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Inherited arrhythmia syndromes include several different diseases, as well as Brugada syndrome (BrS), long QT syndrome (LQTS), catecholaminergic polymorphic ventricular tachycardia (CPVT), and short QT syndrome (SQTS). They represent, together with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C), an important cause of sudden cardiac death in the young. Most arrhythmia syndromes are inherited in an autosomal dominant manner, and genetic studies are suggested.: to report the spectrum of genetic variations and clinical phenotype in an Italian cohort with confirmed inherited arrhythmia syndromes and arrhythmogenic cardiomyopathy using whole-exome sequencing (WES). Patients with confirmed inherited arrhythmia syndromes and hereditary cardiomyopathy were recruited at the Cardiology Unit, University Polyclinic Hospital of Foggia, Italy and were included in this study. Genomic DNA samples were extracted from peripheral blood and conducted for WES. The variants were annotated using BaseSpace Variant Interpreter Annotation Engine 3.15.0.0 (Illumina). Reported variants were investigated using ClinVar, VarSome Franklin and a literature review. They were categorised agreeing to the criteria of the American College of Medical Genetics and Genomics. Overall, 62 patients were enrolled. Most of them had a clinical diagnosis of BrS (n 48, 77%). The remaining patients included in the present study had diagnosis of confirmed LQT (n 7, 11%), AR-DCM (n 4, 6.5%), ARVD (n 2, 3%), and SQT (n 1, 1.6%). Using the WES technique, 22 variants in 15 genes associated with Brugada syndrome were identified in 21 patients (34%). Among these, the SCN5A gene had the highest number of variants (6 variants, 27%), followed by KCNJ5 and CASQ2 (2 variants). Only one variant was identified in the remaining genes. In 27 patients with a clinical diagnosis of BrS, no gene variant was detected. In patients with confirmed LQT, SQT, 10 variants in 9 genes were identified. Among patients with ARVD and AR-DCM, 6 variants in 5 genes were found. Variants found in our cohort were classified as pathogenic (6), likely pathogenic (3), of uncertain significance (26), and benign (1). Two additional gene variants were classified as risk factors. In this study, 13 novel genetic variations were recognized to be associated with inherited arrhythmogenic cardiomyopathies. Our understanding of inherited arrhythmia syndromes continues to progress. The era of next-generation sequencing has advanced quickly, given new genetic evidence including pathogenicity, background genetic noise, and increased discovery of variants of uncertain significance. Although NGS study has some limits in finding the full genetic data of probands, large-scale gene sequencing can promptly be applied in real clinical practices, especially in inherited and possibly fatal arrhythmia syndromes. [ABSTRACT FROM AUTHOR]

Background and Aims Pathogenic variants in the desmoplakin (DSP) gene are associated with the development of a distinct arrhythmogenic cardiomyopathy phenotype not fully captured by either dilated cardiomyopathy (DCM), non-dilated left ventricular cardiomyopathy (NDLVC), or arrhythmogenic right ventricular cardiomyopathy (ARVC). Prior studies have described baseline DSP cardiomyopathy genetic, inflammatory, and structural characteristics. However, cohort sizes have limited full clinical characterization and identification of clinical and demographic predictors of sustained ventricular arrhythmias (VAs), heart failure (HF) hospitalizations, and transplant/death. In particular, the relevance of acute myocarditis-like episodes for subsequent disease course is largely unknown. Methods All patients with pathogenic/likely pathogenic (P/LP) DSP variants in the worldwide DSP -ERADOS Network (26 academic institutions across nine countries) were included. The primary outcomes were the development of sustained VA and HF hospitalizations during follow-up. Fine–Gray regressions were used to test association between clinical and instrumental parameters and the development of outcomes. Results Eight hundred patients [40.3 ± 17.5 years, 47.5% probands, left ventricular ejection fraction (LVEF) 49.5 ± 13.9%] were included. Over 3.7 [1.4–7.1] years, 139 (17.4%, 3.9%/year) and 72 (9.0%, 1.8%/year) patients experienced sustained VA and HF episodes, respectively. A total of 32.5% of individuals did not fulfil diagnostic criteria for ARVC, DCM, or NDLVC; their VA incidence was 0.5%/year. In multivariable regression, risk features associated with the development of VA were female sex [adjusted hazard ratio (aHR) 1.547; P =.025], prior non-sustained ventricular tachycardia (aHR 1.721; P =.009), prior sustained VA (aHR 1.923; P =.006), and LVEF ≤ 50% (aHR: 1.645; P =.032), while for HF, they were the presence of T-wave inversion in 3+ electrocardiogram leads (aHR 2.036, P =.007) and LVEF ≤ 50% (aHR 3.879; P <.001). Additionally, 70 (8.8%) patients experienced a myocardial injury episode at presentation or during follow-up. These episodes were associated with an increased risk of VA and HF thereafter (HR 2.394; P <.001, and HR 5.064, P <.001, respectively). Conclusions Patients with P/LP DSP variants experience high rates of sustained VA and HF hospitalizations. These patients demonstrate a distinct clinical phenotype (DSP cardiomyopathy), whose most prominent risk features associated with adverse clinical outcomes are the presence of prior non-sustained ventricular tachycardia or sustained VA, T-wave inversion in 3+ leads on electrocardiogram, LVEF ≤ 50%, and myocardial injury events. [ABSTRACT FROM AUTHOR]

The article in the European Heart Journal discusses the integration of genetic testing into diagnostic pathways for cardiomyopathies, emphasizing the importance of cardiologists being familiar with the diagnostic process and interpretation of genetic tests. It also explores a new therapeutic target in cardiac remodeling by targeting fibroblast phenotype switching to counteract adverse cardiac fibrosis. Additionally, the document highlights the evolving management of hypertrophic cardiomyopathy and the clinical features and outcomes in carriers of pathogenic desmoplakin variants. The study concludes that targeting Parkin-mediated mitophagy using PR-364 may protect cardiac tissue post-myocardial infarction from progressing to heart failure. [Extracted from the article]

