A combination of many proarrhythmogenic factors, including hyperthermia, stress, hypoxia, electrolyte disturbances, diarrhea, as well as currently used drugs for the treatment of infection could be a potential cause of prolongation of the QTc interval and lead to life-threatening arrhythmias. Therefore, patients with LQTS should exercise special caution and when infected with COVID-19, their hospitalization in a hospital is desirable for adequate monitoring of the QTc interval. Particular diagnostic difficulties are caused by patients with a predisposition to prolongation of the QT interval and the presence of transient or latent prolongation of the QTc interval. The authors present a clinical case of a 29-year-old patient who, against the background of hyperthermia, diarrhea and vomiting caused by COVID-19, had recurrent presyncopal episodes and palpitations. The diagnosis of transient LQTS in the patient was established on the basis of episodes of QTc prolongation up to 609 ms with manual assessment of ECG monitor against a background of tachycardia of more than 120 bpm. The LQTS probability score on the Schwartz scale was 4.0 points. A molecular genetic study revealed a combination of several rare genetic variants with uncertain significance in the genes KCNE1, HCN4 and ANK2 encoding ion channels and associated with channelopathy and cardiac arrhythmias. The combination of several genetic variants could play a significant role both in the variability of the expression of the disease phenotype and in the diversity of responses to various provoking factors caused by COVID-19.

The aim of the study is to evaluate clinical characteristics, including adverse events and outcomes, in patients with various genetic types of long QT syndrome (LQTS).Material and methods. We examined 24 patients with a clinical diagnosis of LQTS, observed in the for 5 years. The clinical and instrumental study included registration of electrocardiography (ECG), Holter monitoring, collection of a genealogical history with an ECG assessment of all family members and identification of cases of sudden cardiac death (SCD) in the family or the presence of a family form of the disease, echocardiography and cardiac magnetic resonance imaging to exclude structural changes in the myocardium. The search for mutations in the coding sequences of genes associated with the development of channelopathy and other hereditary heart rhythm disorders was carried out by next generation sequencing (NGS).Results. Mutations in 4 genes associated with LQTS (KCNQ1, KCNH2, CACNA1C, ANK2) were detected in 18 out of 24 (75.0%) patients. Mutations in the KCNQ1, KCNH2 and CACNA1C genes were detected in 14 (58.0%) patients. In 4 out of 24 (17%) patients, two or more variants of clinical significance (VUS) were detected in the genes associated with LQTS and hereditary arrhythmias, 6 patients had no genetic changes. The most severe form of the disease with pronounced clinical manifestations and episodes of clinical death with subsequent resuscitation measures, as well as a significant increase in the QTc interval exceeding 500 ms, was observed in patients with LQT2 and multiple mutations. Implantation of a cardioverter-defibrillator (CD) was required in 14 (58.3%) patients, including 11 (78.56%) - for secondary prevention of SCD and 3 (21.4%) - for primary prevention.Conclusion. A comparative analysis between different genetic types of LQTS (LQT1; LQT2; patients with multiple VUS) showed that in patients with LQT1 syndrome, despite the early manifestation of the disease and the presence of syncopal conditions, life-threatening arrhythmias, SCD and the frequency of CD implantation were significantly less often recorded than in other LQTS. The most severe form of the disease with pronounced clinical manifestations, episodes of clinical death with subsequent resuscitation and CD implantation was observed both in the group of probands with LQT2 and in patients with several nucleotide variants (VUS), one of which was in the CACNA1C or ANK2 genes.

