Proposed diagnostic criteria for arrhythmogenic cardiomyopathy: European Task Force consensus report

Sudden death of an athlete with concealed arrhythmogenic cardiomyopathy

We report the case of a professional soccer athlete who died suddenly due to early arrhythmogenic cardiomyopathy that was not diagnosed at the time of preparticipation screening. Exercise testing had repeatedly shown effort-induced premature ventricular beats with normal echocardiography, a finding that was considered reassuring. However, there is emerging evidence that cardiac diseases characterized by focal ventricular scarring may not cause wall motion abnormalities and can be revealed only by tissue characterization with cardiac magnetic resonance. Modern interpretation of premature ventricular beats features is essential to select athletes who should undergo advanced cardiac imaging investigations to achieve a correct diagnosis and sport eligibility.

Risk stratification and exercise recommendations in cardiomyopathies and channelopathies: a practical guide for the multidisciplinary team

Exercise offers a plethora of health benefits. However, certain genetic and acquired diseases such as cardiomyopathies and channelopathies are associated with sudden cardiac death during exercise. Several factors complicate exercise prescription in individuals living with these conditions. The lack of high-quality evidence supporting exercise recommendations, variation in the clinical phenotypes within the same condition and sparse physician education around exercise prescription all leads to a reluctance to provide specific guidance on how to engage in physical activity.This article aims to summarise the latest evidence underpinning risk stratification and current guideline recommendations for physical activity in individuals with cardiomyopathies and channelopathies wishing to engage in exercise. It also aims to provide a basic practical approach to exercise prescription for health professionals involved in the care of these patients. This approach may then serve as a foundation that can be easily personalised. Since risk can never be completely eliminated, all decisions regarding exercise participation should be taken following shared dialogue between the physician, patient and wider stake holders where appropriate.

Myocardial Perfusion Imaging with Cardiovascular Magnetic Resonance in Nonischemic Cardiomyopathies: An In-Depth Review of Techniques and Clinical Applications

Background and Objectives: Nonischemic cardiomyopathies comprise a wide spectrum of heart muscle disorders characterized by different morphological, functional, and tissue abnormalities. Cardiovascular magnetic resonance (CMR) represents the gold standard imaging modality for assessing cardiac morphology, systolic function, and tissue characterization, thereby aiding in early diagnosis, precise phenotyping, and tailored treatment. The aim of this review is to provide an up-to-date overview of CMR techniques for studying myocardial perfusion and their applications to nonischemic cardiomyopathy, not only to rule out an underlying ischemic aetiology but also to investigate the pathophysiological characteristics of microcirculatory dysfunction in these patients. Materials and Methods: We performed a structured review of the literature focusing on first-pass gadolinium perfusion sequences, stress protocols, and emerging pixel-wise perfusion mapping approaches. Studies were selected to illustrate the methods for image acquisition, post-processing, and quantification of myocardial blood flow (MBF) and myocardial perfusion reserve (MPR), as well as to highlight associations with clinical endpoints. Results: First-pass CMR perfusion imaging reliably detects diffuse and regional microvascular dysfunction across cardiomyopathies. Semi-quantitative parameters (e.g., upslope, MPRI) and quantitative MBF mapping (mL/g/min) have demonstrated that impaired perfusion correlates with disease severity, extent of fibrosis, and adverse outcomes, including heart failure hospitalization, arrhythmias, and mortality. Novel automated pixel-wise mapping enhances reproducibility and diagnostic accuracy, distinguishing coronary microvascular dysfunction from balanced three-vessel disease. Microvascular dysfunction-present in approximately 50-60% of dilated cardiomyopathy (DCM), 40-80% of hypertrophic cardiomyopathy (HCM), and >95% of cardiac amyloidosis (CA) patients-has emerged as a key driver of adverse outcomes. Perfusion defects appear early, often preceding overt hypertrophy or fibrosis, and provide incremental prognostic value beyond conventional CMR metrics. Conclusions: CMR represents a powerful tool for detecting myocardial perfusion abnormalities in nonischemic cardiomyopathies, improving phenotyping, risk stratification, and personalized management. Further standardization of quantitative perfusion techniques will facilitate broader clinical adoption.

Coexistence of cardiac sarcoidosis and arrhythmogenic cardiomyopathy-associated genetic variants: a multicentre case-control study

BACKGROUND

Cardiac sarcoidosis (CS) is a chronic inflammatory disease characterised by non-caseating granulomas, while arrhythmogenic cardiomyopathy (ACM) is a genetic condition mainly affecting desmosomal proteins. The coexistence of CS and genetic variants associated with ACM is not well understood, creating challenges in diagnosis and management. This study aimed to describe the clinical, imaging and genetic features of patients with both conditions.

METHODS

This was a multicentre retrospective case-control study involving three groups of patients: those with biopsy-proven CS and pathogenic or likely pathogenic genetic variants linked to ACM (n=5); patients with genetic variants but no CS (n=5); and patients with CS without genetic variants (n=5). Clinical data, including symptoms, electrocardiographic findings and imaging results from echocardiography, cardiac magnetic resonance and positron-emission tomography, were analysed.

RESULTS

Patients with CS and genetic variants were more likely to exhibit atrioventricular block (100%), PR prolongation (204 ms vs 160 ms) and paroxysmal atrial fibrillation (80%) compared with those with genetic variants alone (0% for both). Imaging findings showed a higher prevalence of septal involvement in patients with both conditions (80%) than in those with genetic variants alone (20%). No significant differences were observed between patients with CS and genetic variants and those with CS without genetic variants. The genetic variants identified included variants in PKP2 (40%), DSG2 (20%), DSP (20%) and TTN (20%).

CONCLUSIONS

The coexistence of CS and ACM-associated genetic variants is associated with distinct clinical features, including PR prolongation, AVB1°, septal involvement and paroxysmal atrial fibrillation. These findings emphasise the need to evaluate for CS in individuals with ACM and associated genetic variants who present with conduction abnormalities or septal involvement, guiding tailored diagnostic and therapeutic strategies.