Background/Objectives: 123Iodo-metaiodobenzylguanidine single photon emission computed tomography/computed tomography (123I-MIBG SPECT/CT) is used to evaluate the cardiac sympathetic nervous system in cardiac diseases such as arrhythmogenic right ventricular cardiomyopathy (ARVC) and α-synucleinopathies such as Parkinson's diseases. A common feature of these diseases is denervation. We aimed to compare quantitative and semi-quantitative cardiac sympathetic innervation using 123I-MIBG imaging of ARVC and α-synucleinopathies. Methods: Cardiac innervation was assessed using 123I-MIBG SPECT/CT in 20 patients diagnosed with definite ARVC and 8 patients with clinically diagnosed α-synucleinopathies. Heart-to-mediastinum-ratio (H/M-ratio), as semi-quantitative, was evaluated. Additionally, standardized uptake value (SUV), as quantitative, was measured as SUVmedian, SUVmax, and SUVpeak in the left ventricle (LV), the right ventricle (RV), and in the global heart, based on a CT scan following quantitative image reconstruction. Results: The quantification of 123I-MIBG uptake in the LV, the RV, and the global heart was feasible in patients suffering from α-synucleinopathies. SUVmedian, and SUVpeak demonstrated a significant difference between ARVC and α-synucleinopathies across all regions, with the α-synucleinopathy group showing a lower uptake. In addition, the H/M ratio showed significantly lower uptake in patients with α-synucleinopathies than in patients with ARVC. Conclusions: Patients with α-synucleinopathies demonstrate significantly lower cardiac innervation in semi-quantitative and quantitative examinations than ARVC patients. The comparison of semi-quantitative and quantitative examinations suggests that quantitative examination offers an advantage. Quantitative analysis can be performed separately for the LV, RV, and global heart. However, analyzing the LV or RV does not provide additional benefit over analyzing the global heart in distinguishing between α-synucleinopathies and ARVC. Considering the different clinical manifestations of these two diseases, the absolute SUV values should not be generalized across different pathologies, and disease-specific ranges should be used instead. [ABSTRACT FROM AUTHOR]

Background: Myocardial disease is an important component of the wide field of cardiovascular disease. However, the phenomenon of multiple myocardial diseases in a single patient remains understudied. Aim: To investigate the prevalence and impact of myocarditis in patients with genetic cardiomyopathies and to evaluate the outcomes of myocarditis treatment in the context of cardiomyopathies. Methods: A total of 342 patients with primary cardiomyopathies were enrolled. The study cohort included 125 patients with left ventricular non-compaction (LVNC), 100 with primary myocardial hypertrophy syndrome, 70 with arrhythmogenic right ventricular cardiomyopathy (ARVC), 60 with dilated cardiomyopathy (DCM), and 30 with restrictive cardiomyopathy (RCM). The diagnosis of myocarditis was based on data from myocardial morphological examination or a non-invasive diagnostic algorithm consisting of an analysis of clinical presentation, anti-cardiac antibody (Ab) titres, and cardiac MRI. Results: The prevalence of myocarditis was 74.3% in ARVC, 56.7% in DCM, 54.4% in LVNC, 37.5% in RCM, and 30.9% in HCM. Myocarditis had a primary viral or secondary autoimmune nature and manifested with the onset or worsening of chronic heart failure (CHF) and arrhythmias. Treatment of myocarditis in cardiomyopathies has been shown to stabilise or improve patient condition and reduce the risk of adverse outcomes. Conclusions: In cardiomyopathies, the genetic basis and inflammation are components of a single continuum, which forms a complex phenotype. In genetic cardiomyopathies, myocarditis should be actively diagnosed and treated as it is an important therapeutic target. [ABSTRACT FROM AUTHOR]

The article discusses the importance of health policies in addressing cardiomyopathies across Europe, highlighting the prevalence and impact of these inherited heart diseases. It emphasizes the need for national policies to support expert care networks, genetic testing, and family screening. Recommendations include promoting efficient referral to expert care, leveraging genetics for early diagnosis, and supporting patients and families through holistic care and empowerment. The Cardiomyopathies Matter initiative aims to raise awareness and improve outcomes for those affected by cardiomyopathies through policy changes and collaboration with stakeholders. [Extracted from the article]

Background and Objectives: The pathophysiology of arrhythmogenic cardiomyopathy (ACM), previously known as arrhythmogenic right ventricular cardiomyopathy (ARVC), and its specific biological features remain poorly understood. High-throughput plasma proteomic profiling, a powerful tool for gaining insights into disease pathophysiology at the systems biology level, has not been used to study ACM. This study aimed at characterizing plasmatic protein changes in patients with ACM, which were compared with those of healthy controls, and at exploring the potential role of the identified proteins as biomarkers for diagnosis and monitoring. Materials and Methods: Blood samples were collected from six ACM patients, four patients with other cardiomyopathies, and two healthy controls. Plasma was processed to remove high-abundance proteins and analyzed by two-dimensional gel electrophoresis. Differential protein expressions were assessed using PDQuest software, Bio-Rad US version 8.0.1. Results: The analysis revealed several proteins with altered expressions between ACM patients and controls, including plakophilin-2, junctional plakoglobin, desmoplakin, desmin, transmembrane protein 43, and lamin A/C. Conclusions: The plasma proteomic profiling of ACM suggests that ACM is a distinct disease entity characterized by a unique dysregulation of desmosomal proteins. The identification of plasma biomarkers associated with ACM underscores their potential to improve diagnostic accuracy and facilitate early intervention strategies. Further exploration of mutations in desmosomal proteins and their phosphorylation states may provide deeper insights into the pathophysiology of ACM. [ABSTRACT FROM AUTHOR]