The aim of the study is to evaluate clinical characteristics, including adverse events and outcomes, in patients with various genetic types of long QT syndrome (LQTS). Material and methods. We examined 24 patients with a clinical diagnosis of LQTS, observed in the for 5 years. The clinical and instrumental study included registration of electrocardiography (ECG), Holter monitoring, collection of a genealogical history with an ECG assessment of all family members and identification of cases of sudden cardiac death (SCD) in the family or the presence of a family form of the disease, echocardiography and cardiac magnetic resonance imaging to exclude structural changes in the myocardium. The search for mutations in the coding sequences of genes associated with the development of channelopathy and other hereditary heart rhythm disorders was carried out by next generation sequencing (NGS). Results. Mutations in 4 genes associated with LQTS (KCNQ1, KCNH2, CACNA1C, ANK2) were detected in 18 out of 24 (75.0%) patients. Mutations in the KCNQ1, KCNH2 and CACNA1C genes were detected in 14 (58.0%) patients. In 4 out of 24 (17%) patients, two or more variants of clinical significance (VUS) were detected in the genes associated with LQTS and hereditary arrhythmias, 6 patients had no genetic changes. The most severe form of the disease with pronounced clinical manifestations and episodes of clinical death with subsequent resuscitation measures, as well as a significant increase in the QTc interval exceeding 500 ms, was observed in patients with LQT2 and multiple mutations. Implantation of a cardioverter-defibrillator (CD) was required in 14 (58.3%) patients, including 11 (78.56%) for secondary prevention of SCD and 3 (21.4%) for primary prevention. Conclusion. A comparative analysis between different genetic types of LQTS (LQT1; LQT2; patients with multiple VUS) showed that in patients with LQT1 syndrome, despite the early manifestation of the disease and the presence of syncopal conditions, life-threatening arrhythmias, SCD and the frequency of CD implantation were significantly less often recorded than in other LQTS. The most severe form of the disease with pronounced clinical manifestations, episodes of clinical death with subsequent resuscitation and CD implantation was observed both in the group of probands with LQT2 and in patients with several nucleotide variants (VUS), one of which was in the CACNA1C or ANK2 genes.

Катехоламинергическая полиморфная желудочковая тахикардия (КПЖТ) и синдром удлиненного интервала QT (LQTS) являются двумя различными каналопатиями, проявляющимися преимущественно у молодых пациентов при структурно нормальном сердце сходной клинической картиной, но с разным клиническим течением.Авторы представляют клинический случай атипичной КПЖТ у родственных пациентов, характеризующейся транзиторным удлинением интервала QT без связи с физической нагрузкой. У 8-летнего пробанда с рецидивирующими синкопальными состояниями на фоне полиморфной желудочковой тахикардии с транзиторным удлинением интервала QT развилась фибрилляция желудочков (ФЖ) и внезапная сердечная смерть (ВСС). У его 32-летней матери также наблюдались синкопальные состояния, эпизоды полиморфной ЖТ с транзиторным удлинением интервала QT и вероятностью наличия LQTS по шкале Шварца 5,0 балла, что позволило установить диагноз LQTS. Пациентке был имплантирован ИКД с целью первичной профилактики ВСС. При молекулярно-генетическом исследовании у матери и сына обнаружена вероятно патогенная мутация в гене RYR2, описанная ранее у пациентов с КПЖТ. Таким образом, под маской транзиторного удлинения интервала QT может скрываться диагноз КПЖТ, поэтому требуется внимательное рассмотрение клинических данных и обязательное генотипирование пациента. Хотя лечение обеих каналопатий одинаковое, клинические исходы различны, так как КПЖТ проявляется более злокачественным клиническим течением. Catecholaminergic polymorphic ventricular tachycardia (CPVT) and long QT syndrome (LQTS) are two different channelopathies, manifested mainly in young patients with a structurally normal heart with similar clinical manifestations, but with a different clinical course.The authors present a clinical case of atypical CPVT in related patients characterized by transient prolongation of the QT interval without connection with physical exertion. An 8-year-old proband with recurrent syncopal conditions against the background of polymorphic ventricular tachycardia with transient prolongation of the QT interval developed ventricular fibrillation (VF) and sudden cardiac death (SCD). His 32-year- old mother also had syncopal episodes, episodes of polymorphic VT with transient prolongation of the QT interval and a probability of having LQTS on the Schwartz scale of 5.0 points, which allowed the diagnosis of LQTS to be established. The patient was implanted with an ICD for the purpose of primary prevention of SCD. The genetic study of the mother and son revealed a likely pathogenic mutation in the RYR2 gene, previously described in patients with CPVT.Thus, under the mask of a transient prolongation of the QT interval, the diagnosis of CPVT may be hidden, therefore, careful consideration of clinical data and mandatory genotyping of the patient is required. Although the treatment of both channelopathies is the same, the clinical outcomes are different and CPVT is manifested by a more malignant clinical course.