Arrhythmic Risk Stratification in Patients with Arrhythmogenic Cardiomyopathy

Arrhythmogenic cardiomyopathy is a heart disease in which the heart muscle is replaced by scar tissue. This is the main substrate for the development of malignant ventricular arrhythmias. Sudden cardiac death is the most common manifestation and can often be the first sign of the disease, especially in young people. Correct stratification of arrhythmic risk is essential for the management of these patients but remains a challenge for the clinical cardiologist. In this context, the aim of our work was to review the literature and to analyse the most important studies and new developments with regard to the stratification of the risk of arrhythmia in patients suffering from arrhythmogenic cardiopathy.

Cardiac diagnoses and long-term outcomes in ring-like late gadolinium enhancement evaluated by cardiac magnetic resonance

AIMS

Non-ischaemic ring-like late gadolinium enhancement (LGE) in the left ventricle (LV) detected by cardiac magnetic resonance (CMR) is an emerging biomarker associated with adverse outcomes. Data regarding ring-like LGE are limited to small patient cohorts. We aimed to assess the prevalence of ring-like LGE, its association with morpho-functional phenotypes, aetiologic background, and prognostic implications.

METHODS AND RESULTS

This single-centre observational retrospective study included consecutive patients undergoing LGE-CMR between 2002 and 2024. Ring-like LGE was defined as continuous enhancement in ≥3 adjacent segments. Ischaemic and amyloid cardiomyopathies (CMPs) were excluded. Clinical records were reviewed for etiologic diagnosis and clinical outcomes. The primary endpoint was a composite of all-cause mortality, heart transplantation, or LV assist device implantation. The secondary endpoint included sustained ventricular tachycardia, appropriate implantable cardioverter-defibrillator therapies, or sudden cardiac death. Among 14 091 unique patients who underwent LGE-CMR, ring-like LGE was identified in 152 patients (1.1%) with a median number of 10 segments, mostly involving the inferolateral segments. The most frequent morpho-functional phenotypes were dilated and non-dilated LV CMP. Genetic testing identified likely pathogenic/pathogenic variants in 59 (58.4%) patients, affecting both desmosomal and non-desmosomal genes. Inflammatory CMP was diagnosed in 15.8%. Other rare aetiologies included genetic neuromuscular diseases and inborn errors of metabolism. Primary and secondary endpoints occurred in 17.8 and 17.1%, respectively, over a median follow-up of 3 years.

CONCLUSION

Ring-like LGE is an uncommon, non-disease-specific feature found in various morpho-functional CMP phenotypes. It is associated with frequent genetically determined aetiologies and a high burden of adverse outcomes.

Natural History and Clinical Outcomes of Patients With DSG2/DSC2 Variant-Related Arrhythmogenic Right Ventricular Cardiomyopathy

BACKGROUND

Genetic variants in desmosomal cadherins, desmoglein 2 (DSG2) and desmocollin 2 (DSC2), cause a distinct form of arrhythmogenic right ventricular cardiomyopathy (ARVC), which remains poorly reported. In this study, we aimed to provide a comprehensive description of the phenotypic expression, natural history, and clinical outcomes of patients with this ARVC subset.

METHODS

Genetic and clinical data of DSG2 and DSC2 variant carriers were collected from 5 countries in Europe and Asia. We assessed the phenotypic profile of these patients and their clinical outcomes, focusing on heart failure and ventricular arrhythmia events.

RESULTS

Overall, 271 subjects, 254 with DSG2 variants, were included in this study (median age, 38 years [interquartile range, 25-52]; 62.7% male). Of these, 165 were probands, and 200 were diagnosed with definite ARVC. A total of 181 (66.8%) individuals carried missense variants, mainly distributed in the extracellular domains. Notably, we included 78 (28.8%) individuals with multiple variants. Of the 200 cases with diagnosed ARVC, 41 (20.5%) experienced premature cardiac death before the age of 65. Among the 81 individuals for whom both left ventricular ejection fraction and right ventricular fractional area change data were available at presentation, 29 (35.8%) had isolated right ventricular dysfunction, and 16 (19.8%) had biventricular dysfunction. Single-variant carriers who engaged in intense physical exercise were younger at disease onset compared with those who did not (P=0.001). Compared with single-variant carriers, those with multiple variants were more likely to be diagnosed with ARVC (96.2% versus 64.8%; P<0.001) and exhibited more severe left ventricular dysfunction (44.4% versus 22.1%; P=0.001) and right ventricular dilation (88.9% versus 55.8%, P<0.001). Multiple-variant carriers were significantly younger at ARVC diagnosis compared with single-variant carriers (33 [18-49] years versus 42 [27-54] years; P<0.001]. During follow-up, end-stage heart failure (P<0.001) and malignant ventricular arrhythmias (P=0.004) were significantly more frequent in multiple-variant compared with single-variant carriers. Compared with PKP2 patients, DSG2/DSC2 patients exhibited a significantly higher risk of end-stage heart failure (P<0.001).

CONCLUSIONS

ARVC attributable to variants in desmosomal cadherins mostly present with right ventricular or biventricular disease. Multiple variants are common in these patients and are associated with more frequent clinical penetrance, earlier onset of disease, and adverse clinical outcomes.

Arrhythmic risk prediction in non-dilated left ventricular cardiomyopathy: The role of overlap with arrhythmogenic cardiomyopathy

BACKGROUND

Non-dilated left ventricular cardiomyopathy (NDLVC) has been defined as non-ischemic LV scarring or fatty replacement regardless of global or regional wall motion abnormalities, or isolated global LV hypokinesia without scarring. We evaluated the arrhythmic risk in NDLVC and assessed the prognostic value of overlapping features with arrhythmogenic cardiomyopathy (ACM).

METHODS

All patients who underwent cardiovascular magnetic resonance (CMR) scan and genetic testing between 2012 and 2022 and met the diagnostic criteria for NDLVC were selected. All patients were evaluated for the presence of the 2024 diagnostic criteria for ACM. The primary endpoint was a composite of sudden cardiac death (SCD), ventricular fibrillation (VF) or sustained ventricular tachycardia (VT),.

RESULTS

The cohort included 225 patients (35 % women, median age 55 years [interquartile range 44-64]). The etiology was genetic in 44 % of cases, with 51 pathogenetic/likely pathogenetic (P/LP) variant and 49 variant of uncertain significance (VUS). Over 3.3 years (1.5-6.0), 12 patients (5 %) developed an endpoint event. The risk increased in patients meeting the criteria for definite or borderline arrhythmogenic left ventricular (ALVC) and biventricular (ABVC) cardiomyopathy. In the whole cohort, LGE >9 % of LV mass was the most significant predictor of outcome. In patients with LGE >9 %, fatty replacement significantly increased the risk of arrhythmic events.

