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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., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Naxos disease is a rare autosomal recessive condition combining arrhythmogenic right ventricular cardiomyopathy, woolly hair, and palmoplantar keratoderma. The first identified causative variant was in the gene encoding the desmosomal protein plakoglobin. Naxos disease exhibits fibro-fatty myocardial replacement with immunohistological abnormalities in cardiac protein and signaling pathways, highlighting the role of inflammation and potential anti-inflammatory treatments. Childhood cutaneous signs precede cardiac features, which are diagnosed by familial and genetic evaluation, electrocardiography and cardiac imaging. Disease progression necessitates holistic care with risk management and lifestyle adjustments, often needing treatment for arrhythmia and heart failure. Similar phenotypes have been linked to desmoplakin and rarely desmocollin2 gene variants, highlighting the importance of familial and genetic evaluation. This document summarizes current knowledge on Naxos disease and related cardiocutaneous syndromes and initiates an international endeavor to collect and study all global cases, aiming to improve understanding, treatment, and patient care through shared data and research., Competing Interests: Dr Protonotarios holds consulting agreements with Tenaya Therapeutics and Avidity Biosciences. Dr Crisci has received a research grant by the CardioPath program from Federico II University of Naples, Italy. Dr Abrams is a consultant/scientific advisory board for Thryv Therapeutics, Rockets Pharmaceuticals, Solid Biosciences. Dr Anastasakis is on the advisory board of Pfizer, Genesis, Takeda, Sanofi, and BMS. Dr Mestroni has received grant support from Tenaya Therapeutics, Pfizer, AstraZeneca, Owkin, Greenstone Bioscience, and Bristol Myers Squibb; and is a member of the scientific advisory board of Tenaya Therapeutics. Dr Saffitz is consultant for Implicit Bioscience and Rocket Pharmaceuticals. Dr McKenna is a scientific advisor to Health in Code and to Tenaya Therapeutics. Dr Elliott holds consultancies in Biomarin, Pfizer, BMS, and the Patent: US Pat No 62/903,103: GENE THERAPY COMPOSITIONS AND TREATMENT OF RIGHT VENTRICULAR ARRYTHMOGENIC CARDIOMYOPATHY. Dr Kaski has consultancy/advisory board activities with Tenaya Therapeutics, Cytokinetics, Lexeo, Avidity Biosciences, and Accord Healthcare. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2025 The Authors.)

Introduction: Advancements in sequencing technologies have significantly improved clinical genetic testing, yet the diagnostic yield remains around 30-40%. Emerging sequencing technologies are now being deployed in the clinical setting to address the remaining diagnostic gap., Methods: We tested whether short-read genome sequencing could increase diagnostic yield in individuals enrolled into the UCI-GREGoR research study, who had suspected Mendelian conditions and prior inconclusive clinical genetic testing. Two other collaborative research cohorts, focused on aortopathy and dilated cardiomyopathy, consisted of individuals who were undiagnosed but had not undergone harmonized prior testing., Results: We sequenced 353 families (754 participants) and found a molecular diagnosis in 54 (15.3%) of them. Of these diagnoses, 55.5% were previously missed because the causative variants were in regions not interrogated by the original testing. In 9 cases, they were deep intronic variants, 5 of which led to abnormal splicing and cryptic exon inclusion, as directly shown by RNA sequencing. All 5 of these variants had inconclusive spliceAI scores. In 26% of newly diagnosed cases, the causal variant could have been detected by exome sequencing reanalysis., Conclusion: Genome sequencing overcomes multiple limitations of clinical genetic testing, such as inability to call intronic variants and technical limitations. Our findings highlight cryptic exon inclusion as a common mechanism via which deep intronic variants cause Mendelian disease. However, they also reinforce that reanalysis of exome datasets can be a fruitful approach., Competing Interests: Disclosures/Conflict of interest M.H, J.Z. and K.S. are currently employees of Labcorp Genetics Inc, formerly known as Invitae Corp, I.C. is a former employee of Invitae Corp. All other authors declare no conflicts of interest.

Dilated cardiomyopathy (DCM) is a complex disease with multiple causes and various pathogenic mechanisms. Despite improvements in the prognosis of patients with DCM in the past decade, this condition remains a leading cause of heart failure and premature death. Conventional treatment for DCM is based on the foundational therapies for heart failure with reduced ejection fraction. However, increasingly, attention is being directed towards individualized treatments and precision medicine. The ability to confirm genetic causality is gradually being complemented by an increased understanding of genotype-phenotype correlations. Non-genetic factors also influence the onset of DCM, and growing evidence links genetic background with concomitant non-genetic triggers or precipitating factors, increasing the extreme complexity of the pathophysiology of DCM. This Review covers the spectrum of pathophysiological mechanisms in DCM, from monogenic causes to the coexistence of genetic abnormalities and triggering environmental factors (the 'two-hit' hypothesis). The roles of common genetic variants in the general population and of gene modifiers in disease onset and progression are also discussed. Finally, areas for future research are highlighted, particularly novel therapies, such as small molecules, RNA and gene therapy, and measures for the prevention of arrhythmic death., (© 2024. Springer Nature Limited.)

Background and Aims: Pathogenic desmoplakin (DSP) gene variants are associated with the development of a distinct form of arrhythmogenic cardiomyopathy known as DSP cardiomyopathy. Patients harbouring these variants are at high risk for sustained ventricular arrhythmia (VA), but existing tools for individualized arrhythmic risk assessment have proven unreliable in this population., Methods: Patients from the multi-national DSP-ERADOS (Desmoplakin SPecific Effort for a RAre Disease Outcome Study) Network patient registry who had pathogenic or likely pathogenic DSP variants and no sustained VA prior to enrolment were followed longitudinally for the development of first sustained VA event. Clinically guided, step-wise Cox regression analysis was used to develop a novel clinical tool predicting the development of incident VA. Model performance was assessed by c-statistic in both the model development cohort (n = 385) and in an external validation cohort (n = 86)., Results: In total, 471 DSP patients [mean age 37.8 years, 65.6% women, 38.6% probands, 26% with left ventricular ejection fraction (LVEF) < 50%] were followed for a median of 4.0 (interquartile range: 1.6-7.3) years; 71 experienced first sustained VA events {2.6% [95% confidence interval (CI): 2.0, 3.5] events/year}. Within the development cohort, five readily available clinical parameters were identified as independent predictors of VA and included in a novel DSP risk score: female sex [hazard ratio (HR) 1.9 (95% CI: 1.1-3.4)], history of non-sustained ventricular tachycardia [HR 1.7 (95% CI: 1.1-2.8)], natural logarithm of 24-h premature ventricular contraction burden [HR 1.3 (95% CI: 1.1-1.4)], LVEF < 50% [HR 1.5 (95% CI: .95-2.5)], and presence of moderate to severe right ventricular systolic dysfunction [HR 6.0 (95% CI: 2.9-12.5)]. The model demonstrated good risk discrimination within both the development [c-statistic .782 (95% CI: .77-.80)] and external validation [c-statistic .791 (95% CI: .75-.83)] cohorts. The negative predictive value for DSP patients in the external validation cohort deemed to be at low risk for VA (<5% at 5 years; n = 26) was 100%., Conclusions: The DSP risk score is a novel model that leverages readily available clinical parameters to provide individualized VA risk assessment for DSP patients. This tool may help guide decision-making for primary prevention implantable cardioverter-defibrillator placement in this high-risk population and supports a gene-first risk stratification approach., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Aortic valve stenosis (AVS) is a progressive disease wherein males more often develop valve calcification relative to females that develop valve fibrosis. Valvular interstitial cells (VICs) aberrantly activate to myofibroblasts during AVS, driving the fibrotic valve phenotype in females. Myofibroblasts further differentiate into osteoblast-like cells and produce calcium nanoparticles, driving valve calcification in males. We hypothesized the lysine demethylase UTY (ubiquitously transcribed tetratricopeptide repeat containing, Y-linked) decreases methylation uniquely in male VICs responding to nanoscale extracellular matrix cues to promote an osteoblast-like cell phenotype. Here, we describe a hydrogel biomaterial cell culture platform to interrogate how nanoscale cues modulate sex-specific methylation states in VICs activating to myofibroblasts and osteoblast-like cells. We found UTY modulates the osteoblast-like cell phenotype in response to nanoscale cues uniquely in male VICs. Overall, we reveal a novel role of UTY in the regulation of calcification processes in males during AVS progression.

Background: The health-related quality of life (HRQOL) and cardiopulmonary exercise testing (CPET) performance of individuals with subclinical and early stage hypertrophic cardiomyopathy (HCM) have not been systematically studied. Improved understanding will inform the natural history of HCM and factors influencing well-being., Methods: VANISH trial (Valsartan for Attenuating Disease Evolution in Early Sarcomeric HCM) participants with early stage sarcomeric HCM (primary analysis cohort) and subclinical HCM (sarcomere variant without left ventricular hypertrophy comprising the exploratory cohort) who completed baseline and year 2 HRQOL assessment via the pediatric quality of life inventory and CPET were studied. Metrics correlating with baseline HRQOL and CPET performance were identified. The impact of valsartan treatment on these measures was analyzed in the early stage cohort., Results: Two hundred participants were included: 166 with early stage HCM (mean age, 23±10 years; 40% female; 97% White; and 92% New York Heart Association class I) and 34 subclinical sarcomere variant carriers (mean age, 16±5 years; 50% female; and 100% White). Baseline HRQOL was good in both cohorts, although slightly better in subclinical HCM (composite pediatric quality of life score 84.6±10.6 versus 90.2±9.8; P =0.005). Both cohorts demonstrated mildly reduced functional status (mean percent predicted peak oxygen uptake 73±16 versus 78±12 mL/kg per minute; P =0.18). Percent predicted peak oxygen uptake and peak oxygen pulse correlated with HRQOL. Valsartan improved physical HRQOL in early stage HCM (adjusted mean change in pediatric quality of life score +4.1 versus placebo; P =0.01) but did not significantly impact CPET performance., Conclusions: Functional capacity can be impaired in young, healthy people with early stage HCM, despite New York Heart Association class I status and good HRQOL. Peak oxygen uptake was similarly decreased in subclinical HCM despite normal left ventricular wall thickness and excellent HRQOL. Valsartan improved physical pediatric quality of life scores but did not significantly impact CPET performance. Further studies are needed for validation and to understand how to improve patient experience., Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01912534., Competing Interests: Dr Day is involved in consulting for Lexicon Pharmaceuticals; is on the Data Monitoring Committee of Cytokinetics; and receives funding from Lexicon Pharmaceuticals and Bristol Myers Squibb. Dr Canter is a consultant for Bristol Myers Squibb and receives research support from Tenaya, Merck, and Novartis (none relevant). Dr Bach receives research support (institutional only) from MyoKardia, Bristol Myers Squibb, and Cytokinetics, outside of the submitted work. Dr Wheeler receives research support and in-kind support from MyoKardia Inc, a wholly owned subsidiary of Bristol Myers Squibb, and research support from Cytokinetics Inc and Novartis Inc, all outside of the submitted work. Dr Rossano is a consultant for AskBio, American Regent, Bayer, BioMarin, Bristol Myers Squibb, Enzyvant, and Merck. Dr Owens has been consulting for Bristol Myers Squibb, Cytokinetics, Pfizer, Tenaya, BioMarin, Lexicon, Lexeo, Edgewise, and Stealth Therapeutics and receives research support from Bristol Myers Squibb. Dr Mestroni receives research funding from Bristol Myers Squibb, Tenaya Therapeutics, Pfizer, BioMarin, Greenstone Bioscience, and Spark Therapeutics. Dr Taylor receives research funding from Bristol Myers Squibb, Tenaya Therapeutics, Rocket Pharmaceuticals, BioMarin, and Spark Therapeutics. Dr Patel receives a research grant from GE Healthcare. Dr Soslow is involved in unrelated consulting for Sarepta, Pfizer, Immunoforge, and WCG Imaging. Dr Claggett is involved in statistical consulting for Alnylam, Cardurion, Corvia, CVRx, Cytokinetics, Intellia, and Rocket. Dr Ho is a consultant for and receives research funding from Bristol Myers Squib, Pfizer, Cytokinetics, Tenaya, BioMarin, viz.AI, and Lexicon (none relevant). The other authors report no conflicts.