Тахииндуцированная кардиомиопатия (ТИКМП) – это заболевание, проявляющееся обратимым снижением функции левого желудочка, обусловленное тахиаритмией или очень частой желудочковой эктопией, которое без своевременного выявления и лечения может привести к развитию сердечной недостаточности и смерти. В статье представлен обзор литературы, посвященной выделению более точного определения, описанию патофизиологии ТИКМП, а также алгоритмов диагностики и современных методов лечения. Данный тип кардиомиопатии недостаточно изучен, постановка диагноза порой затруднена и производится ретроспективно после проведенного лечения. Методы лечения на данный момент включают в себя лекарственную терапию, радиочастотную абляцию аритмии, абляцию атриовентрикулярного соединения с имплантацией ресинхронизирующего устройства либо электрокардиостимулятора со стимуляцией в области пучка Гиса. С учетом сложности постановки диагноза, а также высокой вероятности восстановления функции сердца при своевременном лечении необходимо проведение дальнейших исследований для выявления дополнительных диагностических критериев ТИКМП и выделения критериев отбора для раннего инвазивного лечения. Tachycardia-induced cardiomyopathy (TICMP) is the disease, which manifests itself with reversible decrease of the left ventricular function due to tachyarrhythmia or very frequent ventricular ectopy, which (without timely detection and treatment) can lead to heart failure and death. The article provides the review of literature on detection of a more accurate definition, the description of the pathophysiology of TICMP, as well as the diagnostic algorithms and modern treatment methods. This type of cardiomyopathy is not well-understood; the diagnosis is difficult and sometimes is done retrospectively after treatment. Treatment options include drug therapy, radiofrequency ablation of arrhythmias, ablation of atrioventricular node plus resynchronization or pacemaker implantation with His-stimulation. Taking into account the complexity of the diagnosis, as well as the high likelihood of recovery of heart function with timely treatment, further studies are necessary to identify additional diagnostic criteria of TICMP and highlight the selection criteria for early invasive treatment.

The TBX5 gene encodes the T-box transcription factor 5 (Tbx5) involved in the regulation of developmental processes in both vertebrates and invertebrates. Mutations in this gene cause rare monogenic Holt–Oram syndrome (HOS) characterized by skeletal anomalies of the upper limbs, a congenital heart defect, and/or сardiac сonduction system diseases. Next generation sequencing (NGS) made it possible to detect a new nucleotide variant c.713G>C (p.Gly238Ala) in the TBX5 gene in a patient with a mild Holt–Oram syndrome phenotype (thoracic spine deformity (scoliosis) and scapula dysplasia and showing signs of mitral and triсuspid valve insufficiency with first- and second-degree regurgitation and atrial septal thinning) and life-threatening tachyarrhythmias that required a cardioverter-defibrillator implantation (CDI). The mutation is localized in the “hot spot” of the TBX5 gene. Evaluation of its pathogenicity by in silico analysis showed that the c.713G>C nucleotide substitution can lead to changes in the protein structure and/or its function. Non-sustained ventricular tachycardia/ventricular fibrillation, which is not characteristic of HOS, could have resulted from two additional rare substitutions (MAF < 0.01%): p.Val3634Asp, rs66785829 in the ANK2 gene and p.Arg1193Gln, rs41261344 in the SCN5A gene. Mutations in these genes affect the voltage-gated sodium channel functioning and cause hereditary arrhythmia.

