Arrhythmogenic right ventricular cardiomyopathy: evaluation of the current diagnostic criteria and differential diagnosis

Characteristics and pharmacological responsiveness in hiPSC models of inherited cardiomyopathy

Inherited cardiomyopathies are a major cause of heart failure in all age groups, often with an onset in adolescence or early adult life. More than a thousand variants in approximately one hundred genes are associated with cardiomyopathies. Interestingly, many genetic cardiomyopathies display overlapping phenotypical defects in patients, despite the diversity of the initial pathogenic variants. Understanding how the underlying pathophysiology of genetic cardiomyopathies leads to these phenotypes will improve insights into a patient's disease course, and creates the opportunity for conceiving treatment strategies. Moreover, therapeutic strategies can be used to treat multiple cardiomyopathies based on shared phenotypes. Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) offer reliable, high-throughput models for studying molecular and cellular characteristics of hereditary cardiomyopathies. hiPSC-CMs are produced relatively easily, either by directly originating them from patients, or by introducing patient-specific genetic variants in healthy lines. This review evaluates 90 studies on 24 cardiomyopathy-associated genes and systematically summarises the morphological and functional phenotypes observed in hiPSC-CMs. Additionally, treatment strategies applied in cardiomyopathic hiPSC-CMs are compiled and scored for effectiveness. Multiple overlapping phenotypic defects were identified in cardiomyocytes with different variants, whereas certain characteristics were only associated with specific genetic variants. Based on these findings, common mechanisms, therapeutic prospects, and considerations for future research are discussed with the aim to improve clinical translation from hiPSC-CMs to patients.

Southeast Asian, African, and Middle East Expert Consensus on Structured Physical Activity-Dance, Exercise, and Sports

Physical inactivity (PIA) is a pressing public health issue globally, contributing significantly to the rise of non-communicable diseases (NCD), such as cardiovascular disease and type 2 diabetes. The World Health Organization emphasises the importance of regular physical activity (PA) for preventing and managing NCDs. Initiatives to promote active living have gained momentum, ranging from community programs to workplace wellness campaigns, all focused on reducing sedentary lifestyles in modern society. Structured Physical Activity-Dance, Exercise, and Sports (SPADES) has emerged as an innovative approach to addressing PIA and promoting holistic health. After thoroughly reviewing existing literature from PubMed and Google Scholar databases, a panel of experts developed consensus statements through in-depth discussions, and the strength of concurrence on these statements was voted on using a Likert scale. The panel reached a consensus on the best strategies for PA, dance, exercise, sports, and key factors to consider during PA. This consensus targets individuals with metabolic diseases, particularly in regions like South Asia, East Africa, the Gulf, and Latin America, where these conditions are highly prevalent. The SPADES guidelines emphasise overcoming the barriers people with metabolic disorders face in achieving adequate PA, providing tailored recommendations to improve health outcomes for this population.

A Unique Case of Biventricular Arrhythmogenic Cardiomyopathy

Arrhythmogenic cardiomyopathy is a type of heart disease that is a well-recognized cause of sudden cardiac death among the young population. It can affect the right ventricle, left ventricle, or both ventricles of the heart. This condition involves the replacement of heart muscle with fatty tissue, which can disrupt the heart's normal electrical and mechanical function, leading to arrhythmias, heart failure, and increased risk of sudden cardiac death. We report the case of a 62-year-old man who came to the emergency room with nausea, vomiting, and palpitations. After further evaluation, he was diagnosed with heart failure secondary to biventricular arrhythmogenic cardiomyopathy. The patient was found to have a genetic mutation in the RYR2 gene, which usually causes dilation of the right ventricle. However, in this case, both the right and left ventricles were dilated, which is unusual since RYR2 mutations are typically linked to right ventricle dilation only. This may represent a potentially novel phenotypic manifestation of the disease associated with this mutation, as no other cases have been reported in the literature.

Before and Beyond Tissue Characterization: Cardiac Magnetic Resonance Imaging in the Morphological, Volumetric, and Functional Evaluation of the Right Ventricle in Arrhythmogenic Right Ventricular Cardiomyopathy, a Narrative Review

Arrhythmogenic right ventricular cardiomyopathy is a condition characterized by fibro-fatty replacement, primarily affecting the right ventricle (RV), with variable involvement of the left ventricle, characterized by an increased risk of ventricular arrhythmias and sudden cardiac death. In addition to tissue characterization, which is not the subject of this review, dilation, global systolic dysfunction, and regional kinetic abnormalities of the RV are important components of the diagnostic process for this disease, serving as essential diagnostic criteria. Cardiac magnetic resonance, a central examination in the evaluation of cardiomyopathies, has gained progressive importance because of its greater diagnostic accuracy than echocardiography in detecting morphological volumetric and functional abnormalities, especially of the RV. However, the accurate assessment of morphological abnormalities of the RV using cardiac magnetic resonance imaging remains challenging, because of variability in the interpretation of individual structural anomalies. Besides, several elements come into play in the differential diagnosis of morphological anomalies of the RV, which often mislead the operator and lead to false positive results. The purpose of this review is to illustrate the use of cardiac magnetic resonance in the morphological, volumetric, and functional evaluation of the RV in this disease.

Features of the electrocardiogram in TMEM43 p.S358L arrhythmogenic cardiomyopathy

BACKGROUND

The electrocardiogram (ECG) is important in the diagnostic evaluation of arrhythmogenic cardiomyopathy (ACM).

OBJECTIVE

The purpose of this study was to identify ECG features associated with TMEM43 p.S358L ACM during long-term assessment.

METHODS

A total of 634 ECGs were collected from a retrospective cohort of 68 patients with TMEM43 p.S358L ACM. Abnormalities in repolarization, depolarization, conduction intervals, QRS voltage, and rhythm were analyzed.

RESULTS

Sixty-eight patients (32 male, 36 female) with ≥5 ECGs (median, 9; range, 5-17) during 20.5 ± 8.0 years were included. During follow-up, 56 of 68 (82.4%) had an abnormality. Task Force criteria repolarization abnormalities were rare. Terminal activation duration ≥55 ms was common (20/32 male patients [62.5%]; 13/36 female patients [36.1%]). An epsilon wave was demonstrated in 2 female patients. Significant prolongation in the QRS duration occurred for male patients (97.3 ± 11.6 ms to 137.6 ± 24.8 ms; P < .001) and female patients (90.4 ± 12.1 ms to 117.4 ± 24.0 ms; P < .001). The most common finding was R wave <3 mm in V3 (poor R-wave progression). Loss of the R wave in V3 <3 mm followed by development of an intraventricular conduction delay or complete left bundle branch block was seen in most patients (42/68 [61.8%]), occurring earlier in male than in female patients (P < .02).

CONCLUSION

Repolarization Task Force criteria and epsilon waves are rare in TMEM43 p.S358L ACM. The ECG in TMEM43 p.S358L ACM is characterized by loss of the R wave in V3 to <3 mm and QRS prolongation with development of an intraventricular conduction delay or left bundle branch block.

