Association between mutation status and left ventricular reverse remodelling in dilated cardiomyopathy

Genetic variants in patients with recurrent pericarditis

AIMS

Presence of family cases and multiple recurrences of pericarditis suggest the existence of a possible genetic background in at least 10% of cases. The aim of the present study is to describe the genetic landscape of a cohort of patients with multiple recurrences (at least two recurrences).

METHODS

Retrospective cohort study of consecutive adult patients referred for at least two episodes of recurrences in a tertiary referral centre. Genetic testing was performed by whole exome sequencing (WES).

RESULTS

Our cohort included 108 consecutive patients with recurrent pericarditis [median age 32 years, interquartile range (IQR) 18.5; 67.6% females, all Caucasian, idiopathic aetiology in 71.1%] with a median number of recurrences of 5 (IQR 2). Overall, 16 patients (14.8%) had variants in genes related to the inflammatory response. Eleven variants were located in genes already associated with recurrent pericarditis (NLRP3, TNFRSF1A and MEFV) and five in inflammation/immunodeficiency-related genes (IFIH1, NFKBIA, JAK1, NOD2 and ALPK1). Furthermore, we identified 10 patients with variants located in genes associated with conduction system-related diseases, and 22 variants in 21 patients with genes associated with heart structural-related diseases.

CONCLUSION

In this first observational study using WES to assess genetic variants in patients with multiple recurrences of pericarditis, about 15% of patients bore at least one variant that may be related to the disease. These findings highlight the importance of addressing the role of genetic predisposition in recurrent pericarditis. Moreover, 28.7% of patients carry variants in different cardiac genes, worthy of a deeper investigation.

Pathophysiology of dilated cardiomyopathy: from mechanisms to precision medicine

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.

Nexilin in cardiomyopathy: unveiling its diverse roles with special focus on endocardial fibroelastosis

Cardiac disorders exhibit considerable heterogeneity, and understanding their genetic foundations is crucial for their diagnosis and treatment. Recent genetic analyses involving a growing number of participants have uncovered novel mutations within both coding and non-coding regions of DNA, contributing to the onset of cardiac conditions. The NEXN gene, encoding the Nexilin protein, an actin filament-binding protein, is integral to normal cardiac function. Mutations in this gene have been linked to cardiomyopathies, cardiovascular disorders, and sudden deaths. Heterozygous or homozygous variants of the NEXN gene are associated with the development of endocardial fibroelastosis (EFE), a rare cardiac condition characterized by excessive collagen and elastin deposition in the left ventricular endocardium predominantly affecting infants and young children. EFE occurs both primary and secondary to other conditions and often leads to unfavorable prognoses and outcomes. This review explores the role of NEXN genetic variants in cardiovascular disorders, particularly EFE, revealing that functional mutations are not clustered in a specific domain of Nexilin based on the cardiac disorder phenotype. Our review underscores the importance of understanding genetic mutations for the diagnosis and treatment of cardiac conditions.

Cardiac genetic test yields and genotype-phenotype correlations from large cohort investigated by medical examiner's office

BACKGROUND

Few reports describe the yield of postmortem genetic testing from medical examiners' offices or correlate genetic test results with autopsy-confirmed phenotypes from a large cohort.

OBJECTIVES

To report results from cardiomyopathy- and cardiac arrhythmia-associated genetic testing in conjunction with autopsy findings of cases investigated at the United States' largest medical examiner office.

METHODS

Postmortem cases tested from 2015 to 2022 with a cardiomyopathy- and cardiac arrhythmia-associated gene panel were reviewed. American College of Medical Genetics and Genomics/Association for Molecular Pathology guidelines were used to classify variant pathogenicity. Correlations of pathogenic/likely pathogenic variants (P/LPVs) with cardiac pathology were evaluated.

RESULTS

The cohort included 1107 decedents of diverse ages and ethnicities. P/LPVs were detected in 87 (7.9%) cases, with 73 and 14 variants in cardiomyopathy and cardiac arrhythmia genes, respectively. Variants of uncertain significance were detected in 437 (39.5%) cases. The diagnostic yield (percentage of P/LPV) in decedents with cardiomyopathy (26.1%) was significantly higher than those without (P<.0001). The diagnostic yield was significantly lower in infants (0.7%) than older age groups (ranging from 1 to 74 years old, 5.7%-25.9%), which had no statistical difference between their yields. The diagnostic yields by cardiac autopsy findings were 54.0% for hypertrophic cardiomyopathy, 47.1% for arrhythmogenic cardiomyopathy, 20.0% for myocardial fibrosis, 19.0% for dilated cardiomyopathy, and 11.3% for myocarditis. Most P/LPVs were in MYBPC3, TTN, PKP2, SCN5A, MYH7, and FLNC. Ten P/LPVs were novel.

CONCLUSIONS

Our results support the importance of performing postmortem genetic testing on decedents of all ages with cardiomyopathy, cardiac lesions insufficient to diagnosis a specific cardiomyopathy (e.g., myocardial fibrosis), and myocarditis. Combined postmortem cardiac examination and genetic analysis are advantageous in accurately determining the underlying cause of death and informing effective clinical care of family members.

Prevalence of Genetically Associated Dilated Cardiomyopathy: A Systematic Literature Review and Meta-Analysis

Background

Dilated cardiomyopathy (DCM) is a leading cause of heart failure and cardiac transplantation globally. Disease-associated genetic variants play a significant role in the development of DCM. Accurately determining the prevalence of genetically associated DCM (genetic DCM) is important for developing targeted prevention strategies. This review synthesized published literature on the global prevalence of genetic DCM across various populations, focusing on two of the most common variants: titin (TTN) and myosin heavy chain 7 (MYH7).

Methods

MEDLINE® and Embase were searched from database inception to September 19, 2022 for English-language studies reporting the prevalence of genetic DCM within any population. Studies using family history as a proxy for genetic DCM were excluded.

Results

Of 2,736 abstracts, 57 studies were included. Among the global adult or mixed (mostly adults with few pediatric patients) DCM population, median prevalence was 20.2% (interquartile range (IQR): 16.3-36.0%) for overall genetic DCM, 11.4% (IQR: 8.2-17.8%) for TTN-associated DCM, and 3.2% (IQR: 1.8-5.2%) for MYH7-associated DCM. Global prevalence of overall pediatric genetic DCM within the DCM population was similar (weighted mean: 21.3%). Few studies reported data on the prevalence of genetic DCM within the general population.

Conclusions

Our study identified variable prevalence estimates of genetic DCM across different populations and geographic locations. The current evidence may underestimate the genetic contributions due to limited screening and detection of potential DCM patients. Epidemiological studies using long-read whole genome sequencing to identify structural variants or non-coding variants are needed, as well as large cohort datasets with genotype-phenotype correlation analyses.

Impact of DCM-Causing Genetic Background on Long-Term Response to Cardiac Resynchronization Therapy

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.

Transient Left Ventricular Dysfunction from Cardiomyopathies to Myocardial Viability: When and Why Cardiac Function Recovers

Transient left ventricular dysfunction (TLVD), a temporary condition marked by reversible impairment of ventricular function, remains an underdiagnosed yet significant contributor to morbidity and mortality in clinical practice. Unlike the well-explored atherosclerotic disease of the epicardial coronary arteries, the diverse etiologies of TLVD require greater attention for proper diagnosis and management. The spectrum of disorders associated with TLVD includes stress-induced cardiomyopathy, central nervous system injuries, histaminergic syndromes, various inflammatory diseases, pregnancy-related conditions, and genetically determined syndromes. Furthermore, myocardial infarction with non-obstructive coronary arteries (MINOCA) origins such as coronary artery spasm, coronary thromboembolism, and spontaneous coronary artery dissection (SCAD) may also manifest as TLVD, eventually showing recovery. This review highlights the range of ischemic and non-ischemic clinical situations that lead to TLVD, gathering conditions like Tako-Tsubo Syndrome (TTS), Kounis syndrome (KS), Myocarditis, Peripartum Cardiomyopathy (PPCM), and Tachycardia-induced cardiomyopathy (TIC). Differentiation amongst these causes is crucial, as they involve distinct clinical, instrumental, and genetic predictors that bode different outcomes and recovery potential for left ventricular function. The purpose of this review is to improve everyday clinical approaches to treating these diseases by providing an extensive survey of conditions linked with TLVD and the elements impacting prognosis and outcomes.

Myocardial DNA Damage Predicts Heart Failure Outcome in Various Underlying Diseases

BACKGROUND

Reliable predictors of treatment efficacy in heart failure have been long awaited. DNA damage has been implicated as a cause of heart failure.

