Predicting arrhythmic risk in arrhythmogenic right ventricular cardiomyopathy: A systematic review and meta-analysis

Clinical features and outcomes in carriers of pathogenic desmoplakin variants

BACKGROUND AND AIMS

Pathogenic variants in the desmoplakin (DSP) gene are associated with the development of a distinct arrhythmogenic cardiomyopathy phenotype not fully captured by either dilated cardiomyopathy (DCM), non-dilated left ventricular cardiomyopathy (NDLVC), or arrhythmogenic right ventricular cardiomyopathy (ARVC). Prior studies have described baseline DSP cardiomyopathy genetic, inflammatory, and structural characteristics. However, cohort sizes have limited full clinical characterization and identification of clinical and demographic predictors of sustained ventricular arrhythmias (VAs), heart failure (HF) hospitalizations, and transplant/death. In particular, the relevance of acute myocarditis-like episodes for subsequent disease course is largely unknown.

METHODS

All patients with pathogenic/likely pathogenic (P/LP) DSP variants in the worldwide DSP-ERADOS Network (26 academic institutions across nine countries) were included. The primary outcomes were the development of sustained VA and HF hospitalizations during follow-up. Fine-Gray regressions were used to test association between clinical and instrumental parameters and the development of outcomes.

RESULTS

Eight hundred patients [40.3 ± 17.5 years, 47.5% probands, left ventricular ejection fraction (LVEF) 49.5 ± 13.9%] were included. Over 3.7 [1.4-7.1] years, 139 (17.4%, 3.9%/year) and 72 (9.0%, 1.8%/year) patients experienced sustained VA and HF episodes, respectively. A total of 32.5% of individuals did not fulfil diagnostic criteria for ARVC, DCM, or NDLVC; their VA incidence was 0.5%/year. In multivariable regression, risk features associated with the development of VA were female sex [adjusted hazard ratio (aHR) 1.547; P = .025], prior non-sustained ventricular tachycardia (aHR 1.721; P = .009), prior sustained VA (aHR 1.923; P = .006), and LVEF ≤ 50% (aHR: 1.645; P = .032), while for HF, they were the presence of T-wave inversion in 3+ electrocardiogram leads (aHR 2.036, P = .007) and LVEF ≤ 50% (aHR 3.879; P < .001). Additionally, 70 (8.8%) patients experienced a myocardial injury episode at presentation or during follow-up. These episodes were associated with an increased risk of VA and HF thereafter (HR 2.394; P < .001, and HR 5.064, P < .001, respectively).

CONCLUSIONS

Patients with P/LP DSP variants experience high rates of sustained VA and HF hospitalizations. These patients demonstrate a distinct clinical phenotype (DSP cardiomyopathy), whose most prominent risk features associated with adverse clinical outcomes are the presence of prior non-sustained ventricular tachycardia or sustained VA, T-wave inversion in 3+ leads on electrocardiogram, LVEF ≤ 50%, and myocardial injury events.

A novel tool for arrhythmic risk stratification in desmoplakin gene variant carriers

BACKGROUND AND AIMS

Pathogenic desmoplakin (DSP) gene variants are associated with the development of a distinct form of arrhythmogenic cardiomyopathy known as DSP cardiomyopathy. Patients harbouring these variants are at high risk for sustained ventricular arrhythmia (VA), but existing tools for individualized arrhythmic risk assessment have proven unreliable in this population.

METHODS

Patients from the multi-national DSP-ERADOS (Desmoplakin SPecific Effort for a RAre Disease Outcome Study) Network patient registry who had pathogenic or likely pathogenic DSP variants and no sustained VA prior to enrolment were followed longitudinally for the development of first sustained VA event. Clinically guided, step-wise Cox regression analysis was used to develop a novel clinical tool predicting the development of incident VA. Model performance was assessed by c-statistic in both the model development cohort (n = 385) and in an external validation cohort (n = 86).

RESULTS

In total, 471 DSP patients [mean age 37.8 years, 65.6% women, 38.6% probands, 26% with left ventricular ejection fraction (LVEF) < 50%] were followed for a median of 4.0 (interquartile range: 1.6-7.3) years; 71 experienced first sustained VA events {2.6% [95% confidence interval (CI): 2.0, 3.5] events/year}. Within the development cohort, five readily available clinical parameters were identified as independent predictors of VA and included in a novel DSP risk score: female sex [hazard ratio (HR) 1.9 (95% CI: 1.1-3.4)], history of non-sustained ventricular tachycardia [HR 1.7 (95% CI: 1.1-2.8)], natural logarithm of 24-h premature ventricular contraction burden [HR 1.3 (95% CI: 1.1-1.4)], LVEF < 50% [HR 1.5 (95% CI: .95-2.5)], and presence of moderate to severe right ventricular systolic dysfunction [HR 6.0 (95% CI: 2.9-12.5)]. The model demonstrated good risk discrimination within both the development [c-statistic .782 (95% CI: .77-.80)] and external validation [c-statistic .791 (95% CI: .75-.83)] cohorts. The negative predictive value for DSP patients in the external validation cohort deemed to be at low risk for VA (<5% at 5 years; n = 26) was 100%.

CONCLUSIONS

The DSP risk score is a novel model that leverages readily available clinical parameters to provide individualized VA risk assessment for DSP patients. This tool may help guide decision-making for primary prevention implantable cardioverter-defibrillator placement in this high-risk population and supports a gene-first risk stratification approach.

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.

Cardiomyopathy and Sudden Cardiac Death: Bridging Clinical Practice with Cutting-Edge Research

Sudden cardiac death (SCD) prevention in cardiomyopathies such as hypertrophic (HCM), dilated (DCM), non-dilated left ventricular (NDLCM), and arrhythmogenic right ventricular cardiomyopathy (ARVC) remains a crucial but complex clinical challenge, especially among younger populations. Accurate risk stratification is hampered by the variability in phenotypic expression and genetic heterogeneity inherent in these conditions. This article explores the multifaceted strategies for preventing SCD across a spectrum of cardiomyopathies and emphasizes the integration of clinical evaluations, genetic insights, and advanced imaging techniques such as cardiac magnetic resonance (CMR) in assessing SCD risks. Advanced imaging, particularly CMR, not only enhances our understanding of myocardial architecture but also serves as a cornerstone for identifying at-risk patients. The integration of new research findings with current practices is essential for advancing patient care and improving survival rates among those at the highest risk of SCD. This review calls for ongoing research to refine risk stratification models and enhance the predictive accuracy of both clinical and imaging techniques in the management of cardiomyopathies.

Long-Term Arrhythmic Follow-Up and Risk Stratification of Patients With Desmoplakin-Associated Arrhythmogenic Right Ventricular Cardiomyopathy

Background

Patients with likely pathogenic/pathogenic desmoplakin (DSP) variants are poorly characterized. Some of them meet diagnostic criteria for arrhythmogenic right ventricular cardiomyopathy (ARVC), but it is unclear how risk stratification strategies for ARVC perform in this setting.

Objectives

The purpose of this study was to characterize arrhythmic outcomes and to test the performance of the recently validated ARVC risk calculator in patients with DSP likely pathogenic/pathogenic variants fulfilling definite 2010 ARVC Task Force Criteria (DSP-TFC+).

Methods

DSP-TFC+ patients were enrolled from 20 institutions across 3 continents. Ventricular arrhythmias (VA), defined as a composite of sustained ventricular tachycardia (VT), appropriate implantable cardioverter defibrillator therapies, and ventricular fibrillation/sudden cardiac death events in follow-up, were reported as the primary outcome. We tested the performance of the ARVC risk calculator for VA prediction, reporting c-statistics.

Results

Among 252 DSP-TFC+ patients (age 39.6 ± 16.9 years, 35.3% male), 94 (37.3%) experienced VA over 44.5 [IQR: 19.6-78.3] months. Patients with left ventricle involvement (n = 194) were at higher VA risk (log-rank P = 0.0239). History of nonsustained VT (aHR 2.097; P = 0.004) showed the strongest association with VA occurrence during the first 5-year follow-up. Neither age (P = 0.723) nor male sex (P = 0.200) was associated with VAs at follow-up. In 204 patients without VA at diagnosis, incident VA rate was high (32.8%; 7.37%/y). The ARVC risk calculator performed poorly overall (c-statistic 0.604 [0.594-0.614]) and very poorly in patients with left ventricular disease (c-statistic 0.558 [0.556-0.560]).