Clinical Considerations for Competitive Sports Participation for Athletes With Cardiovascular Abnormalities: A Scientific Statement From the American Heart Association and American College of Cardiology

COLLABORATORS

Larry A. Allen, MD, MHS, FAHA, FACC; Mats Börjesson, MD, PhD, FACC; Alan C. Braverman, MD, FACC; Julie A. Brothers, MD; Silvia Castelletti, MD, MSc, FESC; Eugene H. Chung, MD, MPH, FHRS, FAHA, FACC; Timothy W. Churchill, MD, FACC; Guido Claessen, MD, PhD; Flavio D'Ascenzi, MD, PhD; Douglas Darden, MD; Peter N. Dean, MD, FACC; Neal W. Dickert, MD, PhD, FACC; Jonathan A. Drezner, MD; Katherine E. Economy, MD, MPH; Thijs M.H. Eijsvogels, PhD; Michael S. Emery, MD, MS, FACC; Susan P. Etheridge, MD, FHRS, FAHA, FACC; Sabiha Gati, BSc (Hons), MBBS, PhD, MRCP, FESC; Belinda Gray, BSc (Med), MBBS, PhD; Martin Halle, MD; Kimberly G. Harmon, MD; Jeffrey J. Hsu, MD, PhD, FAHA, FACC; Richard J. Kovacs, MD, FAHA, MACC; Sheela Krishnan, MD, FACC; Mark S. Link, MD, FHRS, FAHA, FACC; Martin Maron, MD; Silvana Molossi, MD, PhD, FACC; Antonio Pelliccia, MD; Jack C. Salerno, MD, FACC, FHRS; Ankit B. Shah, MD, MPH, FACC; Sanjay Sharma, BSc (Hons), MBChB, MRCP (UK), MD; Tamanna K. Singh, MD, FACC; Katie M. Stewart, NP, MS; Paul D. Thompson, MD, FAHA, FACC; Meagan M. Wasfy, MD, MPH, FACC; Matthias Wilhelm, MD.

This American Heart Association/American College of Cardiology scientific statement on clinical considerations for competitive sports participation for athletes with cardiovascular abnormalities or diseases is organized into 11 distinct sections focused on sports-specific topics or disease processes that are relevant when considering the potential risks of adverse cardiovascular events, including sudden cardiac arrest, during competitive sports participation. Task forces comprising international experts in sports cardiology and the respective topics covered were assigned to each section and prepared specific clinical considerations tables for practitioners to reference. Comprehensive literature review and an emphasis on shared decision-making were integral in the writing of all clinical considerations presented.

Clinical Considerations for Competitive Sports Participation for Athletes With Cardiovascular Abnormalities: A Scientific Statement From the American Heart Association and American College of Cardiology

This American Heart Association/American College of Cardiology scientific statement on clinical considerations for competitive sports participation for athletes with cardiovascular abnormalities or diseases is organized into 11 distinct sections focused on sports-specific topics or disease processes that are relevant when considering the potential risks of adverse cardiovascular events, including sudden cardiac arrest, during competitive sports participation. Task forces comprising international experts in sports cardiology and the respective topics covered were assigned to each section and prepared specific clinical considerations tables for practitioners to reference. Comprehensive literature review and an emphasis on shared decision-making were integral in the writing of all clinical considerations presented.

An unusual thrombus in a patient with arrhythmogenic cardiomyopathy

Herein we present a case of a right ventricular (RV) thrombus in a patient with arrhythmogenic cardiomyopathy (ACM). The 24-year old female patient was diagnosed with ACM after echocardiography, genetic test and cardiac magnetic resonance imaging. Interestingly, at echocardiography, an unusal thrombus formation was detected at RV lateral wall. Also, CMR confirmed the thrombus and oral anticoagulant therapy was started. During the patient's follow-ups, it was observed that the imaging consistent with the reported thrombus disappeared after effective anticoagulant treatment. After the diagnosis was confirmed with genetic tests, an implantable cardioverter-defibrillator (ICD) was implanted in the patient with a high sudden cardiac death (SCD) risk score. Even in arrhythmogenic right ventricular cardiomyopathy patients thrombi are rarely reported. However, the development of imaging techniques may enable more frequent detection and effective treatment of thrombi in these patients.

Echocardiography and Heart Failure: An Echocardiographic Decision Aid for the Diagnosis and Management of Cardiomyopathies

PURPOSE OF REVIEW

The purpose of this review is to highlight the utility of echocardiography in the diagnosis and management of cardiomyopathies.

RECENT FINDINGS

Echocardiographic parameters function synergistically to guide decision-making ranging from early detection of disease and screening to risk stratification of complex disease. The collective wealth of information available from 2D/3D assessment, Doppler, diastology and strain makes echocardiography an invaluable decision aid.

Challenges of genetics in the diagnosis of sudden cardiac death. Interest for forensic and legal medicine

Sudden cardiac death is the leading cause of death in developed countries and a small but significant number of cases cannot be explained after a thorough autopsy process. Cases of sudden cardiac death in people under 40years of age are mainly due to structural heart disease or cardiomyopathies and arrhythmogenic diseases or channelopathies. In these cases, the search for associated genetic factors through molecular autopsy may help to find the cause of unexplained sudden cardiac death, through genetic diagnosis of previously undiagnosed channelopathies or cardiomyopathies. The finding of genetic variants classified as pathogenic associated with cardiac pathology would conclude the autopsy result and provide the possibility of genetic screening in other family members.

Arrhythmogenic Right Ventricular Cardiomyopathy: A Comprehensive Review

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is characterized by structural abnormalities, arrhythmias, and a spectrum of genetic and clinical manifestations. Clinically, ARVC is structurally distinguished by right ventricular dilation due to increased adiposity and fibrosis in the ventricular walls, and it manifests as cardiac arrhythmias ranging from non-sustained ventricular tachycardia to sudden cardiac death. Its prevalence has been estimated to range from 1 in every 1000 to 5000 people, with its large range being attributed to the variability in genetic penetrance from asymptomatic to significant burden. It is even suggested that the prevalence is underestimated, as the presence of genotypic mutations does not always lead to clinical manifestations that would facilitate diagnosis. Additionally, while set criteria have been in place since the 1990s, newer understanding of this condition and advancements in cardiac technology have prompted multiple revisions in the diagnostic criteria for ARVC. Novel discoveries of gene variants predisposing patients to ARVC have led to established screening techniques while providing insight into genetic counseling and management. This review aims to provide an overview of the genetics, pathophysiology, and clinical approach to ARVC. It will also focus on clinical presentation, ARVC diagnostic criteria, electrophysiological findings, including electrocardiogram characteristics, and imaging findings from cardiac MRI, 2D, and 3D echocardiogram. Current management options-including anti-arrhythmic medications, device indications, and ablation techniques-and the effectiveness of treatment will also be reviewed.

The 'Padua classification' of cardiomyopathies into three groups: hypertrophic/restrictive, dilated/hypokinetic, and scarring/arrhythmogenic

The newly proposed classification of cardiomyopathies, referred to as 'the Padua Classification', is based on both pathobiological basis (genetics, molecular biology, and pathology) and clinical features (morpho-functional and structural ventricular remodelling as evidenced by cardiac magnetic resonance). Cardiomyopathies are grouped into tree main categories and characterized by a designation combining both 'anatomical' and 'functional' features: hypertrophic/restrictive, dilated/hypokinetic, and scarring/arrhythmogenic; each cardiomyopathy group includes either genetic or non-genetic aetiologic variants. This novel approach aims to enhance the diagnostic accuracy and to support 'disease-specific' therapeutic strategies, with the objective to improve patient management and outcome.

