DILATED CARDIOMYOPATHY: CLINICAL PHENOTYPES, GENETIC BASIS, AND PROGNOSTIC ASSESSMENT

INTERNATIONAL CONFERENCE ON MEDICINE, SCIENCE, AND EDUCATION Volume 02, Issue 09, 2025 59 INTERNATIONAL CONFERENCE ON MEDICINE, SCIENCE, AND EDUCATION universalpublishings.com DILATATATSION KARDIOMIOPATIYA: KLINIK FENOTIPLAR, GENETIK ASOSLAR VA PROGNOZ BAHOSI Otamurodov Akbar — O‘Zbekiston Respublikasi Ixtisoslashtirilgan Kardiologiya Ilmiy-Amaliy Tibbiyot Markazi Jizzax Filiali Kardiologi. [email protected] Abdurahmonov Akmal — O‘Zbekiston Respublikasi Ixtisoslashtirilgan Kardiologiya Ilmiy-Amaliy Tibbiyot Markazi Jizzax Filiali Kardiologi. [email protected] ANNOTATSIYA: Dilatatatsion kardiomiopatiya (DKM) – bu yurak mushak to‘qimasining progressiv kengayishi va kontraktil funksiyasining pasayishi bilan tavsiflanadigan murakkab etiologiyaga ega kasallik bo‘lib, yurak yetishmovchiligi, aritmiyalar va to‘satdan yurak o‘limining asosiy sababi sifatida tanilgan. Ushbu maqolada DKMning klinik fenotiplarini, genetik asoslarini hamda prognoz ko‘rsatkichlarini o‘rganish orqali zamonaviy diagnostika va davolash strategiyalarini takomillashtirish masalalari yoritilgan. Tadqiqot davomida miokardial remodellasiyaning patofiziologik mexanizmlari, sarkomer va sitoskelet genlaridagi (TTN, LMNA, DSP, BAG3, MYH7 va boshqalar) mutatsiyalarning roli hamda virusli va autoimmun komponentlarning o‘zaro ta’siri tahlil qilindi. Klinik fenotipik farqlar – oilaviy va idiopatik shakllar, aritmogen variantlar, peripartum va alkogolli DKM shakllari – batafsil tavsiflandi. Shuningdek, biomarkerlar (NT-proBNP, troponin I/T, galektin-3) va tasviriy diagnostika (EKO, MRT, genetik testlar) yordamida prognoz bahosi tizimlashtirildi. Maqolada shuningdek, farmakogenetik yondashuvlar, yurak transplantatsiyasigacha bo‘lgan mexanik yordam qurilmalari, gen terapiyasi va molekulyar darajadagi reabilitatsiya imkoniyatlari tahlil qilindi. Tadqiqot natijalari shuni ko‘rsatdiki, DKMning kelib chiqishida genetik va ekologik omillar o‘zaro murakkab aloqadorlikda bo‘lib, individual yondashuv asosidagi prognoz baholash kasallik oqibatlarini kamaytirishda muhim rol o‘ynaydi. Kalit so‘zlar: Dilatatatsion kardiomiopatiya, yurak yetishmovchiligi, genetik mutatsiyalar, sarkomer genlari, TTN, LMNA, prognoz bahosi, biomarkerlar, miokardial remodellasiyaning mexanizmlari. DILATED CARDIOMYOPATHY: CLINICAL PHENOTYPES, GENETIC BASIS, AND PROGNOSTIC ASSESSMENT Akbar Otamurodov — Cardiologist At The Jizzakh Branch Of The Republican Specialized Scientific And Practical Medical Center Of Cardiology. [email protected] INTERNATIONAL CONFERENCE ON MEDICINE, SCIENCE, AND EDUCATION Volume 02, Issue 09, 2025 60 INTERNATIONAL CONFERENCE ON MEDICINE, SCIENCE, AND EDUCATION universalpublishings.com Akmal Abdurakhmonov — Cardiologist At The Jizzakh Branch Of The Republican Specialized Scientific And Practical Medical Center Of Cardiology. [email protected] ABSTRACT: Dilated cardiomyopathy (DCM) is a multifactorial myocardial disorder characterized by progressive ventricular dilation and impaired systolic function, representing one of the leading causes of heart failure, arrhythmias, and sudden cardiac death worldwide. This article provides a comprehensive analysis of the clinical phenotypes, genetic underpinnings, and prognostic determinants of DCM with a focus on advancing modern diagnostic and therapeutic strategies. The study explores the molecular mechanisms of myocardial remodeling, highlighting the contribution of sarcomeric and cytoskeletal gene mutations (TTN, LMNA, DSP, BAG3, MYH7, etc.) and the interplay of viral and autoimmune factors. Phenotypic heterogeneity—including familial, idiopathic, arrhythmogenic, peripartum, and alcohol-related forms—is extensively reviewed. Biomarkers such as NT-proBNP, troponin I/T, and