Cardiac fibrosis refers to the abnormal accumulation of extracellular matrix within the cardiac muscle, leading to increased stiffness and impaired heart function. From a rheological standpoint, knowledge about myocardial behavior is still lacking, partially due to a lack of appropriate techniques to investigate the rheology of in vitro cardiac tissue models. 3D multicellular cardiac spheroids are powerful and versatile platforms for modeling healthy and fibrotic cardiac tissue in vitro and studying how their mechanical properties are modulated. In this study, cardiac spheroids were created by co-culturing neonatal rat ventricular cardiomyocytes and fibroblasts in definite ratios using the hanging-drop method. The rheological characterization of such models was performed by Atomic Force Microscopy-based stress-relaxation measurements on the whole spheroid. After strain application, a viscoelastic bi-exponential relaxation was observed, characterized by a fast relaxation time (τ 1 ) followed by a slower one (τ 2 ). In particular, spheroids with higher fibroblasts density showed reduction for both relaxation times comparing to control, with a more pronounced decrement of τ 1 with respect to τ 2 . Such response was found compatible with the increased production of extracellular matrix within these spheroids, which recapitulates the main feature of the fibrosis pathophysiology. These results demonstrate how the rheological characteristics of cardiac tissue vary as a function of cellular composition and extracellular matrix, confirming the suitability of such system as an in vitro preclinical model of cardiac fibrosis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier Ltd.)

Background: Patients with nonischemic dilated cardiomyopathy (DCM), severe left ventricular (LV) dysfunction, and complete left bundle branch block benefit from cardiac resynchronization therapy (CRT). However, a large heterogeneity of response to CRT is described. Several predictors of response to CRT have been identified, but the role of the underlying genetic background is still poorly explored., Objectives: In the present study, the authors sought to define differences in LV remodeling and outcome prediction after CRT when stratifying patients according to the presence or absence of DCM-causing genetic background., Methods: From our center, 74 patients with DCM subjected to CRT and available genetic testing were retrospectively enrolled. Carriers of causative monogenic variants in validated DCM-causing genes, and/or with documented family history of DCM, were classified as affected by genetically determined disease (GEN+DCM) (n = 25). Alternatively, by idiopathic dilated cardiomyopathy (idDCM) (n = 49). The primary outcome was long-term LV remodeling and prevalence of super response to CRT (evaluated at 24-48 months after CRT); the secondary outcome was heart failure-related death/heart transplant/LV assist device., Results: GEN+DCM and idDCM patients were homogeneous at baseline with the exception of QRS duration, longer in idDCM. The median follow-up was 55 months. Long-term LV reverse remodeling and the prevalence of super response were significantly higher in the idDCM group (27% in idDCM vs 5% in GEN+DCM; P = 0.025). The heart failure-related death/heart transplant/LV assist device outcome occurred more frequently in patients with GEN+DCM (53% vs 24% in idDCM; P = 0.028)., Conclusions: Genotyping contributes to the risk stratification of patients with DCM undergoing CRT implantation in terms of LV remodeling and outcomes., Competing Interests: Funding Support and Author Disclosures This study was supported by CRTrieste Foundation and Cassa di Risparmio di Gorizia Foundation to Dr Sinagra. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Nondilated left ventricular cardiomyopathy (NDLVC) has been recently differentiated from dilated cardiomyopathy (DCM). A comprehensive characterization of these 2 entities using cardiac magnetic resonance (CMR) and genetic testing has never been performed., Objectives: This study sought to provide a thorough characterization and assess clinical outcomes in a large multicenter cohort of patients with DCM and NDLVC., Methods: A total of 462 patients with DCM (227) or NDLVC (235) with CMR data from 4 different referral centers were retrospectively analyzed. The study endpoint was a composite of sudden cardiac death or major ventricular arrhythmias., Results: In comparison to DCM, NDLVC had a higher prevalence of pathogenic or likely pathogenic variants of arrhythmogenic genes (40% vs 23%; P < 0.001), higher left ventricular (LV) systolic function (LV ejection fraction: 51% ± 12% vs 36% ± 15%; P < 0.001) and higher prevalence of free-wall late gadolinium enhancement (LGE) (27% vs 14%; P < 0.001). Conversely, DCM showed higher prevalence of pathogenic or likely pathogenic variants of nonarrhythmogenic genes (23% vs 12%; P = 0.002) and septal LGE (45% vs 32%; P = 0.004). Over a median follow-up of 81 months (Q1-Q3: 40-132 months), the study outcome occurred in 98 (21%) patients. LGE with septal location (HR: 1.929; 95% CI: 1.033-3.601; P = 0.039) was independently associated with the risk of sudden cardiac death or major ventricular arrhythmias together with LV dilatation, older age, advanced NYHA functional class, frequent ventricular ectopic activity, and nonsustained ventricular tachycardia., Conclusions: In a multicenter cohort of patients with DCM and NDLVC, septal LGE together with LV dilatation, age, advanced disease, and frequent and repetitive ventricular arrhythmias were powerful predictors of major arrhythmic events., Competing Interests: Funding Support and Author Disclosures This work was supported by the Paul and Ruby Tsai Family Hypertrophic Cardiomyopathy Career Development Award (Dr Giudicessi); the National Institutes of Health/National Heart, Lung, and Blood Institute R01HL147064 and R01HL164634 (Drs Mestroni and Taylor). The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Prolonged tachycardia-a risk factor for cardiovascular morbidity and mortality-can induce cardiomyopathy in the absence of structural disease in the heart. Here, by leveraging human patient data, a canine model of tachycardia and engineered heart tissue generated from human induced pluripotent stem cells, we show that metabolic rewiring during tachycardia drives contractile dysfunction by promoting tissue hypoxia, elevated glucose utilization and the suppression of oxidative phosphorylation. Mechanistically, a metabolic shift towards anaerobic glycolysis disrupts the redox balance of nicotinamide adenine dinucleotide (NAD), resulting in increased global protein acetylation (and in particular the acetylation of sarcoplasmic/endoplasmic reticulum Ca 2+ -ATPase), a molecular signature of heart failure. Restoration of NAD redox by NAD + supplementation reduced sarcoplasmic/endoplasmic reticulum Ca 2+ -ATPase acetylation and accelerated the functional recovery of the engineered heart tissue after tachycardia. Understanding how metabolic rewiring drives tachycardia-induced cardiomyopathy opens up opportunities for therapeutic intervention., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

Actin-binding filamin C (FLNC) is expressed in cardiomyocytes, where it localizes to Z-discs, sarcolemma, and intercalated discs. Although FLNC truncation variants ( FLNCtv ) are an established cause of arrhythmias and heart failure, changes in biomechanical properties of cardiomyocytes are mostly unknown. Thus, we investigated the mechanical properties of human-induced pluripotent stem cells-derived cardiomyocytes (hiPSC-CMs) carrying FLNCtv . CRISPR/Cas9 genome-edited homozygous FLNC KO-/- hiPSC-CMs and heterozygous knock-out FLNC KO+/- hiPSC-CMs were analyzed and compared to wild-type FLNC (FLNC WT ) hiPSC-CMs. Atomic force microscopy (AFM) was used to perform micro-indentation to evaluate passive and dynamic mechanical properties. A qualitative analysis of the beating traces showed gene dosage-dependent-manner "irregular" peak profiles in FLNC KO+/- and FLNC KO-/- hiPSC-CMs. Two Young's moduli were calculated: E1, reflecting the compression of the plasma membrane and actin cortex, and E2, including the whole cell with a cytoskeleton and nucleus. Both E1 and E2 showed decreased stiffness in mutant FLNC KO+/- and FLNC KO-/- iPSC-CMs compared to that in FLNC WT . The cell adhesion force and work of adhesion were assessed using the retraction curve of the SCFS. Mutant FLNC iPSC-CMs showed gene dosage-dependent decreases in the work of adhesion and adhesion forces from the heterozygous FLNC KO+/- to the FLNC KO-/- model compared to FLNC WT , suggesting damaged cytoskeleton and membrane structures. Finally, we investigated the effect of crenolanib on the mechanical properties of hiPSC-CMs. Crenolanib is an inhibitor of the Platelet-Derived Growth Factor Receptor α (PDGFRA) pathway which is upregulated in FLNCtv hiPSC-CMs. Crenolanib was able to partially rescue the stiffness of FLNC KO-/- hiPSC-CMs compared to control, supporting its potential therapeutic role.

