Natural history and risk stratification of arrhythmogenic right ventricular dysplasia/cardiomyopathy

High risk of heart failure associated with desmoglein-2 mutations compared to plakophilin-2 mutations in arrhythmogenic right ventricular cardiomyopathy/dysplasia

BACKGROUND

Previous studies suggested that genetic status affects the clinical course of arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) patients. The aim of this study was to compare the outcome of desmoglein-2 (DSG2) mutation carriers to those who carry the plakophilin-2 (PKP2) mutation, the most common ARVC/D-associated gene.

METHODS AND RESULTS

Consecutive ARVC/D patients carrying a pathogenic mutation in PKP2 or DSG2 were selected from a national ARVC/D registry. The cumulative freedom from sustained ventricular arrhythmia and cardiac transplantation/death from heart failure (HF) during follow-up was assessed, compared between PKP2 and DSG2, and predictors for ventricular arrhythmia and HF events determined. Overall, 118 patients from 78 families were included: 27 (23%) carried a DSG2 mutation and 91 (77%) a PKP2 mutation. There were no significant differences between DSG2 and PKP2 mutation carriers concerning gender, proband status, age at diagnosis, T-wave inversion, or right ventricular dysfunction at baseline. DSG2 patients displayed more frequent epsilon wave (37% vs. 17%, P = 0.048) and left ventricular dysfunction at diagnosis (54% vs. 10%, P < 0.001). During a median follow-up of 5.6 years (2.5-16), DSG2 and PKP2 mutation carriers displayed a similar risk of sustained ventricular arrhythmia (log-rank P = 0.20), but DSG2 mutation carriers were at higher risk of transplantation/HF-related death (log-rank P < 0.001). The presence of a DSG2 mutation vs. PKP2 mutation was a predictor of transplantation/HF-related death in univariate Cox analysis (P = 0.0005).

CONCLUSIONS

In this multicentre cohort, DSG2 mutation carriers were found to be at high risk of end-stage HF compared to PKP2 mutation carriers, supporting careful haemodynamic monitoring of these patients. The benefit of early HF treatment needs to be assessed in DSG2 carriers.

Diagnostic and therapeutic strategies for arrhythmogenic right ventricular dysplasia/cardiomyopathy patient

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is a rare inherited heart muscle disease characterized by ventricular tachyarrhythmia, predominant right ventricular dysfunction, and sudden cardiac death. Its pathophysiology involves close interaction between genetic mutations and exposure to physical activity. Mutations in genes encoding desmosomal protein are the most common genetic basis. Genetic testing plays important roles in diagnosis and screening of family members. Syncope, palpitation, and lightheadedness are the most common symptoms. The 2010 Task Force Criteria is the standard for diagnosis today. Implantation of a defibrillator in high-risk patients is the only therapy that provides adequate protection against sudden death. Selection of patients who are best candidates for defibrillator implantation is challenging. Exercise restriction is critical in affected individuals and at-risk family members. Antiarrhythmic drugs and ventricular tachycardia ablation are valuable but palliative components of the management. This review focuses on the current diagnostic and therapeutic strategies in ARVD/C and outlines the future area of development in this field.

Life-threatening arrhythmic presentation in patients with arrhythmogenic cardiomyopathy before and after entering the genomic era; a two-decade experience from a large volume center

BACKGROUND

Arrhythmogenic cardiomyopathy (AC) is an inheritable progressive heart disease with high risk of life-threatening ventricular arrhythmia (VA). We aimed to explore the prevalence of VA as presenting event in patients with AC over two decades, symptoms preceding VA and compare the clinical presentations and rate of AC-diagnosis over time.

METHODS

We included consecutive AC-patients from our tertiary referral center. We recorded clinical history, VA (aborted cardiac arrest, sustained ventricular tachycardia or appropriate implantable cardioverter-defibrillator therapy), cardiac symptoms preceding VA in AC, and compared the history of patients diagnosed before and after implementation of genetic testing.