OBJECTIVES

The purpose of this study was to investigate the association of DNA damage in myocardial tissue with treatment response and prognosis of heart failure.

METHODS

The authors performed immunostaining of DNA damage markers poly(ADP-ribose) (PAR) and γ-H2A.X in endomyocardial biopsy specimens from 175 patients with heart failure with reduced ejection fraction (HFrEF) of various underlying etiologies. They calculated the percentage of nuclei positive for each DNA damage marker (%PAR and %γ-H2A.X). The primary outcome was left ventricular reverse remodeling (LVRR) at 1 year, and the secondary outcome was a composite of cardiovascular death, heart transplantation, and ventricular assist device implantation.

RESULTS

Patients who did not achieve LVRR after the optimization of medical therapies presented with significantly higher %PAR and %γ-H2A.X. The ROC analysis demonstrated good performance of both %PAR and %γ-H2A.X for predicting LVRR (AUCs: 0.867 and 0.855, respectively). There was a negative correlation between the mean proportion of DNA damage marker-positive nuclei and the probability of LVRR across different underlying diseases. In addition, patients with higher %PAR or %γ-H2A.X had more long-term clinical events (PAR HR: 1.63 [95% CI: 1.31-2.01]; P < 0.001; γ-H2A.X HR: 1.48 [95% CI: 1.27-1.72]; P < 0.001).

CONCLUSIONS

DNA damage determines the consequences of human heart failure. Assessment of DNA damage is useful to predict treatment efficacy and prognosis of heart failure patients with various underlying etiologies.

Mechanisms of RBM20 Cardiomyopathy: Insights From Model Systems

RBM20 (RNA-binding motif protein 20) is a vertebrate- and muscle-specific RNA-binding protein that belongs to the serine-arginine-rich family of splicing factors. The RBM20 gene was first identified as a dilated cardiomyopathy-linked gene over a decade ago. Early studies in Rbm20 knockout rodents implicated disrupted splicing of RBM20 target genes as a causative mechanism. Clinical studies show that pathogenic variants in RBM20 are linked to aggressive dilated cardiomyopathy with early onset heart failure and high mortality. Subsequent studies employing pathogenic variant knock-in animal models revealed that variants in a specific portion of the arginine-serine-rich domain in RBM20 not only disrupt splicing but also hinder nucleocytoplasmic transport and lead to the formation of RBM20 biomolecular condensates in the sarcoplasm. Conversely, mice harboring a disease-associated variant in the RRM (RNA recognition motif) do not show evidence of adverse remodeling or exhibit sudden death despite disrupted splicing of RBM20 target genes. Thus, whether disrupted splicing, biomolecular condensates, or both contribute to dilated cardiomyopathy is under debate. Beyond this, additional questions remain, such as whether there is sexual dimorphism in the presentation of RBM20 cardiomyopathy. What are the clinical features of RBM20 cardiomyopathy and why do some individuals develop more severe disease than others? In this review, we summarize the reported observations and discuss potential mechanisms of RBM20 cardiomyopathy derived from studies employing in vivo animal models and in vitro human-induced pluripotent stem cell-derived cardiomyocytes. Potential therapeutic strategies to treat RBM20 cardiomyopathy are also discussed.

Heart failure with improved ejection fraction: Beyond diagnosis to trajectory analysis

Left ventricular (LV) systolic dysfunction represents a highly treatable cause of heart failure (HF). A substantial proportion of patients with HF with reduced ejection fraction (EF;HFrEF) demonstrate improvement in LV systolic function (termed HF with improved EF [HFimpEF]), either spontaneously or when treated with guideline-directed medical therapy (GDMT). Although it is a relatively new HF classification, HFimpEF has emerged in recent years as an important and distinct clinical entity. Improvement in LVEF leads to decreased rates of mortality and adverse HF-related outcomes compared to patients with sustained LV systolic dysfunction (HFrEF). While numerous clinical and imaging factors have been associated with HFimpEF, identification of which patients do and do not improve requires further investigation. In addition, patients improve at different rates, and what determines the trajectory of HFimpEF patients after improvement is incompletely characterized. A proportion of patients maintain improvement in LV systolic function, while others experience a recrudescence of systolic dysfunction, especially with GDMT discontinuation. In this review we discuss the contemporary guideline-recommended classification definition of HFimpEF, the epidemiology of improvement in LV systolic function, and the clinical course of this unique patient population. We also offer evidence-based recommendations for the clinical management of HFimpEF and provide a roadmap for future directions in understanding and improving outcomes in the care of patients with HFimpEF.

Your Heart Function Has Normalized-What Next After TRED-HF?

PURPOSE OF REVIEW

With the widespread implementation of contemporary disease-modifying heart failure therapy, the rates of normalization of ejection fraction are continuously increasing. The TRED-HF trial confirmed that heart failure remission rather than complete recovery is typical in patients with dilated cardiomyopathy who respond to therapy. The present review outlines key points related to the management and knowledge gaps of this growing patient group, focusing on patients with non-ischaemic dilated cardiomyopathy.

RECENT FINDINGS

There is substantial heterogeneity among patients with normalized ejection fraction. The specific etiology is likely to affect the outcome, although a multiple-hit phenotype is frequent and may not be identified without comprehensive characterization. A monogenic or polygenic genetic susceptibility is common. Ongoing pathophysiological processes may be unraveled with advanced cardiac imaging, biomarkers, multi-omics, and machine learning technologies. There are limited studies that have investigated the withdrawal of specific heart failure therapies in these patients. Diuretics may be safely withdrawn if there is no evidence of congestion, while continued therapy with at least some disease-modifying therapy is likely to be required to reduce myocardial workload and sustain remission for the vast majority. Understanding the underlying disease mechanisms of patients with normalized ejection fraction is crucial in identifying markers of myocardial relapse and guiding individualized therapy in the future. Ongoing clinical trials should inform personalized approaches to therapy.

From Death to Life/Back to the Future: Detailed Premorbid Clinical and Family History Can Save Lives and Address the Final Diagnosis in Sudden Unexplained Deaths With Negative Autopsy

Sudden cardiac death is a sudden, unexpected death developed by one of the many different causes of cardiac arrest that occur within 1 hour of the onset of new symptoms. Sudden unexplained death (SUD) comprises a normal heart at postmortem examination and negative toxicological analysis. SUD often arises from cardiac genetic disease, particularly channelopathies. Channelopathies, or inherited arrhythmia syndromes, are a group of disorders characterized by an increased risk of sudden cardiac death, abnormal cardiac electrical function, and, typically, a structurally normal heart. They share an underlying genetic etiology where disease-causing genetic variants may lead to the absence or dysfunction of proteins involved in the generation and propagation of the cardiac action potential. Our study aimed to evaluate the importance of next-generation sequencing in the postmortem investigations of SUD cases. In this study, 5 forensic SUD cases were investigated for inherited cardiac disorders. We screened a total of 68 cardiac genes for the sibling of case 1, as well as case 2, and 51 genes for cases 3, 4, and 5. Of the 12 variants identified, 2 likely pathogenic variants (16.7%) were the TMEM43 _ c.1000+2T>C splice site mutation and the SCN5A _ p.W703X nonsense mutation. The remaining 10 variants of uncertain significance were detected in the TRPM4 , RANGRF , A KAP9 , KCND3 , KCNE1 , DSG2 , CASQ1 , and SNTA1 genes. Irrespective of genetic testing, all SUD families require detailed clinical testing to identify relatives who may be at risk. Molecular autopsy and detailed premorbid clinical and family histories can survive family members of SUD cases.

Caenorhabditis elegans models for striated muscle disorders caused by missense variants of human LMNA

Striated muscle laminopathies caused by missense mutations in the nuclear lamin gene LMNA are characterized by cardiac dysfunction and often skeletal muscle defects. Attempts to predict which LMNA variants are pathogenic and to understand their physiological effects lag behind variant discovery. We created Caenorhabditis elegans models for striated muscle laminopathies by introducing pathogenic human LMNA variants and variants of unknown significance at conserved residues within the lmn-1 gene. Severe missense variants reduced fertility and/or motility in C. elegans. Nuclear morphology defects were evident in the hypodermal nuclei of many lamin variant strains, indicating a loss of nuclear envelope integrity. Phenotypic severity varied within the two classes of missense mutations involved in striated muscle disease, but overall, variants associated with both skeletal and cardiac muscle defects in humans lead to more severe phenotypes in our model than variants predicted to disrupt cardiac function alone. We also identified a separation of function allele, lmn-1(R204W), that exhibited normal viability and swimming behavior but had a severe nuclear migration defect. Thus, we established C. elegans avatars for striated muscle laminopathies and identified LMNA variants that offer insight into lamin mechanisms during normal development.