Синдром Холта – Орама (HOS) – генетическое заболевание, вызванное мутацией в гене TBX5, хромосома 12q24, который регулирует широкий спектр процессов развития сердца, сосудов и конечностей. В настоящей работе представлен клинический случай синдрома HOS у 42-летней пациентки с мягким фенотипом заболевания и жизнеугрожающими нарушениями ритма (устойчивая желудочковая тахикардия / фибрилляция желудочков), по поводу которых был имплантирован кардиовертер-дефибриллятор (ИКД). При генетическом исследовании были выявлены мутация c.713G>C (p.Gly238Ala) в гене TBX5, указывающая на наличие у пациентки синдрома HOS, и две редкие замены c.10901T>A (p.Val3634Asp), rs66785829 в гене ANK2, отвечающем за синтез анкирина-В, c.35758G>A (p.Arg1193Gln), rs41261344 в гене SCN5A, кодирующем субъединицу потенциал-зависимого натриевого канала Nav1.5, ассоциированные с развитием наследственных аритмий. Обсуждены вопросы диагностики и стратегии лечения. Holt – Oram syndrome (HOS) is a genetic disease caused bya mutation in theTBX5 gene, chromosome 12q24, which regulates a wide range of heart, vascular, and limb development processes. This paper presents a clinical case of HOS syndrome in a 42-year-old patient with a mild disease phenotype and life-threatening rhythm disorders (sustained ventricular tachycardia/ventricular fibrillation), for which a cardioverter defibrillator (ICD) was implanted. The genetic study revealed a mutation c.713G>C (p.Gly238Ala) in the TBX5 gene, indicating the presence of HOS syndrome in the patient, and two rare substitutions c.10901T>A (p.Val3634Asp), rs66785829 in the ANK2 gene responsible for ankyrin-B synthesis; c.35758G>A (p.Arg1193Gln), rs41261344 in the SCN5A gene encoding the Nav1.5 potential dependent sodium channel subunit associated with the development of hereditary arrhythmias.The issues of diagnostics and treatment were discussed.

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.

Синдром удлиненного интервала QT (LQTS) представляет собой генетически детерминированное заболевание, характеризующееся удлинением интервала QT на электрокардиограмме, высоким риском жизнеугрожающих аритмий и внезапной сердечной смерти. Причиной данного синдрома являются мутации в генах, кодирующих белки ионных каналов, а также протеины, опосредованно связанные с ионными каналами. От 4,5 до 8% пациентов с LQTS имеют более одной мутации в генах, связанных с развитием каналопатий. Цель работы: описание двух клинических случаев пациентов с жизнеугрожающими аритмиями, у которых выявлено сочетание редких мутантных аллелей в генах, ассоциированных с LQTS. Клиническое обследование включало ЭКГ в 12 отведениях, ЭхоКГ, МРТ сердца с отсроченным контрастированием и суточное мониторирование ЭКГ (СМ ЭКГ). Генетическое тестирование выполнено методом высокопроизводительного секвенирования (NGS) с использованием набора реагентов «TruSight™ Cardio Sequencing Panel» (Illumina). Оба пациента без отягощенного семейного анамнеза имели злокачественные желудочковые тахиаритмии, которые потребовали имплантации кардиовертера-дефибриллятора. В результате проведенного генотипирования методом NGS у пациента с идиопатической желудочковой тахикардией выявлено сочетание замен в генах ANK2 (c.9161C>G, p.Ala3054Gly, rs139007578) и KCNE1 (c.253G>A, p.Asp85Asn, rs1805128). У пациента с идиопатической фибрилляцией желудочков обнаружен аллельный вариант также в гене ANK2 (c.1397C>T, p.Thr466Met, rs786205722) и дополнительная замена в гене SNTA1 (c.787G>T, (p.Ala263Ser), rs150576530). При наличии у пациентов нескольких генетических дефектов может наблюдаться «кумулятивный эффект» мутаций, фенотипически проявляющийся тяжелым течением заболевания с неблагоприятными исходами. Показано, что при генотипировании пациентов с идиопатическими жизнеугрожающими тахиаритмиями использование панелей с большим количеством генов, ассоциированных с сердечно-сосудистой патологией, является вполне оправданным. Комплексное исследование генов позволяет увеличить диагностическую и прогностическую ценность генетического скрининга. Long QT syndrome (LQTS) is the genetically determined disease characterized by the QT interval elongation at the electrocardiogram, a high risk of life-threatening arrhythmias and sudden cardiac death. This syndrome is determined by mutations in genes encoding ion channel proteins, as well as proteins indirectly associated with ion channels. 4.5-8% of patients with LQTS have more than one mutation in the genes associated with the development of channelopathies. Purpose of work: description of two clinical cases of patients with life-threatening arrhythmia in which a combination of rare mutant alleles in the genes associated with LQTS was detected. The clinical examination included 12-lead ECG, echocardiography, cardiac MRI with delayed contrast, and 24-hour ECG monitoring (SM ECG). Genetic testing was performed by next generation sequencing (NGS) using the TruSight ™ Cardio Sequencing Panel reagent kit (Illumina). Both patients with no burdened family history had malignant ventricular tachyarrhythmias, which required the implantation of a cardioverter defibrillator. The NGS method allowed to detect a combination of substitutions in the genes ANK2 (c.9161C>G, p.Ala3054Gly, rs139007578) and KCNE1 (c.253G>A, p.Asp85Asn, rs1805128) in a patient with idiopathic ventricular tachycardia. In the patient with idiopathic ventricular fibrillation, the allelic variant was also found in the gene ANK2 (c.1397C>T, p.Thr466Met, rs786205722) and an additional substitution in the gene SNTA1 (c.1877>T, (p.Ala263Ser), rs150576530). If patients have several genetic defects, a “cumulative effect” of mutations can be observed, phenotypically manifested by a severe course of the disease with unfavorable outcomes. It has been shown that when genotyping patients with idiopathic life-threatening tachyarrhythmias, the use of panels with a large number of genes associated with cardiovascular pathology is quite justified. A comprehensive study of genes can increase the diagnostic and prognostic value of genetic screening.