RESULTS

We included 179 consecutive AC-patients and mutation-positive family members (95 [53%] probands, 84 [45%] female, 49 ± 17 years), 33 (18%) diagnosed before and 146 (82%) after genetic testing became available. VA led to the AC-diagnosis in 46 (26%), and was less prevalent after implementation of genetic testing (17[52%] vs. 29[20%], p < 0.001), also when adjusted for proband status (Adjusted OR 2.7, 95% CI 1.1-6.7, p = 0.03). Yearly rate of AC-diagnosis increased after implementation of genetic testing in probands (2.7 ± 1.3 vs. 6.8 ± 4.3, p = 0.01) and family members (0.7 ± 1.1 vs. 7.7 ± 5.9, p = 0.002). Most patients with VA (92%) reported cardiac symptoms prior to event, and exercise-induced syncope was the strongest marker of subsequent VA (Adjusted OR 5.3, 95% CI 1.7-16.4, p = 0.004).

CONCLUSION

VA led to AC-diagnosis in 46% of probands and was preceded by cardiac symptoms in the majority of cases. Yearly rate of AC-diagnoses increased after the implementation of genetic testing and life-threatening presentation of AC-disease seemed to decrease.

Usefulness of Total 12-Lead QRS Voltage for Diagnosis of Arrhythmogenic Right Ventricular Cardiomyopathy in Patients With Heart Failure Severe Enough to Warrant Orthotopic Heart Transplantation and Morphologic Illustration of Its Cardiac Diversity

Although several electrocardiographic features of arrhythmogenic right ventricular cardiomyopathy (ARVC) (also called dysplasia) have been described, total 12-lead QRS voltage is not one of them. This report describes total 12-lead QRS voltage in 11 patients with ARVC who underwent orthotopic heart transplantation (OHT) because of progressively severe heart failure. Additionally, it illustrates the varied morphologic features of ARVC. The total 12-lead nonpaced QRS voltages before OHT ranged from 28 to 118 mm (mean 74 ± 32), and those in the paced tracings, from 33 to 129 mm (62 ± 32). The voltages are the lowest we have encountered among 12 previously reported cardiovascular conditions. The heart weights among the 11 ARVC patients ranged from 285 to 670 g (mean 448 ± 125). Very low 12-lead QRS voltage is characteristic of patients with ARVC with heart failure severe enough to warrant OHT, and thus may serve as a clue to its diagnosis.

Epicardial Fat Distribution Assessed with Cardiac CT in Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy

Purpose To compare epicardial fat in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) with that in healthy subjects. Materials and Methods In this retrospective study, cardiac CT scans in 44 patients with ARVD/C (mean age, 39 years ± 12; 23 men) were compared with those in 45 control group participants between January 2008 and July 2015. Volumes of intrathoracic adipose tissue, mediastinal adipose tissue (MAT), and total epicardial adipose tissue (EAT) were quantified. EAT was subdivided into three regions-right ventricular (RV) EAT, left ventricular (LV) EAT, and peri-atrial EAT (atrial EAT)-and normalized to MAT for all regions. Logistic regression and receiver operating characteristic analysis were performed to evaluate the association between epicardial fat with the diagnosis of ARVD/C. Results Total EAT volume was higher in patients with ARVD/C than in healthy control group participants (median, 98 mL vs 76 mL, respectively; P = .04). Regionally, LV and RV EAT volumes were higher in patients with ARVD/C than in control group participants, most notably when indexed to MAT (median LV EAT index: 0.49 vs 0.15, respectively; median RV EAT index: 0.91 vs 0.52; P ˂ .0005 for both). The optimal cutoff for diagnosis of ARVD/C was an LV EAT index of 0.24, with a sensitivity and specificity of 91% and 71%, respectively. Atrial EAT volume and total intrathoracic adipose tissue volume were not different between groups. RV diameter showed a positive correlation with total EAT index and LV EAT index (r = 0.21, P = .05 and r = 0.33, P = .002, respectively). Conclusion Higher amounts of right ventricular and left ventricular epicardial fat are found in hearts with arrhythmogenic right ventricular dysplasia/cardiomyopathy, particularly adjacent to the left ventricle, which correlates with disease severity and helps differentiate patients from healthy subjects. © RSNA, 2018 Online supplemental material is available for this article.

Arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a progressive cardiomyopathy characterized by fibrofatty infiltration of the myocardium, ventricular arrhythmias, sudden death, and heart failure. ARVC may be an important cause of syncope, sudden death, ventricular arrhythmias, and/or wall motion abnormalities, especially in the young. As the first symptom is sudden death or cardiac arrest in many cases, an early diagnosis and risk stratification are important. Recent advances in diagnostic modalities will be helpful in the early diagnosis and proper management of patients at risk. Restriction of strenuous exercise and implantation of implantable cardioverter-defibrillators are important in addition to medical treatment and catheter ablation of ventricular tachycardia. Recently introduced genetic screening may help to identify asymptomatic carriers with a risk of a disease progression and sudden death.

Epsilon waves: Milestones in the discovery and progress

The Epsilon wave was first identified in 1977. Four decades of progress help people to better understand its pathological electrogenesis and diagnostic value. Currently, the Epsilon wave is on the list of the 2010 Task Force recommendations for the diagnosis of arrhythmogenic right ventricular dysplasia (ARVD). In this review, we provide the history of the first recording of the Epsilon wave in coronary artery disease and Uhl's anomaly, subsequently leading to the signal averaging technique to record late potentials. Based on our experience, we discuss some existing controversies. When we look back at the decades of progress of the Epsilon wave, we conclude that the Epsilon wave is only the tip of the iceberg of ECG abnormalities in ARVD.

Naxos disease: from the origin to today

Naxos disease, first described by Dr. Nikos Protonotarios and colleagues on the island of Naxos, Greece, is a special form of arrhythmogenic right ventricular dysplasia (ARVD). It is an inherited condition with a recessive form of transmission and a familial penetrance of 90%. It is associated with thickening of the skin of the hands and sole, and a propensity to woolly hair. The cardiac anomalies characterized by ventricular arrhythmias with ventricular extrasystoles and tachycardia and histologic features of the myocardium are consistent with ARVD, but in a more severe form of dysplasia with major dilatation of the right ventricle. The identification of the responsible first gene on chromosome 17, and its product plakoglobin as the responsible protein for Naxos disease proved to be a milestone in the study of ARVD, which opened a new field of research. Thanks to those with the determination to discover Naxos disease, there is and will be more clarity in understanding the mechanisms of juvenile sudden death in the young who have an apparently otherwise normal heart.

Cardiomyopathy in the pediatric patients

Pediatric cardiomyopathies are a group of myocardial diseases with complex taxonomies. Cardiomyopathy can occur in children at any age, and it is a common cause of heart failure and heart transplantation in children. The incidence of pediatric cardiomyopathy is increasing with time. They may be associated with variable comorbidities, which are most often arrhythmia, heart failure, and sudden death. Medical imaging technologies, including echocardiography, cardiac magnetic resonance, and nuclear cardiology, are helpful in reaching a diagnosis of cardiomyopathy. Nevertheless, endomyocardial biopsy is the final diagnostic method of diagnosis. Patients warrant surgical operations, such as palliative operations, bridging operations, ventricular septal maneuvers, and heart transplantation, if pharmaceutical therapies are ineffective. Individual therapeutic regimens due to pediatric characteristics, genetic factors, and pathogenesis may improve the effects of treatment and patients' survival.

Cell models of arrhythmogenic cardiomyopathy: advances and opportunities

Arrhythmogenic cardiomyopathy is a rare genetic disease that is mostly inherited as an autosomal dominant trait. It is associated predominantly with mutations in desmosomal genes and is characterized by the replacement of the ventricular myocardium with fibrous fatty deposits, arrhythmias and a high risk of sudden death. In vitro studies have contributed to our understanding of the pathogenic mechanisms underlying this disease, including its genetic determinants, as well as its cellular, signaling and molecular defects. Here, we review what is currently known about the pathogenesis of arrhythmogenic cardiomyopathy and focus on the in vitro models that have advanced our understanding of the disease. Finally, we assess the potential of established and innovative cell platforms for elucidating unknown aspects of this disease, and for screening new potential therapeutic agents. This appraisal of in vitro models of arrhythmogenic cardiomyopathy highlights the discoveries made about this disease and the uses of these models for future basic and therapeutic research.