Regression of cardiac hypertrophy in health and disease: mechanisms and therapeutic potential

Left ventricular hypertrophy is a leading risk factor for cardiovascular morbidity and mortality. Although reverse ventricular remodelling was long thought to be irreversible, evidence from the past three decades indicates that this process is possible with many existing heart disease therapies. The regression of pathological hypertrophy is associated with improved cardiac function, quality of life and long-term health outcomes. However, less than 50% of patients respond favourably to most therapies, and the reversibility of remodelling is influenced by many factors, including age, sex, BMI and disease aetiology. Cardiac hypertrophy also occurs in physiological settings, including pregnancy and exercise, although in these cases, hypertrophy is associated with normal or improved ventricular function and is completely reversible postpartum or with cessation of training. Studies over the past decade have identified the molecular features of hypertrophy regression in health and disease settings, which include modulation of protein synthesis, microRNAs, metabolism and protein degradation pathways. In this Review, we summarize the evidence for hypertrophy regression in patients with current first-line pharmacological and surgical interventions. We further discuss the molecular features of reverse remodelling identified in cell and animal models, highlighting remaining knowledge gaps and the essential questions for future investigation towards the goal of designing specific therapies to promote regression of pathological hypertrophy.

Diuretic dose trajectories in dilated cardiomyopathy: prognostic implications

BACKGROUND

For patients with heart failure, prescription of loop diuretics (LD) and of higher doses are associated with an adverse prognosis. We investigated LD dose trajectories and their associations with outcomes in patients with dilated cardiomyopathy (DCM).

METHODS

Associations between outcomes and both furosemide-equivalent dose (FED) at enrolment and change in FED in the subsequent 24 months were evaluated. According to FED trajectory, patients were classified as (i) dose↑ (FED increase by ≥ 50% or newly initiated); (ii) dose↓ (FED decrease by ≥ 50%); (iii) stable dose (change in FED by < 50%); and (iv) never-users. The primary outcome was all-cause-death/heart transplantation/ventricular-assist-device/heart failure hospitalization. The secondary outcome was all-cause-death/heart transplantation/ventricular-assist-device.

RESULTS

Of 1,131 patients enrolled, 738 (65%) were prescribed LD at baseline. Baseline FED was independently associated with outcome (HR per 20 mg increase: 1.12 [95% CI 1.04-1.22], p = 0.003). Of the 908 with information on FED within 24 months from enrolment, 31% were never-users; 29% were dose↓; 26% were stable dose and 14% were dose↑. In adjusted models, compared to never-users, stable dose had a higher risk of the primary outcome (HR 2.42 [95% CI 1.19-4.93], p = 0.015), while dose↑ had the worst prognosis (HR 2.76 [95% CI 1.27-6.03], p = 0.011). Results were similar for the secondary outcome. Compared to patients who remained on LD, discontinuation of LD (143, 24%) was associated with an improved outcome (HR 0.43 [95% CI 0.28-0.65], p < 0.001).

CONCLUSIONS

In patients with DCM, LD use and increasing FED are powerful markers of adverse outcomes. Patients who never receive LD have an excellent prognosis. Among 1131 DCM patients 65% received loop diuretics at enrolment (upper left side). The bar chart on the upper right side shows the categorization in never-users/ dose↓/stable dose/ dose↑ over 24 months of follow-up. At the bottom is reported on the left side of each panel (observation period) the trajectory of LD dose in the four groups (left panel) and in patients who have their LD suspended vs those who continue LD (right panel) in the first two years. On the right side of each panel is shown the incidence of primary outcomes during the subsequent follow-up in the subgroups (outcome assessment).

Heart failure with recovered ejection fraction: Current understanding and future prospects

Heart failure with reduced ejection fraction (HFrEF) is a prevalent kind of heart failure in which a significant amount of the ejection fraction can be repaired, and left ventricular remodeling and dysfunction can be reversed or even restored completely. However, a considerable number of patients still present clinical signs and biochemical features of incomplete recovery from the pathophysiology of heart failure and are at risk for adverse outcomes such as re-deterioration of systolic function and recurrence of HFrEF. Furthermore, it is revealed from a microscopic perspective that even if partial or complete reverse remodeling occurs, the morphological changes of cardiomyocytes, extracellular matrix deposition, and abnormal transcription and expression of pathological genes still exist. Patients with "recovered ejection fraction" have milder clinical symptoms and better outcomes than those with continued reduction of ejection fraction. Based on the unique characteristics of this subgroup and the existence of many unknowns, the academic community defines it as a new category-heart failure with recovered ejection fraction (HFrecEF). Because there is a shortage of natural history data for this population as well as high-quality clinical and basic research data, it is difficult to accurately evaluate clinical risk and manage this population. This review will present the current understanding of HFrecEF from the limited literature.

Prognostic Prediction of Genotype vs Phenotype in Genetic Cardiomyopathies

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.

Role of the electrocardiogram in differentiating genetically determined dilated cardiomyopathy from athlete's heart

BACKGROUND

Physiological cardiac remodelling in highly trained athletes may overlap with dilated cardiomyopathy (DCM).

OBJECTIVES

The aim of this study was to investigate the role of the electrocardiogram (ECG) in differentiating between physiological and pathological remodelling.

METHODS

The study population consisted of 30 patients with DCM who revealed a pathogenic variant at genetic testing and 30 elite athletes with significant cardiac remodelling defined by a left ventricular (LV) end-diastolic diameter >62 mm and/or LV ejection fraction between 45% and 50%.

RESULTS

The ECG was abnormal in 22 (73%) patients with DCM. The most common abnormalities were low voltages (n = 14, 47%), lateral T-wave inversion (TWI) (n = 6, 20%), ventricular ectopic beats (n = 5, 17%) and anterior TWI (n = 4, 13). Two athletes revealed an abnormal ECG: complete left bundle branch block (LBBB) in one case and atrial flutter in the other. The sensitivity, specificity and accuracy of the ECG in differentiating DCM from physiological adaptation to exercise in athletes was 73% (confidence interval [CI]: 54%-88%), 93% (CI: 78%-99%) and 0.83 (CI: 0.71-0.92) respectively.

CONCLUSIONS

While the ECG is usually normal in athletes exhibiting significant LV dilatation and/or systolic dysfunction, this test is often abnormal in patients with DCM harbouring a pathogenic variant. Low voltages in the limb leads and lateral TWI are the most common abnormalities.

Determining the Likelihood of Disease Pathogenicity Among Incidentally Identified Genetic Variants in Rare Dilated Cardiomyopathy-Associated Genes

Background As utilization of clinical exome sequencing (ES) has expanded, criteria for evaluating the diagnostic weight of incidentally identified variants are critical to guide clinicians and researchers. This is particularly important in genes associated with dilated cardiomyopathy (DCM), which can cause heart failure and sudden death. We sought to compare the frequency and distribution of incidentally identified variants in DCM-associated genes between a clinical referral cohort with those in control and known case cohorts to determine the likelihood of pathogenicity among those undergoing genetic testing for non-DCM indications. Methods and Results A total of 39 rare, non-TTN DCM-associated genes were identified and evaluated from a clinical ES testing referral cohort (n=14 005, Baylor Genetic Laboratories) and compared with a DCM case cohort (n=9442) as well as a control cohort of population variants (n=141 456) derived from the gnomAD database. Variant frequencies in each cohort were compared. Signal-to-noise ratios were calculated comparing the DCM and ES cohort with the gnomAD cohort. The likely pathogenic/pathogenic variant yield in the DCM cohort (8.2%) was significantly higher than in the ES cohort (1.9%). Based on signal-to-noise and correlation analysis, incidental variants found in FLNC, RBM20, MYH6, DSP, ABCC9, JPH2, and NEXN had the greatest chance of being DCM-associated. Conclusions The distribution of pathogenic variants between the ES cohort and the DCM case cohort was gene specific, and variants found in the ES cohort were similar to variants found in the control cohort. Incidentally identified variants in specific genes are more associated with DCM than others.

Clinical Risk Score to Predict Pathogenic Genotypes in Patients With Dilated Cardiomyopathy

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.

