Prospective familial assessment in dilated cardiomyopathy: cardiac autoantibodies predict disease development in asymptomatic relatives

Multidisciplinary approach in cardiomyopathies: From genetics to advanced imaging

Cardiomyopathies are myocardial diseases characterized by mechanical and electrical dysfunction of the heart muscle which could lead to heart failure and life-threatening arrhythmias. Certainly, an accurate anamnesis, a meticulous physical examination, and an ECG are cornerstones in raising the diagnostic suspicion. However, cardiovascular imaging techniques are indispensable to diagnose a specific cardiomyopathy, to stratify the risk related to the disease and even to track the response to the therapy. Echocardiography is often the first exam that the patient undergoes, because of its non-invasiveness, wide availability, and cost-effectiveness. Cardiac magnetic resonance imaging allows to integrate and implement the information obtained with the echography. Furthermore, cardiomyopathies' genetic basis has been investigated over the years and the list of genetic mutations deemed potentially pathogenic is expected to grow further. The aim of this review is to show echocardiographic, cardiac magnetic resonance imaging, and genetic features of several cardiomyopathies: dilated cardiomyopathy (DMC), hypertrophic cardiomyopathy (HCM), arrhythmogenic cardiomyopathy (ACM), left ventricular noncompaction cardiomyopathy (LVNC), myocarditis, and takotsubo cardiomyopathy.

Identification of the Key Genes of Immune Infiltration in Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM) is a common cause of heart failure. In this study, we screened the immune infiltration-related genes associated with DCM to explore the potential molecular mechanisms and provide a basis for the early diagnosis and development of new immunotherapeutic targets. A dataset related to DCM was downloaded from the Gene Expression Omnibus (GEO) database. R software was applied to the genetic differential analysis of patients with DCM and healthy individuals, and the obtained differential expressed genes (DEGs) were screened for differentially expressed immune-related genes (DEIRGs) after comparison with the immune microsatellite database. Gene functional analysis established a protein interaction network (PPI). The immune infiltration in patients with DCM versus normal controls was assessed using the CIBERSORT algorithm, the hub genes were screened using the MOCDE app, and the hubs were validated in multiple datasets. A total of 246 DEGs were screened (adj. P < 0.05 and |logFC| > 0.3), and a total of 170 DEIRGs were compared. Gene Ontology analysis showed significant (adj. P < 0.05) Biological Process entries of 591, Cellular Component of 10, and Molecular Function of 39; Kyoto Encyclopedia of Genes and Genomes showed 20 significant entries, mainly focused on cytokines involved in immune-related response, etc. A protein interaction network comprising 28 hub DEGs was constructed in combination with the PPI network interactions. DEIRG was mainly distributed in the T-cell receptor pathway by immune infiltration detection analysis, and significant changes in central memory T-cells were found by analyzing T-cell-related subpathways, where INSR, HLA-B, IFITM1, and HBEGF were significantly differentially expressed. We selected 632 hospitalized patients for validation and found that INSR and HLA-B expression were associated with DCM development by Nomogram. The expression of HLA-B in peripheral blood T-cells was higher in DCM patients than in the normal group, as verified by qRT-PCR. However, the detailed mechanism needs to be further explored.

Biomarkers in Acute Myocarditis and Chronic Inflammatory Cardiomyopathy: An Updated Review of the Literature

Myocarditis is a disease caused by cardiac inflammation that can progress to dilated cardiomyopathy, heart failure, and eventually death. Several etiologies, including autoimmune, drug-induced, and infectious, lead to inflammation, which causes damage to the myocardium, followed by remodeling and fibrosis. Although there has been an increasing understanding of pathophysiology, early and accurate diagnosis, and effective treatment remain challenging due to the high heterogeneity. As a result, many patients have poor prognosis, with those surviving at risk of long-term sequelae. Current diagnostic methods, including imaging and endomyocardial biopsy, are, at times, expensive, invasive, and not always performed early enough to affect disease progression. Therefore, the identification of accurate, cost-effective, and prognostically informative biomarkers is critical for screening and treatment. The review then focuses on the biomarkers currently associated with these conditions, which have been extensively studied via blood tests and imaging techniques. The information within this review was retrieved through extensive literature research conducted on major publicly accessible databases and has been collated and revised by an international panel of experts. The biomarkers discussed in the article have shown great promise in clinical research studies and provide clinicians with essential tools for early diagnosis and improved outcomes.

The Role of Autoantibodies in Companion Animal Cardiac Disease

Clinical studies exploring the role of autoimmune diseases in cardiac dysfunction have become increasingly common in both human and veterinary literature. Autoantibodies (AABs) specific to cardiac receptors have been found in human and canine dilated cardiomyopathy, and circulating autoantibodies have been suggested as a sensitive biomarker for arrhythmogenic right ventricular cardiomyopathy in people and Boxer dogs. In this article, we will summarize recent literature on AABs and their role in cardiac diseases of small animals. Despite the potential for new discoveries in veterinary cardiology, current data in veterinary medicine are limited and further studies are needed.

Integrated bioinformatics analysis for identifying key genes and pathways in female and male patients with dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is a common cause of heart failure, and males are more likely to suffer from DCM than females. This research aimed at exploring possible DCM-associated genes and their latent regulatory effects in female and male patients. WGCNA analysis found that in the yellow module, 341 and 367 key DEGs were identified in females and males, respectively. A total of 22 hub genes in females and 17 hub genes in males were identified from the PPI networks of the key DEGs based on Metascape database. And twelve and eight potential TFs of the key DEGs were also identified in females and males, respectively. Eight miRNAs of 15 key DEGs were screened in both females and males, which may be differentially expressed in females and males. Dual-luciferase reporter assay demonstrated that miR-21-5P could directly target the key gene MATN2. Furthermore, Sex differences in KEGG pathways were identified. Both KOBAS and GSEA analysis identified 19 significantly enriched pathways related to immune response in both females and males, and the TGF-β signaling pathway was exclusively identified in males. Network pharmacology analysis revealed that seven key DEGs were potential targets for the treatment of DCM, of which the OLR1 gene was only identified in males, the expression levels of the seven genes were verified by RT-PCR. The above results could offer a novel understanding of sex differences in key genes and pathways in DCM progression.

The Heart–Brain Interplay in Multiple Sclerosis from Pathophysiology to Clinical Practice: A Narrative Review

Multiple sclerosis (MS) is a chronic neurological disorder characterized by inflammation in the central nervous system (CNS) that leads to neurodegeneration. The clinical course is highly variable, but its prevalence is rising worldwide, partly thanks to novel disease-modifying therapies. Additionally, the lifespan of people with MS is increasing, and for this reason, it is fundamental to have a multidisciplinary approach to MS. MS may be associated with cardiovascular diseases (CVD), but there is scarce attention on this issue. In particular, CNS is essential in regulating the autonomic system and heart activity. Moreover, cardiovascular risk factors show a higher prevalence in MS patients. On the other hand, conditions like Takotsubo syndrome are rare complications of MS. The parallelism between MS and myocarditis is also interesting. Finally, cardiac toxicity represents a not infrequent adverse reaction to MS drugs. This narrative review aims to provide an overview of cardiovascular complications in MS and their management to prompt further clinical and pre-clinical research on this topic.