Summary:In vitro models of ACM provide insights into the molecular mechanisms of this disease. This reappraisal offers a comprehensive vision of past discoveries and constitutes a tool for future research.

Catheter Ablation of Ventricular Tachycardia in Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is predominantly an inherited cardiomyopathy with typical histopathological characteristics of fibro-fatty infiltration mainly involving the right ventricular (RV) inflow tract, RV outflow tract, and RV apex in the majority of patients. The above pathologic evolution frequently brings patients with ARVD/C to medical attention owing to the manifestation of syncope, sudden cardiac death (SCD), ventricular arrhythmogenesis, or heart failure. To prevent future or recurrent SCD, an implantable cardiac defibrillator (ICD) is highly desirable in patients with ARVD/C who had experienced unexplained syncope, hemodynamically intolerable ventricular tachycardia (VT), ventricular fibrillation, and/or aborted SCD. Notably, the management of frequent ventricular tachyarrhythmias in ARVD/C is challenging, and the use of antiarrhythmic drugs could be unsatisfactory or limited by the unfavorable side effects. Therefore, radiofrequency catheter ablation (RFCA) has been implemented to treat the drug-refractory VT in ARVD/C for decades. However, the initial understanding of the link between fibro-fatty pathogenesis and ventricular arrhythmogenesis in ARVD/C is scarce, the efficacy and prognosis of endocardial RFCA alone were limited and disappointing. The electrophysiologists had broken through this frontier after better illustration of epicardial substrates and broadly application of epicardial approaches in ARVD/C. In recent works of literature, the application of epicardial ablation also successfully results in higher procedural success and decreases VT recurrences in patients with ARVD/C who are refractory to the endocardial approach during long-term follow-up. In this article, we review the important evolution on the delineation of arrhythmogenic substrates, ablation strategies, and ablation outcome of VT in patients with ARVD/C.

Sudden Cardiac Death in Genetic Cardiomyopathies

Sudden cardiac death (SCD) caused by ventricular arrhythmias is common in patients with genetic cardiomyopathies (CMs) including dilated CM, hypertrophic CM, and arrhythmogenic right ventricular CM (ARVC). Phenotypic features can identify individuals at high enough risk to warrant placement of an implantable cardioverter-defibrillator, although risk stratification schemes remain imperfect. Genetic testing is valuable for family cascade screening but with few exceptions (eg, LMNA mutations) do not identify higher risk for SCD. Although randomized trials are lacking, observational data suggest that ICDs can be beneficial. Vigorous exercise can exacerbate ARVC disease progression and increase likelihood of ventricular arrhythmias.

Risk Stratification in Arrhythmogenic Right Ventricular Cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy characterized by ventricular arrhythmias and an increased risk of sudden cardiac death. Although structural abnormalities of the right ventricle predominate, it is well recognized that left ventricular involvement is common, particularly in advanced disease, and that left-dominant forms occur. The pathological characteristic of ARVC is myocyte loss with fibrofatty replacement. Since the first detailed clinical description of the disorder in 1982, significant advances have been made in understanding this disease. Once the diagnosis of ARVC is established, the single most important clinical decision is whether a particular patient's sudden cardiac death risk is sufficient to justify placement of an implantable cardioverter-defibrillator. The importance of this decision reflects the fact that ARVC is a common cause of sudden death in young people and that sudden death may be the first manifestation of the disease. This decision is particularly important because these are often young patients who are expected to live for many years. Although an implantable cardioverter-defibrillator can save lives in individuals with this disease, it is also well recognized that implantable cardioverter-defibrillator therapy is associated with both short- and long-term complications. Decisions about the placement of an implantable cardioverter-defibrillator are based on an estimate of a patient's risk of sudden cardiac death, as well as their preferences and values. The primary purpose of this article is to provide a review of the literature that concerns risk stratification in patients with ARVC and to place this literature in the framework of the 3 authors' considerable lifetime experiences in caring for patients with ARVC. The most important parameters to consider when determining arrhythmic risk include electric instability, including the frequency of premature ventricular contractions and sustained ventricular arrhythmia; proband status; extent of structural disease; cardiac syncope; male sex; the presence of multiple mutations or a mutation in TMEM43; and the patient's willingness to restrict exercise and to eliminate participation in competitive or endurance exercise.