Dilated cardiomyopathy in the era of precision medicine: latest concepts and developments

Dilated cardiomyopathy (DCM) is an umbrella term entailing a wide variety of genetic and non-genetic etiologies, leading to left ventricular systolic dysfunction and dilatation, not explained by abnormal loading conditions or coronary artery disease. The clinical presentation can vary from asymptomatic to heart failure symptoms or sudden cardiac death (SCD) even in previously asymptomatic individuals. In the last 2 decades, there has been striking progress in the understanding of the complex genetic basis of DCM, with the discovery of additional genes and genotype-phenotype correlation studies. Rigorous clinical work-up of DCM patients, meticulous family screening, and the implementation of advanced imaging techniques pave the way for a more efficient and earlier diagnosis as well as more precise indications for implantable cardioverter defibrillator implantation and prevention of SCD. In the era of precision medicine, genotype-directed therapies have started to emerge. In this review, we focus on updates of the genetic background of DCM, characteristic phenotypes caused by recently described pathogenic variants, specific indications for prevention of SCD in those individuals and genotype-directed treatments under development. Finally, the latest developments in distinguishing athletic heart syndrome from subclinical DCM are described.

Cardiac remodelling - Part 2: Clinical, imaging and laboratory findings. A review from the Study Group on Biomarkers of the Heart Failure Association of the European Society of Cardiology

In patients with heart failure, the beneficial effects of drug and device therapies counteract to some extent ongoing cardiac damage. According to the net balance between these two factors, cardiac geometry and function may improve (reverse remodelling, RR) and even completely normalize (remission), or vice versa progressively deteriorate (adverse remodelling, AR). RR or remission predict a better prognosis, while AR has been associated with worsening clinical status and outcomes. The remodelling process ultimately involves all cardiac chambers, but has been traditionally evaluated in terms of left ventricular volumes and ejection fraction. This is the second part of a review paper by the Study Group on Biomarkers of the Heart Failure Association of the European Society of Cardiology dedicated to ventricular remodelling. This document examines the proposed criteria to diagnose RR and AR, their prevalence and prognostic value, and the variables predicting remodelling in patients managed according to current guidelines. Much attention will be devoted to RR in patients with heart failure with reduced ejection fraction because most studies on cardiac remodelling focused on this setting.

The benefits of the earlier use of sacubitril/valsartan in de novo heart failure with reduced ejection fraction patients

Aims

We evaluated the clinical outcomes and trajectory of cardiac reverse remodelling according to the timing of sacubitril/valsartan (Sac/Val) use in patients with heart failure (HF) with reduced ejection fraction (HFrEF).

Methods and results

Patients with de novo HFrEF who used Sac/Val between June 2017 and October 2019 were retrospectively enrolled. Patients were grouped into the earlier use group (initiation of Sac/Val < 3 months after the first HFrEF diagnosis) and the later use group (initiation of Sac/Val ≥ 3 months after the first HFrEF diagnosis). Primary outcome was a composite of HF hospitalization and cardiac death. Secondary outcomes were HF hospitalization, cardiac death, all‐cause death, significant ventricular arrhythmia (ventricular tachycardia or ventricular fibrillation), and echocardiographic evidence of cardiac reverse remodelling including left ventricular ejection fraction (LVEF) change during follow‐up. Among 115 enrolled patients, 67 were classified in the earlier use group, and 48 were classified in the later use group. Mean period of HFrEF diagnosis to Sac/Val use was 52.1 ± 14.3 days in the earlier use group, and 201.8 ± 127.3 days in the later use group. During the median follow‐up of 721 days, primary outcome occurred in 21 patients (18.3%). The earlier use group experienced significantly fewer primary outcome than the later use group (10.4% vs. 29.2%, P = 0.010). The Kaplan–Meier survival curve showed better event‐free survival in the earlier use group than in the later use group (log rank = 0.017). There were no significant differences in cardiac death, all‐cause death, and ventricular arrhythmia between two groups (1.5% vs. 2.1%, P = 0.811; 1.5% vs. 4.2%, P = 0.375; 3.0% vs. 0%, P = 0.227, respectively). Despite a significantly lower baseline LVEF in the earlier use group (21.3 ± 6.4% vs. 24.8 ± 7.9%, P = 0.012), an early prominent increase of LVEF was noted before 6 months (35.2 ± 11.9% vs. 27.8 ± 8.8%, P = 0.007). A delayed improvement of LVEF in the later use group resulted in similar LVEF at last follow‐up in both groups (40.7 ± 13.4% vs. 39.4 ± 10.9%, P = 0.686). Although the trajectory of left ventricular remodelling showed similar pattern in two groups, left atrial (LA) reverse remodelling was less prominent in the later use group during the follow‐up period (final LA volume index: 43.6 ± 14.3 mL/m² vs. 55.2 ± 17.1 mL/m², P = 0.011).

Conclusions

Earlier use of Sac/Val was related with better clinical outcome and earlier left ventricular reverse remodelling. Remodelling of LA was less prominent in the later use group implying delayed response in diastolic function.

Left ventricular reverse remodelling and its predictors in non-ischaemic cardiomyopathy

Adverse remodelling following an initial insult is the hallmark of heart failure (HF) development and progression. It is manifested as changes in size, shape, and function of the myocardium. While cardiac remodelling may be compensatory in the short term, further neurohumoral activation and haemodynamic overload drive this deleterious process that is associated with impaired prognosis. However, in some patients, the changes may be reversed. Left ventricular reverse remodelling (LVRR) is characterized as a decrease in chamber volume and normalization of shape associated with improvement in both systolic and diastolic function. LVRR might occur spontaneously or more often in response to therapeutic interventions that either remove the initial stressor or alleviate some of the mechanisms that contribute to further deterioration of the failing heart. Although the process of LVRR in patients with new‐onset HF may take up to 2 years after initiating treatment, there is a significant portion of patients who do not improve despite optimal therapy, which has serious clinical implications when considering treatment escalation towards more aggressive options. On the contrary, in patients that achieve delayed improvement in cardiac function and architecture, waiting might avoid untimely implantable cardioverter‐defibrillator implantation. Therefore, prognostication of successful LVRR based on clinical, imaging, and biomarker predictors is of utmost importance. LVRR has a positive impact on prognosis. However, reverse remodelled hearts continue to have abnormal features. In fact, most of the molecular, cellular, interstitial, and genome expression abnormalities remain and a susceptibility to dysfunction redevelopment under biomechanical stress persists in most patients. Hence, a distinction should be made between reverse remodelling and true myocardial recovery. In this comprehensive review, current evidence on LVRR, its predictors, and implications on prognostication, with a specific focus on HF patients with non‐ischaemic cardiomyopathy, as well as on novel drugs, is presented.

Association of Titin Variations With Late-Onset Dilated Cardiomyopathy

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.

Missense Mutations in Desmoplakin Plakin Repeat Domains Have Dramatic Effects on Domain Structure and Function

Plakin repeat domains (PRDs) are globular modules that mediate the interaction of plakin proteins with the intermediate filament (IF) cytoskeleton. These associations are vital for maintaining tissue integrity in cardiac muscle and epithelial tissues. PRDs are subject to mutations that give rise to cardiomyopathies such as arrhythmogenic right ventricular cardiomyopathy, characterised by ventricular arrhythmias and associated with an increased risk of sudden heart failure, and skin blistering diseases. Herein, we have examined the functional and structural effects of 12 disease-linked missense mutations, identified from the human gene mutation database, on the PRDs of the desmosomal protein desmoplakin. Five mutations (G2056R and E2193K in PRD-A, G2338R and G2375R in PRD-B and G2647D in PRD-C) rendered their respective PRD proteins either fully or partially insoluble following expression in bacterial cells. Each of the residues affected are conserved across plakin family members, inferring a crucial role in maintaining the structural integrity of the PRD. In transfected HeLa cells, the mutation G2375R adversely affected the targeting of a desmoplakin C-terminal construct containing all three PRDs to vimentin IFs. The deletion of PRD-B and PRD-C from the construct compromised its targeting to vimentin. Bioinformatic and structural modelling approaches provided multiple mechanisms by which the disease-causing mutations could potentially destabilise PRD structure and compromise cytoskeletal linkages. Overall, our data highlight potential molecular mechanisms underlying pathogenic missense mutations and could pave the way for informing novel curative interventions targeting cardiomyopathies and skin blistering disorders.

