Inflammation on Endomyocardial Biopsy Predicts Risk of MACE in Undefined Left Ventricular Arrhythmogenic Cardiomyopathy

Analysis of effector/memory regulatory T cells from arrhythmogenic cardiomyopathy patients identified IL-32 as a novel player in ACM pathogenesis

Arrhythmogenic cardiomyopathy (ACM) is an inherited cardiac disorder that causes sudden cardiac death and progressive heart failure. Besides fibro-fatty replacement and myocyte degenerative changes, inflammatory patchy infiltrates are found in myocardial histological analysis of ACM patients. Inflammatory cells could actively participate in ACM pathogenesis, contributing to the alteration of cardiac microenvironment homeostasis, thus triggering disease evolution. In order to characterize the immune-derived mediators involved in ACM pathogenesis, peripheral blood mononuclear cells from ACM patients were characterized and compared to healthy controls' ones. Flow cytometry analysis revealed a lower frequency of CD4+ T helper type 1 cells, NK cells, and terminally differentiated CD8+ EMRA+ T cells in ACM patients compared to age-matched controls. In contrast, a higher proportion of effector/memory FOXP3+ CCR4+ CD45RO+ regulatory CD4+ T cells (Treg) were found in ACM patients. Single-cell RNA-seq performed on isolated memory Treg cells (mTreg) from ACM patients and healthy controls identified 6 clusters characterized by specific gene signatures related to tissue repair and immunosuppressive pathways. Notably, interleukin 32 (IL-32) was the most differentially expressed gene in ACM patients mTreg with respect to healthy controls. Treatment of human cardiac mesenchymal stromal cells with recombinant IL-32 in vitro promoted lipid droplet accumulation and collagen deposition, thus identifying IL-32 as a new potential player in the immune-mediated trigger of cardiac fibro-fatty replacement in ACM. Overall, we here provide the first complete characterization of circulating ACM immune cells, revealing an abundance of Treg. The high expression of IL-32 in ACM Treg may contribute to accelerated cardiac remodeling in ACM patients' hearts.

Management Status of Myocarditis-Related Sudden Cardiac Death

Myocarditis, a life-threatening disease that can result in cardiac arrest and sudden cardiac death, has garnered significant attention in recent years. This review provides a comprehensive overview of the management of myocarditis-related sudden cardiac death, encompassing its pathology, diagnostic methods, therapeutic strategies, preventive measures, prognostic factors, and risk stratification. Additionally, the review highlights current challenges and future directions in this field. The aim is to enhance understanding of myocarditis-related sudden cardiac death and inform clinical practice, ultimately leading to improved patient outcomes.

'Hot phase' non-dilated left ventricular cardiomyopathy with atypical onset and recurrence: a case report

Non-dilated left ventricular cardiomyopathy (NDLVC) is a newly categorized cardiomyopathy phenotype includingseveral aetiologies with a linking characteristic represented by the normal left ventricular volume. Inflammatory heart disease (InHD) is a heterogeneous process with variegate clinical manifestations, sometimes in overlap with NDLVC. A 26-year-old woman was admitted forcomplete heart block (CHB) and persistently raised troponin. Echocardiography and coronary angiography were normal. Extensive oedema and late gadolinium enhancement was found at cardiac magnetic resonance. Endomyocardial biopsy showed no signs of active myocarditis. Steroid therapy was started with restoration of atrioventricular conduction but subsequently the patient experienced a mild recurrence with a new troponin relapse. Genetic test was negative for mutations related with the clinical scenario. In this case of NDLVC with InHD the precise diagnostic work-up, including genetic test, was crucial for diagnostic, prognostic andtherapeutic purposes. Multimodality approach is crucial to detect and treat possible recurrences.

Desmoplakin Cardiomyopathy in Pediatric Patients: A Distinct, Underrecognized Cohort of Arrhythmogenic Cardiomyopathy

BACKGROUND

DSP cardiomyopathy is a distinct subset of arrhythmogenic cardiomyopathy, reported primarily in adults, that has predominantly left ventricular involvement and features of myocarditis. Clinical characteristics, risk stratification, and management of pediatric patients with DSP variants are not well known. We sought to identify phenotypic features and prognosis of pediatric patients with DSP pathogenic or likely pathogenic variants.