Immunoadsorption therapy in refractory heart failure patients with dilated cardiomyopathy: a potential therapeutic option

OBJECTIVE

Removal of cardiac autoantibodies by immunoadsorption might confer clinical improvement in dilated cardiomyopathy. In this pilot study, we investigated the efficacy and safety of immunoadsorption therapy in refractory heart failure patients with dilated cardiomyopathy.

METHODS

This study consisted of 9 heart failure patients with dilated cardiomyopathy, NYHA III-IV, left ventricular ejection fraction <30%, unresponsive to heart failure therapy, and with cardiac autoantibodies. Patients underwent immunoadsorption therapy for five consecutive days using a tryptophan column. Changes in cardiac function (left ventricular ejection fraction, left ventricular end-diastolic diameter, left ventricular end-systolic diameter), exercise capacity (6-minute walk distance), neurohormonal (N-terminal pro-brain natriuretic peptide), proinflammatory (high-sensitive C-reactive protein), and myocardial (cardiac troponin-I), biochemical, and hematological variables were obtained at baseline and after 3 and 6 months of immunoadsorption therapy.

RESULTS

Mean left ventricular ejection fraction and 6-minute walk distance significantly increased at 3 months (from 23.27±5.09 to 32.1±1.7%, p=0.01 for left ventricular ejection fraction and from 353±118 to 434±159 m, p=0.04 for 6-minute walk distance) and further increased at 6 months after immunoadsorption therapy (to 34.5±7.7%, p=0.02 for ejection fraction and to 441±136 m, p=0.04 for 6-minute walk distance). NT-proBNP level reduced from 1161(392.8-3034) to 385(116.1-656.5) ng/L (p=0.04), and high-sensitive C-reactive protein decreased from 9.74±0.96 to 4.3±5.8 mg/L (p=0.04) at 6 months. Left ventricular end-diastolic diameter (66.1±5.8 vs. 64.7±8.9 mm) and left ventricular end-systolic diameter (56.1±8.6 vs. 52.3±10.8 mm) tended to decrease but did not reach statistical significance. No significant worsening was observed in creatinine, cardiac troponin-I, and hemoglobin levels after the immunoadsorption procedure.

CONCLUSION

In dilated cardiomyopathy patients with refractory heart failure, immunoadsorption may be considered a potentially useful therapeutic option to improve a patient's clinical status.

Exploration of dilated cardiomyopathy for biomarkers and immune microenvironment: evidence from RNA-seq

Background

The pathogenic mechanism of dilated cardiomyopathy (DCM) remains to be defined. This study aimed to identify hub genes and immune cells that could serve as potential therapeutic targets for DCM.

Methods

We downloaded four datasets from the Gene Expression Omnibus (GEO) database: GSE141910, GSE3585, GSE42955 and GSE79962. Weighted gene coexpression network analysis (WGCNA) and differential expression analysis were performed to identify gene panels related to DCM. Meanwhile, the CIBERSORT algorithm was used to estimate the immune cells in DCM tissues. Multiple machine learning approaches were used to screen the hub genes and immune cells. Finally, the diagnostic value of the hub genes was assessed by receiver operating characteristic (ROC) analysis. An experimental mouse model of dilated cardiomyopathy was used to validate the bioinformatics results.

Results

FRZB and EXT1 were identified as hub biomarkers, and the ROC curves suggested an excellent diagnostic ability of the above genes for DCM. In addition, naive B cells were upregulated in DCM tissues, while eosinophils, M2 macrophages, and memory CD4 T cells were downregulated in DCM tissues. The increase in two hub genes and naive B cells was validated in animal experiments.

Conclusion

These results indicated that FRZB and EXT1 could be used as promising biomarkers, and eosinophils, M2 macrophages, resting memory CD4 T cells and naive B cells may also affect the occurrence of DCM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02759-7.

Transcriptome analysis uncovers the autophagy-mediated regulatory patterns of the immune microenvironment in dilated cardiomyopathy

The relationship between autophagy and immunity has been well studied. However, little is known about the role of autophagy in the immune microenvironment during the progression of dilated cardiomyopathy (DCM). Therefore, this study aims to uncover the effect of autophagy on the immune microenvironment in the context of DCM. By investigating the autophagy gene expression differences between healthy donors and DCM samples, 23 dysregulated autophagy genes were identified. Using a series of bioinformatics methods, 13 DCM‐related autophagy genes were screened and used to construct a risk prediction model, which can well distinguish DCM and healthy samples. Then, the connections between autophagy and immune responses including infiltrated immunocytes, immune reaction gene‐sets and human leukocyte antigen (HLA) genes were systematically evaluated. In addition, two autophagy‐mediated expression patterns in DCM were determined via the unsupervised consensus clustering analysis, and the immune characteristics of different patterns were revealed. In conclusion, our study revealed the strong effect of autophagy on the DCM immune microenvironment and provided new insights to understand the pathogenesis and treatment of DCM.

Prevalence of Inherited Cardiac Conditions in Pediatric First-Degree Relatives of Patients with Idiopathic Ventricular Fibrillation

Idiopathic ventricular fibrillation (IVF) is diagnosed in out-of-hospital VF survivors after comprehensive investigations have excluded structural heart disease or inherited channelopathies. Current guidelines recommend clinical screening of first-degree relatives of IVF survivors, but this approach has not been validated in children. This study aimed to assess the yield of clinical cardiac screening in child first-degree relatives of IVF victims. A retrospective observational study was conducted of all consecutive pediatric first-degree relatives of IVF patients referred to our center between December 2007 and April 2020. Patients underwent systematic evaluation including medical and family history; 12-lead resting, signal-averaged, and ambulatory electrocardiogram (ECG); echocardiogram; exercise testing; cardiac magnetic resonance imaging; and ajmaline provocation testing. Sixty child first-degree relatives of 32 IVF survivors were included [median follow-up time of 55 months (IQR 27.0-87.0 months); 30 (50%) females]. Eight patients (13.3%) from 6 families (18.8%) received a cardiac diagnosis: long QT syndrome (n = 4); Brugada syndrome (n = 3); and dilated cardiomyopathy (n = 1). There were no deaths during follow-up. This study demonstrates a high yield of clinical screening for inherited cardiac disease in child first-degree relatives of IVF survivors. These findings highlight the variable expression of inherited cardiac conditions and the importance of comprehensive clinical evaluation in pediatric relatives, even when extensive investigations in the proband have not identified a clear etiology. Moreover, our results support the validity of the investigations proposed by current guidelines in family relatives of IVF survivors.