CONCLUSIONS

LGE >9 % of LV mass and fatty replacement are associated with an increased arrhythmic risk in NDLVC. The risk is also higher if patients meet the 2024 criteria for definite or borderline ALVC/ABVC.

Multimodality Imaging to Understand Mechanisms of Right Ventricular Disease

Right ventricular (RV) disease is commonly encountered in patients with cardiovascular conditions and is associated with adverse prognosis. The principal pathogenic mechanisms giving rise to RV pathology include RV pressure overload, RV volume overload, and RV myocardial diseases. Noninvasive cardiac imaging is commonly used to detect the conditions associated with RV disease and ultimately guide therapeutic decisions. Transthoracic echocardiogram is usually the first-line test in patients with suspected RV disease and it provides relevant information on biventricular size and function, valvular abnormalities, and cardiac hemodynamics including pulmonary pressures. Cardiac magnetic resonance imaging is considered the reference standard noninvasive imaging test for quantifying ventricular size and function and cardiac shunts and has a secondary role for assessing valvular disease when echocardiography is nondiagnostic. Cardiac magnetic resonance imaging also provides insight into RV myocardial diseases such as inflammation, infarction, and infiltration. Nuclear cardiology and cardiac computed tomography imaging can also be used to inform on specific RV disease mechanisms originating from lung disease and pulmonary vasculature disorders. In this review, we discuss the role and utility of cardiac imaging in characterizing RV mechanisms of disease and provide a suggested framework for clinicians to appropriately utilize imaging in these clinical scenarios.

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.

Ventricular arrhythmias during exercise testing in pediatric patients with arrhythmogenic cardiomyopathy at first presentation and with different ventricular involvement

BACKGROUND

Ventricular arrhythmias (VAs) may be the first clinical manifestation in pediatric patients with arrhythmogenic cardiomyopathy (ACM). The arrhythmogenicity of exercise testing (ET) remains unclear.

OBJECTIVE

The aim of this study was to describe the arrhythmogenicity of ET in pediatric early ACM.

METHODS

Pediatric patients diagnosed with definite ACM were enrolled. ET results at the first presentation and after discontinuation of therapy were analyzed. Comparison with a control group (premature ventricular complexes [PVCs] without structural heart disease) was performed.

RESULTS

At baseline, VAs were observed in 20 (80%) patients; 3 had nonsustained ventricular tachycardia and 17 had isolated PVCs. No PVC morphology was significantly more prevalent in ACM phenotypes. At peak exercise, VAs were present in 40% of patients and 10% of controls. During recovery, VAs occurred in 17 (68%) patients and 4 (8%) controls. Polymorphism and nonsustained ventricular tachycardias during recovery were more prevalent in biventricular ACM (BIV-ACM) than in non-biventricular ACM (P = .03; P = .03). Irregular VAs were present in 80% of BIV-ACM. Compared with controls, PVCs with left bundle branch block-superior axis at baseline and VAs during recovery were significantly associated with the probability of having ACM (P = .0038, P < .0001, respectively).

CONCLUSION

The behavior of VAs during ET at the beginning of ACM is highly variable, and suppression during exercise is not uncommon. Nevertheless, presence at the peak of exercise is more common in ACM patients. Baseline left bundle branch block-superior axis PVCs and VAs during recovery correlate with the presence of ACM. VA morphology and ET behavior cannot predict ACM phenotype. Polymorphism and nonsustained ventricular tachycardias are more prevalent in patients with BIV-ACM.

Rapid progression of right ventricular dysfunction: a case report

BACKGROUND

Arrhythmogenic cardiomyopathy (ACM) is a genetic myocardial disease characterized by progressive myocyte loss and fibrofatty (fibrous and adipose) tissue replacement to predispose these patients to fatal ventricular arrhythmias and impairment of ventricular systolic function. The relationship of ACM and myocarditis has gained significant attention.

CASE PRESENTATION

This case presented a 28-year-old female who was admitted to the hospital with complaints of recurrent lower limb edema and palpitations for 6 months. Her electrocardiogram revealed a typical manifestation of an advanced form of biventricular arrhythmogenic cardiomyopathy (ACM). Despite systematic medical management, her right ventricle (RV) function deteriorated rapidly, necessitating heart transplantation. Postoperative histopathological examinations confirmed the RV involvement as reflected in the electrocardiogram. Especially, multiple foci of lymphocytic infiltration were observed throughout the heart, with the RV being the most severe.

CONCLUSION

When a rapid progression of ACM occurs, a concomitant myocarditis should be considered. ACM may be an inflammation-mediated transformation from myocardial tissue to fibrofatty tissue, and myocarditis may be a part of the natural history in some ACM cases.

Illuminating Cardiac Remodeling: Insights From [18F]-Fluorodeoxyglucose Positron Emission Tomography Imaging in Plakoglobin-Associated Arrhythmogenic Cardiomyopathy

BACKGROUND

Arrhythmogenic cardiomyopathy (ACM) is a genetic heart muscle disease, which presents with arrhythmias and sudden cardiac death, along with progressive cardiac remodeling and myocardial inflammation. This study aims to elucidate the patterns of [18F]-fluorodeoxyglucose ([18F]-FDG) uptake in a mouse model of plakoglobin-associated cardiac disease to better understand its diagnostic potential.

METHODS AND RESULTS

Plakoglobin (Jup) knockout mice developed a cardiomyopathy that presented an ACM-like phenotype at 6 weeks of age. Flow cytometry experiments showed a significant increase of immune cells, for example, an expansion of proinflammatory and tissue-injury macrophages. In vivo positron emission tomography and ex vivo autoradiography showed increased [18F]-FDG uptake in genotype positive hearts. A correlative analysis between [18F]-FDG positivity and macrophage infiltration using CD68 and CD206 staining did not show colocalization. CD68 and CD206 positivity was primarily observed within the fibrotic scar, whereas [18F]-FDG uptake was predominantly identified in CD68 and CD206-negative tissue areas. Instead, [18F]-FDG signal seemed to originate from cardiomyocytes adjacent to areas of fibrotic remodeling. Morphometric analysis revealed hypertrophy of these cardiomyocytes, which may reflect metabolic remodeling as a compensatory response.