Aims: Dilated cardiomyopathy (DCM) with arrhythmic phenotype combines phenotypical aspects of DCM and predisposition to ventricular arrhythmias, typical of arrhythmogenic cardiomyopathy. The definition of DCM with arrhythmic phenotype is not universally accepted, leading to uncertainty in the identification of high-risk patients. This study aimed to assess the prognostic impact of arrhythmic phenotype in risk stratification and the correlation of arrhythmic markers with high-risk arrhythmogenic gene variants in DCM patients., Methods and Results: In this multicentre study, DCM patients with available genetic testing were analysed. The following arrhythmic markers, present at baseline or within 1 year of enrolment, were tested: unexplained syncope, rapid non-sustained ventricular tachycardia (NSVT), ≥1000 premature ventricular contractions/24 h or ≥50 ventricular couplets/24 h. LMNA, FLNC, RBM20, and desmosomal pathogenic or likely pathogenic gene variants were considered high-risk arrhythmogenic genes. The study endpoint was a composite of sudden cardiac death and major ventricular arrhythmias (SCD/MVA). We studied 742 DCM patients (45 ± 14 years, 34% female, 410 [55%] with left ventricular ejection fraction [LVEF] <35%). During a median follow-up of 6 years (interquartile range 1.6-12.1), unexplained syncope and NSVT were the only arrhythmic markers associated with SCD/MVA, and the combination of the two markers carried a significant additive risk of SCD/MVA, incremental to LVEF and New York Heart Association class. The probability of identifying an arrhythmogenic genotype rose from 8% to 30% if both early syncope and NSVT were present., Conclusion: In DCM patients, the combination of early detected NSVT and unexplained syncope increases the risk of life-threatening arrhythmic outcomes and can aid the identification of carriers of malignant arrhythmogenic genotypes., (© 2024 European Society of Cardiology.)

Background: Patients with likely pathogenic/pathogenic desmoplakin ( DSP ) variants are poorly characterized. Some of them meet diagnostic criteria for arrhythmogenic right ventricular cardiomyopathy (ARVC), but it is unclear how risk stratification strategies for ARVC perform in this setting., Objectives: The purpose of this study was to characterize arrhythmic outcomes and to test the performance of the recently validated ARVC risk calculator in patients with DSP likely pathogenic/pathogenic variants fulfilling definite 2010 ARVC Task Force Criteria ( DSP -TFC+)., Methods: DSP -TFC+ patients were enrolled from 20 institutions across 3 continents. Ventricular arrhythmias (VA), defined as a composite of sustained ventricular tachycardia (VT), appropriate implantable cardioverter defibrillator therapies, and ventricular fibrillation/sudden cardiac death events in follow-up, were reported as the primary outcome. We tested the performance of the ARVC risk calculator for VA prediction, reporting c-statistics., Results: Among 252 DSP -TFC+ patients (age 39.6 ± 16.9 years, 35.3% male), 94 (37.3%) experienced VA over 44.5 [IQR: 19.6-78.3] months. Patients with left ventricle involvement (n = 194) were at higher VA risk (log-rank P  = 0.0239). History of nonsustained VT (aHR 2.097; P  = 0.004) showed the strongest association with VA occurrence during the first 5-year follow-up. Neither age ( P  = 0.723) nor male sex ( P  = 0.200) was associated with VAs at follow-up. In 204 patients without VA at diagnosis, incident VA rate was high (32.8%; 7.37%/y). The ARVC risk calculator performed poorly overall (c-statistic 0.604 [0.594-0.614]) and very poorly in patients with left ventricular disease (c-statistic 0.558 [0.556-0.560])., Conclusions: DSP -TFC+ patients are at substantial risk for VAs. The ARVC risk calculator performs poorly in DSP -TFC+ patients suggesting need for a gene-specific risk algorithm. Meanwhile, DSP -TFC+ patients with nonsustained VT should be considered as high-risk., Competing Interests: The Johns Hopkins ARVC program (Dr James, Gasperetti, Calkins, Carrick, Murray, and Tondo) is supported by the Leonie-Wild Foundation, the Leyla Erkan Family Fund for ARVD Research, the Hugh Calkins, Marvin H. Weiner, and Jacqueline J. Bernstein Cardiac Arrhythmia Center, the Dr Francis P. Chiramonte Private Foundation, the Dr Satish, Rupal, and Robin Shah ARVD Fund at 10.13039/100007880Johns Hopkins, the Bogle Foundation, the Campanella family, the Patrick J. Harrison family, the 10.13039/501100019817Peter French Memorial Foundation, and the Wilmerding Endowments and 10.13039/100000002NIH/10.13039/100006108NCATS UL1 TR003098. ASJMtR and PVT acknowledge support from the Netherlands Cardiovascular Research Initiative, an initiative with support of the Netherlands Heart Foundation, grant nos. CVON2018-30 PREDICT2, CVON2015-12 eDETECT, 2020B005 Double Dose. ASJMtR is supported by the 10.13039/501100001826ZonMW Off-Road Grant 2021. The Zurich ARVC Program is supported by the 10.13039/501100011561Georg und Bertha Schwyzer-Winiker Foundation, 10.13039/501100007252Baugarten Foundation, Wild Foundation, 10.13039/501100001711Swiss National Science Foundation (SNF), and the 10.13039/501100004362Swiss Heart Foundation. The Bologna Cardiomyopathy Registry has received funding support from the 10.13039/501100003196Italian Ministry of Health, RC-2022-2773270 project AAMW received funding from CVON Predict-2. Dr Mestroni is supported by 10.13039/100000002NIH R01HL69071, R01HL116906, R01HL147064, 10.13039/100000002NIH/10.13039/100006108NCATS UL1 TR002535 and UL1 TR001082. Dr Yazdani is supported by 10.13039/501100000274British Heart Foundation FS/CRTF/23/24448 and Alexander Jansons Myocarditis UK. Dr Prasad has received funding from Alexander Jansons Myocarditis UK, 10.13039/501100000833Rosetrees Trust, and 10.13039/501100000274British Heart Foundation. Dr Medo is supported by the 10.13039/100001825Rose Foundation. This work was supported by the 10.13039/501100000265Medical Research Council (UK), 10.13039/501100000274British Heart Foundation [RE/18/4/34215], the 10.13039/501100013342NIHR Imperial College Biomedical Research Centre, the 10.13039/501100000272NIHR Royal Brompton Biomedical Research Centre, and the 10.13039/501100000282Sir Jules Thorn Charitable Trust [21JTA]. Dr Saguner has received educational grants through his institution from Abbott, Bayer Healthcare, Biosense Webster, Biotronik, Boston Scientific, BMS/Pfizer, and Medtronic; and speaker/advisory board/consulting fees from Abbott, Bayer Healthcare, Daiichi-Sankyo, Medtronic, Novartis, and Pfizer. Dr Lakdawala has received unrestricted research support from Pfizer and the O’Hare and Steggall Family Foundations and consulting fees from BMS, Pfizer, Cytokinetics, Sarepta, and Tenaya. Dr Mestroni received educational grant from Greenstone; and advisory board/consulting fees from Tenaya, StrideBio, and Unicure. Dr Gasperetti received advisory board/consulting fees from Lexeo, and has served as an unpaid consultant for StrideBio. Dr James has received research grants from StrideBio Inc and Lexeo Inc; has received advisory board/consulting fees from Pfizer and Lexeo; and has served as an unpaid consultant for StrideBio and Tenaya. Dr Ware has received research support from Bristol-Myers Squibb; and advisory board/consultancy fees from Bristol-Myers Squibb, Foresite Labs, and Pfizer. Dr Calkins is a consultant for Medtronic Inc, Biosense Webster, Pfizer, StrideBio, Rocket, and Abbott. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2024 The Authors.)

Truncating mutations in filamin C ( FLNC ) are associated with dilated cardiomyopathy and arrhythmogenic cardiomyopathy. FLNC is an actin-binding protein and is known to interact with transmembrane and structural proteins; hence, the ablation of FLNC in cardiomyocytes is expected to dysregulate cell adhesion, cytoskeletal organization, sarcomere structural integrity, and likely nuclear function. Our previous study showed that the transcriptional profiles of FLNC homozygous deletions in human pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are highly comparable to the transcriptome profiles of hiPSC-CMs from patients with FLNC truncating mutations. Therefore, in this study, we used CRISPR-Cas-engineered hiPSC-derived FLNC knockout cardiac myocytes as a model of FLNC cardiomyopathy to determine pathogenic mechanisms and to examine structural changes caused by FLNC deficiency. RNA sequencing data indicated the significant upregulation of focal adhesion signaling and the dysregulation of thin filament genes in FLNC -knockout (FLNC KO ) hiPSC-CMs compared to isogenic hiPSC-CMs. Furthermore, our findings suggest that the complete loss of FLNC in cardiomyocytes led to cytoskeletal defects and the activation of focal adhesion kinase. Pharmacological inhibition of PDGFRA signaling using crenolanib (an FDA-approved drug) reduced focal adhesion kinase activation and partially normalized the focal adhesion signaling pathway. The findings from this study suggest the opportunity in repurposing FDA-approved drug as a therapeutic strategy to treat FLNC cardiomyopathy.

Dilated cardiomyopathy (DCM) is defined as dilation and/or reduced function of one or both ventricles and remains a common disease worldwide. An estimated 40% of cases of familial DCM have an identifiable genetic cause. Accordingly, there is a fast-growing interest in the field of molecular genetics as it pertains to DCM. Many gene mutations have been identified that contribute to phenotypically significant cardiomyopathy. DCM genes can affect a variety of cardiomyocyte functions, and particular genes whose function affects the cell-cell junction and cytoskeleton are associated with increased risk of arrhythmias and sudden cardiac death. Through advancements in next-generation sequencing and cardiac imaging, identification of genetic DCM has improved over the past couple decades, and precision medicine is now at the forefront of treatment for these patients and their families. In addition to standard treatment of heart failure and prevention of arrhythmias and sudden cardiac death, patients with genetic cardiomyopathy stand to benefit from gene mechanism-specific therapies.