DSG2, encoding desmoglein-2, is one of the causative genes of arrhythmogenic cardiomyopathy. We previously identified a homozygous DSG2 p.Arg119Ter stop-gain variant in a patient with juvenile-onset cardiomyopathy and advanced biventricular heart failure. However, the pathological significance and prevalence of the heterozygous DSG2 p.Arg119Ter variant remains uncertain. Here, we identified four unrelated patients with cardiomyopathy with heterozygous DSG2 p.Arg119Ter variants among 808 patients with nonischemic cardiomyopathy; the allele frequency was 0.0037, which is more than 50-fold greater than that reported in the general Japanese population. These patients were clinically diagnosed with arrhythmogenic right ventricular cardiomyopathy (Pt-1), dilated cardiomyopathy (DCM) after ventricular septum defect closure surgery (Pt-2), DCM (Pt-3), and end-stage hypertrophic cardiomyopathy (Pt-4). The patients also exhibited reduced left ventricular contractile function and varying clinical courses. Genetic analysis identified additional possible causative variants, DSG2 p.Arg292Cys in Pt-1 and BAG3 p.His166SerfsTer6 in Pt-3. Immunohistochemical analysis of endomyocardial biopsy samples revealed that the expression of not only desmoglein-2 but also desmoplakin was markedly reduced. Transmission electron microscopy revealed pale and fragmented desmosomes and widened gaps between intercalated discs in the myocardium. A microforce test using human cardiomyocytes differentiated from induced pluripotent stem cells (iPSC-CMs) demonstrated reduced contractility in iPSC-CMs carrying a heterozygous truncating variant in DSG2. These data suggest that the DSG2 p.Arg119Ter variant is concealed in patients with cardiomyopathy with heart failure, and desmosome impairment may be a latent exacerbating factor of contractile dysfunction and disease progression. DSG2 Variant Linked to Severe Cardiomyopathy Cases: This study explores the genetic factors behind certain heart diseases, focusing on a gene called DSG2. Variants in DSG2 can lead to arrhythmogenic cardiomyopathy (AC), a condition causing heart rhythm problems and heart muscle dysfunction. Researchers found a specific DSG2 variant, p.Arg119Ter, in four patients with nonischemic cardiomyopathy.The study involved genetic analysis of 808 patients, identifying five with DSG2 variants. Researchers used techniques like whole-exome sequencing and immunohistochemical analysis. They found that the DSG2 variant might contribute to heart failure by affecting desmosomes.The results suggest that the DSG2 p.Arg119Ter variant is more common in East Asian populations and may worsen heart conditions when combined with other genetic or environmental factors. This research highlights the importance of genetic screening for better understanding and managing heart diseases. "This summary was initially drafted using artificial intelligence, then revised and fact-checked by the author." [ABSTRACT FROM AUTHOR]

ABSTRACT Arrhythmogenic cardiomyopathy (ACM) is a genetically heterogeneous inherited cardiomyopathy with an estimated prevalence of 1:5000–10 000 that predisposes patients to life‐threatening ventricular arrhythmias (VA) and sudden cardiac death (SCD). ACM diagnostic criteria and risk prediction models, particularly for arrhythmogenic right ventricular cardiomyopathy (ARVC), the most common form of ACM, are typically genotype‐agnostic, but numerous studies have established clinically meaningful genotype‐phenotype associations. Early signs of ACM onset differ by genotype indicating the need for genotype‐specific diagnostic criteria and family screening paradigms. Likewise, risk factors for SCD vary by genetic subtype, indicating that genotype‐specific guidelines for management are also warranted. Of particular importance, genotype‐specific therapeutic approaches are being developed. Results from a randomized controlled trial for flecainide use in ARVC patients are currently pending. Research in a plakophilin‐2‐deficient mouse model suggests this antiarrhythmic drug may be particularly useful for patients with likely pathogenic or pathogenic (LP/P) PKP2 variants. Additionally, the first gene therapy clinical trials in ARVC patients harboring LP/P PKP2 variants are currently underway. This review aims to provide clinicians caring for ACM patients with an up‐to‐date overview of the current literature in genotype‐specific natural history of disease and management of ACM patients and describe scientific advances that have led to upcoming clinical trials. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to evaluate the performance of the diagnostic pathway proposed by the European Society of Cardiology (ESC) guidelines for identifying the underlying aetiology of sudden cardiac death (SCD) through the screening of first-degree family members of patients with SCD who either had a negative autopsy or no autopsy performed. Methods: To be eligible for enrolment, patients had to meet the following inclusion criteria: a family history of SCD in a first-degree relative under the age of 50 years; the SCD decedents must not have undergone an autopsy, or if an autopsy was performed, non-cardiac and structural cardiac causes must have been excluded. Patients underwent a comprehensive assessment, including the evaluation of family and medical history, electrocardiography (ECG) and ECG with high precordial leads, Holter ECG monitoring, echocardiography, cardiac magnetic resonance imaging, and exercise stress testing. A sodium channel blocker test (i.e., flecainide test) was performed when other clinical investigations were negative and the suspicion of Brugada syndrome was high. Results: Forty-one patients from 25 different families fulfilled the inclusion criteria and represented the final study cohort. After the comprehensive diagnostic work-up, a total of seven patients from five different families (5/25, 20%) were diagnosed with an inherited cardiac condition: two families with arrhythmogenic right ventricular cardiomyopathy, one with dilated cardiomyopathy, one with non-dilated left ventricular cardiomyopathy, and one with long QT syndrome. Conclusions: The comprehensive cardiologic work-up of relatives of mainly young SCD victims results in the diagnosis of inherited cardiac conditions in one-fifth of cases. [ABSTRACT FROM AUTHOR]

Background Distinguishing right ventricular cardiac sarcoidosis (RVCS) from arrhythmogenic right ventricular cardiomyopathy (ARVC) is often a challenging task particularly when imaging findings are limited to the right ventricle and when electrocardiographic and arrhythmic findings are typical for ARVC. Here, we discuss the challenges of diagnosis and management in a patient whose initial work-up strongly suggested ARVC and was later diagnosed with cardiac sarcoidosis (CS), highlighting the role of multimodality imaging. Case summary On presentation, this patient displayed electrocardiographic abnormalities, arrhythmia morphology, and cardiac magnetic resonance imaging findings consistent with the criteria for a definite diagnosis of ARVC. However, through the use of multimodal imaging, a final diagnosis of CS was made. Subsequent immunosuppressive treatment effectively managed the inflammation, and as a primary prevention measure, an implantable cardioverter-defibrillator was implanted. Almost 2 years following the initial presentation, the patient received an appropriate shock from the device, attributed to rapid ventricular tachycardia arising from myocardial scarring. Discussion Right ventricular cardiac sarcoidosis can closely resemble ARVC, making it challenging to distinguish between the two. Multimodality imaging is pivotal for accurate diagnosis and risk assessment, as well as for adjusting immunosuppressive therapy and monitoring response to treatment in CS. [ABSTRACT FROM AUTHOR]