CONCLUSIONS

In our murine model of Jup-related ACM, strong cardiac [18F]-FDG uptake was detected, which colocalized with regional hypertrophic cardiomyocytes rather than inflammatory cells. These findings indicate that [18F]-FDG positron emission tomography is a valuable tool for identifying and localizing hypermetabolic areas associated with cardiac remodeling in ACM, providing insights into disease mechanisms and potential diagnostic strategies.

Fenotypic expressions and clinical manifestations of arrhythmogenic cardiomyopathy

Arrhythmogenic cardiomyopathy (ACM) is a cardiac disorder characterized by structural alterations of the myocardium, which predisposes individuals to ventricular arrhythmias and increases the risk of sudden cardiac death. Initially described as arrhythmogenic right ventricular cardiomyopathy, the involvement of the left ventricle (LV) has been subsequently recognized, leading to the classification of various phenotypes under LV non-dilated cardiomyopathy. The clinical spectrum of ACM ranges from life-threatening ventricular arrhythmias to overt heart failure, sometimes presenting with acute myocarditis-like episodes and extracardiac symptoms, further contributing to the disease's heterogeneity. Diagnosis relies on imaging modalities, such as echocardiogram and cardiac magnetic resonance imaging, to detect areas of fibro-fatty replacement and/or non-ischemic ventricular scarring, integrated with genetic analysis. The 2023 European Society of Cardiology guidelines on Cardiomyopathies underscore the importance of a comprehensive diagnostic approach, combining imaging and genetics for arrhythmic risk stratification and comprehensive patient management. Growing evidence on genotype-phenotype correlation, along with the validation of specific predictive scores, is improving ACM clinical management and promoting personalized treatment tailored to individual and familial characteristics.

Interpretation and management of T wave inversion in athletes: An expert opinion statement of the Italian Society of Sports Cardiology (SICSPORT)

T wave inversion (TWI) on the electrocardiogram (ECG) is a relatively common finding in athletes. It poses a diagnostic challenge, as it can indicate either a benign physiological pattern or an early sign of serious cardiac pathology. This expert opinion statement provides a comprehensive review of the current understanding of TWI in athletes, emphasizing the importance of its localization, associated clinical features, and demographic factors in guiding its interpretation and management. We explore the potential causes of TWI, including physiological adaptations such as the juvenile pattern and training-induced repolarization variants, as well as pathological conditions like cardiomyopathies, ion channel diseases, and other cardiac abnormalities. Additionally, we discuss the implications of TWI in different ECG leads-anterior, inferior, and lateral-and the diagnostic work-up needed to exclude underlying disease. The importance of follow-up in athletes with TWI is highlighted, particularly for young athletes, to monitor the potential development of cardiomyopathy. Finally, we address considerations for sports eligibility in athletes with TWI, stressing the need for a balanced approach that ensures athlete safety without imposing unnecessary restrictions and investigations.

Characterization of a novel SCN5A mutation associated with long QT syndrome and arrhythmogenic right ventricular cardiomyopathy in a family

Sudden cardiac death represents a significant diagnostic challenge for forensic pathologists, particularly in inherited arrhythmia syndromes or cardiomyopathies resulting from genetic defects. Molecular autopsies can reveal the underlying molecular etiology in such cases. In this study, we investigated a family with a history of sudden cardiac death to elucidate the molecular basis responsible for sudden cardiac death. The proband underwent a comprehensive forensic examination. Family members received thorough clinical evaluations, including electrocardiogram, Holter monitoring, echocardiography, and cardiac magnetic imaging. Whole exome sequencing and genetic analysis were performed on the deceased and her parents. In addition, Western blotting and patch-clamp recordings were employed to evaluate the expression and function of the mutant protein in vitro. Forensic examination diagnosed arrhythmogenic right ventricular cardiomyopathy (ARVC) as the cause of sudden death. Genetic analysis identified a novel missense mutation in SCN5A (p.V1323L), which was assessed as likely pathogenic by the ACMG guideline. Another family member carrying the mutation manifested long QT syndrome and mild cardiac fibrosis. The cellular electrophysiological study demonstrated that the mutation resulted in an enhanced late sodium current, suggesting it was a gain-of-function mutation. This study characterizes a novel SCN5A mutation that putatively causes long QT syndrome and may contribute to the development of ARVC. Our work expands the pathogenic spectrum of SCN5A variants and underscores the importance of molecular autopsy in sudden death cases, especially in those with suspected genetic disorders.

Advances in the study and treatment of genetic cardiomyopathies

Cardiomyopathies are primary disorders of the heart muscle. Three key phenotypes have been defined, based on morphology and arrhythmia burden: hypertrophic cardiomyopathy (HCM), with thickened heart muscle and diastolic dysfunction; dilated cardiomyopathy (DCM), with left ventricular enlargement and systolic dysfunction; and arrhythmogenic cardiomyopathy (ACM), with right, left, or biventricular involvement and arrhythmias out of proportion to systolic dysfunction. Genetic discoveries of the molecular basis of disease are paving the way for greater precision in diagnosis and management and revealing mechanisms that account for distinguishing clinical features. This deeper understanding has propelled the development of new treatments for cardiomyopathies: disease-specific, mechanistically based medicines that counteract pathophysiology, and emergent gene therapies that aim to intercept disease progression and restore cardiac physiology. Together, these discoveries have advanced fundamental insights into cardiac biology and herald a new era for patients with cardiomyopathy.

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.

Targeting Ventricular Arrhythmias in Non-Ischemic Patients: Advances in Diagnosis and Treatment

Ventricular arrhythmias (VAs) in non-ischemic cardiomyopathy (NICM) present significant clinical challenges due to their diverse etiologies and complex arrhythmogenic substrates, which differ from those in ischemic heart disease. Recent advancements in imaging, electrophysiological mapping, and ablative therapy have improved the management of these arrhythmias. This review examines the spectrum of NICM subtypes, discussing their pathophysiology, prevalence, genetic determinants, and associated arrhythmias. It also explores contemporary ablative techniques, including epicardial, bipolar, and irrigated approaches, as well as emerging modalities such as stereotactic body radiation therapy (SBRT). The role of novel technologies, including high-resolution mapping and artificial intelligence, is considered in refining diagnosis and treatment. This article provides a comprehensive overview of current management strategies and discusses future directions in the treatment of VAs in NICM patients.