The Incidence of Myocarditis and Pericarditis in Post COVID-19 Unvaccinated Patients—A Large Population-Based Study

Myocarditis and pericarditis are potential post-acute cardiac sequelae of COVID-19 infection, arising from adaptive immune responses. We aimed to study the incidence of post-acute COVID-19 myocarditis and pericarditis. Retrospective cohort study of 196,992 adults after COVID-19 infection in Clalit Health Services members in Israel between March 2020 and January 2021. Inpatient myocarditis and pericarditis diagnoses were retrieved from day 10 after positive PCR. Follow-up was censored on 28 February 2021, with minimum observation of 18 days. The control cohort of 590,976 adults with at least one negative PCR and no positive PCR were age- and sex-matched. Since the Israeli vaccination program was initiated on 20 December 2020, the time-period matching of the control cohort was calculated backward from 15 December 2020. Nine post-COVID-19 patients developed myocarditis (0.0046%), and eleven patients were diagnosed with pericarditis (0.0056%). In the control cohort, 27 patients had myocarditis (0.0046%) and 52 had pericarditis (0.0088%). Age (adjusted hazard ratio [aHR] 0.96, 95% confidence interval [CI]; 0.93 to 1.00) and male sex (aHR 4.42; 95% CI, 1.64 to 11.96) were associated with myocarditis. Male sex (aHR 1.93; 95% CI 1.09 to 3.41) and peripheral vascular disease (aHR 4.20; 95% CI 1.50 to 11.72) were associated with pericarditis. Post COVID-19 infection was not associated with either myocarditis (aHR 1.08; 95% CI 0.45 to 2.56) or pericarditis (aHR 0.53; 95% CI 0.25 to 1.13). We did not observe an increased incidence of neither pericarditis nor myocarditis in adult patients recovering from COVID-19 infection.

Predictors of relapse, death or heart transplantation in myocarditis before the introduction of immunosuppression: negative prognostic impact of female gender, fulminant onset, lower ejection fraction and serum autoantibodies

AIMS

Outcome predictors in myocarditis are not well defined; we aimed at identifying predictors of death, heart transplantation (HTx) and relapse before the introduction of immunosuppression.

METHODS AND RESULTS

From 1992 to 2012 we consecutively included 466 patients (68% male, 37±17 years, single centre recruitment, median follow-up 50 months), 216 with clinically suspected and 250 with biopsy (Bx)-proven myocarditis. Serum anti heart (AHA) and antiintercalated disk (AIDA) auto-antibodies were measured by indirect immunofluorescence. We performed univariable and multivariable analysis of clinical and diagnostic features at diagnosis. Survival free from death or HTx at 10 years was 83% in the whole group and was lower in Bx- proven vs. clinically suspected myocarditis (76% vs 94% respectively, p<0.001). Female gender (hazard ratio (HR) 2.7, 95% Confidence Intervals (CI) 1.1-6.5), fulminant presentation (HR 13.77, CI 9.7-261.73), high-titre organ-specific AHA (HR 4.2, CI 1.2-14.7) and anti-nuclear antibodies (ANA) (HR 5.2, CI 2.1-12.8) were independent predictors of death or HTx; higher echocardiographic left ventricular ejection fraction (LVEF) at diagnosis was protective, with a 0.93 times risk reduction for each 1% LVEF increase (CI 0.89-0.96). History of myocarditis at diagnosis (HR 8.5, CI 3.5-20.7) was independent predictor of myocarditis relapse at follow-up; older age was protective (HR 0.95, CI 0.91-0.99). Predictors of death, HTx and relapse did not differ in Bx-proven vs. clinically suspected myocarditis.

CONCLUSIONS

Young age and a previous myocarditis were independent relapse predictors; female gender, fulminant onset, lower LVEF at presentation and high-titre organ-specific AHA and ANA were independent predictors of death and HTx, suggesting that autoimmune features predict worse prognosis.

Personalized Management of Myocarditis and Inflammatory Cardiomyopathy in Clinical Practice

Myocarditis is an inflammatory heart disease induced by infectious and non-infectious causes frequently triggering immune-mediated pathologic mechanisms leading to myocardial damage and dysfunction. In approximately half of the patients, acute myocarditis resolves spontaneously while in the remaining cases, it may evolve into serious complications including inflammatory cardiomyopathy, arrhythmias, death, or heart transplantation. Due to the large variability in clinical presentation, unpredictable course of the disease, and lack of established causative treatment, myocarditis represents a challenging diagnosis in modern cardiology. Moreover, an increase in the incidence of myocarditis and inflammatory cardiomyopathy has been observed in recent years. However, there is a growing potential of available non-invasive diagnostic methods (biomarkers, serum anti-heart autoantibodies (AHA), microRNAs, speckle tracking echocardiography, cardiac magnetic resonance T1 and T2 tissue mapping, positron emission tomography), which may refine the diagnostic workup and/or noninvasive follow-up. Personalized management should include the use of endomyocardial biopsy and AHA, which may allow the etiopathogenetic subsets of myocarditis (infectious, non-infectious, and/or immune-mediated) to be distinguished and implementation of disease-specific therapies. In this review, we summarize current knowledge on myocarditis and inflammatory cardiomyopathy, and outline some practical diagnostic, therapeutic, and follow-up algorithms to facilitate comprehensive individualized management of these patients.

Serum Organ-Specific Anti-Heart and Anti-Intercalated Disk Autoantibodies as New Autoimmune Markers of Cardiac Involvement in Systemic Sclerosis: Frequency, Clinical and Prognostic Correlates

BACKGROUND

Heart involvement (HInv) in systemic sclerosis (SSc) may relate to myocarditis and is associated with poor prognosis. Serum anti-heart (AHA) and anti-intercalated disk autoantibodies (AIDA) are organ and disease-specific markers of isolated autoimmune myocarditis. We assessed frequencies, clinical correlates, and prognostic impacts of AHA and AIDA in SSc.

METHODS

The study included consecutive SSc patients (n = 116, aged 53 ± 13 years, 83.6% females, median disease duration 7 years) with clinically suspected heart involvement (symptoms, abnormal ECG, abnormal troponin I or natriuretic peptides, and abnormal echocardiography). All SSc patients underwent CMR. Serum AHA and AIDA were measured by indirect immunofluorescence in SSc and in control groups of non-inflammatory cardiac disease (NICD) (n = 160), ischemic heart failure (IHF) (n = 141), and normal blood donors (NBD) (n = 270). AHA and AIDA status in SSc was correlated with baseline clinical, diagnostic features, and outcome.

RESULTS

The frequency of AHA was higher in SSc (57/116, 49%, p < 0.00001) than in NICD (2/160, 1%), IHF (2/141, 1%), or NBD (7/270, 2.5%). The frequency of AIDA was higher (65/116, 56%, p < 0.00001) in SSc than in NICD (6/160, 3.75%), IHF (3/141, 2%), or NBD (1/270, 0.37%). AHAs were associated with interstitial lung disease (p = 0.04), history of chest pain (p = 0.026), abnormal troponin (p = 0.006), AIDA (p = 0.000), and current immunosuppression (p = 0.01). AHAs were associated with death (p = 0.02) and overall cardiac events during follow-up (p = 0.017).

CONCLUSIONS

The high frequencies of AHA and AIDA suggest a high burden of underdiagnosed autoimmune HInv in SSc. In keeping with the negative prognostic impact of HInv in SSc, AHAs were associated with dismal prognosis.