Contemporary diagnostic approach to arrhythmogenic cardiomyopathy: The three-step work-up

Arrhythmogenic Cardiomyopathy (ACM) is a cardiac disorder characterized by non-ischemic myocardial scarring, which may lead to ventricular electrical instability and systolic dysfunction. Diagnosing ACM is challenging as there is no single gold-standard test and a combination of criteria is required. The first diagnostic criteria were established in 1994 and revised in 2010, focusing primarily on right ventricular involvement. However, in 2019, an international expert report identified limitations of previous diagnostic scoring and developed the 2020 Padua criteria with also included criteria for diagnosis of left ventricular variants and introduced cardiac magnetic resonance tissue characterization findings for detection of left ventricular myocardial scar. These criteria were further refined and published in 2023 as the European Task Force criteria, gaining international recognition. This review provides an overview of the 20 years of progresses on the disease diagnostic from the original 1994 criteria to the most recent 2023 European criteria, highlighting the evolution into our understanding of the pathobiology and morpho-functional features of the disease.

Echocardiographic Updates in the Assessment of Cardiomyopathy

PURPOSE OF REVIEW

This review aims to provide an updated overview of the role of echocardiography in the assessment of cardiomyopathies, highlighting recent findings and technological advancements.

RECENT FINDINGS

Over the past few years, significant advancements in echocardiographic techniques have improved diagnostic accuracy and provided important prognostic value in the assessment of cardiomyopathies. Cardiomyopathy is a group of diseases affecting the heart muscle. Echocardiography, a non-invasive imaging modality provides crucial information on cardiac structure, function, and hemodynamics. Recent advancements, including strain imaging, speckle-tracking, and 3D echocardiography enhance the precision of structural and functional assessments, while artificial intelligence integration improves diagnostic accuracy and workflow efficiency. These advancements not only refine diagnostic capabilities but also provide prognostic insights and facilitate better patient outcomes.

Novel Therapies for Right Ventricular Failure

PURPOSE OF REVIEW

Traditionally viewed as a passive player in circulation, the right ventricle (RV) has become a pivotal force in hemodynamics. RV failure (RVF) is a recognized complication of primary cardiac and pulmonary vascular disorders and is associated with a poor prognosis. Unlike treatments for left ventricular failure (LVF), strategies such as adrenoceptor signaling inhibition and renin-angiotensin system modulation have shown limited success in RVF. This review aims to reassure about the progress in RVF treatment by exploring the potential of contemporary therapies for heart failure, including angiotensin receptor and neprilysin inhibitors, sodium-glucose co-transporter 2 inhibitors, and soluble guanylate cyclase stimulators, which may be beneficial for treating RV failure, particularly when associated with left heart failure. Additionally, it examines novel therapies currently in the pipeline.

RECENT FINDINGS

Over the past decade, a new wave of RVF therapies has emerged, both pharmacological and device-centered. Novel pharmacological interventions targeting metabolism, calcium homeostasis, oxidative stress, extracellular matrix remodeling, endothelial function, and inflammation have shown significant promise in preclinical studies. There is also a burgeoning interest in the potential of epigenetic modifications as therapeutic targets for RVF. Undoubtedly, a deeper understanding of the mechanisms underlying RV failure, both with and without pulmonary hypertension, is urgently needed. This knowledge is not just a theoretical pursuit, but a crucial step that could lead to the development of pharmacological and cell-based therapeutic options that directly target the RV and pulmonary vasculature, aligning with the principles of precision medicine.

Arrhythmogenic Right Ventricular Cardiomyopathy Presenting With VT Electrical Storm

Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) is a right ventricular disease caused by desmosomal gene mutations leading to fibro-fatty replacement of the myocardium causing ventricular arrhythmias such as ventricular tachycardia (VT). A 59-year-old female presented with new onset VT manifesting as shortness of breath and chest discomfort. Diagnostic workup revealed right ventricular dilation/dysfunction on echocardiogram, VT with left bundle branch block (LBBB) and diffuse T wave inversions (TWIs) on EKG. She was discharged with a diagnosis of ARVC. Later, she developed VT storm, treated with epi-endocardial ablation for complete resolution of recurrent VT. Our case demonstrates the rare presentation of ARVC as ventricular storm and the various management strategies such as anti-arrhythmics, automated implantable cardioverter-defibrillator (AICD) and ablation procedures.

The "Padua classification" of cardiomyopathies: Combining pathobiological basis and morpho-functional remodeling

Over the last 20 years, the scientific progresses in molecular biology and genetics in combination with the increasing use in the clinical setting of contrast-enhanced cardiac magnetic resonance (CMR) for morpho-functional imaging and structural myocardial tissue characterization have provided important new insights into our understanding of the distinctive aspects of cardiomyopathy, regarding both the genetic and biologic background and the clinical phenotypic features. This has led to the need of an appropriate revision and upgrading of current nosographic framework and pathobiological categorization of heart muscle disorders. This article proposes a new definition and classification of cardiomyopathies that rely on the combination of the distinctive pathobiological basis (genetics, molecular biology and pathology) and the clinical phenotypic pattern (morpho-functional and structural features), leading to the proposal of three different disease categories, each of either genetic or non-genetic etiology and characterized by a combined designation based on both "anatomic" and "functional" features, i.e., hypertrophic/restrictive (H/RC), dilated/hypokinetic (D/HC) and scarring/arrhythmogenic cardiomyopathy (S/AC). The clinical application of the newly proposed classification approach in the real-world practice appears crucial to design a targeted clinical management and evaluation of outcomes of affected patients. Although current treatment of cardiomyopathies is largely palliative and based on drugs, catheter ablation, device or surgical interventions aimed to prevent and manage heart failure and malignant arrhythmias, better knowledge of basic mechanisms involved in the onset and progression of pathobiologically different heart muscle diseases may allow to the development of disease-specific curative therapy.

Quantifying Cardiac Tissue Composition Using QuPath and Cellpose: An Accessible Approach to Postmortem Diagnosis

Sudden death can be the first symptom of cardiac disease, and establishing a precise postmortem diagnosis is crucial for genetic testing and follow-up of relatives. Arrhythmogenic cardiomyopathy is a structural cardiomyopathy that can be challenging to diagnose postmortem because of differences in structural findings and propagation of the disease at the time of death. Cases can have minimal or no structural findings and later be diagnosed according to genotype, known as concealed cardiomyopathy. Postmortem diagnosis often lacks clinical information, whereas antemortem diagnosis is based on paraclinical investigations that cannot be performed after death. However, the entire substrate is available, which is unique to postmortem diagnosis and research and can provide valuable insights when adding new methods. Reactive changes in the heart, such as myocardial fibrosis and fat, are significant findings. The patterns of these changes in various diseases are not yet fully understood and may be limited by sampling material and conventional microscopic diagnostics. We demonstrate an automated pipeline in QuPath for quantifying postmortem picrosirius red cardiac tissue for collagen, residual myocardium, and adipocytes by integrating Cellpose into a versatile pipeline. This method was developed and tested using cardiac tissues from autopsied individuals. Cases diagnosed with arrhythmogenic cardiomyopathy and age-matched controls were used for validation and testing. This approach is free and easy to implement by other research groups using this paper as a template. This can potentially lead to the development of quantitative diagnostic criteria for postmortem cardiac diseases, eliminating the need to rely on diagnostic criteria from endomyocardial biopsies that are not applicable to postmortem specimens. We propose that this approach serves as a template for creating a more efficient process for evaluating postmortem cardiac measurements in an unbiased manner, particularly for rare cardiac diseases.