Objectives: To perform a bibliometric analysis of publications of arrhythmogenic right ventricular cardiomyopathy (ARVC) from 1981 to 2023 to summarize the current publications and explore frontiers on this topic. Methods: We integrated the scientific publications on ARVC in the Web of Science (WOS) Core Collection database from January 1981 to September 2023, using the retrieval strategy of medical subject headings combined with keywords. We focused on articles and reviews that were published in English. Relevant information such as the journal and publisher, the title, authors, organizations, abstract, keywords, published date, and number of citations, were collected. Bibliometric analysis was performed and visualized by the R software and Microsoft Excel. Results: The results revealed a total of 4792 records related to ARVC from the WOS database, and 2992 original articles or reviews which were selected for bibliometric analysis. There were 79 countries and regions, 3724 research institutions, and 12 157 scholars who have published in this topic. The number of scientific publications of ARVC increased year‐by‐year, with an annual growth rate of 12.12%. We also investigated the top 10 contributing countries, organizations with affiliations, most influential researchers, highest‐cited articles, and highest‐frequency keywords. In addition, the most active areas of research on ARVC included that of fatal complications, molecular pathological mechanisms, diagnosis, therapy, and prognosis respectively according to the keywords trend analysis. Conclusions: Our study reports the publication landscape of ARVC during the past four decades based on bibliometric analysis. This study provides a deeper understanding of the published literature on ARVC. [ABSTRACT FROM AUTHOR]

The article in Circulation discusses the case of a 22-year-old Black male patient with no prior medical history who presented with symptoms of acute systolic heart failure. The patient was diagnosed with Kearns-Sayre syndrome (KSS) and a pathogenic mutation in the PKP2 gene, which is associated with dilated cardiomyopathy. The patient underwent heart transplantation after being stabilized on mechanical support, and his postoperative course was uncomplicated. The case highlights the importance of considering multiple diagnoses in complex cardiac conditions and the significance of genetic testing in accurate diagnosis and management. [Extracted from the article]

The article discusses the recent recommendations from the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) regarding the third-trimester obstetric ultrasound scan, focusing on the evaluation of the fetal heart. It suggests additional recommendations for clinicians implementing these guidelines, particularly in measuring the size of the fetal heart and assessing ventricular and outflow tract disproportion. The article provides detailed methods for measuring the fetal heart, calculating ratios, and identifying abnormalities associated with cardiomegaly and ventricular disproportion, offering calculators to aid in the evaluation process. [Extracted from the article]

Background: Arrhythmogenic cardiomyopathy (ACM) is a genetic disorder responsible for nearly a quarter of sports-related sudden cardiac deaths. ACM cases caused by mutations in desmosome proteins lead to right ventricular enlargement, the loss of cardiomyocytes, and fibrofatty tissue replacement, disrupting electrical and mechanical stability. It is currently unknown how paracrine factors secreted by infiltrating fatty tissues affect ACM cardiomyocyte electrophysiology. Methods: A normal and a PKP2 mutant (c.971_972InsT) ACM hiPSC line were cultivated and differentiated into cardiomyocytes (CMs). Adipocytes were differentiated from human adipose stem cells, and adipocyte conditioned medium (AdCM) was collected. Optical mapping and phenotypic analyses were conducted on human iPSC-cardiomyocytes (hiPSC-CMs) cultured in cardiac maintenance medium (CMM) and either with AdCM or specific cytokines. Results: Significant differences were observed in voltage parameters such as the action potential duration (APD80, APD30), conduction velocity (CV), and CV heterogeneity. When cultured in AdCM relative to CMM, the APD80 increased and the CV decreased significantly in both groups; however, the magnitudes of changes often differed significantly between 1 and 7 days of cultivation. Cytokine exposure (IL-6, IL-8, MCP-1, CFD) affected the APD and CV in both the normal and PKP2 mutant hiPSC-CMs, with opposite effects. NF-kB signaling was also found to differ between the normal and PKP2 mutant hiPSC-CMs in response to AdCM and IL-6. Conclusions: Our study shows that hiPSC-CMs from normal and mPKP2 ACM lines exhibit distinct molecular and functional responses to paracrine factors, with differences in RNA expression and electrophysiology. These different responses to paracrine factors may contribute to arrhythmogenic propensity. [ABSTRACT FROM AUTHOR]