Conclusions

DSP-TFC+ patients are at substantial risk for VAs. The ARVC risk calculator performs poorly in DSP-TFC+ patients suggesting need for a gene-specific risk algorithm. Meanwhile, DSP-TFC+ patients with nonsustained VT should be considered as high-risk.

Implantable cardioverter defibrillator use in arrhythmogenic right ventricular cardiomyopathy in North America and Europe

BACKGROUND AND AIMS

Implantable cardioverter-defibrillators (ICDs) are critical for preventing sudden cardiac death (SCD) in arrhythmogenic right ventricular cardiomyopathy (ARVC). This study aims to identify cross-continental differences in utilization of primary prevention ICDs and survival free from sustained ventricular arrhythmia (VA) in ARVC.

METHODS

This was a retrospective analysis of ARVC patients without prior VA enrolled in clinical registries from 11 countries throughout Europe and North America. Patients were classified according to whether they received treatment in North America or Europe and were further stratified by baseline predicted VA risk into low- (<10%/5 years), intermediate- (10%-25%/5 years), and high-risk (>25%/5 years) groups. Differences in ICD implantation and survival free from sustained VA events (including appropriate ICD therapy) were assessed.

RESULTS

One thousand ninety-eight patients were followed for a median of 5.1 years; 554 (50.5%) received a primary prevention ICD, and 286 (26.0%) experienced a first VA event. After adjusting for baseline risk factors, North Americans were more than three times as likely to receive ICDs {hazard ratio (HR) 3.1 [95% confidence interval (CI) 2.5, 3.8]} but had only mildly increased risk for incident sustained VA [HR 1.4 (95% CI 1.1, 1.8)]. North Americans without ICDs were at higher risk for incident sustained VA [HR 2.1 (95% CI 1.3, 3.4)] than Europeans.

CONCLUSIONS

North American ARVC patients were substantially more likely than Europeans to receive primary prevention ICDs across all arrhythmic risk strata. A lower rate of ICD implantation in Europe was not associated with a higher rate of VA events in those without ICDs.

[Management of cardiomyopathies : New ESC guidelines 2023]

The group of cardiomyopathies has received increasing attention over the last few years after some of the causes were identified and they could be characterized more exactly using modern imaging methods. New definitions and classification schemes were regularly provided by national and international cardiac societies. The new guidelines of the European Society of Cardiology (ESC) from 2023 on the management of cardiomyopathies are the first guidelines that comprehensively address all cardiomyopathies in one document. As these are new guidelines most of the recommendations are also new. An exception is the section on hypertrophic cardiomyopathy (HCM), which provides a targeted update of the 2014 ESC guidelines on the diagnosis and treatment of HCM. The main aim of the guidelines is to provide clear guidance for the diagnosis of cardiomyopathies, to highlight general assessment and management problems and to point out the relevant scientific evidence for the recommendations to the readership. Due to the magnitude detailed descriptions and recommendations cannot be provided for each individual cardiomyopathy phenotype; however, reference is made to the relevant literature.

The pivotal role of compelling high-risk electrocardiographic markers in prediction of ventricular arrhythmic risk in arrhythmogenic right ventricular cardiomyopathy: A systematic review and meta-analysis

INTRODUCTION

Several investigations have shown that existing risk stratification processes remain insufficient for stratifying sudden cardiac death risk in arrhythmogenic right ventricular cardiomyopathy (ARVC). Multiple auxiliary parameters are investigated to offer a more precise prognostic model. Our aim was to assess the association between several ECG markers (epsilon waves, prolonged terminal activation duration (TAD) of QRS, fragmented QRS (fQRS), late potentials on signal-averaged electrocardiogram (SA-ECG), T-wave inversion (TWI) in right precordial leads, and extension of TWI in inferior leads) with the risk of developing poor outcomes in ARVC.

METHODS

A systematic literature search from several databases was conducted until September 9th, 2023. Studies were eligible if it investigated the relationship between the ECG markers with the risk of developing ventricular arrhythmic events.

RESULTS

This meta-analysis encompassed 25 studies with a total of 3767 participants. Our study disclosed that epsilon waves, prolonged TAD of QRS, fQRS, late potentials on SA-ECG, TWI in right precordial leads, and extension of TWI in inferior leads were associated with the incremental risk of ventricular arrhythmias, implantable cardioverter-defibrillator shock, and sudden cardiac death, with the risk ratios ranging from 1.46 to 2.11. In addition, diagnostic test accuracy meta-analysis stipulated that the extension of TWI in inferior leads had the uppermost overall area under curve (AUC) value amidst other ECG markers apropos of our outcomes of interest.

CONCLUSION

A multivariable risk assessment strategy based on the previously stated ECG markers potentially enhances the current risk stratification models in ARVC patients, especially extension of TWI in inferior leads.

Arrhythmogenic Cardiomyopathy: Definition, Classification and Arrhythmic Risk Stratification

Arrhythmogenic cardiomyopathy (ACM) is a heart disease characterized by a fibrotic replacement of myocardial tissue and a consequent predisposition to ventricular arrhythmic events, especially in the young. Post-mortem studies and the subsequent diffusion of cardiac MRI have shown that left ventricular involvement in arrhythmogenic cardiomyopathy is common and often develops early. Regarding the arrhythmic risk stratification, the current scores underestimate the arrhythmic risk of patients with arrhythmogenic cardiomyopathy with left involvement. Indeed, the data on arrhythmic risk stratification in this group of patients are contradictory and not exhaustive, with the consequence of not correctly identifying patients at a high arrhythmic risk who deserve protection from arrhythmic death. We propose a literature review on arrhythmic risk stratification in patients with ACM and left involvement to identify the main features associated with an increased arrhythmic risk in this group of patients.

Arrhythmogenic Right Ventricular Cardiomyopathy in Children: A Systematic Review

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited disease characterized by the progressive replacement of the normal myocardium by fibroadipocytic tissue. The importance of an early diagnosis is supported by a higher risk of sudden cardiac death in the pediatric population. We reviewed the literature on diagnosis, risk stratification, and prognosis in the pediatric population with ARVC. In case reports which analyzed children with ARVC, the most common sign was ventricular tachycardia, frequently presenting as dizziness, syncope, or even cardiac arrest. Currently, there is no gold standard for diagnosing ARVC in children. Nevertheless, genetic analysis may provide a proper diagnosis tool for asymptomatic cases. Although risk stratification is recommended in patients with ARVC, a validated prediction model for risk stratification in children is still lacking; thus, it is a matter of further research. In consequence, even though ARVC is a relatively rare condition in children, it negatively impacts the survival and clinical outcomes of the patients. Therefore, appropriate and validated diagnostic and risk stratification tools are crucial for the early detection of children with ARVC, ensuring a prompt therapeutic intervention.

Incidence, risk assessment and prevention of sudden cardiac death in cardiomyopathies

Cardiomyopathies are a significant contributor to cardiovascular morbidity and mortality, mainly due to the development of heart failure and increased risk of sudden cardiac death (SCD). Despite improvement in survival with contemporary treatment, SCD remains an important cause of mortality in cardiomyopathies. It occurs at a rate ranging between 0.15% and 0.7% per year (depending on the cardiomyopathy), which significantly surpasses SCD incidence in the age- and sex-matched general population. The risk of SCD is affected by multiple factors including the aetiology, genetic basis, age, sex, physical exertion, the extent of myocardial disease severity, conduction system abnormalities, and electrical instability, as measured by various metrics. Over the past decades, the knowledge on the mechanisms and risk factors for SCD has substantially improved, allowing for a better-informed risk stratification. However, unresolved issues still challenge the guidance of SCD prevention in patients with cardiomyopathies. In this review, we aim to provide an in-depth discussion of the contemporary concepts pertinent to understanding the burden, risk assessment and prevention of SCD in cardiomyopathies (dilated, non-dilated left ventricular, hypertrophic, arrhythmogenic right ventricular, and restrictive). The review first focuses on SCD incidence in cardiomyopathies and then summarizes established and emerging risk factors for life-threatening arrhythmias/SCD. Finally, it discusses validated approaches to the risk assessment and evidence-based measures for SCD prevention in cardiomyopathies, pointing to the gaps in evidence and areas of uncertainties that merit future clarification.