The role of genetic testing in management and prognosis of individuals with inherited cardiomyopathies

Inherited cardiomyopathies are a heterogeneous group of heart muscle conditions where disease classification has traditionally been based on clinical characteristics. However, this does not always align with genotype. While there are well described challenges of genetic testing, understanding the role of genotype in patient management is increasingly required. We take a gene-by-gene approach, reviewing current evidence for the role of genetic testing in guiding prognosis and management of individuals with inherited cardiomyopathies. In particular, focusing on causal variants in genes definitively associated with arrhythmogenic cardiomyopathy, dilated cardiomyopathy, and hypertrophic cardiomyopathy. This review identifies genotype-specific disease sub-groups with strong evidence supporting the use of genetics in clinical management and highlights that at present, the spectrum of clinical utility is not reflected in current guidelines. Of 13 guideline or expert consensus statements for management of cardiomyopathies, there are seven gene-specific therapeutic recommendations that have been published from four documents. Understanding how genotype influences phenotype provides evidence for the role of genetic testing for prognostic and therapeutic purposes, moving us closer to precision-medicine based care.

Benefits of Physical Activity in Children with Cardiac Diseases-A Concise Summary for Pediatricians

A physically active lifestyle offers multiple benefits, including lowering the risk of cardiovascular disease, lowering body-mass index (BMI), and, last but not least, improving the quality of life. However, there are still disincentives to physical activity in children with heart diseases due to the high protection of parents and the scarcity of data in the literature. The purpose of this paper is to help pediatricians and pediatric cardiologists identify the type of physical activity allowed in children with congenital cardiac malformations, thus minimizing the risk of major adverse effects, such as acute coronary syndrome and sudden cardiac death. Therefore, we searched various electronic databases, such as PubMed, ScienceDirect, and Embase. We selected 61 articles published between 2008-2024. These articles included data on pediatric patients, from newborn to adolescent age. We decided to choose the 2008 study because of its focus on the essential role of education in schools regarding physical activity and the prevention of complications from sedentary lifestyles. Subsequently, we analyzed the data available in the literature up to 2024 regarding the type, intensity, and duration of exercise for patients with various congenital heart malformations. The conclusions of this review are presented based on the category of heart disease. There are differences in the free practice of sports in children with cardiomyopathies, atrioventricular block, arrhythmias with a genetic substrate, valvulopathies, and cyanogenic and non-cyanogenic congenital malformations. For example, children with arrhythmogenic right ventricle cardiomyopathy are not allowed to participate in sports competitions, but they can perform low physical activity for 150 min/week-golf, table tennis, and photography. However, it is recognized that a physically active lifestyle correlates with a decreased risk of cardiovascular diseases, body mass index, and an improvement in the quality of life. Children with congenital heart disease who are active have improved their cardiovascular systems.

Prognostic Value of Circulating Biomarkers of Fibrotic Remodeling in Arrhythmogenic Cardiomyopathy

Arrhythmogenic cardiomyopathy (ACM) is a nonischemic, familial heart disease with a high risk of sudden cardiac death (SCD) in the pediatric population and accounts for >20% of SCDs worldwide [...].

Description of the Two-Dimensional Layer-Specific Strain Echocardiography Phenotype of Arrhythmogenic Left Ventricular Cardiomyopathy

BACKGROUND

Arrhythmogenic left ventricular cardiomyopathy (ALVC) is characterized by fibrofatty myocardial replacement demonstrated on cardiac magnetic resonance by late gadolinium enhancement (LGE) mainly involving the subepicardium. The aims of this study were to describe the layer-specific strain (LSS) echocardiography phenotype of ALVC and to compare it with LGE features.

METHODS

All consecutive ALVC pathogenic genetic variant carriers and noncarrier relatives were separated into four prespecified groups (overt ALVC [group 1], isolated LGE [group 2], pathogenic genetic variant carrier without ALVC phenotype [group 3], and no genetic variant carrier [group 4]) and studied accordingly using cardiac magnetic resonance and LSS echocardiography.

RESULTS

Eighty-five individuals were included. Endocardial global longitudinal strain (GLS)-epicardial GLS (GLSepi) gradient was altered predominantly in group 1, illustrating transmural strain alteration in overt ALVC (3.8 ± 1.1 in group 1, 4.3 ± 2.2 in group 2, 5.2 ± 1.2 in group 3, and 5.4 ± 1.6 in group 4; P = .0017), whereas GLSepi was impaired predominantly in group 2 (endocardial GLS and GLSepi were 15.0 ± 4.1% and 11.2 ± 3.3%, respectively, in group 1; 20.5 ± 2.8% and 16.2 ± 5.5% in group 2; 23.4 ± 3.3% and 18.2 ± 2.7% in group 3; and 24.6 ± 2.8% and 19.2 ± 1.9% in group 4; P < .0001 for all). GLSepi was able to detect subepicardial LGE in genetic variant carriers without overt ALVC with an area under curve of 0.84 (95% CI, 0.73-0.95). However, segmental epicardial and endocardial strain behaved similarly and showed comparable diagnostic values for segmental LGE detection (areas under the curve, 0.72; [95% CI, 0.69-0.76] and 0.73 [95% CI, 0.70-0.76], respectively, P = .40).

CONCLUSIONS

LSS alteration in ALVC progresses from the epicardium to the endocardium along with disease severity. Irrespective of LSS analysis, which did not provide incremental diagnostic value for the detection and localization of LGE, strain echocardiography was shown to be a potential surrogate marker of LGE, including in apparently healthy individuals with isolated LV fibrosis.

Voltage mapping and right ventriculography to guide ablation for arrhythmogenic right ventricular cardiomyopathy ventricular tachycardia: a case report

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a family inherited cardiomyopathy associated with ventricular arrhythmias. With the development of molecular biology, histology, imaging, and other diagnostic techniques, the diagnosis rate and incidence of ARVC have gradually increased. However, ARVC remains rare in clinical practice. Currently, the diagnosis and management of ARVC is far from satisfactory in clinical practice. In the case report, we described a clinical case of radiofrequency ablation guided by voltage mapping and right ventriculography in the treatment of ARVC with ventricular tachycardia and discussed the relevant literatures.