Key points Atrial arrhythmias occur in 20–40% of patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) and are associated with an increased risk of sustained ventricular arrhythmias and inappropriate implantable cardioverter‐defibrillator shocks. The pathophysiology of atrial arrhythmias in ARVC remains unclear. Most cases of gene‐positive ARVC are linked to pathogenic variants in the desmosomal gene plakophilin‐2 (PKP2). Here, we test the hypothesis that loss of PKP2 expression leads to pro‐arrhythmic changes in atrial cardiomyocytes. Atrial cells/tissue were obtained from a cardiac‐specific, tamoxifen‐activated model of PKP2 deficiency (PKP2cKO). By contrast to PKP2cKO ventricular myocytes, PKP2cKO atrial cardiomyocytes presented no significant differences in intracellular calcium (Ca2+i) transient dynamics, sarcoplasmic reticulum load or action potential morphology. PKP2cKO atrial cardiomyocytes showed elevated reactive oxygen species levels, increased frequency and amplitude of Ca2+ sparks, and increased diastolic [Ca2+]i compared to control; the latter two parameters were further increased by isoproterenol exposure and reversed by exposure to ryanodine receptor blocker dantrolene. We speculate that these isoproterenol‐dependent effects may impact on the exercise‐related atrial arrhythmia risk in ARVC patients. Despite absence of changes in Ca2+i transient dynamics, PKP2cKO atrial cardiomyocytes showed enhanced sarcomere shortening and impaired sarcomere relaxation. Orthogonal transcriptomic analysis of human(GTEx) and PKP2cKO atrial tissue led to identification of 41 transcripts depending on PKP2 expression. Biochemical follow‐up confirmed reduced abundance of sarcomeric protein myosin binding protein C, potentially playing a role in cellular shortening and relaxation changes observed. Our findings provide novel insights into the role of PKP2 in atrial myocardium with potential implications to therapeutic management of atrial fibrillation in patients with PKP2‐related ARVC. Atrial arrhythmias occur in a large group of patients with arrhythmogenic right ventricular cardiomyopathy (ARVC), a cardiac disease mostly caused by pathogenic variants in the desmosomal gene plakophilin‐2 (PKP2). Exercise is considered to be an independent risk factor for arrhythmias consequent to PKP2 deficiency. We show that loss of PKP2 expression affects cellular calcium handling and electrophysiology differently in left atrial vs. ventricular myocardium and causes extensive atrial fibrosis. PKP2‐deficient atrial cardiomyocytes present increased spontaneous sarcoplasmic reticulum calcium release events, further enhanced by isoproterenol exposure and reversible by a ryanodine receptor blocker (dantrolene). In addition, PKP2‐deficient atrial myocytes exhibit impaired relaxation and enhanced sarcomere shortening, most probably related to reduced abundance of myosin binding protein C. We speculate that cellular effects reported upon isoproterenol impact on the exercise‐related atrial arrhythmia risk in ARVC patients. We further propose that therapeutic approaches aimed at mitigating ventricular damage may be effective to treat the atrial disease in ARVC. [ABSTRACT FROM AUTHOR]

Cadherins are calcium dependent adhesion proteins that establish and maintain the intercellular mechanical contact by bridging the gap between adjacent cells. Desmoglein-2 (Dsg2) and desmocollin-2 (Dsc2) are tissue specific cadherin isoforms of the cell-cell contact in cardiac desmosomes. Mutations in the DSG2 -gene and in the DSC2 -gene are related to arrhythmogenic right ventricular cardiomyopathy (ARVC) a rare but severe heart muscle disease. Here, several possible homophilic and heterophilic binding interactions of wild-type Dsg2, wild-type Dsc2, as well as one Dsg2- and two Dsc2-variants, each associated with ARVC, are investigated. Using single molecule force spectroscopy (SMFS) with atomic force microscopy (AFM) and applying Jarzynski's equality the kinetics and thermodynamics of Dsg2/Dsc2 interaction can be determined. The free energy landscape of Dsg2/Dsc2 dimerization exposes a high activation energy barrier, which is in line with the proposed strand-swapping binding motif. Although the binding motif is not affected by any of the mutations, the binding kinetics of the interactions differ significantly from the wild-type. While wild-type cadherins exhibit an average complex lifetime of approx. 0.3 s interactions involving a variant consistently show - lifetimes that are substantially larger. The lifetimes of the wild-type interactions give rise to the picture of a dynamic adhesion interface consisting of continuously dissociating and (re)associating molecular bonds, while the delayed binding kinetics of interactions involving an ARVC-associated variant might be part of the pathogenesis. Our data provide a comprehensive and consistent thermodynamic and kinetic description of cardiac cadherin binding, allowing detailed insight into the molecular mechanisms of cell adhesion. [Display omitted] • Integrity of heart muscle tissue relies on weak molecular bonds between cadherins. • Single molecule force spectroscopy reveals cadherin binding kinetics. • Wild-type cadherin bonds exhibit characteristic fast (re-) binding kinetics. • Specific cardiomyopathy associated cadherin variants slow binding kinetics. • Impaired molecular dynamics could be a cardiomyopathy-specific pathomechanism. [ABSTRACT FROM AUTHOR]

Cardiac electrophysiology and mechanics are strongly interconnected. Their interaction is, among others, mediated by mechano‐electric feedback through stretch‐activated ion channels (SACs). The electrophysiological changes induced by SACs may contribute to arrhythmogenesis, but the precise SAC‐induced electrophysiological changes remain incompletely understood. Here, we provide a systematic characterization of stretch effects through three distinguished SACs on cardiac electrophysiology using computational modelling. We implemented potassium‐selective, calcium‐selective and non‐selective SACs in the Tomek–Rodriguez–O'Hara–Rudy model of human ventricular electrophysiology. The model was calibrated to experimental data from isolated cardiomyocytes undergoing stretch, considering inter‐species differences, and disease‐related remodelling of SACs. SAC‐mediated effects on the action potential (AP) were analysed by varying stretch amplitude, application timing and/or duration. Afterdepolarizations of different amplitudes were observed with transient 10‐ms stretch stimuli of 15–18% applied during phase 4, while stretch ≥18% during phase 4 elicited triggered APs. Longer stimuli shifted the threshold of AP trigger during phase 4 to lower amplitudes, while shorter stimuli increased it. Continuous stretch provoked electrophysiological remodelling. Furthermore, stretch shortened duration or changed morphology of a subsequent electrically evoked AP, and, if applied during a vulnerable time window with sufficient amplitude, prevented its occurrence because of stretch‐induced modulation of sodium and L‐type calcium channel gating. These effects were more pronounced with disease‐related SAC remodelling due to increased stretch sensitivity of diseased hearts. We showed that SACs may induce afterdepolarizations and triggered activities, and prevent subsequent AP generation or change its morphology. These effects depend on cardiomyocyte stretch characteristics and disease‐related SACs remodelling and may contribute to cardiac arrhythmogenesis. Key points: The interplay between cardiac electrophysiology and mechanics is mediated by mechano‐electric feedback through stretch‐activated ion channels (SACs). These channels may be pro‐arrhythmic, but their precise effect on electrophysiology remains unclear.Here we present a systematic in silico characterization of stretch effects through three SACs by implementing inter‐species differences as well as disease‐related remodelling of SACs in a novel computational model of human ventricular cardiomyocyte electrophysiology.Our simulations showed that, at the cellular level, SACs may provoke electrophysiological remodelling, afterdepolarizations, triggered activities, change the morphology or shorten subsequent electrically evoked action potentials. The model further suggests that a vulnerable window exists in which stretch prevents the following electrically triggered beat occurrence.The pro‐arrhythmic effects of stretch strongly depend on disease‐related SAC remodelling as well as on stretch characteristics, such as amplitude, time of application and duration. Our study helps in understanding the role of stretch in cardiac arrhythmogenesis and revealing the underlying cellular mechanisms. [ABSTRACT FROM AUTHOR]