Clinically Suspected and Biopsy-Proven Myocarditis Temporally Associated with SARS-CoV-2 Infection

We review current data on clinically suspected [European Society of Cardiology (ESC) 2013 criteria] and biopsy-proven [ESC and World Health Organization (WHO) criteria] myocarditis that is temporally associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. ESC/WHO etiological diagnosis of viral myocarditis is based on histological, and immunohistological evidence of nonischemic myocyte necrosis and monolymphocytic infiltration, i.e., myocarditis, plus the identification of a specific cardiotropic virus by molecular techniques, in particular polymerase chain reaction (PCR)/in-situ hybridization, on endomyocardial biopsy (EMB)/autopsy tissue. There is not yet definitive EMB/autopsy proof that SARS-CoV-2 causes direct cardiomyocyte damage in association with histological myocarditis. Clinical epidemiology data suggest that myocarditis is uncommon for both SARS-CoV-2-positive and -negative PCR cases. We hypothesize that the rare virus-negative biopsy-proven cases may represent new-onset immune-mediated or latent pre-existing autoimmune forms, triggered or fostered by the hyperinflammatory state of severe COVID-19. We recommend the application of the ESC/WHO definitions and diagnostic criteria in future reports to avoid low-quality scientific information leading to an inaccurate estimate of myocarditis incidence based on misdiagnosis. Expected final online publication date for the Annual Review of Medicine, Volume 73 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

The Immune and Inflammatory Basis of Acquired Pediatric Cardiac Disease

Children with acquired heart disease face significant health challenges, including a lifetime of strict medical management, multiple cardiac surgeries, and a high mortality risk. Though the presentation of these conditions is diverse, a unifying factor is the role of immune and inflammatory responses in their development and/or progression. For example, infectious agents have been linked to pediatric cardiovascular disease, leading to a large health burden that disproportionately affects low-income areas. Other implicated mechanisms include antibody targeting of cardiac proteins, infection of cardiac cells, and inflammation-mediated damage to cardiac structures. These changes can alter blood flow patterns, change extracellular matrix composition, and induce cardiac remodeling. Therefore, understanding the relationship between the immune system and cardiovascular disease can inform targeted diagnostic and treatment approaches. In this review, we discuss the current understanding of pediatric immune-associated cardiac diseases, challenges in the field, and areas of research with potential for clinical benefit.

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.

Inflammatory Cytokines, Immune Cells, and Organ Interactions in Heart Failure

Despite mounting evidence demonstrating the significance of inflammation in the pathophysiological mechanisms of heart failure (HF), most large clinical trials that target the inflammatory responses in HF yielded neutral or even worsening outcomes. Further in-depth understanding about the roles of inflammation in the pathogenesis of HF is eagerly needed. This review summarizes cytokines, cardiac infiltrating immune cells, and extracardiac organs that orchestrate the complex inflammatory responses in HF and highlights emerging therapeutic targets.

Serum Anti-Heart and Anti-Intercalated Disk Autoantibodies: Novel Autoimmune Markers in Cardiac Sarcoidosis

Background: Sarcoidosis is an immune-mediated disease. Cardiac involvement, a granulomatous form of myocarditis, is under-recognized and prognostically relevant. Anti-heart autoantibodies (AHAs) and anti-intercalated disk autoantibodies (AIDAs) are autoimmune markers in nonsarcoidosis myocarditis forms. Objective: The aim was to assess serum AHAs and AIDAs as autoimmune markers in cardiac sarcoidosis. Methods: This is a cross-sectional study on AHA and AIDA frequency in: 29 patients (aged 46 ± 12, 20 male) with biopsy-proven extracardiac sarcoidosis and biopsy-proven or clinically suspected and confirmed by 18-fluorodeoxyglucose positron emission tomography and/or cardiovascular magnetic resonance (CMR) cardiac involvement; 30 patients (aged 44 ± 11, 12 male) with biopsy-proven extracardiac sarcoidosis without cardiac involvement (no cardiac symptoms, normal 12-lead electrocardiogram, echocardiography and CMR), and control patients with noninflammatory cardiac disease (NICD) (n = 160), ischemic heart failure (IHF) (n = 141) and normal blood donors (NBDs) (n = 270). Sarcoidosis patients were recruited in two recruiting tertiary centers in the USA and Italy. AHAs and AIDAs were detected by indirect immunofluorescence on the human myocardium and skeletal muscle. Results: AHA and AIDA frequencies were higher in sarcoidosis with cardiac involvement (86%; 62%) than in sarcoidosis without cardiac involvement (0%; 0%), NICD (8%; 4%), IHF (7%; 2%) and NBD (9%; 0%) (p = 0.0001; p = 0.0001, respectively). Sensitivity and specificity for cardiac sarcoidosis were 86% and 92% for positive AHAs and 62% and 98% for positive AIDAs, respectively. AIDAs in cardiac sarcoidosis were associated with a higher number of involved organs (p = 0.04). Conclusions: Serum AHAs and AIDAs provide novel noninvasive diagnostic autoimmune markers for cardiac sarcoidosis.

The Spectrum of COVID-19-Associated Myocarditis: A Patient-Tailored Multidisciplinary Approach

BACKGROUND

Myocarditis lacks systematic characterization in COVID-19 patients.

METHODS

We enrolled consecutive patients with newly diagnosed myocarditis in the context of COVID-19 infection. Diagnostic and treatment strategies were driven by a dedicated multidisciplinary disease unit for myocarditis. Multimodal outcomes were assessed during prospective follow-up.

RESULTS

Seven consecutive patients (57% males, age 51 ± 9 y) with acute COVID-19 infection received a de novo diagnosis of myocarditis. Endomyocardial biopsy was of choice in hemodynamically unstable patients (n = 4, mean left ventricular ejection fraction (LVEF) 25 ± 9%), whereas cardiac magnetic resonance constituted the first exam in stable patients (n = 3, mean LVEF 48 ± 10%). Polymerase chain reaction (PCR) analysis revealed an intra-myocardial SARS-CoV-2 genome in one of the six cases undergoing biopsy: in the remaining patients, myocarditis was either due to other viruses (n = 2) or virus-negative (n = 3). Hemodynamic support was needed for four unstable patients (57%), whereas a cardiac device implant was chosen in two of four cases showing ventricular arrhythmias. Medical treatment included immunosuppression (43%) and biological therapy (29%). By the 6-month median follow-up, no patient died or experienced malignant arrhythmias. However, two cases (29%) were screened for heart transplantation.

CONCLUSIONS

Myocarditis associated with acute COVID-19 infection is a spectrum of clinical manifestations and underlying etiologies. A multidisciplinary approach is the cornerstone for tailored management.

The Time Has Come to Explore Plasma Biomarkers in Genetic Cardiomyopathies

For patients with hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM) or arrhythmogenic cardiomyopathy (ACM), screening for pathogenic variants has become standard clinical practice. Genetic cascade screening also allows the identification of relatives that carry the same mutation as the proband, but disease onset and severity in mutation carriers often remains uncertain. Early detection of disease onset may allow timely treatment before irreversible changes are present. Although plasma biomarkers may aid in the prediction of disease onset, monitoring relies predominantly on identifying early clinical symptoms, on imaging techniques like echocardiography (Echo) and cardiac magnetic resonance imaging (CMR), and on (ambulatory) electrocardiography (electrocardiograms (ECGs)). In contrast to most other cardiac diseases, which are explained by a combination of risk factors and comorbidities, genetic cardiomyopathies have a clear primary genetically defined cardiac background. Cardiomyopathy cohorts could therefore have excellent value in biomarker studies and in distinguishing biomarkers related to the primary cardiac disease from those related to extracardiac, secondary organ dysfunction. Despite this advantage, biomarker investigations in cardiomyopathies are still limited, most likely due to the limited number of carriers in the past. Here, we discuss not only the potential use of established plasma biomarkers, including natriuretic peptides and troponins, but also the use of novel biomarkers, such as cardiac autoantibodies in genetic cardiomyopathy, and discuss how we can gauge biomarker studies in cardiomyopathy cohorts for heart failure at large.