Unveiling the Spectrum of Minor Genes in Cardiomyopathies: A Narrative Review

Hereditary cardiomyopathies (CMPs), including arrhythmogenic cardiomyopathy (ACM), dilated cardiomyopathy (DCM), and hypertrophic cardiomyopathy (HCM), represent a group of heart disorders that significantly contribute to cardiovascular morbidity and mortality and are often driven by genetic factors. Recent advances in next-generation sequencing (NGS) technology have enabled the identification of rare variants in both well-established and minor genes associated with CMPs. Nowadays, a set of core genes is included in diagnostic panels for ACM, DCM, and HCM. On the other hand, despite their lesser-known status, variants in the minor genes may contribute to disease mechanisms and influence prognosis. This review evaluates the current evidence supporting the involvement of the minor genes in CMPs, considering their potential pathogenicity and clinical significance. A comprehensive analysis of databases, such as ClinGen, ClinVar, and GeneReviews, along with recent literature and diagnostic guidelines provides a thorough overview of the genetic landscape of minor genes in CMPs and offers guidance in clinical practice, evaluating each case individually based on the clinical referral, and insights for future research. Given the increasing knowledge on these less understood genetic factors, future studies are essential to clearly assess their roles, ultimately leading to improved diagnostic precision and therapeutic strategies in hereditary CMPs.

Genetic testing in early-onset atrial fibrillation

Atrial fibrillation (AF) is a globally prevalent cardiac arrhythmia with significant genetic underpinnings, as highlighted by recent large-scale genetic studies. A prominent clinical and genetic overlap exists between AF, heritable ventricular cardiomyopathies, and arrhythmia syndromes, underlining the potential of AF as an early indicator of severe ventricular disease in younger individuals. Indeed, several recent studies have demonstrated meaningful yields of rare pathogenic variants among early-onset AF patients (∼4%-11%), most notably for cardiomyopathy genes in which rare variants are considered clinically actionable. Genetic testing thus presents a promising opportunity to identify monogenetic defects linked to AF and inherited cardiac conditions, such as cardiomyopathy, and may contribute to prognosis and management in early-onset AF patients. A first step towards recognizing this monogenic contribution was taken with the Class IIb recommendation for genetic testing in AF patients aged 45 years or younger by the 2023 American College of Cardiology/American Heart Association guidelines for AF. By identifying pathogenic genetic variants known to underlie inherited cardiomyopathies and arrhythmia syndromes, a personalized care pathway can be developed, encompassing more tailored screening, cascade testing, and potentially genotype-informed prognosis and preventive measures. However, this can only be ensured by frameworks that are developed and supported by all stakeholders. Ambiguity in test results such as variants of uncertain significance remain a major challenge and as many as ∼60% of people with early-onset AF might carry such variants. Patient education (including pretest counselling), training of genetic teams, selection of high-confidence genes, and careful reporting are strategies to mitigate this. Further challenges to implementation include financial barriers, insurability issues, workforce limitations, and the need for standardized definitions in a fast-moving field. Moreover, the prevailing genetic evidence largely rests on European descent populations, underscoring the need for diverse research cohorts and international collaboration. Embracing these challenges and the potential of genetic testing may improve AF care. However, further research-mechanistic, translational, and clinical-is urgently needed.

The 2023 European Task Force Criteria for Diagnosis of Arrhythmogenic Cardiomyopathy: Historical Background and Review of Main Changes

Arrhythmogenic cardiomyopathy (ACM) is a cardiac disease featured by non-ischemic myocardial scarring linked to ventricular electrical instability. As there is no single gold-standard test, diagnosing ACM remains challenging and a combination of specific criteria is needed. The diagnostic criteria were first defined and widespread in 1994 and then revised in 2010, approaching and focusing primarily on right ventricular involvement without considering any kind of left ventricular variant or phenotype. Years later, in 2020, with the purpose of overcoming previous limitations, the Padua Criteria were introduced by an international expert report. The main novel elements were the introduction of specific criteria for left ventricular variants as well as the use of cardiac magnetic resonance for tissue characterization and scar detection. The last modifications and refinement of these criteria were published at the end of 2023 as the European Task Force criteria, by a "head-quarter" of ACM international experts, proving the emerging relevance of this condition besides its difficult diagnosis. In this review, emphasizing the progress in understanding the aetiology of the cardiomyopathy, an analysis of the new criteria is presented. The introduction of the term "scarring/arrhythmogenic cardiomyopathy" sets an important milestone in this field, underlying how non-ischemic myocardial scarring-typical of ACM-and arrhythmic susceptibility could be the main pillars of numerous different phenotypic variants regardless of etiology.

Navigating the penetrance and phenotypic spectrum of inherited cardiomyopathies

Inherited cardiomyopathies are genetic diseases that can lead to heart failure and sudden cardiac death. These conditions tend to run in families, following an autosomal dominant pattern where first-degree relatives have a 50% chance of carrying the pathogenic variant. Despite significant advancements and increased accessibility of genetic testing, accurately predicting the phenotypic expression of these conditions remains challenging due to the inherent variability in their clinical manifestations and the incomplete penetrance observed. This poses challenges in providing patient care and effectively communicating the potential risk of future disease to patients and their families. To address these challenges, this review aims to synthesize the available evidence on penetrance, expressivity, and factors influencing disease expression to improve communication and risk assessment for patients with inherited cardiomyopathies and their family members.

Toward the latest advancements in cardiac regeneration using induced pluripotent stem cells (iPSCs) technology: approaches and challenges

A novel approach to treating heart failures was developed with the introduction of iPSC technology. Knowledge in regenerative medicine, developmental biology, and the identification of illnesses at the cellular level has exploded since the discovery of iPSCs. One of the most frequent causes of mortality associated with cardiovascular disease is the loss of cardiomyocytes (CMs), followed by heart failure. A possible treatment for heart failure involves restoring cardiac function and replacing damaged tissue with healthy, regenerated CMs. Significant strides in stem cell biology during the last ten years have transformed the in vitro study of human illness and enhanced our knowledge of the molecular pathways underlying human disease, regenerative medicine, and drug development. We seek to examine iPSC advancements in disease modeling, drug discovery, iPSC-Based cell treatments, and purification methods in this article.

Natural Course of Electrocardiographic Features in Arrhythmogenic Right Ventricular Cardiomyopathy and Their Relation to Ventricular Arrhythmic Events

BACKGROUND

Electrocardiographic abnormalities are common in arrhythmogenic right ventricular cardiomyopathy and are included in the 2010 Task Force Criteria. Their time course, however, remains uncertain. In this retrospective observational study, we aimed to assess the long-term evolution of electrocardiographic characteristics and their relation to ventricular arrhythmias.

METHODS AND RESULTS

Three hundred fifty-three patients with arrhythmogenic right ventricular cardiomyopathy as per the 2010 Task Force Criteria with 6871 automatically processed 12-lead digital ECGs were included. The relationship between the electrocardiographic parameters and the risk of ventricular arrhythmias was assessed at 10 years from the first ECG. Electrocardiographic parameters were compared between the first contact ECG, the ECG at diagnosis, and the most recent ECG. Median time between the first and the latest ECG was 6 [interquartile range, 1-14] years. Reductions of QRS voltage, R- and T-wave amplitudes between the first, diagnostic, and the latest ECGs were observed across precordial and extremity leads. Mean QRS duration increased from 96 to 102 ms (P<0.001), terminal activation duration (V1) from 47 to 52 ms (P<0.001), and QTc from 419 to 432 ms (P<0.001). T-wave inversions in leads V3 to V6 and aVF at first ECG were associated with ventricular arrhythmias (adjusted hazard ratio [HRadj][V3], 2.03 [95% CI, 1.23-3.34] and HRadj[aVF], 1.87 [95% CI, 1.13-3.08]).