Cardiac arrest as first presentation of arrhythmogenic left ventricular cardiomyopathy due to Filamin C mutation: a case report

Background

Arrhythmogenic left ventricular cardiomyopathy (ALVC) is a rare form of arrhythmogenic cardiomyopathy characterized by fibrofatty replacement of left ventricular myocardium, malignant arrhythmia, and sudden cardiac death. The definition incorporates several genetic causes, including pathogenic variation in the Filamin C gene (FLNC). Although awareness of ALVC has improved, identification remains challenging and diagnostic criteria continue to evolve.

Case summary

A 50-year-old athletic male was admitted following an out-of-hospital cardiac arrest due to ventricular tachycardia (VT) whilst playing football. Coronary angiography revealed unobstructed epicardial vessels and the diagnosis of ALVC was suggested by cardiovascular magnetic resonance imaging, which demonstrated a mildly dilated and moderately impaired left ventricle with epicardial late gadolinium enhancement in the basal to mid-lateral walls and subendocardial septum. Initial testing with a cardiomyopathy and arrhythmia gene panel was negative but extended testing uncovered a likely pathogenic variant in FLNC. Subsequently, the patient experienced a recurrence of sustained VT necessitating implantable cardioverter-defibrillator (ICD) therapies, ultimately undergoing a combined epicardial and endocardial VT ablation 4 years after presentation. Six months post-ablation, he was asymptomatic and his arrhythmia rendered quiescent.

Discussion

Arrhythmogenic cardiomyopathy should be considered in the evaluation of an initially unexplained cardiac arrest. This case characterizes the clinical features of a patient with FLNC cardiomyopathy and emphasizes the utility of genetic testing using modern gene panels in patients with comparable phenotypes. We also demonstrate that optimal medical therapy with antiarrhythmic drugs, exercise restriction, ICD insertion, and catheter ablation can be useful in the management of ALVC with positive outcomes

Association of Genetic Variants With Outcomes in Patients With Nonischemic Dilated Cardiomyopathy

BACKGROUND

The clinical relevance of genetic variants in nonischemic dilated cardiomyopathy (DCM) is unsettled.

OBJECTIVES

The study sought to assess the prognostic impact of disease-causing genetic variants in DCM.

METHODS

Baseline and longitudinal clinical data from 1,005 genotyped DCM probands were retrospectively collected at 20 centers. A total of 372 (37%) patients had pathogenic or likely pathogenic variants (genotype positive) and 633 (63%) were genotype negative. The primary endpoint was a composite of major adverse cardiovascular events. Secondary endpoints were end-stage heart failure (ESHF), malignant ventricular arrhythmia (MVA), and left ventricular reverse remodeling (LVRR).

RESULTS

After a median follow-up of 4.04 years (interquartile range: 1.70-7.50 years), the primary endpoint had occurred in 118 (31.7%) patients in the genotype-positive group and in 125 (19.8%) patients in the genotype-negative group (hazard ratio [HR]: 1.51; 95% confidence interval [CI]: 1.17-1.94; P = 0.001). ESHF occurred in 60 (16.1%) genotype-positive patients and in 55 (8.7%) genotype-negative patients (HR: 1.67; 95% CI: 1.16-2.41; P = 0.006). MVA occurred in 73 (19.6%) genotype-positive patients and in 77 (12.2%) genotype-negative patients (HR: 1.50; 95% CI: 1.09-2.07; P = 0.013). LVRR occurred in 39.6% in the genotype-positive group and in 46.2% in the genotype-negative group (P = 0.047). Among individuals with baseline left ventricular ejection fraction ≤35%, genotype-positive patients exhibited more major adverse cardiovascular events, ESHF, and MVA than their genotype-negative peers (all P < 0.02). LVRR and clinical outcomes varied depending on the underlying affected gene.

CONCLUSIONS

In this study, DCM patients with pathogenic or likely pathogenic variants had worse prognosis than genotype-negative individuals. Clinical course differed depending on the underlying affected gene.

Early Prediction of Left Ventricular Reverse Remodeling in First-Diagnosed Idiopathic Dilated Cardiomyopathy: A Comparison of Linear Model, Random Forest, and Extreme Gradient Boosting

Introduction: Left ventricular reverse remodeling (LVRR) is associated with decreased cardiovascular mortality and improved cardiac survival and also crucial for therapeutic options. However, there is a lack of an early prediction model of LVRR in first-diagnosed dilated cardiomyopathy.

Methods: This single-center study included 104 patients with idiopathic DCM. We defined LVRR as an absolute increase in left ventricular ejection fraction (LVEF) from >10% to a final value >35% and a decrease in left ventricular end-diastolic diameter (LVDd) >10%. Analysis features included demographic characteristics, comorbidities, physical sign, biochemistry data, echocardiography, electrocardiogram, Holter monitoring, and medication. Logistic regression, random forests, and extreme gradient boosting (XGBoost) were, respectively, implemented in a 10-fold cross-validated model to discriminate LVRR and non-LVRR, with receiver operating characteristic (ROC) curves and calibration plot for performance evaluation.

Results: LVRR occurred in 47 (45.2%) patients after optimal medical treatment. Cystatin C, right ventricular end-diastolic dimension, high-density lipoprotein cholesterol (HDL-C), left atrial dimension, left ventricular posterior wall dimension, systolic blood pressure, severe mitral regurgitation, eGFR, and NYHA classification were included in XGBoost, which reached higher AU-ROC compared with logistic regression (AU-ROC, 0.8205 vs. 0.5909, p = 0.0119). Ablation analysis revealed that cystatin C, right ventricular end-diastolic dimension, and HDL-C made the largest contributions to the model.

Conclusion: Tree-based models like XGBoost were able to early differentiate LVRR and non-LVRR in patients with first-diagnosed DCM before drug therapy, facilitating disease management and invasive therapy selection. A multicenter prospective study is necessary for further validation.

Clinical Trial Registration:http://www.chictr.org.cn/usercenter.aspx (ChiCTR2000034128).

Contemporary etiology and prognosis of dilated non-ischemic cardiomyopathy

INTRODUCTION

Non-ischemic dilated cardiomyopathy (NI-DCM) represents a specific etiology of systolic heart failure that usually affect young individuals with a genetic background in up to 40% of cases. Behind the term NI-DCM there is a spectrum of different diseases, and an accurate etiological classification appears pivotal for the clinical management and prognostic stratification of these patients.

EVIDENCE ACQUISITION

In the last years the prognosis of NI-DCM patients dramatically improved thanks to the progresses in medical treatment/ device therapy and earlier diagnosis especially in familial context. In this review we summarize the actual state of art in the management of these patients.

EVIDENCE SYNTHESIS

In the era of precision medicine, a lot of progresses have been made to expand our knowledge on the management of NI-DCM patients. A complex interaction between genotype and external triggers is the main determinant of the clinical phenotype in NI-DCM, and a lot of efforts must be done by clinicians to systematically rule out all the possible causes involved in the pathogenesis. Progresses in cardiac imaging and familial screening led us to detect subtle abnormalities in the initial phase of the disease and also helped us to furtherly stratify the prognosis and arrhythmic risk of these patients. It is plausible that a more precise etiological classification will be needed in the near future.

CONCLUSIONS

NI-DCM contains a spectrum of different diseases. Proper etiological classification, early diagnosis and strict follow-up are essential to tailor care of these patients.

HE4 Predicts Progressive Fibrosis and Cardiovascular Events in Patients With Dilated Cardiomyopathy

Background

Cardiac fibrosis plays a crucial role in the pathogenesis of dilated cardiomyopathy (DCM). HE4 (human epididymis protein 4) is a secretory protein expressed in activated fibroblasts that exacerbates tissue fibrosis. In the present study, we investigated the clinical utility of HE4 measurement in patients with DCM and its pathophysiological role in preclinical experiments in vivo and in vitro.

Methods and Results

We measured serum HE4 levels of 87 patients with DCM. Endomyocardial biopsy expressed severe fibrosis only in the high HE4 group (P<0.0001). Echocardiography showed that left ventricular end‐diastolic diameter tends to decrease over time (58±7.3 to 51±6.6 mm; P<0.0001) in the low HE4 group (<59.65 pmol/L [median value]). HE4 was significantly associated with risk reduction of mortality and cardiovascular hospitalization in multivariate Cox model. In vivo, HE4 was highly expressed in kidney and lung tissue of mouse, and scarcely expressed in heart. In genetically induced DCM mouse model, HE4 expression increased in kidney but not in heart and lung. In vitro, supernatant from HE4‐transfected human embryonic kidney 293T cells enhanced transdifferentiation of rat neonatal fibroblasts and increased expression of fibrosis‐related genes, and this was accompanied by the activation of extracellular signal‐regulated kinase signaling in cardiac fibroblasts. Treatment with an inhibitor of upstream signal of extracellular signal‐regulated kinase or a neutralizing HE4 antibody canceled the profibrotic properties of HE4.