METHODS

Multicenter, retrospective study of patients <21 years of age with DSP variants from 6 tertiary pediatric hospitals.

RESULTS

Thirty-four patients, including 10 probands with clinical disease and 24 genotype-positive phenotype-negative patients, were included in the study. The majority of probands were initially diagnosed with myocarditis (50%) and had biventricular (60%) or left ventricular predominant (40%) disease. Chest pain was the most common symptom at presentation (30%), and all had troponin elevation. Probands with homozygous or compound heterozygous DSP variants were likely to present at an early age (<13 years) with symptoms of heart failure, severe biventricular involvement, and dermatologic abnormalities. Low-voltage QRS was the most prominent ECG abnormality. Of those who underwent implantable cardioverter defibrillator implantation, 50% received appropriate implantable cardioverter defibrillator therapy and were found to have significant biventricular involvement in addition to severe left ventricular dysfunction with an ejection fraction <35%.

CONCLUSIONS

DSP cardiomyopathy in children and adolescents has varied phenotypic manifestations based on age and genotype and often can be diagnosed as myocarditis. Severe left ventricular dysfunction and biventricular involvement may be associated with a higher likelihood of malignant ventricular tachyarrhythmia.

What are the early warning signs of myocarditis during the pathway of care?

INTRODUCTION

Myocarditis is an inflammatory disease of the myocardial layer of the heart that can be prone to dilation of chambers with presentation as heart failure secondary to dilated cardiomyopathy. Myocarditis can lead to remodeling and fibrosis that can affect the heart's relaxation-lusitropy and chronotropic function. The current techniques for identifying myocarditis, such as endomyocardial biopsy and imaging, are costly, and intrusive. The current literature aims to identify reliable, accurate, and prognostically educative biomarkers of myocarditis.

AREAS COVERED

This review covers the definition, clinical features, diagnostic markers, cardiac imaging, prognosis, and complications of myocarditis. PubMed, Embase, and the Cochrane data bank were searched from inception to 1 January 2024 for relevant articles.

EXPERT OPINION

By adopting these diagnostic and prognostic biomarkers, clinicians can have a better comprehension of the progression of the disease and provide early diagnosis and treatment for myocarditis.

Arrhythmic Mitral Valve Prolapse and Sports Activity: Pathophysiology, Risk Stratification, and Sports Eligibility Assessment

Although mitral valve prolapse (MVP) is the most prevalent valvular abnormality in Western countries and generally carries a good prognosis, a small subset of patients is exposed to a significant risk of malignant ventricular arrhythmias (VAs) and sudden cardiac death (SCD), the so-called arrhythmic MVP (AMVP) syndrome. Recent work has emphasized phenotypical risk features of severe AMVP and clarified its pathophysiology. However, the appropriate assessment and risk stratification of patients with suspected AMVP remains a clinical conundrum, with the possibility of both overestimating and underestimating the risk of malignant VAs, with the inappropriate use of advanced imaging and invasive electrophysiology study on one hand, and the catastrophic occurrence of SCD on the other. Furthermore, the sports eligibility assessment of athletes with AMVP remains ill defined, especially in the grey zone of intermediate arrhythmic risk. The definition, epidemiology, pathophysiology, risk stratification, and treatment of AMVP are covered in the present review. Considering recent guidelines and expert consensus statements, we propose a comprehensive pathway to facilitate appropriate counseling concerning the practice of competitive/leisure-time sports, envisioning shared decision making and the multidisciplinary "sports heart team" evaluation of borderline cases. Our final aim is to encourage an active lifestyle without compromising patients' safety.