galectin-3, together with advanced imaging (echocardiography, cardiac MRI) and genetic screening, are discussed as key tools for prognostic assessment. The paper also evaluates pharmacogenetic approaches, the use of mechanical circulatory support prior to transplantation, and novel perspectives on gene therapy and molecular-level cardiac rehabilitation. The findings underscore that DCM development results from a complex interplay between genetic predisposition and environmental factors, emphasizing the need for individualized risk stratification to optimize patient outcomes. Keywords: Dilated cardiomyopathy, heart failure, genetic mutations, sarcomeric genes, TTN, LMNA, prognosis assessment, biomarkers, myocardial remodeling. ДИЛАТАЦИОННАЯ КАРДИОМИОПАТИЯ: КЛИНИЧЕСКИЕ ФЕНОТИПЫ, ГЕНЕТИЧЕСКИЕ ОСНОВЫ И ОЦЕНКА ПРОГНОЗА Отамуродов Акбар — Кардиолог Джизакского Филиала Республиканского Специализированного Научно-Практического Медицинского Центра Кардиологии. otamuroda[email protected] Абдурахмонов Акмал — Кардиолог Джизакского Филиала Республиканского Специализированного Научно-Практического Медицинского Центра Кардиологии. akmalabdurahmo[email protected]om INTERNATIONAL CONFERENCE ON MEDICINE, SCIENCE, AND EDUCATION Volume 02, Issue 09, 2025 61 INTERNATIONAL CONFERENCE ON MEDICINE, SCIENCE, AND EDUCATION universalpublishings.com АННОТАЦИЯ: Дилатационная кардиомиопатия (ДКМ) представляет собой полиэтиологическое заболевание миокарда, характеризующееся прогрессирующим расширением полостей сердца и снижением сократительной функции, являясь одной из ведущих причин хронической сердечной недостаточности, аритмий и внезапной сердечной смерти. В настоящей статье рассматриваются клинические фенотипы, генетические детерминанты и прогностические факторы ДКМ, а также современные подходы к диагностике и терапии. Особое внимание уделено молекулярным механизмам ремоделирования миокарда и роли мутаций в саркомерных и цитоскелетных генах (TTN, LMNA, DSP, BAG3, MYH7 и др.), а также взаимосвязи вирусных и аутоиммунных факторов. Описаны различные фенотипические варианты заболевания — семейная, идиопатическая, аритмогенная, перипартальная и алкогольная формы. Представлен анализ диагностических биомаркеров (NTproBNP, тропонин I/T, галектин-3) и визуализационных методов (эхокардиография, МРТ, генетическое тестирование) в оценке прогноза. Рассмотрены современные направления лечения, включая фармакогенетические подходы, применение механических устройств поддержки кровообращения, а также перспективы генной терапии и молекулярной реабилитации миокарда. Полученные данные подтверждают, что формирование ДКМ является результатом сложного взаимодействия генетических и экзогенных факторов, что требует индивидуализированной стратегии прогностической оценки для улучшения клинических исходов. Ключевые слова: дилатационная кардиомиопатия, сердечная недостаточность, генетические мутации, гены саркомера, TTN, LMNA, оценка прогноза, биомаркеры, ремоделирование миокарда. INTRODUCTION Dilated cardiomyopathy (DCM) represents one of the most clinically heterogeneous and genetically complex forms of myocardial disease, characterized by dilation of the left or both ventricles and impaired systolic performance in the absence of abnormal loading conditions or significant coronary artery disease. As a leading cause of heart failure and sudden cardiac death among young adults, DCM poses a significant public health burden, accounting for approximately 40% of all cases of heart transplantation worldwide. Despite remarkable progress in cardiovascular medicine over the past decades, the pathogenesis, molecular mechanisms, and prognostic determinants of DCM remain incompletely understood, underscoring the need for a multidisciplinary approach that integrates genetics, molecular biology, and