Background and Aims: Emery-Dreifuss muscular dystrophy (EDMD) is caused by variants in EMD (EDMD1) and LMNA (EDMD2). Cardiac conduction defects and atrial arrhythmia are common to both, but LMNA variants also cause end-stage heart failure (ESHF) and malignant ventricular arrhythmia (MVA). This study aimed to better characterize the cardiac complications of EMD variants., Methods: Consecutively referred EMD variant-carriers were retrospectively recruited from 12 international cardiomyopathy units. MVA and ESHF incidences in male and female variant-carriers were determined. Male EMD variant-carriers with a cardiac phenotype at baseline (EMDCARDIAC) were compared with consecutively recruited male LMNA variant-carriers with a cardiac phenotype at baseline (LMNACARDIAC)., Results: Longitudinal follow-up data were available for 38 male and 21 female EMD variant-carriers [mean (SD) ages 33.4 (13.3) and 43.3 (16.8) years, respectively]. Nine (23.7%) males developed MVA and five (13.2%) developed ESHF during a median (inter-quartile range) follow-up of 65.0 (24.3-109.5) months. No female EMD variant-carrier had MVA or ESHF, but nine (42.8%) developed a cardiac phenotype at a median (inter-quartile range) age of 58.6 (53.2-60.4) years. Incidence rates for MVA were similar for EMDCARDIAC and LMNACARDIAC (4.8 and 6.6 per 100 person-years, respectively; log-rank P = .49). Incidence rates for ESHF were 2.4 and 5.9 per 100 person-years for EMDCARDIAC and LMNACARDIAC, respectively (log-rank P = .09)., Conclusions: Male EMD variant-carriers have a risk of progressive heart failure and ventricular arrhythmias similar to that of male LMNA variant-carriers. Early implantable cardioverter defibrillator implantation and heart failure drug therapy should be considered in male EMD variant-carriers with cardiac disease., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

The presence of multiple pathogenic variants in desmosomal genes (DSC2, DSG2, DSP, JUP, and PKP2) in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) has been linked to a severe phenotype. However, the pathogenicity of variants is reclassified frequently, which may result in a changed clinical risk prediction. Here, we present the collection, reclassification, and clinical outcome correlation for the largest series of ARVC patients carrying multiple desmosomal pathogenic variants to date (n = 331). After reclassification, only 29% of patients remained carriers of two (likely) pathogenic variants. They reached the composite endpoint (ventricular arrhythmias, heart failure, and death) significantly earlier than patients with one or no remaining reclassified variant (hazard ratios of 1.9 and 1.8, respectively). Periodic reclassification of variants contributes to more accurate risk stratification and subsequent clinical management strategy. Graphical Abstract., (© 2023. The Author(s).)

Background: Imaging evaluation of arrhythmogenic right ventricular cardiomyopathy (ARVC) remains challenging. Myocardial strain assessment by echocardiography is an increasingly utilized technique for detecting subclinical left ventricular (LV) and right ventricular (RV) dysfunction. We aimed to evaluate the diagnostic and prognostic utility of LV and RV strain in ARVC., Methods: Patients with suspected ARVC (n = 109) from a multicenter registry were clinically phenotyped using the 2010 ARVC Revised Task Force Criteria and underwent baseline strain echocardiography. Diagnostic performance of LV and RV strain was evaluated using the area under the receiver operating characteristic curve analysis against the 2010 ARVC Revised Task Force Criteria, and the prognostic value was assessed using the Kaplan-Meier analysis., Results: Mean age was 45.3±14.7 years, and 48% of patients were female. Estimation of RV strain was feasible in 99/109 (91%), and LV strain was feasible in 85/109 (78%) patients. ARVC prevalence by 2010 ARVC Revised Task Force Criteria is 91/109 (83%) and 83/99 (84%) in those with RV strain measurements. RV global longitudinal strain and RV free wall strain had diagnostic area under the receiver operating characteristic curve of 0.76 and 0.77, respectively (both P <0.001; difference NS). Abnormal RV global longitudinal strain phenotype (RV global longitudinal strain > -17.9%) and RV free wall strain phenotype (RV free wall strain > -21.2%) were identified in 41/69 (59%) and 56/69 (81%) of subjects, respectively, who were not identified by conventional echocardiographic criteria but still met the overall 2010 ARVC Revised Task Force Criteria for ARVC. LV global longitudinal strain did not add diagnostic value but was prognostic for composite end points of death, heart transplantation, or ventricular arrhythmia (log-rank P =0.04)., Conclusions: In a prospective, multicenter registry of ARVC, RV strain assessment added diagnostic value to current echocardiographic criteria by identifying patients who are missed by current echocardiographic criteria yet still fulfill the diagnosis of ARVC. LV strain, by contrast, did not add incremental diagnostic value but was prognostic for identification of high-risk patients., Competing Interests: Disclosures Dr Namasivayam received support from the Nvidia Corporation Academic Hardware Grant for work unrelated to this article. The other authors report no conflicts.

Importance: Valsartan has shown promise in attenuating cardiac remodeling in patients with early-stage sarcomeric hypertrophic cardiomyopathy (HCM). Genetic testing can identify individuals at risk of HCM in a subclinical stage who could benefit from therapies that prevent disease progression., Objective: To explore the potential for valsartan to modify disease development, and to characterize short-term phenotypic progression in subclinical HCM., Design, Setting, and Participants: The multicenter, double-blind, placebo-controlled Valsartan for Attenuating Disease Evolution in Early Sarcomeric Hypertrophic Cardiomyopathy (VANISH) randomized clinical trial was conducted from April 2014 to July 2019 at 17 sites in 4 countries (Brazil, Canada, Denmark, and the US), with 2 years of follow-up. The prespecified exploratory VANISH cohort studied here included sarcomere variant carriers with subclinical HCM and early phenotypic manifestations (reduced E' velocity, electrocardiographic abnormalities, or an increased left ventricular [LV] wall thickness [LVWT] to cavity diameter ratio) but no LV hypertrophy (LVH). Data were analyzed between March and December 2022., Interventions: Treatment with placebo or valsartan (80 mg/d for children weighing <35 kg, 160 mg/d for children weighing ≥35 kg, or 320 mg/d for adults aged ≥18 years)., Main Outcomes and Measures: The primary outcome was a composite z score incorporating changes in 9 parameters of cardiac remodeling (LV cavity volume, LVWT, and LV mass; left atrial [LA] volume; E' velocity and S' velocity; and serum troponin and N-terminal prohormone of brain natriuretic peptide levels)., Results: This study included 34 participants, with a mean (SD) age of 16 (5) years (all were White). A total of 18 participants (8 female [44%] and 10 male [56%]) were randomized to valsartan and 16 (9 female [56%] and 7 male [44%]) were randomized to placebo. No statistically significant effects of valsartan on cardiac remodeling were detected (mean change in composite z score compared with placebo: -0.01 [95% CI, -0.29 to 0.26]; P = .92). Overall, 2-year phenotypic progression was modest, with only a mild increase in LA volume detected (increased by 3.5 mL/m2 [95% CI, 1.4-6.0 mL/m2]; P = .002). Nine participants (26%) had increased LVWT, including 6 (18%) who developed clinically overt HCM. Baseline LA volume index (LAVI; 35 vs 28 mL/m2; P = .01) and average interventricular septum thickness (8.5 vs 7.0 mm; P = .009) were higher in participants who developed HCM., Conclusions and Relevance: In this exploratory cohort, valsartan was not proven to slow progression of subclinical HCM. Minimal changes in markers of cardiac remodeling were observed, although nearly one-fifth of patients developed clinically overt HCM. Transition to disease was associated with greater baseline interventricular septum thickness and LAVI. These findings highlight the importance of following sarcomere variant carriers longitudinally and the critical need to improve understanding of factors that drive disease penetrance and progression., Trial Registration: ClinicalTrials.gov Identifier: NCT01912534.

Background: Dilated cardiomyopathy (DCM) is a major cause of heart failure and carries a high mortality rate. Myocardial recovery in DCM-related heart failure patients is highly variable, with some patients having little or no response to standard drug therapy. A genome-wide association study may agnostically identify biomarkers and provide novel insight into the biology of myocardial recovery in DCM., Methods: A genome-wide association study for change in left ventricular ejection fraction was performed in 686 White subjects with recent-onset DCM who received standard pharmacotherapy. Genome-wide association study signals were subsequently functionally validated and studied in relevant cellular models to understand molecular mechanisms that may have contributed to the change in left ventricular ejection fraction., Results: The genome-wide association study identified a highly suggestive locus that mapped to the 5'-flanking region of the CDCP1 (CUB [complement C1r/C1s, Uegf, and Bmp1] domain containing protein 1) gene (rs6773435; P =7.12×10 -7 ). The variant allele was associated with improved cardiac function and decreased CDCP1 transcription. CDCP1 expression was significantly upregulated in human cardiac fibroblasts (HCFs) in response to the PDGF (platelet-derived growth factor) signaling, and knockdown of CDCP1 significantly repressed HCF proliferation and decreased AKT (protein kinase B) phosphorylation. Transcriptomic profiling after CDCP1 knockdown in HCFs supported the conclusion that CDCP1 regulates HCF proliferation and mitosis. In addition, CDCP1 knockdown in HCFs resulted in significantly decreased expression of soluble ST2 (suppression of tumorigenicity-2), a prognostic biomarker for heart failure and inductor of cardiac fibrosis., Conclusions: CDCP1 may play an important role in myocardial recovery in recent-onset DCM and mediates its effect primarily by attenuating cardiac fibrosis., Competing Interests: Disclosures R.M. Weinshilboum is a cofounder of and stockholder in OneOme, LLC. The other authors report no conflicts.

Background: Variants in RBM20 are reported in 2% to 6% of familial cases of dilated cardiomyopathy and may be associated with fatal ventricular arrhythmia and rapid heart failure progression. We sought to determine the risk of adverse events in RBM20 variant carriers and the impact of sex on outcomes., Methods: Consecutive probands and relatives carrying RBM20 variants were retrospectively recruited from 12 cardiomyopathy units. The primary end point was a composite of malignant ventricular arrhythmia (MVA) and end-stage heart failure (ESHF). MVA and ESHF end points were also analyzed separately and men and women compared. Left ventricular ejection fraction (LVEF) contemporary to MVA was examined. RBM20 variant carriers with left ventricular systolic dysfunction ( RBM20 LVSD ) were compared with variant-elusive patients with idiopathic left ventricular systolic dysfunction., Results: Longitudinal follow-up data were available for 143 RBM20 variant carriers (71 men; median age, 35.5 years); 7 of 143 had an MVA event at baseline. Thirty of 136 without baseline MVA (22.0%) reached the primary end point, and 16 of 136 (11.8%) had new MVA with no significant difference between men and women (log-rank P =0.07 and P =0.98, respectively). Twenty of 143 (14.0%) developed ESHF (17 men and 3 women; log-rank P <0.001). Four of 10 variant carriers with available LVEF contemporary to MVA had an LVEF >35%. At 5 years, 15 of 67 (22.4%) RBM20 LVSD versus 7 of 197 (3.6%) patients with idiopathic left ventricular systolic dysfunction had reached the primary end point (log-rank P <0.001). RBM20 variant carriage conferred a 6.0-fold increase in risk of the primary end point., Conclusions: RBM20 variants are associated with a high risk of MVA and ESHF compared with idiopathic left ventricular systolic dysfunction. The risk of MVA in male and female RBM20 variant carriers is similar, but male sex is strongly associated with ESHF., Competing Interests: Disclosures Dr Sengupta reports speakers fees from Pfizer. Dr Elliott reports consultancies for Pfizer, Sarepta, Bristol Myers Squibb, Biomarin, Leal, and Novo Nordisk. The other authors report no conflict.