Immuno-metabolic interfaces in cardiac disease and failure

The interplay between the cardiovascular system, metabolism, and inflammation plays a central role in the pathophysiology of a wide spectrum of cardiovascular diseases, including heart failure. Here, we provide an overview of the fundamental aspects of the interrelation between inflammation and metabolism, ranging from the role of metabolism in immune cell function to the processes how inflammation modulates systemic and cardiac metabolism. Furthermore, we discuss how disruption of this immuno-metabolic interface is involved in the development and progression of cardiovascular disease, with a special focus on heart failure. Finally, we present new technologies and therapeutic approaches that have recently emerged and hold promise for the future of cardiovascular medicine.

Risk factors analysis of prognosis of adult acute severe myocarditis

BACKGROUND

Adult severe myocarditis is primarily caused by infection with any number of a variety of viruses. It arises quickly, progresses rapidly, and may lead to severe heart failure or circulatory failure presenting as rapid-onset hypotension and cardiogenic shock with a high hospital mortality rate.

AIM

To analyze the risk factors affecting the short-term prognosis of adult acute severe myocarditis (ASM).

METHODS

Adult patients with ASM (ASM group, n = 218) and acute nonsevere myocarditis (ANSM group, n = 80) who came to our department from January 2014 to January 2020 were enrolled in this study. Patients with ASM were divided into the ASM survival group (n = 185) and ASM nonsurvival group (n = 33) according to the treatment results during hospitalization. The clinical symptoms, laboratory examinations, treatment methods, complications, and the relationship between the treatment results of the two groups were retrospectively compared and discussed. The risk factors for death in patients with severe myocarditis were analyzed by binary logistic regression. A follow-up to 5.5 years was conducted on patients in the ASM survival group and ANSM group after discharge, and the readmission rate and incidence rate of dilated cardiomyopathy were analyzed.

RESULTS

Compared with the ASM survival group, the ASM nonsurvival group had longer QRS complex, higher incidence of cardiogenic shock, higher serum creatinine (SCr, 235μmol/L vs 89 μmol/L, P < 0.05), higher sensitive cardiac troponin I (cTnI, 4.45 μg/L vs 1.66 μg/L, P < 0.05) and brain natriuretic peptide (BNP, 1756 pg/mL vs 401 pg/mL, P < 0.05). The binary logistic regression revealed that there were statistical differences between the two groups in SCr, cTnI, and BNP values (all P < 0.05). After discharging from the hospital, patients in the ASM group and ANSM group had no significant differences in the readmission rate and incidence rate of dilated cardiomyopathy.

CONCLUSION

Elevated SCr, cTnI, and BNP are independent predictors for poor prognosis in patients with ASM. The long-term prognosis of patients in the ASM survival group is good.

Myocarditis and inflammatory cardiomyopathy: current evidence and future directions

Inflammatory cardiomyopathy, characterized by inflammatory cell infiltration into the myocardium and a high risk of deteriorating cardiac function, has a heterogeneous aetiology. Inflammatory cardiomyopathy is predominantly mediated by viral infection, but can also be induced by bacterial, protozoal or fungal infections as well as a wide variety of toxic substances and drugs and systemic immune-mediated diseases. Despite extensive research, inflammatory cardiomyopathy complicated by left ventricular dysfunction, heart failure or arrhythmia is associated with a poor prognosis. At present, the reason why some patients recover without residual myocardial injury whereas others develop dilated cardiomyopathy is unclear. The relative roles of the pathogen, host genomics and environmental factors in disease progression and healing are still under discussion, including which viruses are active inducers and which are only bystanders. As a consequence, treatment strategies are not well established. In this Review, we summarize and evaluate the available evidence on the pathogenesis, diagnosis and treatment of myocarditis and inflammatory cardiomyopathy, with a special focus on virus-induced and virus-associated myocarditis. Furthermore, we identify knowledge gaps, appraise the available experimental models and propose future directions for the field. The current knowledge and open questions regarding the cardiovascular effects associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are also discussed. This Review is the result of scientific cooperation of members of the Heart Failure Association of the ESC, the Heart Failure Society of America and the Japanese Heart Failure Society.

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.

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.

Characterization of dendritic cells in human and experimental myocarditis

Aims

Dendritic cells (DCs) are central mediators of adaptive immunity, and there is growing evidence of their role in myocardial inflammatory disease. We hypothesized that plasmacytoid and myeloid DCs are involved in the mechanisms of myocarditis and analysed these two main subtypes in human myocarditis subjects, as well as in a murine model of experimental autoimmune myocarditis (EAM).

Methods and results

Circulating DCs were analysed by flow cytometry in patients with acute myocarditis, dilated cardiomyopathy, and controls. Myocardial biopsies were immunostained for the presence of DCs and compared with non‐diseased controls. In a mouse model of acute myocarditis induced through synthetic cardiac myosine peptide injection, effects of immunomodulation including DC inhibition through MCS‐18 versus placebo treatment were tested at the peak of inflammation (Day 21), as well as 1 week later (partial recovery). Circulatory pDCs and mDCs were significantly reduced in myocarditis patients compared with controls (P < 0.01 for both) and remained so even after 6 months of follow‐up. Human myocarditis biopsies showed accumulation of pDCs (two‐fold CD304+/three‐fold CD123+, all P < 0.05) compared with controls. Myocardial pDCs and mDCs accumulated in EAM (P for both <0.0001). MCS‐18 treatment reduced pDC levels (P = 0.009), reduced myocardial inflammation (myocarditis score reduction from 2.6 to 1.8, P = 0.026), and improved ejection fraction (P = 0.03) in EAM at Day 21 (peak of inflammation). This effect was not observed during the partial recovery of inflammation on Day 28.

Conclusions

Circulating DCs are reduced in human myocarditis and accumulate in the inflamed myocardium. MCS‐18 treatment reduces DCs in EAM, leading to amelioration of inflammation and left ventricular remodelling during the acute phase of myocarditis. Our data further elucidate the role of DCs and their specific subsets in acute inflammatory cardiomyopathies.

Multi-Modality Imaging in Dilated Cardiomyopathy: With a Focus on the Role of Cardiac Magnetic Resonance

Heart failure (HF) is recognized as a leading cause of morbidity and mortality worldwide. Dilated cardiomyopathy (DCM) is a common phenotype in patients presenting with HF. Timely diagnosis, appropriate identification of the underlying cause, individualized risk stratification, and prediction of clinical response to treatment have improved the prognosis of DCM over the last few decades. In this article, we reviewed the current evidence on available imaging techniques used for DCM patients. In this direction, we evaluated appropriate scenarios for the implementation of echocardiography, nuclear imaging, and cardiac computed tomography, and we focused on the primordial role that cardiac magnetic resonance (CMR) holds in the diagnosis, prognosis, and tailoring of therapeutic options in this population of special clinical interest. We explored the predictive value of CMR toward left ventricular reverse remodeling and prediction of sudden cardiac death, thus guiding the decisions for device therapy. Principles underpinning the use of state-of-the-art CMR techniques such as parametric mapping and feature-tracking strain analysis are also provided, along with expectations for the anticipated future advances in this field. We also attempted to correlate the evidence with clinical practice, with the intent to address questions on selecting the optimal imaging method for different indications and clinical needs. Overall, we recommend a comprehensive assessment of DCM patients at baseline and at follow-up intervals depending on the clinical status, with the addition of CMR as a second-line modality to other imaging techniques. We also provide an algorithm to guide the detailed imaging approach of the patient with DCM. We expect that future guidelines will upgrade their clinical recommendations for the utilization of CMR in DCM, which is expected to further improve the quality of care and the outcomes. This review provides an up-to-date perspective on the imaging of dilated cardiomyopathy patients and will be of clinical value to training doctors and physicians involved in the area of heart failure.