Ringlike late gadolinium enhancement provides incremental prognostic value in non-classical arrhythmogenic cardiomyopathy

BACKGROUND

The 2019 arrhythmogenic right ventricular cardiomyopathy (ARVC) risk model has proved insufficient in the capability of predicting ventricular arrhythmia (VA) risk in non-classical arrhythmogenic cardiomyopathy (ACM). Furthermore, the prognostic value of ringlike late gadolinium enhancement (LGE) of the left ventricle in non-classical ACM remains unknown. We aimed to assess the incremental value of ringlike LGE over the 2019 ARVC risk model in predicting sustained VA in patients with non-classical ACM.

METHODS

In this retrospective study, consecutive patients with non-classical ACM who underwent CMR from January 2011 to January 2022 were included. The pattern of LGE was categorized as no, non-ringlike, and ringlike LGE. The primary outcome was defined as the occurrence of sustained VA. Univariable and multivariable Cox regression analysis was used to evaluate the impact of LGE patterns on sustained VA and area under curve (AUC) was calculated for the incremental value of ringlike LGE.

RESULTS

A total of 73 patients were collected in the final cohort (mean age, 39.3 ± 14.4 years, 51 male), of whom 10 (13.7%) had no LGE, 33 (45.2%) had non-ringlike LGE, and 30 (41.1%) had ringlike LGE. There was no statistically significant difference in the 5-year risk score among the three groups (P = 0.190). During a median follow-up of 34 (13-56) months, 34 (46.6%) patients experienced sustained VA, including 1 (10.0%), 13 (39.4%) and 20 (66.7%) of patients with no, non-ringlike and ringlike LGE, respectively. After multivariable adjustment, ringlike LGE remained independently associated with the presence of sustained VA (adjusted hazard ratio: 6.91, 95% confidence intervals: 1.89-54.60; P = 0.036). Adding ringlike LGE to the 2019 ARVC risk model showed significantly incremental prognostic value for sustained VA (AUC: 0.80 vs. 0.67; P = 0.024).

CONCLUSION

Ringlike LGE provides independent and incremental prognostic value over the 2019 ARVC risk model in patients with non-classical ACM.

The added value of abnormal regional myocardial function for risk prediction in arrhythmogenic right ventricular cardiomyopathy

AIMS

A risk calculator for individualized prediction of first-time sustained ventricular arrhythmia (VA) in arrhythmogenic right ventricular cardiomyopathy (ARVC) patients has recently been developed and validated (www.ARVCrisk.com). This study aimed to investigate whether regional functional abnormalities, measured by echocardiographic deformation imaging, can provide additional prognostic value.

METHODS AND RESULTS

From two referral centres, 150 consecutive patients with a definite ARVC diagnosis, no prior sustained VA, and an echocardiogram suitable for deformation analysis were included (aged 41 ± 17 years, 50% female). During a median follow-up of 6.3 (interquartile range 3.1-9.8) years, 37 (25%) experienced a first-time sustained VA. All tested left and right ventricular (LV and RV) deformation parameters were univariate predictors for first-time VA. While LV function did not add predictive value in multivariate analysis, two RV deformation parameters did; RV free wall longitudinal strain and regional RV deformation patterns remained independent predictors after adjusting for the calculator-predicted risk [hazard ratio 1.07 (95% CI 1.02-1.11); P = 0.004 and 4.45 (95% CI 1.07-18.57); P = 0.040, respectively] and improved its discriminative value (from C-statistic 0.78 to 0.82 in both; Akaike information criterion change > 2). Importantly, all patients who experienced VA within 5 years from the echocardiographic assessment had abnormal regional RV deformation patterns at baseline.

CONCLUSIONS

This study showed that regional functional abnormalities measured by echocardiographic deformation imaging can further refine personalized arrhythmic risk prediction when added to the ARVC risk calculator. The excellent negative predictive value of normal RV deformation could support clinicians considering the timing of implantable cardioverter defibrillator implantation in patients with intermediate arrhythmic risk.

Value of cardiac magnetic resonance on the risk stratification of cardiomyopathies

Cardiomyopathies represent a diverse group of heart muscle diseases with varying etiologies, presenting a diagnostic challenge due to their heterogeneous manifestations. Regular evaluation using cardiac imaging techniques is imperative as symptoms can evolve over time. These imaging approaches are pivotal for accurate diagnosis, treatment planning, and optimizing prognostic outcomes. Among these, cardiovascular magnetic resonance (CMR) stands out for its ability to provide precise anatomical and functional assessments. This manuscript explores the significant contributions of CMR in the diagnosis and management of patients with cardiomyopathies, with special attention to risk stratification. CMR's high spatial resolution and tissue characterization capabilities enable early detection and differentiation of various cardiomyopathy subtypes. Additionally, it offers valuable insights into myocardial fibrosis, tissue viability, and left ventricular function, crucial parameters for risk stratification and predicting adverse cardiac events. By integrating CMR into clinical practice, clinicians can tailor patient-specific treatment plans, implement timely interventions, and optimize long-term prognosis. The non-invasive nature of CMR reduces the need for invasive procedures, minimizing patient discomfort. This review highlights the vital role of CMR in monitoring disease progression, guiding treatment decisions, and identifying potential complications in patients with cardiomyopathies. The utilization of CMR has significantly advanced our understanding and management of these complex cardiac conditions, leading to improved patient outcomes and a more personalized approach to care.

Myocarditis as a trigger for the expression of biventricular arrhythmogenic cardiomyopathy in desmosomal gene mutation

Arrhythmogenic-cardiomyopathy (ACM) is an inherited heart disease with right, left, or biventricular (BVACM) involvement based on EKG, imaging, family history, and genetic testing. We present a 64-year-old woman with prior myocarditis and diagnosis of BVACM 29 years later. We propose myocarditis as a promoter of gene expression of plakophilin-2 mutation.

Nomogram for predicting cardiac death and heart transplantation in arrhythmogenic right ventricular cardiomyopathy

AIMS

In this study, we aimed to develop and validate a competing risk nomogram for predicting cardiac death and heart transplantation (HT) in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC).

METHODS

We retrospectively enrolled 149 consecutive patients with ARVC diagnosed at our institution between 2008 and 2022. Cox proportional hazards model was primarily used to identify variables associated with cardiac death and HT. On the basis of these indicators, a competing risk nomogram was developed to predict the 1, 3, and 5 year probabilities of cardiac death and HT. The area under the receiver operating characteristic curve (AUC), Harrell's C-index, and calibration curves were used to evaluate and internally validate the performance of the model. Decision curve analysis was performed to assess the clinical utility of the nomogram.

RESULT

Of the 149 patients with ARVC, the mean age was 38.77 ± 15.94 years, and most of the patients were men (67.11%, 100/149). Fourteen patients experienced cardiac death and nine underwent HT, during a median follow-up period of 5.8 years (interquartile range, 0.62-5.56 years). Multivariable COX analysis revealed that extent of TWI in the anterior and inferior leads (P = 0.0057), right atrial diameter on transthoracic echocardiography (P = 0.0498), RVEF (P = 0.1036), and LVEF (P < 0.001) all showed statistical significance. The 1-, 3-, and 5-year cumulative incidence of cardiac death and HT were 3.35%, 8.05%, and 11.4%, respectively. The area under the receiver operating characteristic curve of the nomogram for predicting cardiac death and HT at 1, 3, and 5 years after diagnosis of ARVC were 0.860, 0.935, and 0.956. The value of Harrell's C-index is 0.9273 (95% confidence interval 0.8954-0.9590; P < 0.001), indicating that the model had good discriminative ability in internal validation. Decision curve analysis revealed that our model was clinically useful within the entire range of potential treatment thresholds in most cases. The cumulative incidence of the primary outcomes was significantly different between the three risk groups according to nomogram-derived scores (P < 0.001).