Conclusions

HE4 functions as a secretory factor, activating cardiac fibroblasts, thereby inducing cardiac interstitial fibrosis. HE4 could be a promising biomarker for assessing ongoing fibrosis and a novel therapeutic target in DCM.

Registration

URL: https://upload.umin.ac.jp/cgi‐open‐bin/ctr; Unique identifier: UMIN000043062.

Prevalence and Evolution of Right Ventricular Dysfunction Among Different Genetic Backgrounds in Dilated Cardiomyopathy

BACKGROUND

Titin (TTN)-related dilated cardiomyopathy (DCM) has a higher likelihood of left ventricular reverse remodelling compared with other genetic etiologies. No data regarding the evolution of right ventricular dysfunction (RVD) according to genetic background are available.

METHODS

Consecutive 104 DCM patients with confirmed pathogenic genetic variants (51 TTN-related DCM; 53 other genetic DCM) and a control group of 139 patients with negative genetic testing and available follow-up data at 12-24 months were analysed. RVD was defined as a right ventricular fractional area change (RVFAC) < 35%. The main study end point was the comparison of the evolution of RVD and the change of RVFAC throughout the follow-up according to etiology. A composite of all-cause mortality and heart transplantation was included as outcome measure.

RESULTS

At enrollment, RVD was present in 29.1% of genetically positive DCM without differences between genetic cohorts. At 14 months follow-up, 5.9% of TTN-related DCM patients vs 35.8% of other genetic DCM patients had residual RVD after treatment (P < 0.001). Accordingly, RVFAC significantly improved in the TTN-related DCM cohort and remained stably impaired in other genetic DCM patients. However, the evolution of RVD was similar between TTN-related DCM and patients without a genetic mutation. After adjusting for RVD at follow-up, no differences in the outcome measure were seen in the study cohorts.

CONCLUSIONS

The evolution of RVD in DCM is heterogeneous in different genetic backgrounds. TTN-related DCM is associated with a higher chance of RVD recovery compared with other genetic etiologies.

Phenotypic clustering of dilated cardiomyopathy patients highlights important pathophysiological differences

AIMS

The dilated cardiomyopathy (DCM) phenotype is the result of combined genetic and acquired triggers. Until now, clinical decision-making in DCM has mainly been based on ejection fraction (EF) and NYHA classification, not considering the DCM heterogenicity. The present study aimed to identify patient subgroups by phenotypic clustering integrating aetiologies, comorbidities, and cardiac function along cardiac transcript levels, to unveil pathophysiological differences between DCM subgroups.

METHODS AND RESULTS

We included 795 consecutive DCM patients from the Maastricht Cardiomyopathy Registry who underwent in-depth phenotyping, comprising extensive clinical data on aetiology and comorbodities, imaging and endomyocardial biopsies. Four mutually exclusive and clinically distinct phenogroups (PG) were identified based upon unsupervised hierarchical clustering of principal components: [PG1] mild systolic dysfunction, [PG2] auto-immune, [PG3] genetic and arrhythmias, and [PG4] severe systolic dysfunction. RNA-sequencing of cardiac samples (n = 91) revealed a distinct underlying molecular profile per PG: pro-inflammatory (PG2, auto-immune), pro-fibrotic (PG3; arrhythmia), and metabolic (PG4, low EF) gene expression. Furthermore, event-free survival differed among the four phenogroups, also when corrected for well-known clinical predictors. Decision tree modelling identified four clinical parameters (auto-immune disease, EF, atrial fibrillation, and kidney function) by which every DCM patient from two independent DCM cohorts could be placed in one of the four phenogroups with corresponding outcome (n = 789; Spain, n = 352 and Italy, n = 437), showing a feasible applicability of the phenogrouping.

CONCLUSION

The present study identified four different DCM phenogroups associated with significant differences in clinical presentation, underlying molecular profiles and outcome, paving the way for a more personalized treatment approach.

High-Resolution Cryo-EM Structure of the Cardiac Actomyosin Complex

Heart contraction depends on a complicated array of interactions between sarcomeric proteins required to convert chemical energy into mechanical force. Cyclic interactions between actin and myosin molecules, controlled by troponin and tropomyosin, generate the sliding force between the actin-based thin and myosin-based thick filaments. Alterations in this sophisticated system due to missense mutations can lead to cardiovascular diseases. Numerous structural studies proposed pathological mechanisms of missense mutations at the myosin-myosin, actin-tropomyosin, and tropomyosin-troponin interfaces. However, despite the central role of actomyosin interactions a detailed structural description of the cardiac actomyosin interface remained unknown. Here, we report a cryo-EM structure of a cardiac actomyosin complex at 3.8 Å resolution. The structure reveals the molecular basis of cardiac diseases caused by missense mutations in myosin and actin proteins.

MAGGIC Risk Model Predicts Adverse Events and Left Ventricular Remodeling in Non-Ischemic Dilated Cardiomyopathy

Purpose

We aimed to study the Meta-analysis Global Group in Chronic Heart Failure (MAGGIC) risk model’s prognostic value and relationship with left ventricular remodeling in dilated cardiomyopathy.

Patients and Methods

Dilated cardiomyopathy patients were prospectively recruited and underwent clinical assessments. MAGGIC risk score was calculated. Patients were followed up for adverse events and echocardiography. Primary endpoints were all-cause mortality and first rehospitalization due to heart failure. Secondary endpoint was left ventricular remodeling defined as a decline in left ventricular ejection fraction >10% or an increase in left ventricular end-diastolic diameter >10%. Survival status was examined using Cox regression analysis. The model’s ability to discriminate adverse events and left ventricular remodeling was calculated using a receiver operating characteristics curve.

Results

In total, 114 patients were included (median follow-up time = 31 months). The risk score was independently related to adverse events (2-year all-cause mortality: hazard ratio [HR] = 1.122; 95% confidence interval [CI], 1.043–1.208; 1-year first rehospitalization due to heart failure: HR = 1.094; 95% CI, 1.032–1.158; 2-year first rehospitalization due to heart failure: HR = 1.088; 95% CI, 1.033–1.147, all P < 0.05). One-year change in left ventricular end-diastolic diameter was correlated with the risk score (r = 0.305, P = 0.002). The model demonstrated modest ability in discriminating adverse events and left ventricular remodeling (all areas under the curve were 0.6–0.7).

Conclusion

The MAGGIC risk score was related to adverse events and left ventricular remodeling in dilated cardiomyopathy.

High prevalence of subtle systolic and diastolic dysfunction in genotype-positive phenotype-negative relatives of dilated cardiomyopathy patients

BACKGROUND

The early diagnosis of genetically determined dilated cardiomyopathy (DCM) could improve the prognosis in mutation carriers. Left ventricular global longitudinal strain (LV GLS) and peak left atrial longitudinal strain (PALS) are promising techniques for the detection of subtle systolic and diastolic dysfunction. We sought to evaluate the prevalence of subtle systolic and diastolic dysfunction by LV GLS and PALS in a cohort of genotype-positive phenotype-negative (GPFN) DCM relatives.

METHODS AND RESULTS

In this retrospective study, we analyzed echocardiograms of forty-one GPFN relatives of DCM patients. They were compared with age and sex matched healthy individuals (control group). Reduced LV GLS and PALS were defined as >18% and <23.1%, respectively. GPFN relatives (37 ± 14 years, 48.8% male) and controls were similar according to standard echocardiographic measurements. Conversely, LV GLS was -18.8 ± 2.7% in the GPFN group vs. -24.0 ± 1.8% in the control group (p < 0.001). Twenty subjects (48.8%) in the GPFN group and no subjects in the control group had a reduced LV GLS. PALS was 29.2 ± 6.7% in the GPFN group vs. 40.8 ± 8.5% in the control group (p < 0.001). Seven subjects (18.4%) in the GPFN group and one (2%) in the control group had a reduced PALS. A cohort of 17 genotype-negative phenotype-negative relatives showed higher values of LV GLS compared to GPFN.

CONCLUSIONS

Despite standard echocardiographic parameters are within the normal range, LV GLS and PALS are lower in GPFN relatives of DCM patients when compared to healthy individuals, suggesting a consistent proportion of subtle systolic and diastolic dysfunction in this population.