The subcutaneous implantable cardioverter defibrillator (S‐ICD) is often used in young patients such as arrhythmogenic right ventricular cardiomyopathy (ARVC) and Brugada syndrome due to long‐term lead durability issues. Although S‐ICD lead dislodgement is rare, we encountered such an incident in a young ARVC patient during the chronic phase following the two‐incision technique. Remote monitoring system is useful for early diagnosis of electrode movement (Graphical abstract image). When S‐ICD lead dislodgement occurs in active young patients, lead revision using the three‐incision technique may be an option. [ABSTRACT FROM AUTHOR]

The Annual Report on Cardiovascular Health and Diseases in China (2022) intricate landscape of cardiovascular health in China. In connection with the previous section, this ninth section of the report offers a comprehensive analysis of valvular heart disease and cardiomyopathy. Although rheumatic valve disease is still the main cause of valvular heart disease in China, with the aging of the population and the improvement of living standards, the prevalence of degenerative valvular heart disease is on the rise. Because many patients with valvular heart disease have only mild to moderate valve stenosis or insufficiency, and no symptoms, the detection rate in the population is low and late, resulting in many patients been in the severe late stage of disease at visit, increasing the difficulty of treatment and affecting effectiveness and prognosis. Therefore, we should strengthen the examination and screening of valvular heart disease in order to find and prevent it as early as possible. In addition, compared with other diseases, the treatment of valvular heart disease needs more and higher technical support (surgery, intervention, etc). However, not all hospitals can provide relevant technologies. At present, the treatment of valvular heart disease is still mainly concentrated in the provincial hospitals. It is necessary to carry out more professional training so that more doctors and hospitals can participate in the treatment of valvular heart disease. Cardiomyopathy is a group of myocardial diseases with abnormal myocardial structure and/or function, but couldn't be explained by hypertension, coronary atherosclerosis, valvular heart disease and congenital heart disease. It includes hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), arrhythmogenic cardiomyopathy (also known as arrhythmogenic right ventricular cardiomyopathy), restrictive cardiomyopathy (RCM) and undifferentiated cardiomyopathy. [ABSTRACT FROM AUTHOR]

The article in the European Heart Journal discusses the genetic basis of desmoplakin cardiomyopathy and its impact on clinical outcomes. It highlights the diverse phenotypes associated with DSP variants, including arrhythmogenic right ventricular cardiomyopathy, dilated cardiomyopathy, and non-dilated left ventricular cardiomyopathy. The study examines the correlation between specific DSP mutations and clinical outcomes, emphasizing the importance of genetic evaluation in managing patients with cardiomyopathy. Additionally, the article addresses the occurrence of myocarditis-like episodes and dermatological features in patients with DSP variants, underscoring the need for comprehensive evaluation and ongoing vigilance in clinical practice. [Extracted from the article]

Key points Arrhythmogenic cardiomyopathy (AC) is a familial cardiac disease, mainly caused by mutations in desmosomal genes, which accounts for most cases of stress‐related arrhythmic sudden death, in young and athletes. AC hearts display fibro‐fatty lesions that generate the arrhythmic substrate and cause contractile dysfunction. A correlation between physical/emotional stresses and arrhythmias supports the involvement of sympathetic neurons (SNs) in the disease, but this has not been confirmed previously. Here, we combined molecular, in vitro and ex vivo analyses to determine the role of AC‐linked DSG2 downregulation on SN biology and assess cardiac sympathetic innervation in desmoglein‐2 mutant (Dsg2mut/mut) mice. Molecular assays showed that SNs express DSG2, implying that DSG2‐mutation carriers would harbour the mutant protein in SNs. Confocal immunofluorescence of heart sections and 3‐D reconstruction of SN network in clarified heart blocks revealed significant changes in the physiologialc SN topology, with massive hyperinnervation of the intact subepicardial layers and heterogeneous distribution of neurons in fibrotic areas. Cardiac SNs isolated from Dsg2mut/mut neonatal mice, prior to the establishment of cardiac innervation, show alterations in axonal sprouting, process development and distribution of varicosities. Consistently, virus‐assisted DSG2 downregulation replicated, in PC12‐derived SNs, the phenotypic alterations displayed by Dsg2mut/mut primary neurons, corroborating that AC‐linked Dsg2 variants may affect SNs. Our results reveal that altered sympathetic innervation is an unrecognized feature of AC hearts, which may result from the combination of cell‐autonomous and context‐dependent factors implicated in myocardial remodelling. Our results favour the concept that AC is a disease of multiple cell types also hitting cardiac SNs. Arrhythmogenic cardiomyopathy is a genetically determined cardiac disease, which accounts for most cases of stress‐related arrhythmic sudden death. Arrhythmogenic cardiomyopathy linked to mutations in desmoglein‐2 (DSG2) is frequent and leads to a left‐dominant form of the disease. Arrhythmogenic cardiomyopathy has been approached thus far as a disease of cardiomyocytes, but we here unveil that DSG2 is expressed, in addition to cardiomyocytes, by cardiac and extracardiac sympathetic neurons, although not organized into desmosomes. AC‐linked DSG2 downregulation primarily affect sympathetic neurons, resulting in the significant increase in cardiac innervation density, accompanied by alterations in sympathetic neuron distribution. Our data supports the notion that AC develops with the contribution of several ‘desmosomal protein‐carrying’ cell types and systems. [ABSTRACT FROM AUTHOR]