CONCLUSIONS

On the basis of a retrospective review of patients with ARVC at a single centre, we developed a novel nomogram for predicting the risk of cardiac death and HT after ARVC diagnosis. This competing risk nomogram based on four readily available clinical parameters (right atrial diameter, right and left ventricular ejection fraction, and T-wave inversion) is a potentially useful tool for individualized prognostic assessment in patients with ARVC.

Prevention of Sudden Death and Management of Ventricular Arrhythmias in Arrhythmogenic Cardiomyopathy

Arrhythmogenic cardiomyopathy is an umbrella term for a group of inherited diseases of the cardiac muscle characterized by progressive fibro-fatty replacement of the myocardium. As suggested by the name, the disease confers electrical instability to the heart and increases the risk of the development of life-threatening arrhythmias, representing one of the leading causes of sudden cardiac death (SCD), especially in young athletes. In this review, the authors review the current knowledge of the disease, highlighting the state-of-the-art approaches to the prevention of the occurrence of SCD.

Personalized Management of Sudden Death Risk in Primary Cardiomyopathies: From Clinical Evaluation and Multimodality Imaging to Ablation and Cardioverter-Defibrillator Implant

Sudden cardiac death represents the leading cause of death worldwide; although the majority of sudden deaths occur in an elderly population with coronary artery disease, some occur in young and otherwise healthy individuals, as is the case of cardiomyopathies. The aim of the present review is to provide a stepwise hierarchical approach for the global sudden death risk estimation in primary cardiomyopathies. Each individual risk factor is analyzed for its contribution to the overall risk of sudden death for each specific cardiomyopathy as well as across all primary myocardial diseases. This stepwise hierarchical and personalized approach starts from the clinical evaluation, subsequently passes through the role of electrocardiographic monitoring and multimodality imaging, and finally concludes with genetic evaluation and electro-anatomical mapping. In fact, the sudden cardiac death risk assessment in cardiomyopathies depends on a multiparametric approach. Moreover, current indications for ventricular arrhythmia ablation and defibrillator implantation are discussed.

Machine learning of electrophysiological signals for the prediction of ventricular arrhythmias: systematic review and examination of heterogeneity between studies

BACKGROUND

Ventricular arrhythmia (VA) precipitating sudden cardiac arrest (SCD) is among the most frequent causes of death and pose a high burden on public health systems worldwide. The increasing availability of electrophysiological signals collected through conventional methods (e.g. electrocardiography (ECG)) and digital health technologies (e.g. wearable devices) in combination with novel predictive analytics using machine learning (ML) and deep learning (DL) hold potential for personalised predictions of arrhythmic events.

METHODS

This systematic review and exploratory meta-analysis assesses the state-of-the-art of ML/DL models of electrophysiological signals for personalised prediction of malignant VA or SCD, and studies potential causes of bias (PROSPERO, reference: CRD42021283464). Five electronic databases were searched to identify eligible studies. Pooled estimates of the diagnostic odds ratio (DOR) and summary area under the curve (AUROC) were calculated. Meta-analyses were performed separately for studies using publicly available, ad-hoc datasets, versus targeted clinical data acquisition. Studies were scored on risk of bias by the PROBAST tool.

FINDINGS

2194 studies were identified of which 46 were included in the systematic review and 32 in the meta-analysis. Pooling of individual models demonstrated a summary AUROC of 0.856 (95% CI 0.755-0.909) for short-term (time-to-event up to 72 h) prediction and AUROC of 0.876 (95% CI 0.642-0.980) for long-term prediction (time-to-event up to years). While models developed on ad-hoc sets had higher pooled performance (AUROC 0.919, 95% CI 0.867-0.952), they had a high risk of bias related to the re-use and overlap of small ad-hoc datasets, choices of ML tool and a lack of external model validation.

INTERPRETATION

ML and DL models appear to accurately predict malignant VA and SCD. However, wide heterogeneity between studies, in part due to small ad-hoc datasets and choice of ML model, may reduce the ability to generalise and should be addressed in future studies.

FUNDING

This publication is part of the project DEEP RISK ICD (with project number 452019308) of the research programme Rubicon which is (partly) financed by the Dutch Research Council (NWO). This research is partly funded by the Amsterdam Cardiovascular Sciences (personal grant F.V.Y.T).

Programmed Ventricular Stimulation as an Additional Primary Prevention Risk Stratification Tool in Arrhythmogenic Right Ventricular Cardiomyopathy: A Multinational Study

BACKGROUND

A novel risk calculator based on clinical characteristics and noninvasive tests that predicts the onset of clinical sustained ventricular arrhythmias (VA) in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) has been proposed and validated by recent studies. It remains unknown whether programmed ventricular stimulation (PVS) provides additional prognostic value.

METHODS

All patients with a definite ARVC diagnosis, no history of sustained VAs at diagnosis, and PVS performed at baseline were extracted from 6 international ARVC registries. The calculator-predicted risk for sustained VA (sustained or implantable cardioverter defibrillator treated ventricular tachycardia [VT] or fibrillation, [aborted] sudden cardiac arrest) was assessed in all patients. Independent and combined performance of the risk calculator and PVS on sustained VA were assessed during a 5-year follow-up period.

RESULTS

Two hundred eighty-eight patients (41.0±14.5 years, 55.9% male, right ventricular ejection fraction 42.5±11.1%) were enrolled. At PVS, 137 (47.6%) patients had inducible ventricular tachycardia. During a median of 5.31 [2.89-10.17] years of follow-up, 83 (60.6%) patients with a positive PVS and 37 (24.5%) with a negative PVS experienced sustained VA (P<0.001). Inducible ventricular tachycardia predicted clinical sustained VA during the 5-year follow-up and remained an independent predictor after accounting for the calculator-predicted risk (HR, 2.52 [1.58-4.02]; P<0.001). Compared with ARVC risk calculator predictions in isolation (C-statistic 0.72), addition of PVS inducibility showed improved prediction of VA events (C-statistic 0.75; log-likelihood ratio for nested models, P<0.001). PVS inducibility had a 76% [67-84] sensitivity and 68% [61-74] specificity, corresponding to log-likelihood ratios of 2.3 and 0.36 for inducible (likelihood ratio+) and noninducible (likelihood ratio-) patients, respectively. In patients with a ARVC risk calculator-predicted risk of clinical VA events <25% during 5 years (ie, low/intermediate subgroup), PVS had a 92.6% negative predictive value.

CONCLUSIONS

PVS significantly improved risk stratification above and beyond the calculator-predicted risk of VA in a primary prevention cohort of patients with ARVC, mainly for patients considered to be at low and intermediate risk by the clinical risk calculator.

Importance of genotype for risk stratification in arrhythmogenic right ventricular cardiomyopathy using the 2019 ARVC risk calculator

AIMS

To study the impact of genotype on the performance of the 2019 risk model for arrhythmogenic right ventricular cardiomyopathy (ARVC).

METHODS AND RESULTS

The study cohort comprised 554 patients with a definite diagnosis of ARVC and no history of sustained ventricular arrhythmia (VA). During a median follow-up of 6.0 (3.1,12.5) years, 100 patients (18%) experienced the primary VA outcome (sustained ventricular tachycardia, appropriate implantable cardioverter defibrillator intervention, aborted sudden cardiac arrest, or sudden cardiac death) corresponding to an annual event rate of 2.6% [95% confidence interval (CI) 1.9-3.3]. Risk estimates for VA using the 2019 ARVC risk model showed reasonable discriminative ability but with overestimation of risk. The ARVC risk model was compared in four gene groups: PKP2 (n = 118, 21%); desmoplakin (DSP) (n = 79, 14%); other desmosomal (n = 59, 11%); and gene elusive (n = 160, 29%). Discrimination and calibration were highest for PKP2 and lowest for the gene-elusive group. Univariable analyses revealed the variable performance of individual clinical risk markers in the different gene groups, e.g. right ventricular dimensions and systolic function are significant risk markers in PKP2 but not in DSP patients and the opposite is true for left ventricular systolic function.

CONCLUSION

The 2019 ARVC risk model performs reasonably well in gene-positive ARVC (particularly for PKP2) but is more limited in gene-elusive patients. Genotype should be included in future risk models for ARVC.