Implications of Genetic Testing in Dilated Cardiomyopathy

BACKGROUND

Genetic analysis is a first-tier test in dilated cardiomyopathy (DCM). Electrical phenotypes are common in genetic DCM, but their exact contribution to the clinical course and outcome is unknown. We determined the prevalence of pathogenic gene variants in a large unselected DCM population and determined the role of electrical phenotypes in association with outcome.

METHODS

This study included 689 patients with DCM from the Maastricht Cardiomyopathy Registry, undergoing genetic evaluation using a 48 cardiomyopathy-associated gene-panel, echocardiography, endomyocardial biopsies, and Holter monitoring. Upon detection of a pathogenic variant in a patient with DCM, familial segregation was performed. Outcome was defined as cardiovascular death, heart transplantation, heart failure hospitalization, and/or occurrence of life-threatening arrhythmias.

RESULTS

A (likely) pathogenic gene variant was found in 19% of patients, varying from 36% in familial to 13% in nonfamilial DCM. Family segregation analysis showed familial disease in 46% of patients with DCM who were initially deemed nonfamilial by history. Overall, 18% of patients with a nongenetic risk factor had a pathogenic gene variant. Almost all pathogenic gene variants occurred in just 12 genes previously shown to have robust disease association with DCM. Genetic DCM was independently associated with electrical phenotypes such as atrial fibrillation, nonsustained ventricular tachycardia, and atrioventricular block and inversely correlated with the presence of a left bundle branch block (P<0.01). After a median follow-up of 4 years, event-free survival was reduced in genetic versus patients with nongenetic DCM (P=0.01). This effect on outcome was mediated by the associated electrical phenotypes of genetic DCM (P<0.001).

CONCLUSIONS

One in 5 patients with an established nongenetic risk factor or a nonfamilial disease still carries a pathogenic gene variant. Genetic DCM is characterized by a profile of electrical phenotypes (atrial fibrillation, nonsustained ventricular tachycardia, and atrioventricular block), which carries increased risk for adverse outcomes. Based on these findings, we envisage a broader role for genetic testing in DCM.

Management of nonischemic-dilated cardiomyopathies in clinical practice: a position paper of the working group on myocardial and pericardial diseases of Italian Society of Cardiology

: Nonischemic-dilated cardiomyopathy (NIDCM) is an entity that gathers extremely heterogeneous diseases. This awareness, although leading to continuous improvement in survival, has increased the complexity of NIDCM patients' management. Even though the endorsed 'red-flags' approach helps clinicians in pursuing an accurate etiological definition in clinical practice, it is not clear when and how peripheral centers should interact with referral centers with specific expertise in challenging scenarios (e.g. postmyocarditis and genetically determined dilated cardiomyopathy) and with easier access to second-line diagnostic tools and therapies. This position paper will summarize each step in NIDCM management, highlighting the multiple interactions between peripheral and referral centers, from first-line diagnostic workup and therapy to advanced heart failure management and long-term follow-up.

Prognostic value of left ventricular remodelling index in idiopathic dilated cardiomyopathy

AIMS

To evaluate the prognostic value of left ventricular (LV) remodelling index (RI) in idiopathic dilated cardiomyopathy (DCM) patients.

METHODS AND RESULTS

We prospectively enrolled 412 idiopathic DCM patients and 130 age- and sex-matched healthy volunteers who underwent cardiovascular magnetic resonance imaging between September 2013 and March 2018. RI was defined as the cubic root of the LV end-diastolic volume divided by the mean LV wall thickness on basal short-axis slice. The primary endpoint included all-cause mortality and heart transplantation. The secondary endpoint included the primary endpoint and heart failure (HF) readmission. During the median follow-up of 28.1 months (interquartile range: 19.3-43.0 months), 62 (15.0%) and 143 (34.7%) patients reached the primary and secondary endpoints, respectively. Stepwise multivariate Cox regression showed that RI [hazard ratio (HR) 1.20, 95% confidence interval (CI) 1.11-1.30, P < 0.001], late gadolinium enhancement (LGE) presence and log (N-terminal pro-B-type natriuretic peptide) were independent predictors of the primary endpoint, while RI (HR 1.15, 95% CI 1.08-1.23, P < 0.001) and extracellular volume were independent predictors of the secondary endpoint. The addition of RI to LV ejection fraction (EF) and LGE presence showed significantly improved global χ2 for predicting primary and secondary endpoints (both P < 0.001). Furthermore, RI derived from echocardiography also showed independent prognostic value for primary and secondary endpoints with clinical risk factors.

CONCLUSIONS

RI is an independent predictor of all-cause mortality, heart transplantation, and HF readmission in DCM patients and provides incremental prognostic value to LVEF and LGE presence.

Genetic Risk of Arrhythmic Phenotypes in Patients With Dilated Cardiomyopathy

BACKGROUND

Genotype-phenotype correlations in dilated cardiomyopathy (DCM) and, in particular, the effects of gene variants on clinical outcomes remain poorly understood.

OBJECTIVES

The purpose of this study was to investigate the prognostic role of genetic variant carrier status in a large cohort of DCM patients.

METHODS

A total of 487 DCM patients were analyzed by next-generation sequencing and categorized the disease genes into functional gene groups. The following composite outcome measures were assessed: 1) all-cause mortality; 2) heart failure-related death, heart transplantation, or destination left ventricular assist device implantation (DHF/HTx/VAD); and 3) sudden cardiac death/sustained ventricular tachycardia/ventricular fibrillation (SCD/VT/VF).

RESULTS

A total of 183 pathogenic/likely pathogenic variants were found in 178 patients (37%): 54 (11%) Titin; 19 (4%) Lamin A/C (LMNA); 24 (5%) structural cytoskeleton-Z disk genes; 16 (3.5%) desmosomal genes; 46 (9.5%) sarcomeric genes; 8 (1.6%) ion channel genes; and 11 (2.5%) other genes. All-cause mortality was no different between variant carriers and noncarriers (p = 0.99). A trend toward worse SCD/VT/VF (p = 0.062) and DHF/HTx/VAD (p = 0.061) was found in carriers. Carriers of desmosomal and LMNA variants experienced the highest rate of SCD/VT/VF, which was independent of the left ventricular ejection fraction.

CONCLUSIONS

Desmosomal and LMNA gene variants identify the subset of DCM patients who are at greatest risk for SCD and life-threatening ventricular arrhythmias, regardless of the left ventricular ejection fraction.

Arrhythmic risk stratification in non-ischaemic dilated cardiomyopathy beyond ejection fraction

Sudden cardiac death and arrhythmia-related events in patients with non-ischaemic dilated cardiomyopathy (NICM) have been significantly reduced over the last couple of decades as a result of evidence-based pharmacological and non-pharmacological therapeutic strategies. Nevertheless, the arrhythmic stratification in patients with NICM remains extremely challenging, and the simple indication based on left ventricular ejection fraction appears to be insufficient. Therefore, clinicians need to go beyond the current criteria for implantable cardioverter-defibrillator implantation in the direction of a multiparametric evaluation of arrhythmic risk. Several parameters for arrhythmic risk stratification, ranging from electrocardiographic, echocardiographic, imaging-derived and genetic markers, are crucial for proper arrhythmic risk stratification and a multiparametric evaluation of risk in patients with NICM. In particular, integration of cardiac magnetic resonance parameters (mostly late gadolinium enhancement) and specific genetic information (ie, presence of LMNA, PLN, FLNC mutations) appears fundamental for proper implementation of the current arrhythmic risk stratification. Finally, a novel approach focused on both arrhythmic risk and prediction of left ventricular reverse remodelling during follow-up might be useful for effective multiparametric and dynamic arrhythmic risk stratification in NICM. In the future, a complete and integrated evaluation might be mandatory to implement arrhythmic risk prediction in patients with NICM and to discriminate the competing risk between heart failure-related events and life-threatening arrhythmias.

ECG in dilated cardiomyopathy: specific findings and long-term prognostic significance

OBJECTIVE

The objective was to provide an exhaustive characterization of ECG features in a large cohort of dilated cardiomyopathies (DCMs) and then investigate their possible prognostic role in the long term.

BACKGROUND

ECG is an accessible, reproducible, low-cost diagnostic and prognostic tool. However, an extensive description of ECG features and their long-term prognostic role in a large cohort of DCM is lacking.

METHODS

All available baseline ECGs of DCM patients enrolled from 1992 to 2013 were systematically analysed. Patients underwent to a complete clinical-laboratory evaluation. The study outcome measures were death or heart transplant (D/HT) and sudden death or malignant ventricular arrhythmias (SD/MVA).