Background: Nuclear factor κB (NF-κB) signaling in cardiac myocytes causes disease in a mouse model of arrhythmogenic cardiomyopathy (ACM) by mobilizing CCR2-expressing macrophages that promote myocardial injury and arrhythmias. Buccal mucosa cells exhibit pathologic features similar to those seen in cardiac myocytes in patients with ACM., Objectives: We sought to determine if persistent innate immune signaling via NF-κB occurs in cardiac myocytes in patients with ACM and if this is associated with myocardial infiltration of proinflammatory cells expressing CCR2. We also determined if buccal mucosa cells from young subjects with inherited disease alleles exhibit NF-κB signaling., Methods: We analyzed myocardium from ACM patients who died suddenly or required cardiac transplantation. We also analyzed buccal mucosa cells from young subjects with inherited disease alleles. The presence of immunoreactive signal for RelA/p65 in nuclei of cardiac myocytes and buccal cells was used as a reliable indicator of active NF-κB signaling. We also counted myocardial CCR2-expressing cells., Results: RelA/p65 signal was seen in numerous cardiac myocyte nuclei in 34 of 36 cases of ACM but not in 19 age-matched control individuals. Cells expressing CCR2 were increased in patient hearts in numbers directly correlated with the number of cardiac myocytes showing NF-κB signaling. NF-κB signaling was observed in buccal cells in young subjects with active disease., Conclusions: Patients with clinically active ACM exhibit persistent innate immune responses in cardiac myocytes and buccal mucosa cells, reflecting a local and systemic inflammatory process. Such individuals may benefit from anti-inflammatory therapy., (© 2023 Heart Rhythm Society. Published by Elsevier Inc.)

Carbon nanotubes (CNTs) have become promising advanced materials and a new tool to specifically interact with electroresponsive cells. Likewise, conductive polymers (CP) appear promising electroactive biomaterial for proliferation of cells. Herein, we have investigated CNT blends with two different conductive polymers, polypyrrole/CNT (PPy/CNT) and PEDOT/CNT to evaluate the growth, survival, and beating behavior of neonatal rat ventricular myocytes (NRVM). The combination of CP/CNT not only shows excellent biocompatibility on NRVM, after 2 weeks of culture, but also exerts functional effects on networks of cardiomyocytes. NRVMs cultured on CNT-based substrates exhibited improved cellular function, i.e., homogeneous, non-arrhythmogenic, and more frequent spontaneous beating; particularly PEDOT/CNT substrates, which yielded to higher beating amplitudes, thus suggesting a more mature cardiac phenotype. Furthermore, cells presented enhanced structure: aligned sarcomeres, organized and abundant Connexin 43 (Cx43). Finally, no signs of induced hypertrophy were observed. In conclusion, the combination of CNT with CP produces high viability and promotes cardiac functionality, suggesting great potential to generate scaffolding supports for cardiac tissue engineering., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

Background: Truncating variants in filamin C (FLNC) can cause arrhythmogenic cardiomyopathy (ACM) through haploinsufficiency. Noncanonical splice-altering variants may contribute to this phenotype., Objective: The purpose of this study was to investigate the clinical and functional consequences of a recurrent FLNC intronic variant of uncertain significance (VUS), c.970-4A>G., Methods: Clinical data in 9 variant heterozygotes from 4 kindreds were obtained from 5 tertiary health care centers. We used in silico predictors and functional studies with peripheral blood and patient-specific induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). Isolated RNA was studied by reverse transcription polymerase chain reaction. iPSC-CMs were further characterized at baseline and after nonsense-mediated decay (NMD) inhibition, using quantitative polymerase chain reaction (qPCR), RNA-sequencing, and cellular electrophysiology. American College of Medical Genetics and Genomics (ACMG) criteria were used to adjudicate variant pathogenicity., Results: Variant heterozygotes displayed a spectrum of disease phenotypes, spanning from mild ventricular dysfunction with palpitations to severe ventricular arrhythmias requiring device shocks or progressive cardiomyopathy requiring heart transplantation. Consistent with in silico predictors, the c.970-4A>G FLNC variant activated a cryptic splice acceptor site, introducing a 3-bp insertion containing a premature termination codon. NMD inhibition upregulated aberrantly spliced transcripts by qPCR and RNA-sequencing. Patch clamp studies revealed irregular spontaneous action potentials, increased action potential duration, and increased sodium late current in proband-derived iPSC-CMs. These findings fulfilled multiple ACMG criteria for pathogenicity., Conclusion: Clinical, in silico, and functional evidence support the prediction that the intronic c.970-4A>G VUS disrupts splicing and drives ACM, enabling reclassification from VUS to pathogenic., (Copyright © 2023. Published by Elsevier Inc.)

Objectives: We sought to determine if persistent innate immune signaling via NFκB occurs in cardiac myocytes in patients with arrhythmogenic cardiomyopathy and if this is associated with myocardial infiltration of pro-inflammatory cells expressing CCR2. We also determined if buccal mucosa cells from young subjects with inherited disease alleles exhibit NFκB signaling., Background: NFκB signaling in cardiac myocytes causes disease in a mouse model of arrhythmogenic cardiomyopathy by mobilizing CCR2-expressing macrophages which promote myocardial injury and arrhythmias. Buccal mucosa cells exhibit pathologic features similar to those seen in cardiac myocytes in patients with arrhythmogenic cardiomyopathy., Methods: We analyzed myocardium from arrhythmogenic cardiomyopathy patients who died suddenly or required cardiac transplantation. We also analyzed buccal mucosa cells from young subjects with inherited disease alleles. The presence of immunoreactive signal for RelA/p65 in nuclei of cardiac myocytes and buccal cells was used as a reliable indicator of active NFκB signaling. We also counted myocardial CCR2-expressing cells., Results: NFκB signaling was seen in cardiac myocytes in 34 of 36 cases of arrhythmogenic cardiomyopathy but in none of 19 age-matched controls. Cells expressing CCR2 were increased in patient hearts in numbers directly correlated with the number of cardiac myocytes showing NFκB signaling. NFκB signaling also occurred in buccal cells in young subjects with active disease., Conclusions: Patients with clinically active arrhythmogenic cardiomyopathy exhibit persistent innate immune responses in cardiac myocytes and buccal mucosa cells reflecting an inflammatory process that fails to resolve. Such individuals may benefit from anti-inflammatory therapy., Condensed Abstract: NFκB signaling in cardiac myocytes causes arrhythmias and myocardial injury in a mouse model of arrhythmogenic cardiomyopathy by mobilizing pro-inflammatory CCR2-expressing macrophages to the heart. Based on these new mechanistic insights, we analyzed hearts of arrhythmogenic cardiomyopathy patients who died suddenly or required cardiac transplantation. We observed active NFκB signaling in cardiac myocytes associated with marked infiltration of CCR2-expressing cells. We also observed NFκB signaling in buccal mucosa cells obtained from young subjects with active disease. Thus, anti-inflammatory therapy may be effective in arrhythmogenic cardiomyopathy. Screening buccal cells may be a reliable way to identify patients most likely to benefit., Highlights: Inflammation likely contributes to the pathogenesis of arrhythmogenic cardiomyopathy but the responsible mechanisms and the roles of specific classes of immune cells remain undefined.NFκB signaling in cardiac myocytes is sufficient to cause disease in a mouse model of arrhythmogenic cardiomyopathy by mobilizing injurious myeloid cells expressing CCR2 to the heart.Here, we provide evidence of persistent NFκB signaling in cardiac myocytes and increased CCR2-expressing cells in hearts of patients with arrhythmogenic cardiomyopathy. We observed a close correlation between the number of cardiac myocytes with active NFκB signaling and the number of CCR2-expressing cells in patient hearts.We also provide evidence of active NFκB signaling in buccal mucosa cells associated with initial onset of disease and/or disease progression in young subjects with arrhythmogenic cardiomyopathy alleles.

SARS CoV-2 enters host cells via its Spike protein moiety binding to the essential cardiac enzyme angiotensin-converting enzyme (ACE) 2, followed by internalization. COVID-19 mRNA vaccines are RNA sequences that are translated into Spike protein, which follows the same ACE2-binding route as the intact virion. In model systems, isolated Spike protein can produce cell damage and altered gene expression, and myocardial injury or myocarditis can occur during COVID-19 or after mRNA vaccination. We investigated 7 COVID-19 and 6 post-mRNA vaccination patients with myocardial injury and found nearly identical alterations in gene expression that would predispose to inflammation, coagulopathy, and myocardial dysfunction., Competing Interests: This work was supported by American Heart Association COVID-19 Rapid Response Award 811960, “Myocardial Virus and Gene Expression in SARS CoV-2 Positive Patients With Clinically Important Myocardial Dysfunction,” Michael R. Bristow, Principal Investigator. On May 12, 2021 the institutional review board–approved protocol was expanded by an amendment to investigate patients with vaccine-associated myocarditis. This work was also supported by National Institutes of Allergy and Infectious Diseases Subcontract 3 UM1 AI068614-14S1 Subaward no. 0001089814, “Myocardial Injury and Dysfunction Associated With COVID-19 Vaccination (MIDAVAX; NCT05359250),” Lawrence Corey, MD, Principal Investigator, Michael R. Bristow, Sub–Principal Investigator. Dr Bristow is an officer and shareholder and Dr Carroll and Ms Huebler are employees of ARCA Biopharma, a precision therapeutics biotechnology company developing pharmacogenetic heart failure drugs, as well as a drug for COVID-19–associated coagulopathy. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2023 The Authors.)