Ablation of ventricular tachycardia from right ventricular aneurysms in patients with arrhythmogenic cardiomyopathy guided by intracardiac echocardiography

BACKGROUND

The best approach for ablating ventricular tachycardia (VT) targeting right ventricular (RV) free wall aneurysms in arrhythmogenic right ventricular cardiomyopathy (ARVC) remains undefined.

OBJECTIVE

We aimed to describe the technical approach, safety, and long-term efficacy of endocardial ablation of VT originating from RV free wall aneurysms in ARVC patients.

METHODS

We identified ARVC patients with VT mapped to intracardiac echocardiography (ICE)-defined RV free wall aneurysms who underwent endocardial ablation targeting the aneurysmal area. RV free wall aneurysm on ICE was defined as an akinetic or dyskinetic area with diastolic bulging. The primary ablation end point was VT control, defined as freedom from any or multiple (>1) VT recurrences.

RESULTS

From 2012 to 2023, 14 ARVC patients underwent endocardial VT ablation within ICE-defined RV free wall aneurysms. The median age at first arrhythmia event was 55.5 years (interquartile range [IQR], 32.3-59.8 years). Pathogenic genetic variants were identified in 82% of the patients. Ablation inside the RV aneurysms during ICE monitoring used prolonged radiofrequency applications (median, 111 seconds; IQR, 81-180 seconds), with power titrated up to 29 W (IQR, 29-33 W) to achieve 10%-15% impedance drops. No steam pops occurred. VT noninducibility was achieved in 86% with no complications. During median follow-up of 4.3 years (IQR, 3.1-6.0 years), the primary end point was achieved in 13 patients (93%): 10 VT free and 3 with a single episode of VT.

CONCLUSION

Endocardial ablation targeting VT from ICE-defined RV free wall aneurysms in ARVC patients using prolonged radiofrequency applications is safe and effective, precluding the need for adjunctive epicardial ablation. Patients with aneurysm-dependent VT were typically older and carried pathogenic genetic variants.

The diagnostic value of electrocardiogram in the left variants of desmosomal arrhythmogenic cardiomyopathy

Electrocardiogram (ECG) may play a crucial role in the diagnosis of left-sided variants of desmosomal arrhythmogenic cardiomyopathies. This article discusses the most common ECG changes, such as T-wave inversion and low QRS voltages, and new ECG signs such as Q-waves, low voltages in specific leads, posterior fascicle block, and R/S ratio ≥ 0.5 in V1. In addition, ventricular arrhythmias have peculiar features in these patients. Electrocardiogram may be an early marker of this insidious cardiomyopathy and allow to avoid sudden cardiac death often in young people. Electrocardiogram abnormalities may also be indicators of disease evolution over time.

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.

Risk stratification in arrhythmogenic cardiomyopathy: scoring or personalized medicine?

Almost 40 years after the description of arrhythmogenic cardiomyopathy (ACM), arrhythmic risk stratification remains central to patient management. Antiarrhythmic therapy may involve the use of antiarrhythmic drugs as well as invasive tools such as catheter ablation, with the implantation of an implantable cardioverter defibrillator being of utmost importance. Given the wide phenotypic variability of ACM, the first step in arrhythmic risk stratification requires a thorough assessment of clinical, morphological, and electrical parameters. Moreover, in the last years, genetic testing has become increasingly important, not only for family screening but also in determining prognosis. Finally, data from large series of ACM patients have led to the creation of risk calculators, which are now available online for the medical community. While newly available methods for stratifying arrhythmic risk can be useful, the thoughtful clinical decision-making by clinicians with specific expertise in cardiomyopathies remains of fundamental importance. Additionally, as ACM is a progressive disease, arrhythmic risk stratification should be periodically revised based on newly emerging clinical and instrumental parameters.

Editorial commentary: "Three steps to ACM diagnosis - is it that easy?"

Arrhythmogenic cardiomyopathy (ACM) is an inherited cardiac disease which predisposes to ventricular arrhythmias and sudden cardiac death. Since the introduction of the first diagnostic criteria in 1994, which focused exclusively on right ventricular involvement, diagnostic guidelines have evolved significantly over the past 30 years to encompass the full complexity of the ACM phenotype. In this issue of Trends in Cardiovascular Medicine, Graziano and colleagues review the advancements in ACM diagnostics which emphasizes a comprehensive evaluation of morpho-functional, structural, electrical, and genetic characteristics. The review outlines a three-step clinical approach for diagnosing ACM that involves assessing left and/or right ventricular involvement, identifying the specific ACM subtype, and determining its underlying etiology. This highlights the importance of interdisciplinary teamwork when approaching the complexities of diagnosing ACM and managing the family at risk.

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.

Ring-like late gadolinium enhancement: differential diagnosis and mimics

Advances in cardiac magnetic resonance have promoted tissue characterization with high spatial and contrast resolution, and late gadolinium enhancement (LGE) sequences have improved the detection of myocardial fibrosis. The distribution pattern of LGE facilitates differentiation between ischemic and nonischemic etiologies and aids in refining diagnoses within nonischemic cardiomyopathies, suggesting specific etiological factors. A distinctive nonischemic LGE pattern that has recently gained prominence is the ring-like pattern, defined as a subepicardial or mid-wall circumferential or semi-circumferential enhancement, which involves at least three contiguous segments within the same short-axis slice. Initially identified as a diagnostic marker for desmoplakin and filamin C-related cardiomyopathies, the pattern has been reported in nongenetic conditions; nevertheless, it remains an uncommon finding in these diseases. In this article, we aim to present the differential diagnoses of ring-like LGE and its mimics. The combination of epidemiological, clinical, electrocardiographic, and additional features enables a focused refinement of the differential diagnosis associated with ring-like LGE.