Arrhythmogenic Right Ventricular Cardiomyopathy: Risk Stratification and Indications for Defibrillator Therapy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetically determined disease which predisposes to life-threatening ventricular arrhythmias. The main goal of ARVC therapy is prevention of sudden cardiac death (SCD). Implantable cardioverter defibrillator (ICD) is the most effective therapy for interruption of potentially lethal ventricular tachyarrhythmias. Despite its life-saving potential, ICD implantation is associated with a high rate of complications and significant impact on quality of life. Accurate risk stratification is needed to identify individuals who most benefit from the therapy. While there is general agreement that patients with a history of cardiac arrest or hemodynamically unstable ventricular tachycardia are at high risk of SCD and needs an ICD, indications for primary prevention remain a matter of debate. The article reviews the available scientific evidence and guidelines that may help to stratify the arrhythmic risk of ARVC patients and guide ICD implantation. Other therapeutic strategies, either alternative or additional to ICD, will be also addressed.

A classic case of arrhythmogenic right ventricular cardiomyopathy (ARVC) and literature review

Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) is a relatively under-recognized hereditary cardiomyopathy. It is characterized pathologically by fibro-fatty infiltration of right ventricular (RV) myocardium and clinically by consequences of RV electrical instability. Timely intervention with device therapy and pharmacotherapy may help reduce the risk of arrhythmic events or sudden cardiac death. Here, we describe a classic case of a young adult with ARVC and a brief literature review. The patient presented with exertional palpitations and ARVC was suspected after his routine electrocardiogram (EKG) revealed symmetric T wave inversions and possible epsilon waves in right precordial leads. Subsequent work up showed fatty infiltration of RV myocardium on cardiac magnetic resonance imaging and inducible ventricular tachycardia from the right ventricle during electrophysiologic study. Those findings confirmed the diagnosis of ARVC and warranted treatment with implantable cardioverter defibrillator. It is always exciting to encounter rare pathological entities with classic clinical findings, especially when they present as a diagnostic challenge.We were able to provide correct diagnosis and management, thereby preventing the potentially lethal consequences. Therefore, it is important to recognize the possible EKG findings of ARVC and to know when to pursue further investigations and to implement therapies.

Palpitations and a Left Ventricular Mass: An Odd Presentation of Left Dominant Arrhythmogenic Cardiomyopathy

A 20-year-old woman presented with palpitations. Echocardiography demonstrated a left ventricular mass involving the posterolateral apical wall and protruding into the ventricular cavity. Evaluation with magnetic resonance imaging (MRI) suggested fatty consistency with all edges well defined except the medial, which was ill defined, raising concern for an invasive liposarcoma. Open core needle biopsy demonstrated mature adipocytes infiltrating the myocardium with extensive interstitial fibrosis. The diagnosis was left-dominant arrhythmogenic cardiomyopathy. Two-year MRI follow-up demonstrates no change in size. This case illustrates the use and limits of cardiac MRI and the value of open cardiac biopsy in diagnosis.

Right ventricular ejection fraction measurements using two-dimensional transthoracic echocardiography by applying an ellipsoid model

Background

There is today no established approach to estimate right ventricular ejection fraction (RVEF) using 2D transthoracic echocardiography (TTE). The aim of this study was to evaluate a new method for RVEF calculations using 2D TTE and compare the results with cardiac magnetic resonance (CMR) imaging and tricuspid annular plane systolic excursion (TAPSE).

Methods

A total of 37 subjects, 25 retrospectively included patients and twelve healthy volunteers, were included to give a wide range of RVEF. The right ventricle (RV) was modeled as a part of an ellipsoid enabling calculation of the RV volume by combining three distance measurements. RVEF calculated according to the model, RVEF_TTE, were compared with reference CMR-derived RVEF, RVEF_CMR. Further, TAPSE was measured in the TTE images and the correlations were calculated between RVEF_TTE, TAPSE and RVEF_CMR.