What Is This Plain Language Summary About?: This plain language summary describes the results of a study looking at the effects of a medicine called ARRY-371797 (also known as PF-07265803) in people with dilated cardiomyopathy (DCM for short) caused by a faulty LMNA gene. This condition is called LMNA-related DCM. DCM happens when the heart becomes bigger and weaker than normal, impacting functional capacity and leading to symptoms of heart failure. This means the heart is not able to pump blood around the body as easily, and people are unable to do as much in their daily lives (like getting dressed and going shopping). People may inherit a faulty LMNA gene from one of their parents, or a faulty LMNA gene may develop when mistakes happen during cell growth and replication. ARRY-371797 targets a specific mechanism in the body that can lead to heart problems in people with a faulty LMNA gene. As ARRY-371797 is not currently approved for use outside of clinical trials, it doesn't currently have an easily recognizable trade name., What Were the Results?: 12 American people (average age 50 years) with LMNA-related DCM took part in the study and received 400 mg or 100 mg of ARRY-371797 twice daily for 48 weeks. People knew which dose of ARRY-371797 they were taking. People were checked after 4, 12, 24, 36 and 48 weeks of taking ARRY-371797 to see how far they could walk in the 6-minute walk test (6MWT for short). The level of NT-proBNP in their blood was also measured. NT-proBNP is a biomarker used to measure the severity of heart failure. A biomarker is something found in the body that can be measured to indicate the extent of a disease. -After taking ARRY-371797 for 12 weeks, people were able to walk further in the 6MWT and had lower levels of NT-proBNP in their blood. This suggests improvement in functional capacity (exercise tolerance) and heart function. Researchers also asked people about their quality of life using the Kansas City Cardiomyopathy Questionnaire (KCCQ for short), and looked for any side effects. -Researchers saw some improvement in KCCQ scores. -Researchers saw no major side effects that they considered to be related to ARRY-371797 treatment. A side effect is something that people feel was caused by a medicine or treatment. Overall, this study showed that people with LMNA-related DCM who took ARRY-371797 had improved functional capacity (exercise tolerance), improved heart function, and improved quality of life. Phase 2 study (NCT02057341) Phase 2 long-term extension study (NCT02351856) Phase 3 REALM-DCM study (NCT03439514).

Background: Lamin A/C gene ( LMNA )-related dilated cardiomyopathy is a serious and life-threatening condition with a high unmet medical need. This phase 2 study assessed the effects of the oral selective p38 mitogen-activated protein kinase inhibitor ARRY-371797 on functional capacity and cardiac function in patients with LMNA -related dilated cardiomyopathy., Methods: Patients with LMNA -related dilated cardiomyopathy in New York Heart Association class II-IIIA, on background heart failure treatment, received ARRY-371797 100 or 400 mg twice daily for 48 weeks. The primary end point was change from baseline in the 6-minute walk test distance at 12 weeks. Secondary end points included changes over time in 6-minute walk test distance, NT-proBNP (N-terminal pro-B-type natriuretic peptide) concentration, left ventricular ejection fraction, and quality-of-life scores on the Kansas City Cardiomyopathy Questionnaire. Data from the 2 dose groups were combined., Results: Twelve patients were enrolled; median (minimum, maximum) 6-minute walk test distance at baseline was 314 (246, 412) m. At week 12, the mean (80% CI) increase from baseline in 6-minute walk test distance was 69 (39, 100) m (median, 47 m). Median NT-proBNP concentration declined from 1409 pg/mL at baseline to 848 pg/mL at week 12. Mean left ventricular ejection fraction was stable at week 12. There was a trend toward improvement in Kansas City Cardiomyopathy Questionnaire Overall and Clinical Summary scores at week 12. No clinically significant drug-related safety concerns were identified., Conclusions: ARRY-371797 was well tolerated and resulted in potential increases in functional capacity and lower concentrations of cardiac biomarker NT-proBNP in patients with LMNA -related dilated cardiomyopathy., Registration: URL: https://clinicaltrials.gov; Unique identifier: NCT02057341.

Given the clinical effect of progeria syndrome, understanding the cell mechanical behavior of this pathology could benefit the patient's treatment. Progeria patients show a point mutation in the lamin A/C gene (LMNA), which could change the cell's biomechanical properties. This paper reports a mechano-dynamic analysis of a progeria mutation (c.1824 C > T, p.Gly608Gly) in neonatal rat ventricular myocytes (NRVMs) using cell indentation by atomic force microscopy to measure alterations in beating force, frequency, and contractile amplitude of selected cells within cell clusters. Furthermore, we examined the beating rate variability using a time-domain method that produces a Poincaré plot because beat-to-beat changes can shed light on the causes of arrhythmias. Our data have been further related to our cell phenotype findings, using immunofluorescence and calcium transient analysis, showing that mutant NRVMs display changes in both beating force and frequency. These changes were associated with a decreased gap junction localization (Connexin 43) in the mutant NRVMs even in the presence of a stable cytoskeletal structure (microtubules and actin filaments) when compared with controls (wild type and non-treated cells). These data emphasize the kindred between nucleoskeleton (LMNA), cytoskeleton, and the sarcolemmal structures in NRVM with the progeria Gly608Gly mutation, prompting future mechanistic and therapeutic investigations.

Aims: The role of sex in determining the profile and the outcomes of patients with myocarditis is largely unexplored. We evaluated the impact of sex as a modifier factor in the clinical characterization and natural history of patients with definite diagnosis of myocarditis., Methods and Results: We retrospectively analysed a single-centre cohort of consecutive patients with definite diagnosis of myocarditis (i.e. endomyocardial biopsy or cardiac magnetic resonance proven). Specific sub-analyses were performed in cohorts of patients with chest pain, ventricular arrhythmias, and heart failure as different main symptoms at presentation. The primary outcome measure was a composite of all-cause mortality or heart transplantation (HTx). We included 312 patients, of which 211, 68% of the whole population, were males. Despite no clinically relevant differences found at baseline presentation, males had a higher indexed left ventricular end-diastolic volume (62 ± 23 mL/m2 vs. 52 ± 20 mL/m2, P = 0.011 in males vs. females, respectively) at follow-up evaluation. At a median follow-up of 72 months, 36 (17%) males vs. 8 (8%) females experienced death or HTx (P = 0.033). Male sex emerged as predictors of all-cause mortality or HTx in every combination of covariates (HR 2.600; 1.163-5.809; P = 0.020). Results were agreeable regardless of the main symptom of presentation., Conclusions: In a large cohort of patients with definite diagnosis of myocarditis, females experienced a more favourable long-term prognosis than males, despite a similar clinical profile at presentation., (© 2022 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of European Society of Cardiology.)