Novel Risk Prediction Model to Determine Adverse Heart Failure Outcomes in Arrhythmogenic Right Ventricular Cardiomyopathy

Background

Patients with arrhythmogenic right ventricular cardiomyopathy are at risk for life‐threatening ventricular tachyarrhythmias, but progressive heart failure (HF) may occur in later stages of disease. This study aimed to characterize potential risk predictors and develop a model for individualized assessment of adverse HF outcomes in arrhythmogenic right ventricular cardiomyopathy.

Methods and Results

Longitudinal and observational cohorts with 290 patients with arrhythmogenic right ventricular cardiomyopathy from the Fuwai Hospital in Beijing, China, and 99 patients from the University Heart Center in Zurich, Switzerland, with follow‐up data were studied. The primary end point of the study was heart transplantation or death attributable to HF. The model was developed by Cox regression analysis for predicting risk and was internally validated. During 4.92±3.03 years of follow‐up, 48 patients reached the primary end point. The determinants of the risk prediction model were left ventricular ejection fraction, serum creatinine levels, moderate‐to‐severe tricuspid regurgitation, and atrial fibrillation. Implantable cardioverter‐defibrillators did not reduce the occurrence of adverse HF outcomes.

Conclusions

A novel risk prediction model for arrhythmogenic right ventricular cardiomyopathy has been developed using 2 large and well‐established cohorts, incorporating common clinical parameters such as left ventricular ejection fraction, serum creatinine levels, tricuspid regurgitation, and atrial fibrillation, which can identify patients who are at risk for terminal HF events, and may guide physicians to assess individualized HF risk and to optimize management strategies.

Arrhythmic risk prediction in arrhythmogenic right ventricular cardiomyopathy: external validation of the arrhythmogenic right ventricular cardiomyopathy risk calculator

AIMS

Arrhythmogenic right ventricular cardiomyopathy (ARVC) causes ventricular arrhythmias (VAs) and sudden cardiac death (SCD). In 2019, a risk prediction model that estimates the 5-year risk of incident VAs in ARVC was developed (ARVCrisk.com). This study aimed to externally validate this prediction model in a large international multicentre cohort and to compare its performance with the risk factor approach recommended for implantable cardioverter-defibrillator (ICD) use by published guidelines and expert consensus.

METHODS AND RESULTS

In a retrospective cohort of 429 individuals from 29 centres in North America and Europe, 103 (24%) experienced sustained VA during a median follow-up of 5.02 (2.05-7.90) years following diagnosis of ARVC. External validation yielded good discrimination [C-index of 0.70 (95% confidence interval-CI 0.65-0.75)] and calibration slope of 1.01 (95% CI 0.99-1.03). Compared with the three published consensus-based decision algorithms for ICD use in ARVC (Heart Rhythm Society consensus on arrhythmogenic cardiomyopathy, International Task Force consensus statement on the treatment of ARVC, and American Heart Association guidelines for VA and SCD), the risk calculator performed better with a superior net clinical benefit below risk threshold of 35%.

CONCLUSION

Using a large independent cohort of patients, this study shows that the ARVC risk model provides good prognostic information and outperforms other published decision algorithms for ICD use. These findings support the use of the model to facilitate shared decision making regarding ICD implantation in the primary prevention of SCD in ARVC.

Arrhythmogenic Right Ventricular Cardiomyopathy Prevalence and Arrhythmic Outcomes in At-Risk Family Members: A Systematic Review and Meta-Analysis

Background:

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a complex cardiomyopathy with autosomal dominant inheritance and age-related incomplete penetrance, characterized by a high risk of sudden cardiac death. Recent professional consensus guidelines recommend clinical cardiac lifelong serial screening for at-risk family members refined only by age, but family genotype might influence necessary screening. Although numerous studies report prevalence of disease and arrhythmia in family members and explore predictors of penetrance and arrhythmic risk, a systematic review consolidating this evidence is lacking.

Methods:

We searched Medline (PubMed), Embase, The Cochrane Library, and Web of Science for studies that reported prevalence of (1) diagnosis of ARVC per 2010 Task Force Criteria and/or (2) sustained ventricular arrhythmias (VA) in at least 10 family members of definite patients with ARVC.

Results:

We identified 41 studies, including 36 that reported diagnosis by Task Force Criteria and 22 VA. Meta-analysis of 1359 family members, from 13 unique cohorts showed an average prevalence estimate of 25% for diagnosis as per Task Force Criteria (95% CI, 0.15–0.35, I 2 = 96.44%). Overall prevalence of VA among gene-positive family members was 18% (95% CI, 0.13–0.23, I 2 =33.25%) in 7 independent studies (n=597). Family genotype was a significant risk factor for diagnosis of both ARVC (odds ratio, 6.91 [95% CI, 1.27–37.70]; P =0.0005) and VA (odds ratio, 13.62 [95% CI, 0.91–204.13]; P =0.06). Male gender was not associated with disease prevalence (odds ratio, 1.18 [95% CI, 0.72–1.95]; P =0.42) or VA (odds ratio, 0.81 [95% CI, 0.51–1.29]; P =0.91).

Conclusions:

The prevalence of ARVC and VA in at-risk family members differs significantly based on family genotype. Although recent recommendations provide a guideline based only on age, we propose screening every 1 to 2 years for gene-positive family members and every 3 to 5 years for first-degree relatives of gene-elusive cases, as long as they are asymptomatic and not athletes.

New Variant in Placophilin-2 Gene Causing Arrhythmogenic Myocardiopathy

Introduction: Arrhythmogenic cardiomyopathy (ACM) is an inherited disease characterized by progressive fibroadipose replacement of cardiomyocytes. Its diagnosis is based on imaging, electrocardiographic, histological and genetic/familial criteria. The development of the disease is based mainly on desmosomal genes. Knowledge of the phenotypic expression of each of these genes will help in both diagnosis and prognosis. The objective of this study is to describe the genotype–phenotype association of an unknown PKP2 gene variant in a family diagnosed with ACM. Methods: Clinical and genetic study of a big family carrying the p.Tyr168* variant in the PKP2 gene, in order to demonstrate pathogenicity of this variant, causing ACM. Results: Twenty-two patients (proband and relatives) were evaluated. This variant presented with high arrhythmic load at an early age, but without evidence of structural heart disease after 20 years of follow-up, with low risk in predictive scores. We demonstrate evidence of its pathogenicity. Conclusions: The p.Tyr168* variant in the PKP2 gene causes ACM with a high arrhythmic load and with an absence of structural heart disease. This fact emphasizes the value of knowing the phenotypic expression of each variant.

A new prediction model for ventricular arrhythmias in arrhythmogenic right ventricular cardiomyopathy

AIMS

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVC) is characterized by ventricular arrhythmias (VAs) and sudden cardiac death (SCD). We aimed to develop a model for individualized prediction of incident VA/SCD in ARVC patients.

METHODS AND RESULTS

Five hundred and twenty-eight patients with a definite diagnosis and no history of sustained VAs/SCD at baseline, aged 38.2 ± 15.5 years, 44.7% male, were enrolled from five registries in North America and Europe. Over 4.83 (interquartile range 2.44-9.33) years of follow-up, 146 (27.7%) experienced sustained VA, defined as SCD, aborted SCD, sustained ventricular tachycardia, or appropriate implantable cardioverter-defibrillator (ICD) therapy. A prediction model estimating annual VA risk was developed using Cox regression with internal validation. Eight potential predictors were pre-specified: age, sex, cardiac syncope in the prior 6 months, non-sustained ventricular tachycardia, number of premature ventricular complexes in 24 h, number of leads with T-wave inversion, and right and left ventricular ejection fractions (LVEFs). All except LVEF were retained in the final model. The model accurately distinguished patients with and without events, with an optimism-corrected C-index of 0.77 [95% confidence interval (CI) 0.73-0.81] and minimal over-optimism [calibration slope of 0.93 (95% CI 0.92-0.95)]. By decision curve analysis, the clinical benefit of the model was superior to a current consensus-based ICD placement algorithm with a 20.3% reduction of ICD placements with the same proportion of protected patients (P < 0.001).

CONCLUSION

Using the largest cohort of patients with ARVC and no prior VA, a prediction model using readily available clinical parameters was devised to estimate VA risk and guide decisions regarding primary prevention ICDs (www.arvcrisk.com).