CONCLUSIONS

Depolarization and repolarization parameters evolved over time in patients with arrhythmogenic right ventricular cardiomyopathy, supporting the progressive nature of arrhythmogenic right ventricular cardiomyopathy. Electrocardiographic abnormalities may be detected before diagnosis and might, although not fulfilling the 2010 Task Force Criteria, be markers of early disease. T-wave inversion in leads V3 or aVF before diagnosis was associated with ventricular arrhythmias during follow-up.

Filamin C (FLNC) truncating mutation in a fatal arrhythmogenic left ventricular cardiomyopathy (ALVC)

Forensic pathologists are frequently asked to investigate cases of sudden death (SD), and identifying the cause of death can be of particular importance, especially where it may be necessary to perform family screening among the relatives of the victim. A multidisciplinary approach inclusive of genetic analysis is therefore strongly recommended. According to forensic practice, arrhythmogenic cardiomyopathy (ACM) is a well-known cause of SD. However, cases of SD caused by a left ventricular pattern of ACM diagnosed at autopsy are rarely reported in the literature. We present the case of an apparently healthy, 37-year-old male found dead at his home. At autopsy, multiple foci of epicardial and mid-wall fibrous and fibro-adipose tissue were observed within the left ventricle and, to a lesser extent, within the interventricular septum. Toxicology was negative, whereas a filamin C truncating mutation was detected through genetic analysis. To our knowledge, this is the first instance of arrhythmogenic left ventricular cardiomyopathy being diagnosed at autopsy.

LV-predominant arrhythmogenic cardiomyopathy related to pathogenic DSP-variant

Key Clinical Message

In contrast to previously thought, arrhythmogenic cardiomyopathy can occur exclusively in the left ventricle in association with autosomal dominant mutation, even without any skin manifestations.

Abstract

We present a case of a 43-year-old male with left ventricle (LV)-predominant arrhythmogenic cardiomyopathy (ACM) caused by a novel p.Q1830 mutation in the desmoplakin (DSP) gene. The patient had a significant family history of sudden cardiac death (SCD) and presented with presyncope and exertional dyspnea. The patient's electrocardiography (ECG) showed frequent premature ventricular complexes (PVCs) with bigeminy and couplet patterns. Cardiac magnetic resonance imaging (CMR) revealed late gadolinium enhancement of the left ventricle (LV) and ventricular systolic dysfunction, suggesting LV-predominant arrhythmogenic cardiomyopathy. The patient was started on guideline-directed medical therapy (GDMT), and an implantable cardioverter-defibrillator (ICD) was implanted for primary prevention. The patient reported significant improvement in his heart failure symptoms at the 2-year follow-up. The article highlights the importance of timely diagnosis with multimodality imaging and genetic testing and management of the rare DSP-related LV-predominant ACM associated with a high risk of SCD.

Right Ventricular Strain Derived from Cardiac MRI Feature Tracking for the Diagnosis and Prognosis of Arrhythmogenic Right Ventricular Cardiomyopathy

Purpose To demonstrate the myocardial strain characteristics of patients with arrhythmogenic right ventricular cardiomyopathy (ARVC), based on revised Task Force Criteria (rTFC), and to explore the prognostic value of strain analysis in ARVC. Materials and Methods This retrospective study included 247 patients (median age, 38 years [IQR, 28-48 years]; 167 male, 80 female) diagnosed with ARVC, based on rTFC, between 2014 and 2018. Patients were divided into "possible" (n =25), "borderline" (n = 40), and "definite" (n = 182) ARVC groups following rTFC. Biventricular global strain parameters were calculated using cardiac MRI feature tracking (FT). The primary outcome was defined as a composite of cardiovascular events, including cardiovascular death, heart transplantation, and appropriate implantable cardioverter defibrillator discharge. Univariable and multivariable cumulative logistic regression and Cox proportional hazards regression analysis were used to evaluate the diagnostic and prognostic value of right ventricle (RV) strain parameters. Results Patients with definite ARVC had significantly reduced RV global strain in all three directions compared with possible or borderline groups (all P < .001). RV global longitudinal strain (GLS) was an independent predictor for disease (odds ratio, 1.09 [95% CI: 1.02, 1.16]; P = .009). During a median follow-up of 3.4 years (IQR, 2.0-4.9 years), 55 patients developed primary end point events. Multivariable analysis showed that RV GLS was independently associated with the occurrence of cardiovascular events (hazard ratio, 1.15 [95% CI: 1.07, 1.24]; P < .001). Kaplan-Meier analysis showed that patients with RV GLS worse than median had a higher risk of combined cardiovascular events (log-rank P < .001). Conclusion RV GLS derived from cardiac MRI FT demonstrated good diagnostic and prognostic value in ARVC. Keywords: MR Imaging, Image Postprocessing, Cardiac, Right Ventricle, Cardiomyopathies, Arrhythmogenic Right Ventricular Cardiomyopathy, Revised Task Force Criteria, Cardiovascular MR, Feature Tracking, Cardiovascular Events Supplemental material is available for this article. © RSNA, 2024.

Arrhythmogenic right ventricular cardiomyopathy with sustained ventricular tachycardia: a case report

INTRODUCTION

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an infrequent hereditary disorder distinguished by fibrofatty replacement of the myocardium in the right ventricular, which predisposes individuals to life-threatening arrhythmias. This case delineates an ARVC patient who suffered recurrent bouts of sustained ventricular tachycardia (VT). In this case, we mainly discuss the application of myocardial contrast echocardiography (MCE) in displaying myocardial fibrosis in patients with ARVC.

CASE PRESENTATION

A 43-year-old male experienced three episodes of unexplained VT over an eight-year period, accompanied by symptoms of chest discomfort, palpitations and dizziness. Coronary angiography revealed no significant coronary stenosis. The electrocardiogram (ECG) results indicated characteristic epsilon waves in right precordial leads, and subsequent echocardiography identified right ventricular enlargement and right ventricular systolic dysfunction. MCE further disclosed regional myocardial ischemia at the epicardium of the left ventricular apex. Ultimately, cardiovascular magnetic resonance imaging (CMR) corroborated the ARVC diagnosis, highlighting linear intensification in the right ventricle during the delayed enhancement.

CONCLUSION

Prompt identification of ARVC is crucial for timely intervention and management. MCE may offer an effective and valuable technique for the detection of myocardial involvement in ARVC patient.