Results

The mean values were RVEF_CMR = 43 ± 12% (range 20–66%) and RVEF_TTE = 50 ± 9% (range 34–65%). There was a high correlation (r = 0.80, p < 0.001) between RVEF_TTE and RVEF_CMR. Bland-Altman analysis showed a mean difference between RVEF_CMR and RVEF_TTE of 6 percentage points (ppt) with limits of agreement from −11 to 23 ppt. The mean value for TAPSE was 19 ± 5 mm and the correlation between TAPSE and RVEF_CMR was moderate (r = 0.54, p < 0.001). The correlation between RVEF_TTE and RVEF_CMR was significantly higher (p < 0.05) than the correlation between TAPSE and RVEF_CMR.

Conclusions

The ellipsoid model shows promise for RVEF calculations using 2D TTE for a wide range of RVEF, providing RVEF estimates that were significantly better correlated to RVEF obtained from CMR compared to TAPSE.

Electronic supplementary material

The online version of this article (doi:10.1186/s12947-017-0096-5) contains supplementary material, which is available to authorized users.

Arrhythmogenic right ventricular cardiomyopathy: ECG progression over time and correlation with long-term follow-up

AIMS

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited heart muscle disease primarily affecting the right ventricle and potentially causing sudden death in young people. Our aims are to analyse the progression over time of electrocardiographic (ECG) findings and to investigate their prognostic impact.

METHODS

Sixty-eight patients (69% men; age 31 ± 19 years) with ARVC diagnosis were followed up for a mean of 17 ± 8 years. Follow-up included baseline ECG, 24-h Holter ECG, signal-averaged ECG, stress test, echocardiography, cardiac magnetic resonance and electrophysiologic study.

RESULTS

During follow-up 12 (18%) patients died: three of sudden cardiac death (SCD), four of end-stage heart failure and five of noncardiac causes. Aborted SCD occurred in 7 (10%) patients, syncope in 31 (46%), sustained ventricular tachycardia in 43 (63%), heart failure in 18 (26%), atrial fibrillation in 16 (24%) and 3 (4%) patients underwent heart transplant. Twenty-four (35%) patients had implantable cardiac defibrillator (15 and 5 of them received both appropriate and inappropriate interventions, respectively and 7 experienced device-related complications). Of the ECG parameters registered at the enrolment, left anterior fascicular block (P = 0.001), QRS duration in lead 1 (P < 0.001), Epsilon wave (P < 0.001), T wave inversion in V4-V5-V6 (P = 0.012, P = 0.001 and P = 0.006) and low QRS voltages (P = 0.001) progressed over time. At multivariate analysis Epsilon wave (odds ratio 20.9, confidence interval 95% 1.8-239.8, P = 0.015) was the only predictor of the composite endpoint of SCD, heart failure-related death or heart transplant.

CONCLUSION

Apart from playing a pivotal role in ARVC diagnosis, a simple ECG feature such as Epsilon wave is a marker of poor prognosis.

Acute and Chronic Right Ventricular Failure

Right ventricular failure is the subject of renewed attention as the importance of RV function in a variety of disease states has been recognized. The RV is highly compliant, and is able to accommodate a wide range of preload conditions. Yet, it is afterload-sensitive, and normal physiology is dependent on its association with the low resistance of the pulmonary vasculature. Changes in the pulmonary vascular resistance, either acutely or over time, provoke a series of adaptations that are designed to maintain a normal cardiac output, but ultimately lead to decompensation and RV failure. Through ventricular interdependence, RV failure may impair left ventricular diastolic and systolic function, further reducing cardiac performance. Both echocardiography and magnetic resonance imaging can provide detailed information about RV structure, with MRI providing better assessment of ventricular volumes and RV function. Right heart catheterization is often necessary for definitive diagnosis of the etiology of RV failure and for determining the best therapeutic options. The treatment of RV failure is highly dependent on the underlying etiology, which should be corrected if possible. Targeted medical therapy is particularly useful in cases of pulmonary arterial hypertension, and is under investigation for broader use in other causes of pulmonary hypertension.