Incidence and predictors of sudden cardiac death in arrhythmogenic right ventricular cardiomyopathy: a pooled analysis

AIMS

Arrhythmogenic right ventricular cardiomyopathy (ARVC), an inherited heart muscle abnormality, is a major cause of sudden cardiac death (SCD). However, the burden of SCD and risk factors in ARVC are not clearly described. Thus, we estimated the rates and predictors of SCD in ARVC in a meta-analysis.

METHODS AND RESULTS

PubMed, Embase, and Web of Science were searched through 7 April 2021. Prospective studies reporting SCD from ARVC cohorts were included. Data were independently extracted by two reviewers and pooled in a random-effects meta-analysis. Fifty-two studies (n = 5485 patients) with moderate-to-low risk of bias were included. The pooled annualized rates of SCD were 0.65 per 1000 [95% confidence interval 0.00-6.43, I2 0.00%] in those with an implantable cardioverter-defibrillator (ICD) and 7.21 (2.38-13.79, I2 0.0%) in non-ICD cohorts: 7.14 in probands and 8.44 for 2010 Task Force Criteria (TFC). Multivariable predictors of life-threatening arrhythmic events including SCD were: age at presentation [adjusted hazard ratio 0.98 (0.97-0.99)], male sex [2.08 (1.29-3.36)], right ventricular (RV) dysfunction [6.99 (2.17-22.49)], QRS fragmentation [6.55 (3.33-12.90)], T-wave inversion [1.12 (1.02-1.24)], syncope at presentation [2.83 (2.40-4.08)], previous non-sustained ventricular tachyarrhythmia [2.53 (1.44-4.45)], and the TFC score [1.96 (1.02-3.76)], (P < 0.05). Predictors of appropriate ICD therapy were RV dysfunction, syncope, and inducible ventricular arrhythmia (P < 0.01).

CONCLUSION

This meta-analysis demonstrates a high burden of SCD in ARVC patients, especially among probands and ARVC defined by the modified TFC. Better strategies are required to improve patient management and prevent SCD in ARVC. PROSPERO ID: CRD42020211761.

Recent Non-Invasive Parameters to Identify Subjects at High Risk of Sudden Cardiac Death

Cardiovascular diseases remain among the leading causes of death worldwide and sudden cardiac death (SCD) accounts for ~25% of these deaths. Despite its epidemiologic relevance, there are very few diagnostic strategies available useful to prevent SCD mainly focused on patients already affected by specific cardiovascular diseases. Unfortunately, most of these parameters exhibit poor positive predictive accuracy. Moreover, there is also a need to identify parameters to stratify the risk of SCD among otherwise healthy subjects. This review aims to provide an update on the most relevant non-invasive diagnostic features to identify patients at higher risk of developing malignant ventricular arrhythmias and SCD.

Clinical Characteristics and Follow-Up of Pediatric-Onset Arrhythmogenic Right Ventricular Cardiomyopathy

OBJECTIVES

The goal of this study was to describe characteristics, cascade screening results, and predictors of adverse outcome in pediatric-onset arrhythmogenic right ventricular cardiomyopathy (ARVC).

BACKGROUND

Although ARVC is increasingly recognized in children, pediatric ARVC cohorts remain underrepresented in the literature.

METHODS

This study included 12 probands with pediatric-onset ARVC (aged <18 years at diagnosis) and 68 pediatric relatives (aged <18 years at first evaluation) referred for cascade screening. ARVC diagnosis was based on 2010 Task Force Criteria. Clinical presentation, diagnostic testing, and outcomes (sustained ventricular tachycardia [VT]; heart failure) were ascertained. Predictors of adverse outcome were determined by using univariable logistic regression.

RESULTS

Pediatric-onset ARVC was diagnosed in 12 probands and 12 (18%) relatives at a median age of 16.6 years (interquartile range: 13.8-17.4 years), whereas 12 (18%) relatives reached ARVC diagnosis as adults (median age, 22.0 years; interquartile range: 20.0-26.7 years). Sudden cardiac death/arrest was the first disease manifestation in 3 (25%) probands and 3 (4%) relatives. In patients without ARVC diagnosis at presentation (n = 61), electrocardiogram and Holter monitoring abnormalities occurred before development of imaging Task Force Criteria (7.3 ± 5.0 years vs 8.4 ± 5.0 years). Clinical course was characterized by sustained VT (91%) and heart failure (36%) in probands, which were rare in relatives (2% and 0%, respectively). Male sex (P < 0.01), T-wave inversion V₁-V₃ (P < 0.01), premature ventricular complexes/runs (P ≤ 0.01), and decrease in biventricular ejection fraction (P ≤ 0.01) were associated with VT occurrence.

CONCLUSIONS

Pediatric ARVC carries high arrhythmic risk, especially in probands. Disease progression is particularly observed on electrocardiogram or Holter monitoring. Arrhythmic events are associated with male sex, T-wave inversions, premature ventricular complexes/runs, and reduced biventricular ejection fraction.

Comparing clinical performance of current implantable cardioverter-defibrillator implantation recommendations in arrhythmogenic right ventricular cardiomyopathy

AIMS

Arrhythmogenic right ventricular cardiomyopathy (ARVC) patients have an increased risk of ventricular arrhythmias (VA). Four implantable cardioverter-defibrillator (ICD) recommendation algorithms are available The International Task Force Consensus ('ITFC'), an ITFC modification by Orgeron et al. ('mITFC'), the AHA/HRS/ACC guideline for VA management ('AHA'), and the HRS expert consensus statement ('HRS'). This study aims to validate and compare the performance of these algorithms in ARVC.

METHODS AND RESULTS

We classified 617 definite ARVC patients (38.5 ± 15.1 years, 52.4% male, 39.2% prior sustained VA) according to four algorithms. Clinical performance was evaluated by sensitivity, specificity, ROC-analysis, and decision curve analysis for any sustained VA and for fast VA (>250 b.p.m.). During 6.4 [2.8-11.5] years follow-up, 282 (45.7%) patients experienced any sustained VA, and 63 (10.2%) fast VA. For any sustained VA, ITFC and mITFC provide higher sensitivity than AHA and HRS (94.0-97.8% vs. 76.7-83.5%), but lower specificity (15.9-32.0% vs. 42.7%-60.1%). Similarly, for fast VA, ITFC and mITFC provide higher sensitivity than AHA and HRS (95.2-97.1% vs. 76.7-78.4%) but lower specificity (42.7-43.1 vs. 76.7-78.4%). Decision curve analysis showed ITFC and mITFC to be superior for a 5-year sustained VA risk ICD indication threshold between 5-25% or 2-9% for fast VA.

CONCLUSION

The ITFC and mITFC provide the highest protection rates, whereas AHA and HRS decrease unnecessary ICD placements. ITFC or mITFC should be used if we consider the 5-year threshold for ICD indication to lie within 5-25% for sustained VA or 2-9% for fast VA. These data will inform decision-making for ICD placement in ARVC.

Running the Risk: Exercise and Arrhythmogenic Cardiomyopathy

Purpose of review

The purpose of this review is to summarize what is known about the relationship between exercise and arrhythmogenic right ventricular cardiomyopathy (ARVC) with regard to disease onset, diagnosis, progression, and clinical severity. This relationship forms the basis of the management recommendations for restricting physical activity in individuals with and at risk for ARVC.

Recent findings

While ARVC can be challenging to diagnose, there are several diagnostic testing and imaging modalities that may help distinguish athletic heart remodeling from ARVC. There is an increased risk of adverse clinical outcomes in ARVC from endurance and competitive sports participation, including a dose-dependent relationship between exercise intensity and risk of disease penetrance and progression.

Summary

High-intensity exercise can lead to earlier disease onset, increased penetrance, and clinical progression among individuals with and at risk for ARVC. Both amount and intensity of exercise are correlated with adverse outcomes, including ventricular arrhythmias and worsening biventricular function. All individuals with and at risk for ARVC should undergo detailed clinical phenotyping and risk stratification to reduce the risk of such outcomes, including sudden cardiac death. Consensus guidelines recommend against participation in competitive or high-intensity and endurance exercise for individuals with and at risk for ARVC.