Immunosuppressive Therapy and Risk Stratification of Patients With Myocarditis Presenting With Ventricular Arrhythmias

OBJECTIVES

This study sought to investigate the effects of immunosuppression on arrhythmic myocarditis.

BACKGROUND

The effects of immunosuppressive therapy (IST) on ventricular arrhythmia (VA) have not been reported in patients with immune-mediated biopsy-proven myocarditis. Furthermore, myocarditis arrhythmic risk is still unpredictable.

METHODS

We enrolled 255 patients with biopsy-proven virus-negative myocarditis and VA (major: ventricular fibrillation, ventricular tachycardia; minor: nonsustained ventricular tachycardia, Lown grade ≥2 premature ventral complexes) at presentation. Serum cardiac autoantibodies (antiheart antibodies, anti-intercalated disk autoantibodies [AIDA]) were detected by a standardized indirect immunofluorescence technique. Whenever accepted and noncontraindicated, IST was started. Control individuals (IST^-) were chosen after 1:1 matching to IST⁺ patients by age, sex, ethnicity, left ventricular ejection fraction, VA type, and treatment.

RESULTS

A total of 58 matched patient couples (age 42 ± 13 years; 67% male) were analyzed in the main study cohort. IST duration was 12 ± 1 months. By the 24-month prospective follow-up, major VA occurred in 6 IST⁺ versus 10 IST^- patients (p = 0.42), with no episodes following IST termination. As compared to IST^- patients, IST⁺ patients showed a significant reduction in minor VA burden, as well as improvement in clinical, laboratory, and imaging findings (all p < 0.05). Major VA onset and positive AIDA status were independently associated with major VA at follow-up (hazard ratio [HR]: 14.2; 95% confidence interval [CI]: 2.9 to 68.7 and HR: 8.0; 95% CI: 2.6 to 25.2, respectively; both p < 0.001). Furthermore, in the whole study population (N = 255), IST was independently associated with protection from major VA (HR: 0.3; 95% CI: 0.2 to 0.7; p = 0.01) at 38 ± 21 months of follow-up.

CONCLUSIONS

In patients with immune-mediated virus-negative myocarditis presenting with VA, IST is associated with positive effects on minor VA and nonarrhythmic endpoints. Short-term effects are limited on major VA, which were independently associated with major VA onset and positive AIDA.

Evidence From Family Studies for Autoimmunity in Arrhythmogenic Right Ventricular Cardiomyopathy: Associations of Circulating Anti-Heart and Anti-Intercalated Disk Autoantibodies With Disease Severity and Family History

BACKGROUND

Serum anti-heart autoantibodies (AHAs) and anti-intercalated disk autoantibodies (AIDAs) are autoimmune markers in myocarditis. Myocarditis has been reported in arrhythmogenic right ventricular cardiomyopathy (ARVC). To provide evidence for autoimmunity, we searched for AHAs and AIDAs in ARVC.

METHODS

We studied: 42 ARVC probands, 23 male, aged 42, interquartile range 33-49, 20 from familial and 22 nonfamilial pedigrees; 37 clinically affected relatives (ARs), 24 male aged 35, interquartile range 18-46; and 96 healthy relatives, 49 male, aged 27, interquartile range 17-45. Serum AHAs and AIDAs were tested by indirect immunofluorescence on human myocardium and skeletal muscle in 171 of the 175 ARVC individuals and in controls with noninflammatory cardiac disease (n=160), ischemic heart failure (n=141), and healthy blood donors (n=270). Screening of 5 desmosomal genes was performed in probands; when a sequence variant was identified, cascade family screening followed, blind to immunologic results.

RESULTS

AHA frequency was higher (36.8%) in probands, ARs (37.8%), and healthy relatives (25%) than in noninflammatory cardiac disease (1%), ischemic heart failure (1%), or healthy blood donors (2.5%; P=0.0001). AIDA frequency was higher in probands (8%, P=0.006), in ARs (21.6%, P=0.00001), and in healthy relatives (14.6%, P=0.00001) than in noninflammatory cardiac disease (3.75%), ischemic heart failure (2%), or healthy blood donors (0.3%). AHA-positive status was associated with higher frequency of palpitation (P=0.004), implantable cardioverter defibrillator implantation (P=0.021), lower left ventricular ejection fraction (P=0.004), AIDA-positive status with both lower right ventricular and left ventricular ejection fractions (P=0.027 and P=0.027, respectively). AHA- and/or AIDA-positive status in the proband and at least one of the respective relatives was more common in familial (17/20, 85%) than in sporadic (10/22, 45%) pedigrees (P=0.007).

CONCLUSIONS

The presence of AHAs and AIDAs provides evidence of autoimmunity in the majority of familial and in almost half of sporadic ARVC. In probands and in ARs, these antibodies were associated with features of disease severity. Longitudinal studies are needed to clarify whether they may predict ARVC development in healthy relatives or if they be a result of manifest ARVC.

β1-Adrenoreceptor Autoantibodies in Heart Failure: Physiology and Therapeutic Implications

Antibodies that activate the β₁-AR (β₁-adrenoreceptor) can induce heart failure in animal models. These antibodies are often found in patients with heart failure secondary to varying etiologies. Their binding to the β₁ receptor leads to prolonged receptor activation with subsequent induction of cellular dysfunction, apoptosis, and arrhythmias. β-blocker therapy while highly effective for heart failure, may not be sufficient treatment for patients who have β₁ receptor autoantibodies. Removal of these autoantibodies by immunoadsorption has been shown to improve heart failure in small studies. However, immunoadsorption is costly, time consuming, and carries potential risks. An alternative to immunoadsorption is neutralization of autoantibodies through the intravenous application of small soluble molecules, such as peptides or aptamers, which specifically target and neutralize β₁-AR autoantibodies. Peptides may induce immunogenicity. Animal as well as early phase human studies with aptamers have not shown safety concerns to date and have demonstrated effectiveness in reducing autoantibody levels. Novel aptamers have the potential advantage of having a wide spectrum of action, neutralizing a variety of known circulating G-protein coupled receptor autoantibodies. These aptamers, therefore, have the potential to be novel therapeutic option for patients with heart failure who have positive for β₁-AR autoantibodies. However, clinical outcomes trials are needed to assess the clinical utility of this novel approach to treat heart failure.