Proteomics studies often explore phenotypic differences between whole organs and systems. Within the heart, more subtle variation exists. To date, differences in the underlying proteome are only described between whole cardiac chambers. This study, using the bovine heart as a model, investigates inter-regional differences and assesses the feasibility of measuring detailed, cross-tissue variance in the cardiac proteome. Using a bovine heart, we created a two-dimensional section through a plane going through two chambers. This plane was further sectioned into 4 × 4 mm cubes and analysed using label-free proteomics. We identified three distinct proteomes. When mapped to the extracted sections, the proteomes corresponded largely to the outer wall of the right ventricle and secondly to the outer wall of the left ventricle, right atrial appendage, tricuspid and mitral valves, modulator band, and parts of the left atrium. The third separate proteome corresponded to the inner walls of the left and right ventricles, septum, and left atrial appendage. Differential protein abundancies indicated differences in energy metabolism between regions. Data analyses of the mitochondrial proteins revealed a variable pattern of abundances of complexes I–V between the proteomes, indicating differences in the bioenergetics of the different cardiac sub-proteomes. Mapping of disease-associated proteins interestingly showed desmoglein-2, for which defects in this protein are known to cause Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy, which was present predominantly in the outer wall of the left ventricle. This study highlights that organs can have variable proteomes that do not necessarily correspond to anatomical features. [ABSTRACT FROM AUTHOR]

Objectives: The present study aimed to investigate the incremental prognostic value of the right ventricular fractal dimension (FD), a novel marker of myocardial trabecular complexity by cardiac magnetic resonance (CMR) in patients with arrhythmogenic cardiomyopathy (ACM). Methods: Consecutive patients with ACM undergoing CMR were followed up for major cardiac events, including sudden cardiac death, aborted cardiac arrest, and appropriate implantable cardioverter defibrillator intervention. Prognosis prediction was compared by Cox regression analysis. We established a multivariable model supplemented with RV FD and evaluated its discrimination by Harrell's C-statistic. We compared the category-free, continuous net reclassification improvement (cNRI) and integrated discrimination index (IDI) before and after the addition of FD. Results: A total of 105 patients were prospectively included from three centers and followed up for a median of 60 (48, 66) months; experienced 36 major cardiac events were recorded. Trabecular FD displayed a strong unadjusted association with major cardiac events (p < 0.05). In the multivariable Cox regression analysis, RV maximal apical FD maintained an independent association with major cardiac events (hazard ratio, 1.31 (1.11–1.55), p < 0.002). The Hosmer–Lemeshow goodness of fit test displayed good fit (X2 = 0.68, p = 0.99). Diagnostic performance was significantly improved after the addition of RV maximal apical FD to the multivariable baseline model, and the continuous net reclassification improvement increased 21% (p = 0.001), and the integrated discrimination index improved 16% (p = 0.045). Conclusions: In patients with ACM, CMR-assessed myocardial trabecular complexity was independently correlated with adverse cardiovascular events and provided incremental prognostic value. Clinical relevance statement: The application of FD values for assessing RV myocardial trabeculae may become an accessible and promising parameter in monitoring and early diagnosis of risk factors for adverse cardiovascular events in patients with ACM. Key Points: • Ventricular trabecular morphology, a novel quantitative marker by CMR, has been explored for the first time to determine the severity of ACM. • Patients with higher maximal apical fractal dimension of RV displayed significantly higher cumulative incidence of major cardiac events. • RV maximal apical FD was independently associated with major cardiac events and provided incremental prognostic value in patients with ACM. [ABSTRACT FROM AUTHOR]

Aims Arrhythmogenic right ventricular cardiomyopathy (ARVC) is characterized by progressive myocardial dysfunction and associated with an increased risk of major cardiovascular (CV) events. To determine right heart strain (ventricular and atrial global longitudinal strain (RVGLS and RAGLS) in patients with definite ARVC and its association with adverse events during follow-up. Methods and results RVGLS and RAGLS were analysed in focused right heart apical views from 70 patients using TomTec ImageArena and association with a composite endpoint was determined (sustained ventricular arrhythmia and cardiovascular death). Over a median follow-up duration of 4.9 years, 26 (37%) patients met the endpoint. RVGLS was significantly impaired in the event group (−11.5 [−13.3 to −10.2] %) vs. the no-event group (−15.8 [−17.1 to −14.5] %, P < 0.001), and so was RAGLS (22.8 [21.4–27.4] % vs. 31.5 [25.1–39.6] %, respectively, P < 0.001). In Cox regression, RVGLS (HR 1.36, P < 0.001) and RAGLS (HR 0.92, P = 0.002) were associated with a higher risk of adverse events. In multivariable Cox regression models, RVGLS and RAGLS remained independent of and were incremental to age, gender, and conventional RV parameters, and model fitness was improved when RVGLS and RAGLS were applied together rather than alone. Conclusion RVGLS and RAGLS are more impaired in patients with adverse events and associated with adverse events independent of age, gender, and conventional RV parameters. When RVGLS and RAGLS are applied together, prediction models are improved suggesting that right heart strain may form part of the echocardiographic routine protocol in patients with ARVC. [ABSTRACT FROM AUTHOR]