Clinical and genetic features of arrhythmogenic cardiomyopathy: diagnosis, management and the heart failure perspective

Background

Arrhythmogenic cardiomyopathy (ACM) is an emerging new concept of a life-threatening heart muscle disorder due not only to desmosome gene mutations, but also to non-desmosome genes, such as filamin C, lamin A/C, phospholamban, transmembrane protein 43, titin, SCN5A and RNA binding motif protein 20.Multi-modality imaging along with genetic testing are important tools for risk stratification to tailor treatment to a single patient. Cardiac magnetic resonance imaging (CMR) with late gadolinium enhancement (LGE) is the gold standard for evaluating left and right ventricular structure and function, edema, and fibrosis. The identification of regional fibrosis with LGE has prognostic value. The management of ACM involves several aspects: treatment of arrhythmias and heart failure, risk stratification, implantable cardioverter-defibrillator (ICD) placement, exercise restrictions, and life-style changes. The decision for ICD placement in ACM patients is not well established and should be made weighing risks and benefits. However, the presence of specific genotypes can allow a precision medicine approach. In ACM patients with only mild left ventricular dysfunction but phospholamban, filamin C or lamin A/C mutations, an ICD is now considered a reasonable approach.

Aim of Review

We sought to provide an overview of clinical and genetic feature of arrhythmogenic cardiomyopathy providing epidemiology, imaging, diagnostic and treatment information, using a systematic genetic approach.

Arrhythmogenic right ventricular cardiomyopathy in the pediatric population

PURPOSE OF REVIEW

Review the current state of the art of arrhythmogenic right ventricular cardiomyopathy (ARVC) diagnosis and risk stratification in the pediatric population.

RECENT FINDINGS

ARVC is an inherited cardiomyopathy characterized by progressive myocyte loss and fibrofatty replacement of predominantly the right ventricle and high risk of ventricular arrhythmias and sudden cardiac death (SCD). ARVC is one of the leading causes of arrhythmic cardiac arrest in young people. Early diagnosis and accurate risk assessment are challenging, especially in children who often exhibit little to no phenotype, even if genotype positive. Multimodal imaging provides more detailed assessment of the right ventricle and has been shown in pediatric patients to identify earlier preclinical disease expression. Identification of patients with ARVC allows the clinician to intervene early with appropriate exercise restrictions, even if genotype positive only without phenotypic expression. Emphasis should be placed on stratifying the patient's risk of ventricular arrhythmias and SCD.

SUMMARY

ARVC is a challenging diagnosis to make in adolescents who often do not exhibit clinical symptoms. Newer multimodal imaging techniques and improvements in genetic testing and biomarkers should help improve early diagnosis. Exercise restriction for children with ARVC has been shown to reduce disease advancement and decreases the risk of a life-threatening event.

Angiotensin-Converting Enzyme Inhibitors/Angiotensin Receptor Blockers: Anti-arrhythmic Drug for Arrhythmogenic Right Ventricular Cardiomyopathy

Background: Current treatment guidelines for arrhythmogenic right ventricular cardiomyopathy (ARVC) mainly emphasize on prevention of ventricular arrhythmic events. Despite the progressive nature of ARVC, therapeutic options focusing on decelerating disease progression are scarce.

Methods and Results: This retrospective observational cohort study included 311 patients [age, 39.1 ± 14.4 years; male, 233 (74.9%)] with a definite diagnosis of ARVC as determined by the 2010 Task Force Diagnostic Criteria. Among them, 113 patients (36.3%) received ACEI/ARB treatment. Disease progression was evaluated according to repeat transthoracic echocardiograms with a linear mixed model. Patients receiving ACEI/ARB treatment were associated with slower disease progression reflected by a gradual decrease in tricuspid annular plane systolic excursion than those not receiving ACEI/ARB treatment (0.37 vs. 0.61 mm per year decrease, P < 0.001) and slower dilation of right ventricular outflow tract (0.57 vs. 1.06 mm per year increased, P = 0.003). Cox proportional hazard regression models were used to evaluate the association between life-threatening ventricular tachycardia events and ACEI/ARB treatment. A reduced risk of life-threatening ventricular arrhythmia was associated with ACEI/ARB treatment compared to that without ACEI/ARB treatment (adjusted HR: 0.71, 95% CI: 0.52–0.96, P = 0.031).

Conclusions: ACEI/ARB treatment is associated with slower disease progression and lower risk of life-threatening ventricular arrhythmia in patients with ARVC. Delaying disease progression may pave way for reducing life-threatening ventricular arrhythmia risk.

Heart Failure in Patients with Arrhythmogenic Cardiomyopathy

Arrhythmogenic cardiomyopathy (ACM) is a rare inherited cardiomyopathy characterized as fibro-fatty replacement, and a common cause for sudden cardiac death in young athletes. Development of heart failure (HF) has been an under-recognized complication of ACM for a long time. The current clinical management guidelines for HF in ACM progression have nowadays been updated. Thus, a comprehensive review for this great achievement in our understanding of HF in ACM is necessary. In this review, we aim to describe the research progress on epidemiology, clinical characteristics, risk stratification and therapeutics of HF in ACM.

Insights Into Genetics and Pathophysiology of Arrhythmogenic Cardiomyopathy

Purpose of Review

Arrhythmogenic cardiomyopathy (ACM) is a genetic disease characterized by life-threatening ventricular arrhythmias and sudden cardiac death (SCD) in apparently healthy young adults. Mutations in genes encoding for cellular junctions can be found in about half of the patients. However, disease onset and severity, risk of arrhythmias, and outcome are highly variable and drug-targeted treatment is currently unavailable.

Recent Findings

This review focuses on advances in clinical risk stratification, genetic etiology, and pathophysiological concepts. The desmosome is the central part of the disease, but other intercalated disc and associated structural proteins not only broaden the genetic spectrum but also provide novel molecular and cellular insights into the pathogenesis of ACM. Signaling pathways and the role of inflammation will be discussed and targets for novel therapeutic approaches outlined.

Summary

Genetic discoveries and experimental-driven preclinical research contributed significantly to the understanding of ACM towards mutation- and pathway-specific personalized medicine.

Arrhythmogenic cardiomyopathy: pathogenesis, pro-arrhythmic remodelling, and novel approaches for risk stratification and therapy

Arrhythmogenic cardiomyopathy (ACM) is a life-threatening cardiac disease caused by mutations in genes predominantly encoding for desmosomal proteins that lead to alterations in the molecular composition of the intercalated disc. ACM is characterized by progressive replacement of cardiomyocytes by fibrofatty tissue, ventricular dilatation, cardiac dysfunction, and heart failure but mostly dominated by the occurrence of life-threatening arrhythmias and sudden cardiac death (SCD). As SCD appears mostly in apparently healthy young individuals, there is a demand for better risk stratification of suspected ACM mutation carriers. Moreover, disease severity, progression, and outcome are highly variable in patients with ACM. In this review, we discuss the aetiology of ACM with a focus on pro-arrhythmic disease mechanisms in the early concealed phase of the disease. We summarize potential new biomarkers which might be useful for risk stratification and prediction of disease course. Finally, we explore novel therapeutic strategies to prevent arrhythmias and SCD in the early stages of ACM.

Desmoplakin cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy: two distinct forms of cardiomyopathy?

The confirmation of a hypothesis that desmoplakin-related (DSP) cardiomyopathy could represent a distinct clinical entity from the classical, RV-dominant, form of arrhythmogenic cardiomyopathy (ACM), most frequently caused by PKP2 mutations, would without any shadow of doubt signify a turning point in the history of this disease. The concept of gene-specific diseases underneath the umbrella diagnosis of ACM would bring fundamental changes not only in the clinical, diagnostic and therapeutic approach, but also in terms of risk stratification, pushing the scientific community towards a more patient-centred view of the disease, similarly to what has already been done in other inherited arrhythmogenic disease (e.g., Long QT Syndrome; LQTS). We provide a state-of-the-art review, starting with a brief historical framework to give the necessary context and better focus the question. Then, we proceed with a novel, genotype-tophenotype-based comparison of the most important aspects of DSP-related cardiomyopathy with the classical, RV-dominant ACM: this allows us to ascertain not only that the differences between the forms exist, but are also clinically relevant and actionable, leading to the underrecognition of the atypical, DSP-related, LV-dominant forms when applying the current diagnostic criteria. These findings will usher an exciting era, in which the scientific community will try to answer a range of questions, starting from the reasons why different desmosomal mutations cause such different phenotypes.