Genetic testing in cardiovascular disease

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality globally and is responsible for an estimated one-third of deaths as well as significant morbidity and health care utilisation. Technological and bioinformatic advances have facilitated the discovery of pathogenic germline variants for some specific CVDs, including familial hypercholesterolaemia, cardiomyopathies and arrhythmic syndromes. Use of these genetic tests for earlier disease identification is increasing due, in part, to decreasing costs, Medicare rebates, and consumer comfort with genetic testing. However, CVDs that occur more commonly, including coronary artery disease and atrial fibrillation, do not display monogenic inheritance patterns. Genetically, these diseases have generally been associated with many genetic variants each with a small effect size. This complexity can be expressed mathematically as a polygenic risk score. Genetic testing kits that provide polygenic risk scoring are becoming increasingly available directly to private-paying consumers outside the traditional clinical setting. An improved understanding of the evidence of genetics in CVD will offer clinicians new opportunities for individualised risk prediction and preventive therapy.

The rare cause of ST segment elevation in left precordial leads - Diagnostic clues from subtle waveforms

We report a case of ST segment elevation in left precordial leads with a convex shape caused by a rare etiology. By carefully analyzing the electrocardiogram (leads I, II, V3 to V9) of a patient with convex ST segment elevation in the left-sided chest leads, relevant etiological clues were derived. The findings were further supported by cardiac ultrasound and cardiac magnetic resonance imaging, ruling out other common causes. Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) was postulated as the underlying cause, and potential mechanisms were discussed. The diagnosis was further confirmed through a follow-up period of over three years.

NFĸB signaling drives myocardial injury via CCR2+ macrophages in a preclinical model of arrhythmogenic cardiomyopathy

Nuclear factor κ-B (NFκB) is activated in iPSC-cardiac myocytes from patients with arrhythmogenic cardiomyopathy (ACM) under basal conditions, and inhibition of NFκB signaling prevents disease in Dsg2mut/mut mice, a robust mouse model of ACM. Here, we used genetic approaches and single-cell RNA-Seq to define the contributions of immune signaling in cardiac myocytes and macrophages in the natural progression of ACM using Dsg2mut/mut mice. We found that NFκB signaling in cardiac myocytes drives myocardial injury, contractile dysfunction, and arrhythmias in Dsg2mut/mut mice. NFκB signaling in cardiac myocytes mobilizes macrophages expressing C-C motif chemokine receptor-2 (CCR2+ cells) to affected areas within the heart, where they mediate myocardial injury and arrhythmias. Contractile dysfunction in Dsg2mut/mut mice is caused both by loss of heart muscle and negative inotropic effects of inflammation in viable muscle. Single nucleus RNA-Seq and cellular indexing of transcriptomes and epitomes (CITE-Seq) studies revealed marked proinflammatory changes in gene expression and the cellular landscape in hearts of Dsg2mut/mut mice involving cardiac myocytes, fibroblasts, and CCR2+ macrophages. Changes in gene expression in cardiac myocytes and fibroblasts in Dsg2mut/mut mice were dependent on CCR2+ macrophage recruitment to the heart. These results highlight complex mechanisms of immune injury and regulatory crosstalk between cardiac myocytes, inflammatory cells, and fibroblasts in the pathogenesis of ACM.

Prognostic impact of the findings of the genetic test in left dominant arrhythmogenic cardiomyopathy

Background

The diagnosis of left dominant arrhythmogenic cardiomyopathy (LDAC) is sometimes complex. The Padua group recently published a document with criteria to identify patients with LDAC, requiring a compatible genetic variant for diagnosis. Due to the gaps in the knowledge of the role of genetics in its pathogenesis, our objective is to describe the findings of the genetic test in patients with LDAC in our center and its prognostic impact.

Methods

Single-center prospective cohort study, in which we recruited 77 patients diagnosed with LDAC or biventricular arrhythmogenic cardiomyopathy according to the criteria of Sen-Chowdhry et al.

Results

We obtained a positive result in the genetic test in 53.2 %. The desmoplakin gene was the most affected (16.9 %). The mean value of left ventricular (LV) ejection fraction was 45.6 ± 13.1 %, with no significant differences in the severity of the dysfunction according to genetics (p = 0.187). Among the patients with positive genetics there was a greater number of segments in the LV affected by fibrosis (p = 0.043). Regarding fatty infiltration in the LV and number of affected segments, there were no significant differences between groups (p = 0.144). MACE was recorded in 23 patients (29.9 %). The positive result in the genetic test was not significantly associated with the occurrence of MACE (p = 0.902).

Conclusion

In our study, we did not find mutations responsible for the disease in practically half of the cases. Despite the existence of a high proportion of MACE during follow-up, there were no prognostic differences according to the result of the genetic test.

Imaging Features of Arrhythmogenic Cardiomyopathies

Arrhythmogenic cardiomyopathy (ACM) is a genetic disease characterized by replacement of ventricular myocardium with fibrofatty tissue, predisposing the patient to ventricular arrhythmias and/or sudden cardiac death. Most cases of ACM are associated with pathogenic variants in genes that encode desmosomal proteins, an important cell-to-cell adhesion complex present in both the heart and skin tissue. Although ACM was first described as a disease predominantly of the right ventricle, it is now acknowledged that it can also primarily involve the left ventricle or both ventricles. The original right-dominant phenotype is traditionally diagnosed using the 2010 task force criteria, a multifactorial algorithm divided into major and minor criteria consisting of structural criteria based on two-dimensional echocardiographic, cardiac MRI, or right ventricular angiographic findings; tissue characterization based on endomyocardial biopsy results; repolarization and depolarization abnormalities based on electrocardiographic findings; arrhythmic features; and family history. Shortfalls in the task force criteria due to the modern understanding of the disease have led to development of the Padua criteria, which include updated criteria for diagnosis of the right-dominant phenotype and new criteria for diagnosis of the left-predominant and biventricular phenotypes. In addition to incorporating cardiac MRI findings of ventricular dilatation, systolic dysfunction, and regional wall motion abnormalities, the new Padua criteria emphasize late gadolinium enhancement at cardiac MRI as a key feature in diagnosis and imaging-based tissue characterization. Conditions to consider in the differential diagnosis of the right-dominant phenotype include various other causes of right ventricular dilatation such as left-to-right shunts and variants of normal right ventricular anatomy that can be misinterpreted as abnormalities. The left-dominant phenotype can mimic myocarditis at imaging and clinical examination. Additional considerations for the differential diagnosis of ACM, particularly for the left-dominant phenotype, include sarcoidosis and dilated cardiomyopathy. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Role of genetics in inflammatory cardiomyopathy

Traditional cardiomyopathy paradigms segregate inflammatory etiologies from those caused by genetic variants. An identified or presumed trigger is implicated in acute myocarditis or chronic inflammatory cardiomyopathy but growing evidence suggests a significant proportion of patients have an underlying cardiomyopathy-associated genetic variant often even when a clear inflammatory trigger is identified. Recognizing a possible genetic contribution to inflammatory cardiomyopathy may have major downstream implications for both the patient and family. The presenting features of myocarditis (i.e. chest pain, arrhythmia, and/or heart failure) may provide insight into diagnostic considerations. One example is isolated cardiac sarcoidosis, a distinct inflammatory cardiomyopathy that carries diagnostic challenges and clinical overlap; genetic testing has increasingly reclassified cases of isolated cardiac sarcoidosis as genetic cardiomyopathy, notably altering management. On the other side, inflammatory presentations of genetic cardiomyopathies are likewise underappreciated and a growing area of investigation. Inflammation plays an important role in the pathogenesis of several familial cardiomyopathies, especially arrhythmogenic phenotypes. Given these clinical scenarios, and the implications on clinical decision making such as initiation of immunosuppression, sudden cardiac death prevention, and family screening, it is important to recognize when genetics may be playing a role.