Ventricular Depolarization Abnormalities and Their Role in Cardiac Risk Stratification - A Narrative Review

Ventricular depolarization refers to the electrical activation and subsequent contraction of the ventricles, visible as the QRS complex on a 12-lead electrocardiogram (ECG). A well-organized and efficient depolarization is critical for cardiac function. Abnormalities in ventricular depolarization may indicate various pathologies and can be present in all leads if the condition is general, or in a subgroup of anatomically contiguous leads if the condition is limited to the corresponding anatomic location of the heart. Furthermore, the assessment of depolarization abnormalities on the ECG may either be identified visually or this may depend on further processing. In recent decades, assessment of depolarization abnormalities has received a lot of attention for cardiac risk stratification. This risk stratification aims to identify patients at high risk of adverse cardiac events, to tailor preventive or therapeutic interventions. In this review, we provide an oversight of different techniques for assessing abnormal ventricular depolarization and their value in diagnosing certain conditions, in risk stratification of adverse events, and in guiding therapeutic decisions. This includes QRS alterations directly corresponding to cardiac conditions, such as bundle branch blocks, or the presence of a delta wave, and also metrics aiming to qualitatively or quantitatively assess myocardial scarring, such as QRS (micro)fragmentation and QRS-scoring, and techniques assessing abnormal late depolarizations, such as signal-averaged ECG. While most established assessments of abnormal depolarization rely on human interpretation and are limited by visual detection, recently introduced analyses, such as QRS micro-fragmentation, aim to tackle these limitations. Besides eliminating bias, these automated analyses bypass the need for human interpretation, thereby paving the way for large population studies.

Patient Preferences in Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) Screening and ICD Implantation: Canadian ARVC Registry Substudy

Background

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is typically diagnosed following an arrhythmic event or during screening after a family member experiences sudden cardiac death. Implantation of a defibrillator (ICD) improves survival but can be associated with morbidity and risks, an important consideration within a shared decision-making context. This study examined patient decisional needs and preferences surrounding ARVC screening and prophylactic ICD implantation.

Methods

This Canadian ARVC registry substudy included 20 new patients and/or families offered ARVC screening (the screen group), and 27 diagnosed ARVC patients who were offered an ICD. Measures included the following: the Decisional Conflict Scale; preference and benefit-risk visual analogue scales; the Medical Outcomes Study Short Form-36 (SF-36); and exercise restriction. Descriptive analysis was employed, and results are reported as mean (standard deviation) or proportions.

Results

ICD patients reported having lower decisional conflict scores-19.6 (13.6) compared to the screen group patients-33.1 (32.2). The visual analogue scale results showed lower benefit and risk clarity scores for screen group patients-6.6 (3.6)-compared to those offered ICD implantation-7.4 (2.6). More screen group patients (55%) reported restricting exercise than did ICD patients (30%). In both groups, the Medical Outcomes Study Short Form-36 Physical Component Summary scores were higher than population norms-50 (standard deviation 10): the screen group, 52.0 (8.8); the ICD group, 54.1 (7.4), and the Mental Component Summary scores were slightly lower-the screen group, 47.7 (10.8); the ICD group, 49.7 (8.9).

Conclusions

Patients undergoing ARVC screening reported greater decisional conflict and lower benefit and risk clarity compared to patients diagnosed with ARVC who were offered an ICD. Screen group patients were more restrictive in their exercise. Understanding patient preferences and needs during ARVC screening and ICD candidacy can assist in improving decision support with patients and families.

A new prediction model for sustained ventricular tachycardia in arrhythmogenic cardiomyopathy

Background

Arrhythmogenic cardiomyopathy (ACM) is an inherited cardiomyopathy characterized by high risks of sustained ventricular tachycardia (sVT) and sudden cardiac death. Identifying patients with high risk of sVT is crucial for the management of ACM.

Methods

A total of 147 ACM patients were retrospectively enrolled in the observational study and divided into training and validation groups. The least absolute shrinkage and selection operator (LASSO) regression model was employed to identify factors associated with sVT. Subsequently, a nomogram was constructed based on multivariable logistic regression analysis. The performance of the nomogram was evaluated using the area under the curve (AUC) of the receiver operating characteristic (ROC) curve and calibration curve. Decision curve analysis was conducted to assess the clinical utility of the nomogram.

Results

Seven parameters were incorporated into the nomogram: age, male sex, syncope, heart failure, T wave inversion in precordial leads, left ventricular ejection fraction (LVEF), SDNN level. The AUC of the nomogram to predict the probability of sVT was 0.867 (95% CI, 0.797-0.938) in the training group and 0.815 (95% CI, 0.673-0.958) in the validation group. The calibration curve demonstrated a good consistency between the actual clinical results and the predicted outcomes. Decision curve analysis indicated that the nomogram had higher overall net benefits in predicting sVT.

Conclusion

We have developed and internally validated a new prediction model for sVT in ACM. This model could serve as a valuable tool to accurately identify ACM patients with high risk of sVT.

Ventricular arrhythmias in association with athletic cardiac remodelling

Athletes are predisposed to atrial arrhythmias but the association between intense endurance exercise training, ventricular arrhythmias (VAs), and sudden cardiac death is less well established. Thus, it is unclear whether the 'athlete's heart' promotes specific arrhythmias or whether it represents a more general pro-arrhythmogenic phenotype. Whilst direct causality has not been established, it appears possible that repeated exposure to high-intensity endurance exercise in some athletes contributes to formation of pro-arrhythmic cardiac phenotypes that underlie VAs. Theories regarding potential mechanisms for exercise-induced VAs include repeated bouts of myocardial inflammation and stretch-induced cellular remodelling. Small animal models provide some insights, but larger animal and human data are sparse. The current clinical approach to VAs in athletes is to differentiate those with and without structural or electrical heart disease. However, if the athlete's heart involves a degree of pro-arrhythmogenic remodelling, then this may not be such a simple dichotomy. Questions are posed by athletes with VAs in combination with extreme remodelling. Some markers, such as scar on magnetic resonance imaging, may point towards a less benign phenotype but are also quite common in ostensibly healthy athletes. Other clinical and invasive electrophysiology features may be helpful in identifying the at-risk athlete. This review seeks to discuss the association between athletic training and VAs. We will discuss the potential mechanisms, clinical significance, and approach to the management of athletes with VAs.

Describing and Mapping the Research Trend of Scientific Publications on Arrhythmogenic Right Ventricular Cardiomyopathy Across Four Decades: A Bibliometric Analysis

OBJECTIVES

To perform a bibliometric analysis of publications of arrhythmogenic right ventricular cardiomyopathy (ARVC) from 1981 to 2023 to summarize the current publications and explore frontiers on this topic.