Prediction of ventricular arrhythmia in phospholamban p.Arg14del mutation carriers-reaching the frontiers of individual risk prediction

AIMS

This study aims to improve risk stratification for primary prevention implantable cardioverter defibrillator (ICD) implantation by developing a new mutation-specific prediction model for malignant ventricular arrhythmia (VA) in phospholamban (PLN) p.Arg14del mutation carriers. The proposed model is compared to an existing PLN risk model.

METHODS AND RESULTS

Data were collected from PLN p.Arg14del mutation carriers with no history of malignant VA at baseline, identified between 2009 and 2020. Malignant VA was defined as sustained VA, appropriate ICD intervention, or (aborted) sudden cardiac death. A prediction model was developed using Cox regression. The study cohort consisted of 679 PLN p.Arg14del mutation carriers, with a minority of index patients (17%) and male sex (43%), and a median age of 42 years [interquartile range (IQR) 27-55]. During a median follow-up of 4.3 years (IQR 1.7-7.4), 72 (10.6%) carriers experienced malignant VA. Significant predictors were left ventricular ejection fraction, premature ventricular contraction count/24 h, amount of negative T waves, and presence of low-voltage electrocardiogram. The multivariable model had an excellent discriminative ability {C-statistic 0.83 [95% confidence interval (CI) 0.78-0.88]}. Applying the existing PLN risk model to the complete cohort yielded a C-statistic of 0.68 (95% CI 0.61-0.75).

CONCLUSION

This new mutation-specific prediction model for individual VA risk in PLN p.Arg14del mutation carriers is superior to the existing PLN risk model, suggesting that risk prediction using mutation-specific phenotypic features can improve accuracy compared to a more generic approach.

Long-term follow-up analysis of a highly characterized arrhythmogenic cardiomyopathy cohort with classical and non-classical phenotypes-a real-world assessment of a novel prediction model: does the subtype really matter

AIMS

To provide long-term outcome data on arrhythmogenic cardiomyopathy (ACM) patients with non-classical forms [left dominant ACM (LD-ACM) and biventricular ACM (Bi-ACM)] and an external validation of a recently proposed algorithm for ventricular arrhythmia (VA) prediction in ACM patients.

METHODS AND RESULTS

Demographic, clinical, and outcome data were retrieved from all ACM patients encountered at our institution. Patients were classified according to disease phenotype (R-ACM; Bi-ACM; LD-ACM). Overall and by phenotype long-term survival were calculated; the novel Cadrin-Tourigny et al. algorithm was used to calculate the a priori predicted VA risk, and it was compared with the observed outcome to test its reliability. One hundred and one patients were enrolled; three subgroups were defined (R-ACM, n = 68; Bi-ACM, n = 14; LD-ACM, n = 19). Over a median of 5.41 (2.59-8.37) years, the non-classical form cohort experienced higher rates of VAs than the classical form [5-year freedom from VAs: 0.58 (0.43-0.78) vs. 0.76 (0.66-0.89), P = 0.04]. The Cadrin-Tourigny et al. predictive model adequately described the overall cohort risk [mean observed-predicted risk difference (O-PRD): +6.7 (-4.3, +17.7) %, P = 0.19]; strafing by subgroup, excellent goodness-of-fit was demonstrated for the R-ACM subgroup (mean O-PRD, P = 0.99), while in the Bi-ACM and LD-ACM ones the real observed risk appeared to be underestimated [mean O-PRD: -20.0 (-1.1, -38.9) %, P < 0.0001; -22.6 (-7.8, -37.5) %, P < 0.0001, respectively].

CONCLUSION

Non-classical ACM forms appear more prone to VAs than classical forms. The novel prediction model effectively predicted arrhythmic risk in the classical R-ACM cohort, but seemed to underestimate it in non-classical forms.

Arrhythmogenic right ventricular cardiomyopathy: a focused update on diagnosis and risk stratification

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy characterised by fibrofatty replacement of predominantly the right ventricle and high risk of ventricular arrhythmias and sudden cardiac death (SCD). Early diagnosis and accurate risk assessment are challenging yet essential for SCD prevention. This manuscript summarises the current state of the art on ARVC diagnosis and risk stratification. Improving the 2010 diagnostic criteria is an ongoing discussion. Several studies suggest that early diagnosis may be facilitated by including deformation imaging ('strain') for objective assessment of wall motion abnormalities, which was shown to have high sensitivity for preclinical disease. Adding fibrofatty replacement detected by late gadolinium enhancement or T1 mapping in cardiac MRI as criterion for diagnosis is increasingly suggested but requires more supporting evidence from consecutive patient cohorts. In addition to the traditional right-dominant ARVC, standard criteria for arrhythmogenic cardiomyopathy (ACM) and arrhythmogenic left ventricular cardiomyopathy (ALVC) are on the horizon. After diagnosis confirmation, the primary management goal is SCD prevention, for which an implantable cardioverter-defibrillator is the only proven therapy. Prior studies determined that younger age, male sex, previous (non-) sustained ventricular tachycardia, syncope, extent of T-wave inversion, frequent premature ectopic beats and lower biventricular ejection fraction are risk factors for subsequent events. Previous implantable cardioverter-defibrillator indication guidelines were however limited to three expert-opinion flow charts stratifying patients in risk groups. Now, two multivariable risk prediction models (arvcrisk.com) combine the abovementioned risk factors to estimate individual risks. Of note, both the flow charts and prediction models require clinical validation studies to determine which should be recommended.

Risk Stratification in Arrhythmogenic Right Ventricular Cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC), also called arrhythmogenic right ventricular dysplasia or arrhythmogenic cardiomyopathy, is a genetic disease characterised by progressive myocyte loss with replacement by fibrofatty tissue. This structural change leads to the prominent features of ARVC of ventricular arrhythmia and increased risk for sudden cardiac death (SCD). Emphasis should be placed on determining and stratifying the patient’s risk of ventricular arrhythmia and SCD. ICDs should be used to treat the former and prevent the latter, but ICDs are not benign interventions. ICDs come with their own complications in this overall young population of patients. This article reviews the literature regarding the factors that contribute to the assessment of risk stratification in ARVC patients.

Left ventricular involvement assessed by LGE-CMR in predicting the risk of adverse outcomes of arrhythmogenic cardiomyopathy with ICDs

BACKGROUND

Arrhythmogenic cardiomyopathy (ACM) is characterized by a high incidence of ventricular tachyarrhythmia and sudden death. Implantable cardioverter-defibrillator (ICD) implantation is the cornerstone of management.

OBJECTIVE

This study aims to reveal the prognostic value of the contrast-enhanced cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) amount in predicting varying lethal outcomes among ACM patients with ICDs.

METHODS

The 88 patients with definite ACM who were all referred for contrast-enhanced CMR received an ICD and were followed up for a median of 4.0 years.

RESULTS

Fifty-four patients had no left ventricular (LV) involvement and sixteen had an LV LGE amount > 15%. During the follow-up time, appropriate ICD therapy was seen in 57, electrical storm (ES) in 19, and cardiac death in 9 patients. Compared with those without LV involvement, patients with LV LGE amount > 15% had a higher risk of cardiac death (log-rank P = 0.021). LV LGE amount was associated with an increased risk of ICD therapy [adjusted hazard ratio (HR) 1.035, 95% confidence interval (CI) 1.008-1.062, P = 0.010], and cardiac death (adjusted HR 1.082, 95% 1.006-1.164, P = 0.034), independently of LV ejection fraction. LV LGE mass of >15% demonstrated an over 2-fold increase in ICD therapy (adjusted HR 2.180, 95%CI 1.058-4.488, P = 0.035) and an over 7-fold increase in cardiac death (unadjusted HR 7.198, 95%CI 1.399-37.043, P = 0.018) than those without LV involvement, respectively.

CONCLUSIONS

The LV LGE-CMR in ACM shows a dose-dependent association with ICD therapy and cardiac death. And LV LGE amount of >15% is a strong predictor.