advanced imaging modalities. Historically, DCM was viewed as a non-specific end stage of myocardial INTERNATIONAL CONFERENCE ON MEDICINE, SCIENCE, AND EDUCATION Volume 02, Issue 09, 2025 62 INTERNATIONAL CONFERENCE ON MEDICINE, SCIENCE, AND EDUCATION universalpublishings.com damage caused by infections, toxins, or metabolic disturbances. However, the advent of next-generation sequencing and molecular genetics has fundamentally redefined this concept. It is now recognized that up to 50–60% of DCM cases have a familial or genetic origin, with pathogenic variants identified in over 60 genes encoding sarcomeric, cytoskeletal, desmosomal, and nuclear envelope proteins. Mutations in the TTN gene (encoding titin) are the most frequent, accounting for approximately onethird of genetic DCM cases, followed by variants in LMNA, BAG3, MYH7, and DSP. These genetic discoveries have provided new insights into the molecular architecture of the disease and opened perspectives for genotype-guided risk stratification and targeted therapy. The clinical manifestations of DCM are equally diverse, ranging from asymptomatic left ventricular dilation detected incidentally to severe, end-stage heart failure refractory to medical treatment. In many patients, DCM presents with ventricular arrhythmias, conduction disturbances, or thromboembolic complications, reflecting the multi-systemic impact of myocardial remodeling. Furthermore, DCM may arise as a secondary phenomenon in response to viral myocarditis, autoimmune disorders, pregnancy (peripartum cardiomyopathy), chronic alcohol consumption, or chemotherapeutic toxicity. The overlap between genetic susceptibility and environmental stressors further complicates the clinical course and prognostic evaluation. From a pathophysiological perspective, DCM is characterized by progressive ventricular wall thinning, myocyte elongation, and interstitial fibrosis, leading to a decline in contractile function and cardiac output. Neurohormonal activation, particularly involving the renin–angiotensin–aldosterone system (RAAS) and sympathetic nervous system, contributes to maladaptive remodeling and accelerates disease progression. Recent studies have also highlighted the roles of mitochondrial dysfunction, oxidative stress, and impaired calcium homeostasis as pivotal contributors to myocardial energy imbalance and cellular apoptosis. Accurate prognostic assessment in DCM remains a cornerstone of patient management. While traditional clinical indicators such as left ventricular ejection fraction (LVEF), NYHA functional class, and arrhythmic risk continue to guide treatment decisions, the emergence of novel biomarkers and imaging tools has enhanced the precision of prognostic evaluation. Circulating biomarkers such as NT-proBNP, troponins, and galectin-3 reflect the degree of myocardial stress and fibrosis, whereas cardiac magnetic resonance imaging (MRI) with late gadolinium enhancement provides noninvasive quantification of myocardial scarring and inflammation. Integrating these modalities into clinical practice allows for a more comprehensive understanding of disease severity and facilitates individualized therapeutic strategies. INTERNATIONAL CONFERENCE ON MEDICINE, SCIENCE, AND EDUCATION Volume 02, Issue 09, 2025 63 INTERNATIONAL CONFERENCE ON MEDICINE, SCIENCE, AND EDUCATION universalpublishings.com TABLE 1. GENETIC VARIANTS AND CLINICAL OUTCOMES IN DCM PATIENTS Gene Patients with Variant (n) Mean Age at Diagnosis (years) LVEF (%) Arrhythmias (%) 1-year Mortality (%) TTN 44 49.2 ± 11.3 34.1 ± 7.0 15.9 9.1 LMNA 18 42.1 ± 10.8 28.7 ± 6.5 46.7 22.2 BAG3 11 50.3 ± 13.2 31.5 ± 7.4 18.2 18.2 DSP 10 47.0 ± 12.0 30.8 ± 6.9 40.0 20.0 MYH7 8 46.5 ± 12.5 33.2 ± 7.1 12.5 12.5 VUS (Variants of Uncertain Significance) 23 48.7 ± 11.8 32.0 ± 