RESULTS

Four hundred and fourteen DCM patients were enrolled. During a median follow-up of 125 months, 55 and 57 patients experienced D/HT and SD/MVA, respectively. At multivariate analysis, left ventricular hypertrophy (P = 0.017), heart rate (HR, P = 0.005) and anterolateral T-wave inversion (P = 0.041) predicted D/HT. Regarding SD/MVA, S wave amplitude in V2 (P = 0.008), R wave amplitude in DIII (P = 0.007), anterolateral T-wave inversion (P = 0.017) emerged as predictors. At receiver-operating curve analyses, the addition of ECG models to the clinical-laboratory evaluation significantly increased the area under the curve both for D/HT (from 0.68 to 0.74, P = 0.042) and SD/MVA (from 0.70 to 0.77, P = 0.048).

CONCLUSION

The exhaustive systematic evaluation of ECG has an incremental impact in the prognostication of a large cohort of DCM patients, also regarding the arrhythmic stratification.

Dilated Cardiomyopathy Due to BLC2-Associated Athanogene 3 (BAG3) Mutations

BACKGROUND

The BAG3 (BLC2-associated athanogene 3) gene codes for an antiapoptotic protein located on the sarcomere Z-disc. Mutations in BAG3 are associated with dilated cardiomyopathy (DCM), but only a small number of cases have been reported to date, and the natural history of BAG3 cardiomyopathy is poorly understood.

OBJECTIVES

This study sought to describe the phenotype and prognosis of BAG3 mutations in a large multicenter DCM cohort.

METHODS

The study cohort comprised 129 individuals with a BAG3 mutation (62% males, 35.1 ± 15.0 years of age) followed at 18 European centers. Localization of BAG3 in cardiac tissue was analyzed in patients with truncating BAG3 mutations using immunohistochemistry.

RESULTS

At first evaluation, 57.4% of patients had DCM. After a median follow-up of 38 months (interquartile range: 7 to 95 months), 68.4% of patients had DCM and 26.1% who were initially phenotype-negative developed DCM. Disease penetrance in individuals >40 years of age was 80% at last evaluation, and there was a trend towards an earlier onset of DCM in men (age 34.6 ± 13.2 years vs. 40.7 ± 12.2 years; p = 0.053). The incidence of adverse cardiac events (death, left ventricular assist device, heart transplantation, and sustained ventricular arrhythmia) was 5.1% per year among individuals with DCM. Male sex, decreased left ventricular ejection fraction. and increased left ventricular end-diastolic diameter were associated with adverse cardiac events. Myocardial tissue from patients with a BAG3 mutation showed myofibril disarray and a relocation of BAG3 protein in the sarcomeric Z-disc.

CONCLUSIONS

DCM caused by mutations in BAG3 is characterized by high penetrance in carriers >40 years of age and a high risk of progressive heart failure. Male sex, decreased left ventricular ejection fraction, and enlarged left ventricular end-diastolic diameter are associated with adverse outcomes in patients with BAG3 mutations.

Clinical Phenotype and Genotype Associations With Improvement in Left Ventricular Function in Dilated Cardiomyopathy

BACKGROUND

Improvement of left ventricular function (also called left ventricular reverse remodeling [LVRR]) is an important treatment goal in patients with dilated cardiomyopathy (DCM) and hypokinetic non-DCM (HNDC) and is prognostically favorable. We tested whether genetic DCM mutations impact LVRR independent from clinical parameters.

METHODS AND RESULTS

Patients with DCM and hypokinetic non-DCM (n=346; mean left ventricular ejection fraction, 30%) underwent genotyping for 47 DCM-associated genes in addition to extensive phenotyping. LVRR was defined as improvement of left ventricular ejection fraction >50% or ≥10% absolute increase, with cardiac dimensions (left ventricular end diastolic diameter) ≤33 mm/m² or ≥10% relative decrease. LVRR occurred in 180 (52%) patients after a median follow-up of 12-month optimal medical treatment. Low baseline left ventricular ejection fraction, a hypokinetic non-DCM phenotype, high systolic blood pressure, absence of a family history of DCM, female sex, absence of atrioventricular block, and treatment with β-blockers were all independent positive clinical predictors of LVRR. With the exception of TTN, genetic mutations were strongly associated with a lower rate of LVRR (odds ratio, 0.19 [0.09-0.42]; P<0.0001). TTN and LMNA were independently associated with LVRR (odds ratio, 2.49 [1.09-6.20]; P=0.038 and 0.11 [0.01-0.99]; P=0.049, respectively). Adding mutation status significantly improved discrimination (C statistics) and reclassification (integrated discrimination improvement/net reclassification index) of the clinical model predicting LVRR. Furthermore, the risk for heart failure hospitalization and cardiovascular death is lower in the LVRR patients on the long term (hazard ratio, 0.47 [0.24-0.91]; P=0.009 and 0.18 [0.04-0.82]; P=0.007, respectively), and LVRR is an independent predictor for event-free survival.

CONCLUSIONS

The genetic substrate is associated with the clinical course and long-term prognosis of patients with DCM/hypokinetic non-DCM.

Imaging, Biomarker, and Clinical Predictors of Cardiac Remodeling in Heart Failure With Reduced Ejection Fraction

In response to injury, hemodynamic changes, or neurohormonal activation, the heart undergoes a series of structural and functional changes that have been termed cardiac remodeling. Remodeling is defined as changes in cardiac geometry and/or function over time and can be measured in terms of changes in cardiac chamber dimensions, wall thickness, volumes, mass, and ejection fraction at serial imaging examinations. As to cardiac chambers, left ventricular (LV) remodeling has been best studied in patients with heart failure with reduced ejection fraction. Although LV remodeling may compensate for abnormal hemodynamic parameters and function in the short term, left unchecked, it is associated with worsening cardiac function and poor prognosis. On the other hand, reversing LV geometry and/or function closer to that of a normal heart (also known as reverse remodeling) is associated with improved cardiac function and better prognosis. Because of its close relationship with clinical outcomes, remodeling may potentially be targeted in clinical management and used in trials as a surrogate endpoint. Standardized definition of remodeling and reliable tools to predict and monitor the presence, direction, and magnitude of cardiac remodeling are needed. Together with clinical and imaging findings, circulating biomarkers (most notably N-terminal pro-B-type natriuretic peptide, high-sensitivity troponin, and soluble suppression of tumorigenesis-2) may be helpful in this respect.

Prevalence of TTN mutations in patients with dilated cardiomyopathy : A meta-analysis

A meta-analysis was performed to assess the prevalence of TTN mutations in patients with dilated cardiomyopathy (DCM). Prevalence point estimates and 95% confidence intervals were computed using the logit transformation formula. The prevalence of TTN mutations in patient with DCM, familial dilated cardiomyopathy (FDCM), and sporadic dilated cardiomyopathy (SDCM) was 0.17 (95% CI: 0.14-0.19), 0.23 (95% CI: 0.20-0.26), and 0.16 (95% CI: 0.12-0.21), respectively. No individual study had a marked influence on the pooled prevalence in the meta-analysis. Meta-regression analysis between the logit event for prevalence and sample size explained 32% of between-study variance (p < 0.05). Cumulative meta-analysis confirmed the influence of sample size on the reported prevalence among the different studies. In conclusion, the present analysis suggests that TTN mutations are familial in DCM patients. More attention should be paid to TTN mutations in clinical examinations.

Left bundle branch block-induced cardiomyopathy: a diagnostic proposal for a poorly explored pathological entity

Despite being increasingly recognized as a specific disease, at the present time left bundle branch block (LBBB)-induced cardiomyopathy is neither formally included among unclassified cardiomyopathies nor among the acquired/non-genetic forms of dilated cardiomyopathy (DCM). Currently, a post-hoc diagnosis of LBBB-induced cardiomyopathy is possible when evaluating patients' response to cardiac resynchronization therapy (CRT). However, an early detection of a LBBB-induced cardiomyopathy could have significant clinical and therapeutic implications. Patients with the aforementioned form of dyssynchronopathy may benefit from early CRT and overall prognosis might be better as compared to patients with a primary muscle cell disorder (i.e. "true" DCM). The real underlying mechanisms, the possible genetic background as well as the early identification of this specific form of DCM remain largely unknown. In this review the complex relationship between LBBB and left ventricular non-ischaemic dysfunction is described. Furthermore, a multiparametric approach based on clinical, electrocardiographic and imaging red flags, is provided in order to allow an early detection of the LBBB-induced cardiomyopathy.