Therapeutic Advances in Emergency Cardiology: A Focus on Acute Myocarditis

BACKGROUND

Myocarditis, defined as an inflammation of the myocardium, is an important cause of dilated cardiomyopathy and congestive heart failure. Unfortunately, its diagnosis and etiology is often challenging in clinical practice, and thus, improving diagnosis and therapeutic approach of this cardiac pathology is a matter of great interest.

AREAS OF UNCERTAINTY

The etiology of the disease may be represented by not only infectious agents, usually with viral determination, but also autoimmune and systemic diseases or drugs. Regarding diagnostic techniques, endomyocardial biopsy remains the gold standard; but beyond histological findings, an important step in achieving an accurate diagnosis was represented by the use immunohistochemical criteria and noninvasive diagnostic tests such as cardiac magnetic resonance imaging.

DATA SOURCES

We reviewed current data on the current diagnosis and therapeutic approach of acute myocarditis.

THERAPEUTIC ADVANCES

In addition to the standard heart failure therapy, some specific therapeutic options are available in selected cases. Viral myocarditis with persistent inflammation and viral clearance may be responsive to immunosuppressive therapy with azathioprine and cortisone or to immunoadsorption technique. Also, some chronic viral myocardial infections may benefit from 6 months of interferon-β therapy.

CONCLUSIONS

The diagnosis of acute myocarditis still remains a great challenge, despite advances related to new diagnostic procedures. Endomyocardial biopsy, an invasive diagnostic tool that is not always usually available in clinical practice, still remains the standard diagnostic technique. Due to the potential evolution of acute myocarditis, identifying new parameters that may allow an early selection of patients with great risk of evolution toward myocardial fibrosis and dilated cardiomyopathy may be a field of great interest for future studies.

Dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is a clinical diagnosis characterized by left ventricular or biventricular dilation and impaired contraction that is not explained by abnormal loading conditions (for example, hypertension and valvular heart disease) or coronary artery disease. Mutations in several genes can cause DCM, including genes encoding structural components of the sarcomere and desmosome. Nongenetic forms of DCM can result from different aetiologies, including inflammation of the myocardium due to an infection (mostly viral); exposure to drugs, toxins or allergens; and systemic endocrine or autoimmune diseases. The heterogeneous aetiology and clinical presentation of DCM make a correct and timely diagnosis challenging. Echocardiography and other imaging techniques are required to assess ventricular dysfunction and adverse myocardial remodelling, and immunological and histological analyses of an endomyocardial biopsy sample are indicated when inflammation or infection is suspected. As DCM eventually leads to impaired contractility, standard approaches to prevent or treat heart failure are the first-line treatment for patients with DCM. Cardiac resynchronization therapy and implantable cardioverter-defibrillators may be required to prevent life-threatening arrhythmias. In addition, identifying the probable cause of DCM helps tailor specific therapies to improve prognosis. An improved aetiology-driven personalized approach to clinical care will benefit patients with DCM, as will new diagnostic tools, such as serum biomarkers, that enable early diagnosis and treatment.

Editor's Choice- Pathophysiology, diagnosis and management of MINOCA: an update

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is a syndrome with different causes, characterised by clinical evidence of myocardial infarction with normal or near-normal coronary arteries on angiography. Its prevalence ranges between 5% and 25% of all myocardial infarction. The prognosis is extremely variable, depending on the cause of MINOCA. The key principle in the management of this syndrome is to clarify the underlying individual mechanisms to achieve patient-specific treatments. Clinical history, electrocardiogram, cardiac enzymes, echocardiography, coronary angiography and left ventricular angiography represent the first level diagnostic investigations to identify the causes of MINOCA. Regional wall motion abnormalities at left ventricular angiography limited to a single epicardial coronary artery territory identify an 'epicardial pattern'whereas regional wall motion abnormalities extended beyond a single epicardial coronary artery territory identify a 'microvascular pattern'. The most common causes of MINOCA are represented by coronary plaque disease, coronary dissection, coronary artery spasm, coronary microvascular spasm, Takotsubo cardiomyopathy, myocarditis, coronary thromboembolism, other forms of type 2 myocardial infarction and MINOCA of uncertain aetiology. This review aims at summarising the diagnosis and management of MINOCA, according to the underlying physiopathology.

Cardiac magnetic resonance imaging in heart failure: where the alphabet begins!

Cardiac Magnetic Resonance Imaging has become a cornerstone in the evaluation of heart failure. It provides a comprehensive evaluation by answering all the pertinent clinical questions across the full pathological spectrum of heart failure. Nowadays, CMR is considered the gold standard in evaluation of ventricular volumes, wall motion and systolic function. Through its unique ability of tissue characterization, it provides incremental diagnostic and prognostic information and thus has emerged as a comprehensive imaging modality in heart failure. This review outlines the role of main conventional CMR sequences in the evaluation of heart failure and their impact in the management and prognosis.

The Contribution of Autoantibodies to Inflammatory Cardiovascular Pathology

Chronic inflammation and resulting tissue damage underlie the vast majority of acquired cardiovascular disease (CVD), a general term encompassing a widely diverse array of conditions. Both innate and adaptive immune mechanisms contribute to chronic inflammation in CVD. Although maladies, such as atherosclerosis and cardiac fibrosis, are commonly conceptualized as disorders of inflammation, the cellular and molecular mechanisms that promote inflammation during the natural history of these diseases in human patients are not fully defined. Autoantibodies (AAbs) with specificity to self-derived epitopes accompany many forms of CVD in humans. Both adaptive/induced iAAbs (generated following cognate antigen encounter) and also autoantigen-reactive natural antibodies (produced independently of infection and in the absence of T cell help) have been demonstrated to modulate the natural history of multiple forms of CVD including atherosclerosis (atherosclerotic cardiovascular disease), dilated cardiomyopathy, and valvular heart disease. Despite the breadth of experimental evidence for the role of AAbs in CVD, there is a lack of consensus regarding their specific functions, primarily due to disparate conclusions reached, even when similar approaches and experimental models are used. In this review, we seek to summarize the current understanding of AAb function in CVD through critical assessment of the clinical and experimental evidence in this field. We additionally highlight the difficulty in translating observations made in animal models to human physiology and disease and provide a summary of unresolved questions that are critical to address in future studies.

IL-27 genetic variation and susceptibility of dilated cardiomyopathy in Chinese Han population

AIM

Accumulating data showed that IL-27 polymorphisms are linked to the susceptibility of some autoimmune diseases. We assessed whether there was an association between two single nucleotide polymorphisms (SNPs) of IL-27 gene and dilated cardiomyopathy (DCM).

MATERIALS & METHODS

Two SNPs (rs153109 and rs17855750) of IL-27 gene were genotyped by PCR-restriction fragment length polymorphism in 261 DCM patients and 303 unrelated healthy subjects in Chinese Han population.

RESULTS

Compared with controls, our results showed that SNP rs153109 displayed significant associations with DCM in Chinese Han population, whereas no differences in genotype or allele frequencies were found between DCM patients and controls at SNP rs17855750.

CONCLUSION

Our study showed that, for the first time, the association of the IL-27 gene SNP with the patients with DCM.