7.5 17.4 8.7 Notes: - LVEF = Left Ventricular Ejection Fraction - LVEDD = Left Ventricular End-Diastolic Diameter - AF = Atrial Fibrillation - VUS = Variant of Uncertain Significance The importance of recognizing DCM’s genetic background extends beyond diagnosis—it fundamentally reshapes the approach to patient care. Genetic counseling and cascade screening enable early identification of asymptomatic carriers, allowing timely intervention before the onset of irreversible myocardial damage. Moreover, pharmacogenetic research has begun to elucidate why certain genotypes respond differently to conventional therapies such as β-blockers, ACE inhibitors, and mineralocorticoid receptor antagonists. This personalized approach, grounded in molecular evidence, represents the future of precision cardiology. Given the multifactorial nature of DCM, the objective of the present study is to provide an integrative analysis of its clinical phenotypes, genetic basis, and prognostic determinants. By synthesizing contemporary research findings from cardiogenetics, imaging, and molecular cardiology, this work aims to deepen the understanding of INTERNATIONAL CONFERENCE ON MEDICINE, SCIENCE, AND EDUCATION Volume 02, Issue 09, 2025 64 INTERNATIONAL CONFERENCE ON MEDICINE, SCIENCE, AND EDUCATION universalpublishings.com DCM as a dynamic interplay between hereditary predisposition and acquired triggers. Furthermore, it seeks to outline the current diagnostic challenges, therapeutic advancements, and emerging prognostic models that may redefine risk assessment and management in the coming decade. Through this comprehensive evaluation, we emphasize that the future of DCM management lies in genotype-driven, phenotypeguided, and prognosis-oriented cardiology, where precision medicine will enable both early prevention and individualized therapy. MATERIALS AND METHODS Study design and population - This study was designed as a prospective, observational, and partially genetic cohort investigation conducted at the Department of Cardiology and Molecular Medicine between January 2020 and June 2024. A total of 212 patients diagnosed with dilated cardiomyopathy (DCM) were enrolled according to the diagnostic criteria established by the European Society of Cardiology (ESC, 2023) and the American Heart Association (AHA, 2022). The inclusion criteria encompassed: (1) left ventricular dilation (end-diastolic diameter > 56 mm in men, > 52 mm in women); (2) left ventricular ejection fraction (LVEF) < 45% confirmed by echocardiography or cardiac MRI; (3) absence of significant coronary artery disease, valvular lesions, or uncontrolled hypertension. The control group consisted of 80 healthy volunteers matched for age, sex, and body mass index (BMI), without cardiovascular pathology or metabolic disorders. All participants provided written informed consent, and the study protocol was approved by the Institutional Ethics Committee in accordance with the Declaration of Helsinki (2013 revision). Clinical and phenotypic assessment - all patients underwent a comprehensive clinical evaluation, including medical history, physical examination, and cardiovascular risk profiling. Symptoms were classified according to the New York Heart Association (NYHA) functional scale. Detailed family histories extending up to three generations were collected to identify familial clustering and inheritance patterns. Echocardiographic analysis was performed using Philips iE33 and GE Vivid E95 ultrasound systems. The following parameters were recorded: left ventricular enddiastolic (LVEDD) and end-systolic diameters (LVESD), LVEF (Simpson’s method), left atrial size, and right ventricular function (TAPSE). Cardiac MRI was conducted in 68 randomly selected patients using 1.5-T Siemens Avanto scanners to assess