Long QT syndrome (LQTS) is the genetically determined disease characterized by the QT interval elongation at the electrocardiogram, a high risk of life-threatening arrhythmias and sudden cardiac death. This syndrome is determined by mutations in genes encoding ion channel proteins, as well as proteins indirectly associated with ion channels. 4.5-8% of patients with LQTS have more than one mutation in the genes associated with the development of channelopathies. Purpose of work: description of two clinical cases of patients with life-threatening arrhythmia in which a combination of rare mutant alleles in the genes associated with LQTS was detected. The clinical examination included 12-lead ECG, echocardiography, cardiac MRI with delayed contrast, and 24-hour ECG monitoring (SM ECG). Genetic testing was performed by next generation sequencing (NGS) using the TruSight ™ Cardio Sequencing Panel reagent kit (Illumina). Both patients with no burdened family history had malignant ventricular tachyarrhythmias, which required the implantation of a cardioverter defibrillator. The NGS method allowed to detect a combination of substitutions in the genes ANK2 (c.9161C>G, p.Ala3054Gly, rs139007578) and KCNE1 (c.253G>A, p.Asp85Asn, rs1805128) in a patient with idiopathic ventricular tachycardia. In the patient with idiopathic ventricular fibrillation, the allelic variant was also found in the gene ANK2 (c.1397C>T, p.Thr466Met, rs786205722) and an additional substitution in the gene SNTA1 (c.1877>T, (p.Ala263Ser), rs150576530). If patients have several genetic defects, a “cumulative effect” of mutations can be observed, phenotypically manifested by a severe course of the disease with unfavorable outcomes. It has been shown that when genotyping patients with idiopathic life-threatening tachyarrhythmias, the use of panels with a large number of genes associated with cardiovascular pathology is quite justified. A comprehensive study of genes can increase the diagnostic and prognostic value of genetic screening.

Framingham Heart Study identified left ventricular hypertrophy (LVH) as an independent risk factor for cardiovascular morbidity and mortality, including sudden cardiac death, and acute myocardial infarction. Thickened myocardial wall is also a source for heart rhythm disturbances. Objective. To estimate the rate of arrhythmias in hypertensive patients depending on left ventricular myocardial mass index (MMI). Design and methods. The study cohort included 107 hypertensive patients. The average age was 49,4 ± 10,9 years. Based on MMI value patients were divided into four groups. Ventricular arrhythmias were categorized according to Lown-Wolf classification. Results. The tendency to the increase of high gradation ventricular arrhythmias with the MMI augmentation was found out. There are significant differences of high gradation ventricular arrhythmias rate between the groups with different MMI values. There are positive correlations between LV MMI and the number of both ventricular and supraventricular arrhythmias per hour; between one-dimensional left atrium size and MMI (r = 0,53; p < 0,0001), left atrium volume and MMI (r = 0,32; p = 0,001); between one-dimensional left atrium size and isovolumetric ventricular relaxation time (IVRT) (r = 0,36; p < 0,001), as well as between MMI and IVRT (r = 0,43; p < 0,001). Conclusion. The frequency of threatening ventricular arrhythmias increases with MMI growth. MMI can be a prognostic factor of threatening ventricular arrhythmias in hypertensive patients with LVH.