Background: Diverse genetic backgrounds often lead to phenotypic heterogeneity in cardiomyopathies (CMPs). Previous genotype-phenotype studies have primarily focused on the analysis of a single phenotype, and the diagnostic and prognostic features of the CMP genotype across different phenotypic expressions remain poorly understood., Objectives: We sought to define differences in outcome prediction when stratifying patients based on phenotype at presentation compared with genotype in a large cohort of patients with CMPs and positive genetic testing., Methods: Dilated cardiomyopathy (DCM), arrhythmogenic right ventricular cardiomyopathy, left-dominant arrhythmogenic cardiomyopathy, and biventricular arrhythmogenic cardiomyopathy were examined in this study. A total of 281 patients (80% DCM) with pathogenic or likely pathogenic variants were included. The primary and secondary outcomes were: 1) all-cause mortality (D)/heart transplant (HT); 2) sudden cardiac death/major ventricular arrhythmias (SCD/MVA); and 3) heart failure-related death (DHF)/HT/left ventricular assist device implantation (LVAD)., Results: Survival analysis revealed that SCD/MVA events occurred more frequently in patients without a DCM phenotype and in carriers of DSP, PKP2, LMNA, and FLNC variants. However, after adjustment for age and sex, genotype-based classification, but not phenotype-based classification, was predictive of SCD/MVA. LMNA showed the worst trends in terms of D/HT and DHF/HT/LVAD., Conclusions: Genotypes were associated with significant phenotypic heterogeneity in genetic cardiomyopathies. Nevertheless, in our study, genotypic-based classification showed higher precision in predicting the outcome of patients with CMP than phenotype-based classification. These findings add to our current understanding of inherited CMPs and contribute to the risk stratification of patients with positive genetic testing., Competing Interests: Funding Support and Author Disclosures This study was supported by National Institutes of Health (NIH) grants R01HL69071, R01HL116906, and R01HL147064, and American Heart Association grant 17GRNT33670495 (to Dr Mestroni); NIH grant 1K23HI067915; NIH grants 2UM1HG006542 and R01HL109209 (to Dr Taylor); and CRTrieste Foundation and Cassa di Risparmio di Gorizia Foundation (to Dr Sinagra). This work is also supported by NIH/National Center for Advancing Translational Sciences Colorado CTSA grant numbers UL1 TR002535 and UL1 TR001082. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Dilated cardiomyopathy associated with lamin A/C (LMNA) gene variants (LMNA-related dilated cardiomyopathy [DCM]) is a life-threatening condition with a high unmet need, accounting for approximately 6% of idiopathic DCM cases. Currently, no disease-specific treatments target the underlying disease mechanism. ARRY-371797 (PF-07265803), a potent, selective, oral, small-molecule inhibitor of the p38α mitogen-activated protein kinase pathway, improved 6-minute walk test (6MWT) distance in 12 patients with symptomatic LMNA-related DCM in a 48-week, open-label, phase 2 study. This long-term extension study examined the safety and efficacy of ARRY-371797 in patients from the phase 2 study. 6MWT, N-terminal pro-B-type natriuretic peptide concentration, and 12-item Kansas City Cardiomyopathy Questionnaire score were assessed at weeks 48, 72, 96, 120, and 144 from phase 2 study baseline. Eight patients enrolled (mean [SD] age, 51 [10] years, 4 male). Mean 6MWT increased by >30 m (>10%) from phase 2 study baseline up to week 120. The decrease in N-terminal pro-B-type natriuretic peptide observed in the phase 2 study was maintained throughout the present study. Twelve-item Kansas City Cardiomyopathy Questionnaire Physical Limitation increased from baseline at all visits except week 96 (range: -0.8 [week 96] to 13.8 [week 120]); results for other domains were variable. Treatment was generally well tolerated; 2 patients discontinued because of causes not considered treatment-related. There were no deaths. ARRY-371797 was generally well tolerated over median (range) 155.7 (61 to 327)-week exposure; evidence suggested preserved exercise capacity over the study period. The ongoing, pivotal, phase 3, randomized, placebo-controlled study REALM-DCM investigates the efficacy and safety of ARRY-371797 (PF-07265803) in LMNA-related DCM. (ClinicalTrials.gov Identifier: NCT02351856)., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Although genotyping allows family screening and influences risk-stratification in patients with nonischemic dilated cardiomyopathy (DCM) or isolated left ventricular systolic dysfunction (LVSD), its result is negative in a significant number of patients, limiting its widespread adoption., Objectives: This study sought to develop and externally validate a score that predicts the probability for a positive genetic test result (G+) in DCM/LVSD., Methods: Clinical, electrocardiogram, and echocardiographic variables were collected in 1,015 genotyped patients from Spain with DCM/LVSD. Multivariable logistic regression analysis was used to identify variables independently predicting G+, which were summed to create the Madrid Genotype Score. The external validation sample comprised 1,097 genotyped patients from the Maastricht and Trieste registries., Results: A G+ result was found in 377 (37%) and 289 (26%) patients from the derivation and validation cohorts, respectively. Independent predictors of a G+ result in the derivation cohort were: family history of DCM (OR: 2.29; 95% CI: 1.73-3.04; P < 0.001), low electrocardiogram voltage in peripheral leads (OR: 3.61; 95% CI: 2.38-5.49; P < 0.001), skeletal myopathy (OR: 3.42; 95% CI: 1.60-7.31; P = 0.001), absence of hypertension (OR: 2.28; 95% CI: 1.67-3.13; P < 0.001), and absence of left bundle branch block (OR: 3.58; 95% CI: 2.57-5.01; P < 0.001). A score containing these factors predicted a G+ result, ranging from 3% when all predictors were absent to 79% when ≥4 predictors were present. Internal validation provided a C-statistic of 0.74 (95% CI: 0.71-0.77) and a calibration slope of 0.94 (95% CI: 0.80-1.10). The C-statistic in the external validation cohort was 0.74 (95% CI: 0.71-0.78)., Conclusions: The Madrid Genotype Score is an accurate tool to predict a G+ result in DCM/LVSD., Competing Interests: Funding Support and Author Disclosures This work was supported by grants from the Instituto de Salud Carlos III (ISCIII) (PI17/01941, PI18/0004, PI19/01283, PI20/0320) (co-funded by European Regional Development Fund/European Social Fund "A way to make Europe"/"Investing in your future"). The CNIC is supported by the ISCIII, MCIN, the Pro-CNIC Foundation, and the Severo Ochoa Centers of Excellence program (CEX2020-001041-S). This study was also supported by the Netherlands Cardiovascular Research Initiative, an initiative with support from the Dutch Heart Foundation, DCVA Double Dosis 2020B005. The Hospital Universitario Puerta de Hierro, the Hospital Universitario Virgen de la Arrixaca and the Azienda Sanitaria Universitaria Giuliano-Isontina are members of the European Reference Network for rare, low-prevalence, and complex diseases of the heart (ERN GUARD-Heart). Dr Ochoa is an employee of Health in Code. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Cardiac fibroblasts are the main non-myocyte population responsible for extracellular matrix (ECM) production. During perinatal development, fibroblast expansion coincides with the transition from hyperplastic to hypertrophic myocardial growth. Therefore, we investigated the consequences of fibroblast loss at the time of cardiomyocyte maturation by depleting fibroblasts in the perinatal mouse., Methods and Results: We evaluated the microenvironment of the perinatal heart in the absence of fibroblasts and the potential functional impact of fibroblast loss in regulation of cardiomyocyte cell cycle arrest and binucleation. Cre-mediated expression of diphtheria toxin A in PDGFRα expressing cells immediately after birth eliminated 70-80% of the cardiac fibroblasts. At postnatal day 5, hearts lacking fibroblasts appeared similar to controls with normal morphology and comparable numbers of endothelial and smooth muscle cells, despite a pronounced reduction in fibrillar collagen. Immunoblotting and proteomic analysis of control and fibroblast-deficient hearts identified differential abundance of several ECM proteins. In addition, fibroblast loss decreased tissue stiffness and resulted in increased cardiomyocyte mitotic index, DNA synthesis, and cytokinesis. Moreover, decellularized matrix from fibroblast-deficient hearts promoted cardiomyocyte DNA replication. While cardiac architecture was not overtly affected by fibroblast reduction, few pups survived past postnatal day 11, suggesting an overall requirement for PDGFRα expressing fibroblasts., Conclusions: These studies demonstrate the key role of fibroblasts in matrix production and cardiomyocyte cross-talk during mouse perinatal heart maturation and revealed that fibroblast-derived ECM may modulate cardiomyocyte maturation in vivo. Neonatal depletion of fibroblasts demonstrated that although hearts can tolerate reduced ECM composition, fibroblast loss eventually leads to perinatal death as the approach simultaneously reduced fibroblast populations in other organs., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Importance: Dilated cardiomyopathy (DCM) is frequently caused by genetic factors. Studies identifying deleterious rare variants have predominantly focused on early-onset cases, and little is known about the genetic underpinnings of the growing numbers of patients with DCM who are diagnosed when they are older than 60 years (ie, late-onset DCM)., Objective: To investigate the prevalence, type, and prognostic impact of disease-associated rare variants in patients with late-onset DCM., Design, Setting, and Participants: A population of patients with late-onset DCM who had undergone genetic testing in 7 international tertiary referral centers worldwide were enrolled from March 1990 to August 2020. A positive genotype was defined as the presence of pathogenic or likely pathogenic (P/LP) variants., Main Outcomes and Measures: The study outcome was all-cause mortality., Results: A total of 184 patients older than 60 years (103 female [56%]; mean [SD] age, 67 [6] years; mean [SD] left ventricular ejection fraction, 32% [10%]) were studied. Sixty-six patients (36%) were carriers of a P/LP variant. Titin-truncating variants were the most prevalent (present in 46 [25%] of the total population and accounting for 46 [69%] of all genotype-positive patients). During a median (interquartile range) follow-up of 42 (10-115) months, 23 patients (13%) died; 17 (25%) of these were carriers of P/LP variants, while 6 patients (5.1%) were genotype-negative., Conclusions and Relevance: Late-onset DCM might represent a distinct subgroup characterized by and a high genetic variation burden, largely due to titin-truncating variants. Patients with a positive genetic test had higher mortality than genotype-negative patients. These findings support the extended use of genetic testing also in older patients.

Aims: Cardiac implantable electronic device (CIED) therapy is fundamental to the management of LMNA cardiomyopathy due to the high frequency of atrioventricular block and ventricular tachyarrhythmias. We aimed to define the role of cardiac resynchronization therapy (CRT) in impacting heart failure in LMNA cardiomyopathy., Methods and Results: From nine referral centres, LMNA cardiomyopathy patients who underwent CRT with available pre- and post-echocardiograms were identified retrospectively. Factors associated with CRT response were identified (defined as improvement in left ventricular ejection fraction [LVEF] ≥5% 6 months post-implant) and the associated impact on the primary outcome of death, implantation of a left ventricular assist device or cardiac transplantation was assessed. We identified 105 patients (mean age 51 ± 10 years) undergoing CRT, including 70 (67%) who underwent CRT as a CIED upgrade. The mean change in LVEF ∼6 months post-CRT was +4 ± 9%. A CRT response occurred in 40 (38%) patients and was associated with lower baseline LVEF or a high percentage of right ventricular pacing prior to CRT in patients with pre-existing CIED. In patients with a European Society of Cardiology class I guideline indication for CRT, response rates were 61%. A CRT response was evident at thresholds of LVEF ≤45% or percent pacing ≥50%. There was a 1.3 year estimated median difference in event-free survival in those who responded to CRT (p = 0.04)., Conclusion: Systolic function improves in patients with LMNA cardiomyopathy who undergo CRT, especially with strong guideline indications for implantation. Post-CRT improvements in LVEF are associated with survival benefits in this population with otherwise limited options., (© 2022 European Society of Cardiology.)

Arrhythmogenic cardiomyopathy (ACM) is an inherited heart muscle disorder characterized by progressive replacement of cardiomyocytes by fibrofatty tissue, ventricular dilatation, cardiac dysfunction, arrhythmias, and sudden cardiac death. Interest in molecular biomechanics for these disorders is constantly growing. Atomic force microscopy (AFM) is a well-established technic to study the mechanobiology of biological samples under physiological and pathological conditions at the cellular scale. However, a review which described all the different data that can be obtained using the AFM (cell elasticity, adhesion behavior, viscoelasticity, beating force, and frequency) is still missing. In this review, we will discuss several techniques that highlight the potential of AFM to be used as a tool for assessing the biomechanics involved in ACM. Indeed, analysis of genetically mutated cells with AFM reveal abnormalities of the cytoskeleton, cell membrane structures, and defects of contractility. The higher the Young's modulus, the stiffer the cell, and it is well known that abnormal tissue stiffness is symptomatic of a range of diseases. The cell beating force and frequency provide information during the depolarization and repolarization phases, complementary to cell electrophysiology (calcium imaging, MEA, patch clamp). In addition, original data is also presented to emphasize the unique potential of AFM as a tool to assess fibrosis in cardiac tissue.

Single-cell adhesion measured with atomic force microscopy (AFM) offers outstanding time and force resolution and allows the investigation of many important phenomena with unmatched precision. However, this technique suffers from serious practical limitations that hinder its effective application to a broader set of situations. Here we propose a different strategy based on the fabrication of large cantilevers and on the culture of the cells directly on them. Cantilevers are fabricated by standard micromachining, with an active area of 300 × 300 µm. A wedged structure is created so that the cantilever surface lies parallel to the substrate when mounted on an AFM system, so that the adhesion measurement probes the whole surface area at the same time. Thanks to the large area, cells can be seeded and grown on the cantilevers the day before the experiment, and let recover to optimal condition for the experiment. We used Human Embryonic Kidney cells, HEK 293A, to demonstrate the measurement of adhesion forces of up to 100 cells in parallel, and obtain a straightforward measurement of the average single cell adhesion energy. Our approach can improve significantly the cell-cell and cell-substrate adhesion statistics, reduce the experiment time and allow the investigation of the adhesion properties of cells that do not grow well in solution or on low adherent substrates, or that develop their characteristic features only after several hours or days of culture on a solid and adherent substrate., (© 2021. European Biophysical Societies' Association.)