Basic and translational mechanisms in inflammatory arrhythmogenic cardiomyopathy

Arrhythmogenic cardiomyopathy (ACM) is a familial, nonischemic heart disease typically inherited via an autosomal dominant pattern (Nava et al., [1]; Wlodarska et al., [2]). Often affecting the young and athletes, early diagnosis of ACM can be complicated as incomplete penetrance with variable expressivity are common characteristics (Wlodarska et al., [2]; Corrado et al., [3]). That said, of the five desmosomal genes implicated in ACM, pathogenic variants in desmocollin-2 (DSC2) and desmoglein-2 (DSG2) have been discovered in both an autosomal-recessive and autosomal-dominant pattern (Wong et al., [4]; Qadri et al., [5]; Chen et al., [6]). Originally known as arrhythmogenic right ventricular dysplasia (ARVD), due to its RV prevalence and manifesting in the young, the disease was first described in 1736 by Giovanni Maria Lancisi in his book "De Motu Cordis et Aneurysmatibus" (Lancisi [7]). However, the first comprehensive clinical description and recognition of this dreadful disease was by Guy Fontaine and Frank Marcus in 1982 (Marcus et al., [8]). These two esteemed pathologists evaluated twenty-two (n = 22/24) young adult patients with recurrent ventricular tachycardia (VT) and RV dysplasia (Marcus et al., [8]). Initially, ARVD was thought to be the result of partial or complete congenital absence of ventricular myocardium during embryonic development (Nava et al., [9]). However, further research into the clinical and pathological manifestations revealed acquired progressive fibrofatty replacement of the myocardium (McKenna et al., [10]); and, in 1995, ARVD was classified as a primary cardiomyopathy by the World Health Organization (Richardson et al., [11]). Thus, now classifying ACM as a cardiomyopathy (i.e., ARVC) rather than a dysplasia (i.e., ARVD). Even more recently, ARVC has shifted from its recognition as a primarily RV disease (i.e., ARVC) to include left-dominant (i.e., ALVC) and biventricular subtypes (i.e., ACM) as well (Saguner et al., [12]), prompting the use of the more general term arrhythmogenic cardiomyopathy (ACM). This review aims to discuss pathogenesis, clinical and pathological phenotypes, basic and translational research on the role of inflammation, and clinical trials aimed to prevent disease onset and progression.

Clinical profiling and outcomes of viral myocarditis manifesting with ventricular arrhythmias

Aims

Clinical features and risk stratification of patients with viral myocarditis (VM) complicated by ventricular arrhythmias (VA) are incompletely understood. We aim to describe arrhythmia patterns and outcomes in patients with VM and early-onset VA.

Methods and results

We present a single-centre study, enrolling patients with VM proven by endomyocardial biopsy, and evidence of VA within 24 h of hospitalization. The incidence of major adverse events (MAE), including all-cause death, severe heart failure, advanced atrioventricular blocks, or major VA, was evaluated during a 24-month follow-up (FU) and compared with a matched group of virus-negative myocarditis. Of patients with VM (n = 74, mean age 47 ± 16 years, 66% males, and left ventricular ejection fraction 51 ± 13%), 20 (27%) presented with major VA [ventricular tachycardia/ventricular fibrillation (VT/VF)], and 32 (44%) had polymorphic VA. Patients with polymorphic VA more commonly had evidence of ongoing systemic infection (24/32 vs. 10/42, P = 0.004) and experienced greater occurrence of MAE at discharge (15/32 vs. 2/42, P < 0.001). However, the incidence of MAE during FU was higher in patients with monomorphic VA compared to those with polymorphic VA (17/42 vs. 2/28, P = 0.002). Patients with monomorphic VA displayed frequently signs of chronic cardiomyopathy and had outcomes comparable with virus-negative myocarditis (log rank P = 0.929). Presentation with VT/VF was independently associated with MAE [at discharge: hazard ratio (HR) 4.7, 95% confidence interval (CI) 1.6-14.0, P = 0.005; during FU: HR 6.3, 95% CI 2.3-17.6, P < 0.001].

Conclusion

In patients with VM, polymorphic VA point to ongoing systemic infection and early adverse outcomes, whereas monomorphic VA suggest chronic cardiomyopathy and greater incidence of MAE during FU. Presentation with VT/VF is independently associated with MAE.