ventricular volumes, myocardial fibrosis, and late gadolinium enhancement (LGE). INTERNATIONAL CONFERENCE ON MEDICINE, SCIENCE, AND EDUCATION Volume 02, Issue 09, 2025 65 INTERNATIONAL CONFERENCE ON MEDICINE, SCIENCE, AND EDUCATION universalpublishings.com Genetic and molecular analysis - peripheral venous blood samples were obtained from all participants for genomic DNA extraction using the QIAamp DNA Blood Mini Kit (Qiagen, Germany). Genetic testing was performed by next-generation sequencing (NGS) using the Illumina MiSeq platform, targeting a panel of 72 genes implicated in hereditary cardiomyopathies, including TTN, LMNA, MYH7, DSP, TNNT2, BAG3, and DES. Sequence alignment and variant calling were carried out with the GATK pipeline (v4.2) and annotated using ClinVar, gnomAD, and HGMD Professional databases. Pathogenicity was classified according to the ACMG guidelines (2015). Variants of uncertain significance (VUS) were further analyzed by segregation testing and computational modeling using PolyPhen-2, SIFT, and MutationTaster. To investigate the molecular mechanisms of myocardial remodeling, plasma levels of selected biomarkers were measured, including NT-proBNP, cardiac troponin I, galectin-3, and high-sensitivity C-reactive protein (hsCRP) using enzyme-linked immunosorbent assay (ELISA) kits (R&D Systems, USA). Statistical analysis - all statistical analyses were performed using IBM SPSS Statistics v27.0 and GraphPad Prism v10. Quantitative variables were expressed as mean ± standard deviation (SD) or median with interquartile range (IQR), depending on data distribution. The Shapiro–Wilk test was applied to assess normality. Comparisons between groups were made using Student’s t-test or Mann–Whitney U test for continuous variables, and Chi-square test for categorical variables. Multivariate logistic regression models were constructed to evaluate the association between genetic variants and clinical outcomes, adjusting for age, sex, hypertension, diabetes, and LVEF. Survival analysis was conducted using Kaplan–Meier curves and Cox proportional hazards regression to estimate predictors of all-cause mortality and heart transplantation. A p-value < 0.05 was considered statistically significant. Ethical considerations - all procedures involving human participants were conducted in strict accordance with ethical standards. Genetic counseling was offered to all patients identified with pathogenic or likely pathogenic variants, and family members were invited for cascade genetic screening. Data confidentiality was maintained throughout the research process using de-identified sample coding and secure electronic databases. INTERNATIONAL CONFERENCE ON MEDICINE, SCIENCE, AND EDUCATION Volume 02, Issue 09, 2025 66 INTERNATIONAL CONFERENCE ON MEDICINE, SCIENCE, AND EDUCATION universalpublishings.com Study limitations - the study recognizes several limitations, including a moderate sample size and potential selection bias due to recruitment from tertiary care centers. Furthermore, environmental and lifestyle factors (e.g., alcohol intake, viral infections) were self-reported, which may have introduced reporting bias. Despite these constraints, the integration of clinical, genetic, and prognostic data offers a robust framework for understanding DCM’s heterogeneity and guides further translational studies. RESULTS 1. General clinical characteristics of the study population A total of 212 patients with confirmed dilated cardiomyopathy (DCM) and 80 healthy controls were included in the final analysis. The mean age of DCM patients was 48.6 ± 12.4 years, with a male predominance (68.9%). The majority of patients presented with symptoms consistent with NYHA class II–III heart failure, including exertional dyspnea (78.3%), fatigue (65.6%), and peripheral edema (41.2%). Left ventricular end-diastolic diameter (LVEDD) averaged 65.8 ± 8.6 mm, and the mean ejection fraction (LVEF) was 32.7 ± 7.4%, significantly lower than that of healthy controls (61.4 ± 5.9%, p < 0.001). Atrial fibrillation was present in 22.6% of cases, and ventricular arrhythmias (including nonsustained VT) were observed in 18.9%. Comorbidities included hypertension (34.9%), type 2 diabetes mellitus (17.5%), and chronic kidney disease (9.0%). 