METHODS

We integrated the scientific publications on ARVC in the Web of Science (WOS) Core Collection database from January 1981 to September 2023, using the retrieval strategy of medical subject headings combined with keywords. We focused on articles and reviews that were published in English. Relevant information such as the journal and publisher, the title, authors, organizations, abstract, keywords, published date, and number of citations, were collected. Bibliometric analysis was performed and visualized by the R software and Microsoft Excel.

RESULTS

The results revealed a total of 4792 records related to ARVC from the WOS database, and 2992 original articles or reviews which were selected for bibliometric analysis. There were 79 countries and regions, 3724 research institutions, and 12 157 scholars who have published in this topic. The number of scientific publications of ARVC increased year-by-year, with an annual growth rate of 12.12%. We also investigated the top 10 contributing countries, organizations with affiliations, most influential researchers, highest-cited articles, and highest-frequency keywords. In addition, the most active areas of research on ARVC included that of fatal complications, molecular pathological mechanisms, diagnosis, therapy, and prognosis respectively according to the keywords trend analysis.

CONCLUSIONS

Our study reports the publication landscape of ARVC during the past four decades based on bibliometric analysis. This study provides a deeper understanding of the published literature on ARVC.

Advances in Cardiac Imaging and Genetic Testing for Diagnosis and Risk Stratification in Cardiomyopathies: 2024 Update

Cardiomyopathies represent a diverse group of heart muscle diseases marked by structural and functional abnormalities that are not primarily caused by coronary artery disease. Recent advances in non-invasive imaging techniques, such as echocardiography, cardiac magnetic resonance, and computed tomography, have transformed diagnostic accuracy and risk stratification, reemphasizing the role of cardiac imaging in diagnosis, phenotyping, and management of these conditions. Genetic testing complements imaging by clarifying inheritance patterns, assessing sudden cardiac death risk, and informing therapeutic choices. Integrating imaging data, such as left ventricular wall thickness, fibrosis, and apical aneurysms, with genetic findings enhances decision-making for implantable cardioverter-defibrillators in high-risk patients. Emerging technologies like artificial intelligence, strain imaging, and molecular imaging, alongside genetic testing, hold the promise of further refining diagnosis and personalized treatment approaches. This article summarizes the current state and future perspectives of cardiac imaging and genetic testing for diagnosis and risk stratification in cardiomyopathies, offering practical insights for patients' management.

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 [...].

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.

Arrhythmic risk stratification in patients with left ventricular ring-like scar

AIMS

Left ventricular (LV) ring-like scar on cardiac magnetic resonance (CMR) has been linked to malignant arrhythmias in patients with non-ischemic cardiomyopathy. This study aimed to perform a comprehensive evaluation of this phenotype and to identify risk factors for life-threatening arrhythmic events (LAEs), a composite of sudden cardiac death (SCD), aborted SCD, and sustained ventricular tachycardia.

METHODS AND RESULTS

One-hundred-fifteen patients (median age 39 [IQR 28-52], 42% females) were identified at 6 referral centres. Inclusion criteria were ring-like LV scar (≥ 3 contiguous segments with subepicardial/midwall late gadolinium enhancement (LGE) in the same slice) and one among: pathogenic/likely pathogenic genetic variant, family history for cardiomyopathy, or arrhythmogenic cardiomyopathy diagnosis. During the study follow-up, survival-free from LAEs was 60% (3.8 events/100 patients/year); at a median follow-up of 4.6 years (IQR 1.7-8.4) it was 84%. On multivariable analysis, anterior Q waves (HR:1.030, 95% CI:1.014-1.046, p < 0.001), QRS width (HR:4.642, 95% CI:1.296-16.628, p=0.018), and LV end-diastolic volume index (LVEDVi) (HR:1.011, 95% CI:1.001-1.021, per mL/m2 increase, p=0.040) were independently associated with LAEs; with good discrimination power (Harrell's C-index=0.796). Three risk categories were identified: normal ECG, abnormal ECG and no LAEs predictive variables, abnormal ECG and ≥ 1 LAEs predictive variables, with a decreasing survival from 100% to 65% and 49%, respectively (Log-rank test = 0.015).

CONCLUSIONS

In this study, the LV ring-like scar phenotype was associated with a high rate of malignant arrhythmias in presence of anterior Q waves, QRS prolongation, and increased LVEDVi. A normal ECG identified a lower risk subgroup.

Understanding the Key Determinants of Cardiovascular and Metabolic Disease Progression to Develop Effective Therapeutic Strategies

Cardiovascular disease (CVD) is a general term that is used to describe a range of conditions affecting the cardiovascular system [...].

Lifetime cumulative activity burden is associated with symptomatic heart failure and arrhythmic risk in patients with arrhythmogenic right ventricular cardiomyopathy: a retrospective cohort study

AIMS

Sports-related physical activity is associated with an increased risk of ventricular dysfunction and arrhythmias in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). However, there are currently no standardized strategies for activity assessment. Thresholds for harmful levels of physical activity suggested by previous studies vary substantially and neither lifetime activity burden nor continuous modelling approaches were considered.

METHODS AND RESULTS

For this single-centre retrospective study, ARVC patients were interviewed to assess sports-related and non-sports-related physical activity between the age of 10 years and the last follow-up. Activity data were aggregated to the median metabolic equivalent of task-hours (METh) per week for each year. The association between cumulative physical activity burden and clinical study endpoints was investigated using Cox regression models. A total of 124 patients (median age: 39.5 years, 48% male) were included in the analysis, of whom 93 had been diagnosed with definite ARVC. Study participants reported a median overall activity of 202.3 METh/week, with 38.7 METh/week attributed to sports-related activity. In the continuous model, cumulative overall activity burden was associated with the occurrence of symptomatic heart failure [hazard ratio (HR) per 100 METh/week: 1.017, 95% CI (1.003, 1.032), P = 0.015], sustained ventricular tachycardia [HR: 1.021, 95% CI (1.006, 1.037), P = 0.007], and implantable cardioverter defibrillator interventions [HR: 1.017, 95%CI (1.000, 1.034), P = 0.048]. This finding was consistent when considering sports-related activity separately as a predictor variable, whereas the resulting hazard ratios did not show a significant association for non-sports-related physical activity.