Arrhythmogenic cardiomyopathy is an inherited entity characterized by irregular cell–cell adhesion, cardiomyocyte death and fibro-fatty replacement of ventricular myocytes, leading to malignant ventricular arrythmias, contractile dysfunction and sudden cardiac death. Pathogenic variants in genes that encode desmosome are the predominant cause of arrhythmogenic cardiomyopathy. Moreover, signalling pathways such as Wnt/ß-catenin and transforming growth factor-β have been involved in the disease progression. However, still little is known about the molecular pathophysiological mechanisms that underlie arrhythmogenic cardiomyopathy pathogenesis. We used mRNA and small RNA sequencing to analyse the transcriptome of health and arrhythmogenic cardiomyopathy of autopsied human hearts. Our results showed 697 differentially expressed genes and eight differentially expressed miRNAs. Functional enrichment revealed mitochondrial respiratory-related pathways, impaired response to oxidative stress, apoptotic signalling pathways and inflammatory response-related and extracellular matrix response pathways. Furthermore, analysis of the miRNA–mRNA interactome identified eleven negatively correlated miRNA-target pairs for arrhythmogenic cardiomyopathy. Our finding revealed novel arrhythmogenic cardiomyopathy-related miRNAs with important regulatory function in disease pathogenesis, highlighting their value as potential key targets for therapeutic approaches. [ABSTRACT FROM AUTHOR]

Background Lamin A/C gene (LMNA) mutations cause myocardial fibrosis manifesting as arrhythmogenic, non-compaction, or dilated cardiomyopathies. Fibro-fatty replacement largely involves the conduction system and conduction disease commonly occurs prior to contractile dysfunction. Case summary Two young, unrelated Caucasian males, aged 34 and 25, were referred to our centre for treatment of advanced heart failure. Both patients had a family history of heart failure and sudden cardiac death among their first-degree relatives and were diagnosed with Lamin A/C mutations, but they had not been screened prior to disease onset. Although the initial phenotypes were dilated cardiomyopathy and left ventricular non-compaction cardiomyopathy, both patients' disease progressed rapidly to include ventricular arrhythmias, severe global left ventricular hypokinesis, and dependence on outpatient milrinone to complete activities of daily living. Both patients received heart transplantation within 2 years of initial disease onset. The surgical pathology of the explanted hearts revealed characteristic findings of fibro-fatty degeneration of the conduction system, and using light microscopy, they were found to have nuclear membrane thinning, bubbling, and convolution throughout all areas sampled. Discussion Lamin A/C–related cardiomyopathy is associated with sudden cardiac death early in the disease course, warranting early consideration of implantable cardioverter defibrillator implantation, and rapid progression to end-stage cardiomyopathy refractory to standard medical therapies, necessitating early referral to an advanced heart failure centre. We report a newly observed and recorded finding of morphologic nuclear alterations in late-stage disease using high-power light microscopy. These alterations underscore the pathophysiology of Lamin A/C–related cardiomyopathy and provide a basis for future research into disease-specific therapies. [ABSTRACT FROM AUTHOR]

Background Cardiac sarcoidosis (CS) is a granulomatous disease that can manifest as conduction defects, ventricular arrhythmias, and heart failure. The diagnosis of CS is inherently difficult due to variable presentations; as such, endomyocardial biopsy is often required but lacks sensitivity due to patchy myocardial involvement. Moreover, the diagnostic criteria of CS and arrhythmogenic cardiomyopathy overlap, particularly in right-side dominant or biventricular presentations, which further complicates an already challenging differential diagnosis. Case summary A 53-year-old man with no prior chronic medical conditions presented with ventricular tachycardia (VT) and heart failure with reduced ejection fraction. He was found to have biventricular cardiomyopathy and late gadolinium enhancement on cardiac magnetic resonance imaging, resulting in an initial diagnosis of arrhythmogenic cardiomyopathy. Implantable cardioverter-defibrillator was placed, but he was readmitted for recurrent VT 2 months later. Despite an aggressive VT therapy (combination of antiarrhythmic drugs, epicardial and endocardial ablation, and stellate ganglion block), he continued with refractory VT and developed cardiogenic shock. Extra-corporeal membrane oxygenation was initiated as a bridge to heart transplantation. Pathology of the explanted heart revealed the underlying disease to be CS. Discussion Cardiac sarcoidosis can mimic arrhythmogenic biventricular cardiomyopathy and may be difficult to distinguish by the proposed diagnostic criteria. High clinical suspicion and thorough investigation are necessary for an earlier diagnosis and initiation of treatment. [ABSTRACT FROM AUTHOR]

Background: Genetic diagnostics support the diagnosis of hereditary arrhythmogenic diseases, but variants of uncertain significance (VUS) complicate matters, emphasising the need for regular reassessment. Our study aims to reanalyse rare variants in different genes in order to decrease VUS diagnoses and thus improve risk stratification and personalized treatment for patients with arrhythmogenic disorders. Methods: Genomic DNA was analysed using Sanger sequencing and next-generation sequencing (NGS). The Data was evaluated using various databases and in silico prediction tools and classified according to current ACMG standards by two independent experts. Results: We identified 53 VUS in 30 genes, of which 17 variants (32%) were reclassified. 13% each were downgraded to likely benign (LB) and benign (B) and 6% were upgraded to likely pathogenic (LP). Reclassifications mainly occurred among variants initially classified in 2017–2019, with rates ranging from 50 to 60%. Conclusion: The results support the assumption that regular reclassification of VUS is important, as it provides new insights for genetic diagnostics, that benefit patients and guide therapeutic approach. [ABSTRACT FROM AUTHOR]

Sudden cardiac death (SCD) prevention in cardiomyopathies such as hypertrophic (HCM), dilated (DCM), non-dilated left ventricular (NDLCM), and arrhythmogenic right ventricular cardiomyopathy (ARVC) remains a crucial but complex clinical challenge, especially among younger populations. Accurate risk stratification is hampered by the variability in phenotypic expression and genetic heterogeneity inherent in these conditions. This article explores the multifaceted strategies for preventing SCD across a spectrum of cardiomyopathies and emphasizes the integration of clinical evaluations, genetic insights, and advanced imaging techniques such as cardiac magnetic resonance (CMR) in assessing SCD risks. Advanced imaging, particularly CMR, not only enhances our understanding of myocardial architecture but also serves as a cornerstone for identifying at-risk patients. The integration of new research findings with current practices is essential for advancing patient care and improving survival rates among those at the highest risk of SCD. This review calls for ongoing research to refine risk stratification models and enhance the predictive accuracy of both clinical and imaging techniques in the management of cardiomyopathies. [ABSTRACT FROM AUTHOR]