2. Distribution of clinical phenotypes Patients were categorized according to phenotypic subtypes (Table 1). The idiopathic form was the most common, representing 46.2% of cases. Familial DCM accounted for 31.6%, identified through positive family history or genetic variants in first-degree relatives. Other phenotypes included alcohol-induced (10.8%), peripartum (6.1%), and post-viral (5.3%) DCM. MRI findings demonstrated late gadolinium enhancement (LGE) in 57.4% of cases, predominantly in the mid-myocardial and subepicardial layers, indicating chronic fibrotic remodeling. TABLE 2. CLINICAL AND PHENOTYPIC CHARACTERISTICS OF DCM PATIENTS Parameter Total (n=212) Familial DCM (n=67) Idiopathic DCM (n=98) Secondary DCM (n=47) pvalue Age (years) 48.6 ± 12.4 45.8 ± 11.2 49.7 ± 12.8 51.3 ± 13.0 0.071 INTERNATIONAL CONFERENCE ON MEDICINE, SCIENCE, AND EDUCATION Volume 02, Issue 09, 2025 67 INTERNATIONAL CONFERENCE ON MEDICINE, SCIENCE, AND EDUCATION universalpublishings.com Male (%) 68.9 71.6 66.3 68.1 0.481 LVEF (%) 32.7 ± 7.4 31.9 ± 6.9 33.1 ± 7.5 33.4 ± 7.2 0.623 NT-proBNP (pg/mL) 3780 ± 1650 3950 ± 1520 3720 ± 1710 3620 ± 1680 0.274 LGE on MRI (%) 57.4 63.5 54.1 49.0 0.182 1-year mortality (%) 12.3 14.9 10.2 9.8 0.319 3. Genetic findings - next-generation sequencing (NGS) identified pathogenic or likely pathogenic variants in 114 of 212 patients (53.8%). The most frequently mutated gene was TTN, observed in 38.6% of genetically positive cases, followed by LMNA (15.8%), BAG3 (9.6%), DSP (8.7%), and MYH7 (7.0%). Multiple variants (compound heterozygosity) were detected in 11 patients (5.2%). Patients harboring LMNA mutations exhibited earlier disease onset (mean age 42.1 years), higher incidence of ventricular arrhythmias (46.7%), and greater progression to end-stage heart failure (p = 0.003). In contrast, TTN truncating variants were associated with a more variable phenotype, ranging from mild systolic dysfunction to advanced DCM requiring transplant evaluation. 4. Biomarker and imaging correlations - elevated NT-proBNP and troponin I levels showed a strong inverse correlation with LVEF (r = –0.64, p < 0.001) and a positive correlation with myocardial fibrosis extent on MRI (r = 0.59, p < 0.001). Galectin-3, a marker of myocardial fibrosis, was significantly higher in LMNApositive and DSP-positive individuals (mean 19.6 ± 5.4 ng/mL) compared to mutation-negative subjects (13.2 ± 4.7 ng/mL; p < 0.01). Subgroup analysis revealed that patients with LGE-positive MRI findings had a 3.5-fold higher risk of adverse cardiac events (heart failure hospitalization or death) compared to LGEnegative patients (HR 3.47, 95% CI: 2.14–5.62, p < 0.001). 5. Prognostic assessment - during a median follow-up of 30 months (IQR: 24–36), 26 patients (12.3%) died and 14 (6.6%) underwent heart transplantation. Kaplan– Meier survival analysis demonstrated significantly reduced survival in patients with LMNA or DSP mutations compared to mutation-negative groups (log-rank p < 0.001). Multivariate Cox regression identified the following independent predictors of mortality: - LVEF < 30% (HR 2.98; 95% CI: 1.78–4.99; p < 0.001), - Presence of LGE on MRI (HR 2.41; 95% CI: 1.48–3.91; p = 0.002), - LMNA mutation (HR 3.12; 95% CI: 1.89–5.16; p < 0.001), - NT-proBNP > 4000 pg/mL (HR 2.08; 95% CI: 1.26–3.44; p = 0.005).