CONCLUSION

This study demonstrates for the first time that cumulative physical activity as a continuous predictor variable is associated with symptomatic heart failure and arrhythmic risk in ARVC patients. Collaborative research is required in larger cohorts to investigate the influence of potential confounders on event occurrence and to develop threshold recommendations for clinical practice.

Prevalence and determinants of low QRS voltages and QRS fragmentation in children and adolescents undergoing sports pre-participation screening

AIMS

Low QRS voltages (LQRSV) in limb leads and QRS fragmentation (FQRS) are possible electrocardiographic signs of myocardial fibrosis and cardiomyopathy, but they are not listed in current criteria for interpreting athlete's electrocardiogram (ECG). We investigated the prevalence and determinants of LQRSV and FQRS in a cohort of young apparently healthy athletes undergoing pre-participation screening (PPS).

METHODS AND RESULTS

We analysed a consecutive series of 2140 ECG obtained during PPS of young athletes (mean age 12.5 ± 2.6 years, 7-18-year-old, 49% males). The peak-to-peak QRS voltage was measured in all limb leads, and LQRSV were defined when maximum value was <0.5 mV. Fragmented QRS morphologies were grouped into five patterns. Lead aVR was not considered. Maximum peak-to-peak QRS voltage in limb leads was 1.4 ± 0.4 mV, similar between younger and older athletes, but significantly lower in females than males (1.35 ± 0.38 mV vs. 1.45 ± 0.42 mV; P < 0.001). There was a weak correlation between maximal QRS voltages and body mass index (BMI), but not with type of sport or training load. Only five (0.2%) individuals showed LQRSV. At least one fragmented QRS complex was identified in 831 (39%) individuals but excluding the rSr' pattern in V1-V2, only 10 (0.5%) showed FQRS in ≥2 contiguous leads. They were older than those without FQRS, but did not differ in terms of gender, BMI, type of sport, or training load.

CONCLUSION

Low QRS voltages in limb leads and FQRS in ≥2 contiguous leads excluding V1-V2 are rare in young apparently healthy athletes and are not related to the type and intensity of sport activity. Therefore, they may require additional testing to rule out an underlying disease particularly when other abnormalities are present.

The role of echocardiography in sports cardiology: An expert opinion statement of the Italian Society of Sports Cardiology (SIC sport)

Transthoracic echocardiography (TTE) is routinely required during pre-participation screening in the presence of symptoms, family history of sudden cardiac death or cardiomyopathies <40-year-old, murmurs, abnormal ECG findings or in the follow-up of athletes with a history of cardiovascular disease (CVD). TTE is a cost-effective first-line imaging modality to evaluate the cardiac remodeling due to long-term, intense training, previously known as the athlete's heart, and to rule out the presence of conditions at risk of sudden cardiac death, including cardiomyopathies, coronary artery anomalies, congenital, aortic and heart valve diseases. Moreover, TTE is useful for distinguishing physiological cardiac adaptations during intense exercise from pathological behavior due to an underlying CVD. In this expert opinion statement endorsed by the Italian Society of Sports Cardiology, we discussed common clinical scenarios where a TTE is required and conditions falling in the grey zone between the athlete's heart and underlying cardiomyopathies or other CVD. In addition, we propose a minimum dataset that should be included in the report for the most common indications of TTE in sports cardiology clinical practice.

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.

Multimodality Imaging for Right Ventricular Function Assessment in Severe Tricuspid Regurgitation

Severe tricuspid regurgitation (TR) is a pathological condition associated with worse cardiovascular outcomes. In the vicious cycle of right ventricular compensation and maladaptation to TR, the development of right ventricle (RV) dysfunction has significant prognostic implications, especially in patients undergoing surgical or percutaneous treatments. Indeed, RV dysfunction is associated with increased operative morbidity and mortality in both surgical and percutaneously treated patients. In this context, the identification of clinical or subtle right ventricle dysfunction plays a critical role inpatient selection and timing of surgical or percutaneous tricuspid valve intervention. However, in the presence of severe TR, evaluation of RV function is challenging, given the increase in preload that may lead to an overestimation of systolic function for the Frank-Starling law, reduced reliability of pulmonary artery pressure estimation, the sensitivity of RV to afterload that may result in afterload mismatch after treatment. Consequently, conventional echocardiographic indices have some limitations, and the use of speckle tracking for right ventricular free wall longitudinal strain (RV-FWLS) analysis and the use of 3D echocardiography for RV volumes and ejection fraction estimation are showing promising data. Cardiac magnetic resonance (CMR) represents the gold standards for volumes and ejection fraction evaluation and may add further prognostic information. Finally, cardiac computer tomography (CCT) provides measurements of RV and annulus dimensions that are particularly useful in the transcatheter field. Identification of subtle RV dysfunction may need, therefore, more than one imaging technique, which will lead to tip the balance between medical therapy and early intervention towards the latter before disease progression. Therefore, the aim of this review is to describe the main imaging techniques, providing a comprehensive assessment of their role in RV function evaluation in the presence of severe TR.

Role of miRNA-mRNA Interactome in Pathophysiology of Arrhythmogenic Cardiomyopathy

Arrhythmogenic cardiomyopathy is an inherited entity characterized by irregular cell-cell adhesion, cardiomyocyte death and fibro-fatty replacement of ventricular myocytes, leading to malignant ventricular arrythmias, contractile dysfunction and sudden cardiac death. Pathogenic variants in genes that encode desmosome are the predominant cause of arrhythmogenic cardiomyopathy. Moreover, signalling pathways such as Wnt/ß-catenin and transforming growth factor-β have been involved in the disease progression. However, still little is known about the molecular pathophysiological mechanisms that underlie arrhythmogenic cardiomyopathy pathogenesis. We used mRNA and small RNA sequencing to analyse the transcriptome of health and arrhythmogenic cardiomyopathy of autopsied human hearts. Our results showed 697 differentially expressed genes and eight differentially expressed miRNAs. Functional enrichment revealed mitochondrial respiratory-related pathways, impaired response to oxidative stress, apoptotic signalling pathways and inflammatory response-related and extracellular matrix response pathways. Furthermore, analysis of the miRNA-mRNA interactome identified eleven negatively correlated miRNA-target pairs for arrhythmogenic cardiomyopathy. Our finding revealed novel arrhythmogenic cardiomyopathy-related miRNAs with important regulatory function in disease pathogenesis, highlighting their value as potential key targets for therapeutic approaches.