Muscular dystrophies (MDs) are a group of inherited disorders caused by mutations that interfere with muscular structure, contraction, or relaxation. As the cardiac sarcomeric unit shares multiple proteins with the skeletal muscle unit, the heart is affected in several MDs, sometimes without apparent musculoskeletal involvement. Early detection of MD-related cardiomyopathy is crucial as timely initiation of cardioprotective therapy can slow adverse cardiac remodeling. Although transthoracic echocardiography is widely used for the evaluation of cardiac morphology and function, it has limitations in terms of reproducibility and image quality. The need for an optimal acoustic window may be particularly challenging to obtain in patients with MDs given their body habitus and position. Cardiac magnetic resonance (CMR) imaging has emerged as a useful tool in the evaluation of patients with MDs. Its superb tissue characterization capability through late gadolinium enhancement, T1 mapping, extracellular volume fraction quantification, and edema imaging detects early cardiac involvement, even when echocardiography and electrocardiogram are unremarkable. MDs that frequently present with cardiac involvement include Duchenne MD, Becker MD, Emery Dreifuss MD, Limb-Girdle MDs, and myotonic dystrophy. The purpose of this review article is to briefly describe the pathophysiology of these entities, discuss their clinical presentation and expected evolution, explain the role of CMR in the diagnosis and follow-up of these patients, and portray the different CMR findings present in MD patients., (Copyright © 2021 Elsevier Inc. All rights reserved.)

FLNC truncating mutations ( FLNCtv ) are prevalent causes of inherited dilated cardiomyopathy (DCM), with a high risk of developing arrhythmogenic cardiomyopathy. We investigated the molecular mechanisms of mutant FLNC in the pathogenesis of arrhythmogenic DCM (a-DCM) using patient-specific induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). We demonstrated that iPSC-CMs from two patients with different FLNCtv mutations displayed arrhythmias and impaired contraction. FLNC ablation induced a similar phenotype, suggesting that FLNCtv are loss-of-function mutations. Coimmunoprecipitation and proteomic analysis identified β-catenin (CTNNB1) as a downstream target. FLNC deficiency induced nuclear translocation of CTNNB1 and subsequently activated the platelet-derived growth factor receptor alpha (PDGFRA) pathway, which were also observed in human hearts with a-DCM and FLNCtv . Treatment with the PDGFRA inhibitor, crenolanib, improved contractile function of patient iPSC-CMs. Collectively, our findings suggest that PDGFRA signaling is implicated in the pathogenesis, and inhibition of this pathway is a potential therapeutic strategy in FLNC-related cardiomyopathies.

Dilated cardiomyopathy (DCM) is one of the most common cardiac phenotypes caused by mutations of lamin A/C (LMNA) gene in humans. In our study, a cohort of 57 patients who underwent heart transplant for dilated cardiomyopathy was screened for variants in LMNA. We identified a synonymous variant c.936G>A in the last nucleotide of exon 5 of LMNA in a DCM family. Clinically, the LMNA variant carriers presented with severe familial DCM, conduction disease, and high creatine-kinase level. The LMNA c.936G>A variant is novel and has not been reported in current genetic variant databases. Sanger sequencing results showed the presence of LMNA c.936G>A variant in the genomic DNA but not in the cDNA derived from one family member's heart tissue. Real-time quantitative polymerase chain reaction showed significantly lower LMNA mRNA levels in the patient's heart compared to the controls, suggesting that the c.936G>A LMNA variant resulted in reduced mRNA and possibly lower protein expression of LMNA. These findings expand the understanding on the association between synonymous variant of LMNA and the molecular pathogenesis in DCM patients., (© 2021 Wiley Periodicals LLC.)

In the wide phenotypic spectrum of cardiomyopathies, sudden cardiac death (SCD) has always been the most visible and devastating disease complication. The introduction of implantable cardioverter-defibrillators for SCD prevention by the late 1980s has moved the question from how to whom we should protect from SCD, leaving clinicians with a measure of uncertainty regarding the most reliable option to guide identification of the highest-risk patients. In this review, we will go through all the available evidence in the field of arrhythmic expression and arrhythmic risk stratification in the different phenotypes of cardiomyopathies to provide practical suggestions in daily clinical management., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background Myocardial strain can identify subclinical left ventricular dysfunction in various cardiac diseases, but its association with clinical outcomes in genetic cardiomyopathies remains unknown. Herein, we assessed myocardial strain in patients with Danon disease (DD), a rare X-linked autophagic disorder that causes severe cardiac manifestations. Methods and Results Echocardiographic images were reviewed and used to calculate myocardial strain from a retrospective, international registry of patients with DD. Regression analyses were performed to evaluate for an association of global longitudinal strain (GLS) and ejection fraction with the composite outcome (death, ventricular assist device, heart transplantation, and implantable cardioverter defibrillator for secondary prevention). A total of 22 patients with DD (male 14 [63.6%], median age 16.5 years) had sufficient echocardiograms for analysis. Absolute GLS was reduced with a mean of 12.2% with an apical-sparing pattern observed. Univariable regression for GLS and composite outcome showed an odds ratio of 1.32 (95% CI, 1.02-1.71) with P =0.03. For receiver operating characteristic analysis, the areas under the curve for GLS and ejection fraction were 0.810 ( P =0.02) and 0.605 ( P =0.44), respectively. An absolute GLS cutoff of 10.0% yielded a true positive rate of 85.7% and false positive rate of 13.3%. Conclusions In this cohort of patients with DD, GLS may be a useful assessment of myocardial function and may predict clinical outcomes. This study highlights the potential use of myocardial strain phenotyping to monitor disease progression and potentially to predict clinical outcomes in DD and other genetic cardiomyopathies.

Background: Arrhythmogenic cardiomyopathy (ACM) is an emerging new concept of a life-threatening heart muscle disorder due not only to desmosome gene mutations, but also to non-desmosome genes, such as filamin C, lamin A/C, phospholamban, transmembrane protein 43, titin, SCN5A and RNA binding motif protein 20.Multi-modality imaging along with genetic testing are important tools for risk stratification to tailor treatment to a single patient. Cardiac magnetic resonance imaging (CMR) with late gadolinium enhancement (LGE) is the gold standard for evaluating left and right ventricular structure and function, edema, and fibrosis. The identification of regional fibrosis with LGE has prognostic value. The management of ACM involves several aspects: treatment of arrhythmias and heart failure, risk stratification, implantable cardioverter-defibrillator (ICD) placement, exercise restrictions, and life-style changes. The decision for ICD placement in ACM patients is not well established and should be made weighing risks and benefits. However, the presence of specific genotypes can allow a precision medicine approach. In ACM patients with only mild left ventricular dysfunction but phospholamban, filamin C or lamin A/C mutations, an ICD is now considered a reasonable approach., Aim of Review: We sought to provide an overview of clinical and genetic feature of arrhythmogenic cardiomyopathy providing epidemiology, imaging, diagnostic and treatment information, using a systematic genetic approach., Competing Interests: Declaration of interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Aims: This study aimed to estimate the annual mortality risk and its determinants in chronic Chagas cardiomyopathy., Methods and Results: We conducted a systematic search in MEDLINE, Web of Science Core Collection, Embase, Cochrane Library, and LILACS. Longitudinal studies published between 1 January 1946 and 24 October 2018 were included. A random-effects meta-analysis using the death rate over the mean follow-up period in years was used to obtain pooled estimated annual mortality rates. Main outcomes were defined as all-cause mortality, including cardiovascular, non-cardiovascular, heart failure, stroke, and sudden cardiac deaths. A total of 5005 studies were screened for eligibility. A total of 52 longitudinal studies for chronic Chagas cardiomyopathy including 9569 patients and 2250 deaths were selected. The meta-analysis revealed an annual all-cause mortality rate of 7.9% [95% confidence interval (CI): 6.3-10.1; I 2  = 97.74%; T 2  = 0.70] among patients with chronic Chagas cardiomyopathy. The pooled estimated annual cardiovascular death rate was 6.3% (95% CI: 4.9-8.0; I 2  = 96.32%; T 2  = 0.52). The annual mortality rates for heart failure, sudden death, and stroke were 3.5%, 2.6%, and 0.4%, respectively. Meta-regression showed that low left ventricular ejection fraction (coefficient = -0.04; 95% CI: -0.07, -0.02; P = 0.001) was associated with an increased mortality risk. Subgroup analysis based on American Heart Association (AHA) classification revealed pooled estimate rates of 4.8%, 8.7%, 13.9%, and 22.4% (P < 0.001) for B1/B2, B2/C, C, and C/D stages of cardiomyopathy, respectively., Conclusions: The annual mortality risk in chronic Chagas cardiomyopathy is substantial and primarily attributable to cardiovascular causes. This risk significantly increases in patients with low left ventricular ejection fraction and those classified as AHA stages C and C/D., (© 2021 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of European Society of Cardiology.)

Background: Filamin C truncating variants ( FLNCtv ) cause a form of arrhythmogenic cardiomyopathy: the mode of presentation, natural history, and risk stratification of FLNCtv remain incompletely explored. We aimed to develop a risk profile for refractory heart failure and life-threatening arrhythmias in a multicenter cohort of FLNCtv carriers., Methods: FLNCtv carriers were identified from 10 tertiary care centers for genetic cardiomyopathies. Clinical and outcome data were compiled. Composite outcomes were all-cause mortality/heart transplantation/left ventricle assist device (D/HT/LVAD), nonarrhythmic death/HT/LVAD, and sudden cardiac death/major ventricular arrhythmias. Previously established cohorts of 46 patients with LMNA and 60 with DSP -related arrhythmogenic cardiomyopathies were used for prognostic comparison., Results: Eighty-five patients carrying FLNCtv were included (42±15 years, 53% men, 45% probands). Phenotypes were heterogeneous at presentation: 49% dilated cardiomyopathy, 25% arrhythmogenic left dominant cardiomyopathy, 3% arrhythmogenic right ventricular cardiomyopathy. Left ventricular ejection fraction was <50% in 64% of carriers and 34% had right ventricular fractional area changes (RVFAC=(right ventricular end-diastolic area - right ventricular end-systolic area)/right ventricular end-diastolic area) <35%. During follow-up (median time 61 months), 19 (22%) carriers experienced D/HT/LVAD, 13 (15%) experienced nonarrhythmic death/HT/LVAD, and 23 (27%) experienced sudden cardiac death/major ventricular arrhythmias. The sudden cardiac death/major ventricular arrhythmias incidence of FLNCtv carriers did not significantly differ from LMNA carriers and DSP carriers. In FLNCtv carriers, left ventricular ejection fraction was associated with the risk of D/HT/LVAD and nonarrhythmic death/HT/LVAD., Conclusions: Among patients referred to tertiary referral centers, FLNCtv arrhythmogenic cardiomyopathy is phenotypically heterogeneous and characterized by a high risk of life-threatening arrhythmias, which does not seem to be associated with the severity of left ventricular dysfunction.