Arrhythmogenic Left Ventricular Cardiomyopathy: From Diagnosis to Risk Management

PURPOSE OF REVIEW

Left ventricular arrhythmogenic cardiomyopathy (ALVC) is a rare and poorly characterized cardiomyopathy that has recently been reclassified in the group of non-dilated left ventricular cardiomyopathies. This review aims to summarize the background, diagnosis, and sudden cardiac death risk in patients presenting this cardiomyopathy.

RECENT FINDINGS

Although there is currently a lack of data on this condition, arrhythmogenic left ventricular dysplasia can be considered a specific disease of the left ventricle (LV). We have collected the latest evidence about the management and the risks associated with this cardiomyopathy.

SUMMARY

Left ventricular arrhythmogenic cardiomyopathy is still poorly characterized. ALVC is characterized by fibrofatty replacement in the left ventricular myocardium, with variable phenotypic expression. Diagnosis is based on a multiparametric approach, including cardiac magnetic resonance (CMR) and genetic testing, and is important for sudden cardiac death (SCD) risk stratification and management. Recent guidelines have improved the management of left ventricular arrhythmogenic cardiomyopathy. Further studies are necessary to improve knowledge of this cardiomyopathy.

AAV9:PKP2 improves heart function and survival in a Pkp2-deficient mouse model of arrhythmogenic right ventricular cardiomyopathy

BACKGROUND

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a familial cardiac disease associated with ventricular arrhythmias and an increased risk of sudden cardiac death. Currently, there are no approved treatments that address the underlying genetic cause of this disease, representing a significant unmet need. Mutations in Plakophilin-2 (PKP2), encoding a desmosomal protein, account for approximately 40% of ARVC cases and result in reduced gene expression.

METHODS

Our goal is to examine the feasibility and the efficacy of adeno-associated virus 9 (AAV9)-mediated restoration of PKP2 expression in a cardiac specific knock-out mouse model of Pkp2.

RESULTS

We show that a single dose of AAV9:PKP2 gene delivery prevents disease development before the onset of cardiomyopathy and attenuates disease progression after overt cardiomyopathy. Restoration of PKP2 expression leads to a significant extension of lifespan by restoring cellular structures of desmosomes and gap junctions, preventing or halting decline in left ventricular ejection fraction, preventing or reversing dilation of the right ventricle, ameliorating ventricular arrhythmia event frequency and severity, and preventing adverse fibrotic remodeling. RNA sequencing analyses show that restoration of PKP2 expression leads to highly coordinated and durable correction of PKP2-associated transcriptional networks beyond desmosomes, revealing a broad spectrum of biological perturbances behind ARVC disease etiology.

CONCLUSIONS

We identify fundamental mechanisms of PKP2-associated ARVC beyond disruption of desmosome function. The observed PKP2 dose-function relationship indicates that cardiac-selective AAV9:PKP2 gene therapy may be a promising therapeutic approach to treat ARVC patients with PKP2 mutations.

Electrocardiographic predictors of left ventricular scar in athletes with right bundle branch block premature ventricular beats

AIMS

Right bundle branch block (RBBB) morphology non-sustained ventricular arrhythmias (VAs) have been associated with the presence of non-ischaemic left ventricular scar (NLVS) in athletes. The aim of this cross-sectional study was to identify clinical and electrocardiogram (ECG) predictors of the presence of NLVS in athletes with RBBB VAs.

METHODS AND RESULTS

Sixty-four athletes [median age 39 (24-53) years, 79% males] with non-sustained RBBB VAs underwent cardiac magnetic resonance (CMR) with late gadolinium enhancement in order to exclude the presence of a concealed structural heart disease. Thirty-six athletes (56%) showed NLVS at CMR and were assigned to the NLVS positive group, whereas 28 athletes (44%) to the NLVS negative group. Family history of cardiomyopathy and seven different ECG variables were statistically more prevalent in the NLVS positive group. At univariate analysis, seven ECG variables (low QRS voltages in limb leads, negative T waves in inferior leads, negative T waves in limb leads I-aVL, negative T waves in precordial leads V4-V6, presence of left posterior fascicular block, presence of pathologic Q waves, and poor R-wave progression in right precordial leads) proved to be statistically associated with the finding of NLVS; these were grouped together in a score. A score ≥2 was proved to be the optimal cut-off point, identifying NLVS athletes in 92% of cases and showing the best accuracy (86% sensitivity and 100% specificity, respectively). However, a cut-off ≥1 correctly identified all patients with NLVS (absence of false negatives).

CONCLUSION

In athletes with RBBB morphology non-sustained VAs, specific ECG abnormalities at 12-lead ECG can help in detecting subjects with NLVS at CMR.

The International Criteria for Electrocardiogram Interpretation in Athletes: Common Pitfalls and Future Directions

Preparticipation cardiovascular screening (PPCS) in young athletes is performed to detect conditions associated with sudden cardiac death. Many medical societies and sports governing bodies support the addition of a 12-lead electrocardiogram (ECG) to the history and physical to improve PPCS sensitivity. The current standard for ECG interpretation in athletes, the International Criteria, was developed to distinguish physiologic from pathologic ECG findings in athletes. Although application of the International Criteria has reduced the PPCS false-positive rate, interpretative challenges and potential areas of improvement remain. This review provides an overview of common pitfalls and future directions for ECG interpretation in athletes.

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.

A Heterozygous Phospholamban Variant (p.R14del) Leads to Left Ventricular Involvement and Heart Failure Phenotypes in Arrhythmogenic Right Ventricular Cardiomyopathy

This study aimed to determine the prevalence and clinical features of Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) caused by pathogenic mutations in the Phospholamban (PLN) gene. The study included 170 patients who had a confirmed diagnosis of ARVC and underwent PLN genetic screening using next-generation sequencing. The findings of this study provide valuable insights into the association between PLN mutations and ARVC, which can aid in the development of more effective diagnostic and treatment strategies for ARVC patients. Out of the patients evaluated, six had a rare pathogenic mutation in PLN with the same p.R14del variant. Family screening revealed that heterozygous carriers of p.R14del exhibited a definite ARVC phenotype. In clinical studies, individuals with the p.R14del mutation experienced a similar rate of malignant arrhythmia events as those with classic desmosome mutations. After adjusting for covariates, individuals with PLN mutations had a two point one seven times greater likelihood of experiencing transplant-related risks compared to those who did not possess PLN mutations (95% CI 1.08-6.82, p = 0.035). The accumulation of left ventricular fat and fibers is a pathological marker for ARVC patients with p.R14del mutations. In a cohort of 170 Chinese ARVC patients, three point five percent of probands had the PLN pathogenic variant (p.R14del) and all were female. Our data shows that PLN-related ARVC patients are at high risk for ventricular arrhythmias and heart failure, which requires clinical differentiation from classic ARVC. Furthermore, carrying the p.R14del mutation can be an independent prognostic risk factor in ARVC patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43657-023-00126-w.