Mechanisms of Autoantibody-Induced Pathology

Autoantibodies are frequently observed in healthy individuals. In a minority of these individuals, they lead to manifestation of autoimmune diseases, such as rheumatoid arthritis or Graves' disease. Overall, more than 2.5% of the population is affected by autoantibody-driven autoimmune disease. Pathways leading to autoantibody-induced pathology greatly differ among different diseases, and autoantibodies directed against the same antigen, depending on the targeted epitope, can have diverse effects. To foster knowledge in autoantibody-induced pathology and to encourage development of urgently needed novel therapeutic strategies, we here categorized autoantibodies according to their effects. According to our algorithm, autoantibodies can be classified into the following categories: (1) mimic receptor stimulation, (2) blocking of neural transmission, (3) induction of altered signaling, triggering uncontrolled (4) microthrombosis, (5) cell lysis, (6) neutrophil activation, and (7) induction of inflammation. These mechanisms in relation to disease, as well as principles of autoantibody generation and detection, are reviewed herein.

A humanized HLA-DR4 mouse model for autoimmune myocarditis

Myocarditis, the principal cause of dilated cardiomyopathy and heart failure in young adults, is associated with autoimmunity to human cardiac α-myosin (hCAM) and the DR4 allele of human major histocompatibility II (MHCII). We developed an hCAM-induced myocarditis model in human HLA-DR4 transgenic mice that lack all mouse MHCII genes, demonstrating that immunization for 3 weeks significantly increased splenic T-cell proliferative responses and titres of IgG1 and IgG2c antibodies, abolished weight gain, provoked cardiac inflammation and significantly impaired cardiac output and fractional shortening, by echocardiography, compared to adjuvant-injected mice. Neither cardiac dilatation nor fibrosis occurred at this time point but prolonging the experiment was associated with mortality. Treatment with mixtures of hCAM derived peptides predicted to have high affinity for DR4 significantly preserved ejection fraction and fractional shortening. Our new humanized mouse model of autoimmune cardiomyopathy should be useful to refine hCAM-derived peptide treatment.

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We developed a novel fully-humanized mouse model of autoimmune myocarditis.

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Human leukocyte antigen DR4 transgenic mice were immunized with human cardiac myosin.

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After 3 weeks, mice developed myocarditis and impaired myocardial function.

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A pilot study established the feasibility of peptide immunotherapy in this model.

Contextualizing Genetics for Regional Heart Failure Care

Congestive heart failure (CHF) is a chronic and often devastating cardiovascular disorder with no cure. There has been much advancement in the last two decades that has seen improvements in morbidity and mortality. Clinicians have also noted variations in the responses to therapies. More detailed observations also point to clusters of diseases, phenotypic groupings, unusual severity and the rates at which CHF occurs. Medical genetics is playing an increasingly important role in answering some of these observations. This developing field in many respects provides more information than is currently clinically applicable. This includes making sense of the established single gene mutations or uncommon private mutations. In this thematic series which discusses the many factors that could be relevant for CHF care, once established treatments are available in the communities; this section addresses a contextual role for medical genetics.

Identification of novel antigens contributing to autoimmunity in cardiovascular diseases

In myocarditis and dilated cardiomyopathy (DCM) patients the immune system may play an important role in disease progression. In this study, we aimed to identify new antigens as a target for autoimmune response that might play a crucial role in these diseases. Therefore, a peptide-array was used to investigate antibody binding profiles in patients with autoimmune myocarditis or DCM compared to healthy controls and thus to identify disease relevant antigens. To analyze the pathogenicity of the identified antigens, an experimental autoimmune myocarditis (EAM) model was used. Hereby, 3 peptide sequences, derived from myosin-binding-protein-C (MYBPC) fast-type, RNA-binding-protein 20 (RBM20), and dystrophin, showed pathogenic effects on the myocardium of mice. In summary, 3 potentially cardiopathogenic peptides (MYBPC fast-type, RBM20, dystrophin) were identified. Thus, this study could serve as a basis for future investigations aimed at determining further antigens leading to pathogenic effects on the myocardium of DCM as well as myocarditis patients.

The role of invasive diagnostics and its impact on the treatment of dilated cardiomyopathy: A systematic review

BACKGROUND

Dilated cardiomyopathy is one of the most frequent causes of non-ischemic heart failure. Many factors including genetic disorders, infectious agents, toxins, drugs and autoimmune disorders might take part in the development of dilated cardiomyopathy. Diagnosis of left ventricular dilatation is most often limited to performing echocardiography and excluding ischemic etiology (coronary angiography). Since many pathologies take place at the cellular and subcellular level the only way to clarify the etiology of the disease is to examine the myocardium itself (endomyocardial biopsy).

METHODS

A systematic literature search was conducted for studies published between September 2000 and September 2015 using the PubMed database.

RESULTS

Of 7104 studies identified, 73 studies were included in this review. Controversies raised by opponents of the endomyocardial biopsy collide with the low percentage of serious complications confirmed in several single-center registries. Based on the available data the overall complication rate varies from 1% to about 3%, with 0.5% risk of serious complications. According to the current recommendations of the European and American scientific societies endomyocardial biopsy should be performed in most cases of left ventricular dilatation and heart failure of non-ischemic etiology. Endomyocardial biopsy allows for making the diagnosis and providing prognostic information especially in patients with familial dilated cardiomyopathy, diabetic cardiomyopathy with dilated phenotype, alcoholic cardiomyopathy, peripartum cardiomyopathy, iron overload cardiomyopathy, as well as inflammatory and viral cardiomyopathy. Iron overload cardiomyopathy, peripartum cardiomyopathy, inflammatory and viral cardiomyopathy are potentially treatable and reversible.

CONCLUSIONS

Targeted therapies are more effective when started early before myocardial injury becomes irreversible. Unfortunately, non-invasive techniques are not precise enough to decide if and which targeted therapy is required. Therefore endomyocardial biopsy should be mainly recognized as the essential diagnostic tool and should not be postponed.

Changes of myocardial gene expression and protein composition in patients with dilated cardiomyopathy after immunoadsorption with subsequent immunoglobulin substitution

Immunoadsorption with subsequent immunoglobulin substitution (IA/IgG) represents a therapeutic approach for patients with dilated cardiomyopathy (DCM). Here, we studied which molecular cardiac alterations are initiated after this treatment. Transcription profiling of endomyocardial biopsies with Affymetrix whole genome arrays was performed on 33 paired samples of DCM patients collected before and 6 months after IA/IgG. Therapy-related effects on myocardial protein levels were analysed by label-free proteome profiling for a subset of 23 DCM patients. Data were analysed regarding therapy-associated differences in gene expression and protein levels by comparing responders (defined by improvement of left ventricular ejection fraction ≥20 % relative and ≥5 % absolute) and non-responders. Responders to IA/IgG showed a decrease in serum N-terminal proBNP levels in comparison with baseline which was accompanied by a decreased expression of heart failure markers, such as angiotensin converting enzyme 2 or periostin. However, despite clinical improvement even in responders, IA/IgG did not trigger general inversion of DCM-associated molecular alterations in myocardial tissue. Transcriptome profiling revealed reduced gene expression for connective tissue growth factor, fibronectin, and collagen type I in responders. In contrast, in non-responders after IA/IgG, fibrosis-associated genes and proteins showed elevated levels, whereas values were reduced or maintained in responders. Thus, improvement of LV function after IA/IgG seems to be related to a reduced gene expression of heart failure markers and pro-fibrotic molecules as well as reduced fibrosis progression.