Arrhythmogenic Right Ventricular Dysplasia in Neuromuscular Disorders

OBJECTIVES

Arrhythmogenic right ventricular dysplasia (ARVD) is a rare, genetic disorder predominantly affecting the right ventricle. There is increasing evidence that in some cases, ARVD is due to mutations in genes, which have also been implicated in primary myopathies. This review gives an overview about myopathy-associated ARVD and how these patients can be managed.

METHODS

A literature review was done using appropriate search terms.

RESULTS

The myopathy, which is most frequently associated with ARVD, is the myofibrillar myopathy due to desmin mutations. Only in a single patient, ARVD was described in myotonic dystrophy type 1. However, there are a number of genes causing either myopathy or ARVD. These genes include lamin A/C, ZASP/cypher, transmembrane protein-43, titin, and the ryanodine receptor-2 gene. Diagnosis and treatment are identical for myopathy-associated ARVD and nonmyopathy-associated ARVD.

CONCLUSIONS

Patients with primary myopathy due to mutations in the desmin, dystrophia myotonica protein kinase, lamin A/C, ZASP/cypher, transmembrane protein-43, titin, or the ryanodine receptor-2 gene should be screened for ARVD. Patients carrying a pathogenic variant in any of these genes should undergo annual cardiological investigations for cardiac function and arrhythmias.

Risk Stratification in Arrhythmic Right Ventricular Cardiomyopathy Without Implantable Cardioverter-Defibrillators

OBJECTIVES

The primary objective of this study is risk stratification of patients with arrhythmic right ventricular cardiomyopathy (ARVC).

BACKGROUND

There is a need to identify those who need an automatic implantable defibrillator (ICD) to prevent sudden death.

METHODS

This is an analysis of 88 patients with ARVC from three centers who were not treated with an ICD.

RESULTS

Risk factors for subsequent arrhythmic deaths were pre-enrollment sustained or nonsustained ventricular tachycardia (VT) and decreased left ventricular function.

CONCLUSION

These factors serve as proposed guidelines for implantation of an ICD in patients with ARVC to prevent sudden death.

Recommendations for participation in competitive sport and leisure-time physical activity in individuals with cardiomyopathies, myocarditis and pericarditis

Several relatively uncommon, but important cardiovascular diseases are associated with increased risk for acute cardiac events during exercise (including sudden death), such as hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), arrhythmogenic right ventricular cardiomyopathy (ARVC) and myo-pericarditis. Practising cardiologists are frequently asked to advise on exercise programmes and sport participation in young individuals with these cardiovascular diseases. Indeed, many asymptomatic (or mildly symptomatic) patients with cardiomyopathies aspire to a physically active lifestyle to take advantage of the many documented benefits of exercise. While recommendations dictating the participation in competitive sport for athletes with cardiomyopathies and myo-pericarditis have recently been published as a consensus document of the European Society of Cardiology, no European guidelines have addressed the possible participation of patients with cardiomyopathies in recreational and amateur sport activities. The present document is intended to offer a comprehensive overview to practising cardiologists and sport physicians of the recommendations governing safe participation in different types of competitive sport, as well as the participation in a variety of recreational physical activities and amateur sports in individuals with cardiomyopathies and myo-pericarditis. These recommendations, based largely on the experience and insights of the expert panel appointed by the European Society of Cardiology, include the most up-to-date information concerning regular exercise and sports activity in patients with cardiomyopathies and myo-pericarditis.

Arrhythmogenic Cardiomyopathy: Electrical and Structural Phenotypes

This overview gives an update on the molecular mechanisms, clinical manifestations, diagnosis and therapy of arrhythmogenic cardiomyopathy (ACM). ACM is mostly hereditary and associated with mutations in genes encoding proteins of the intercalated disc. Three subtypes have been proposed: the classical right-dominant subtype generally referred to as ARVC/D, biventricular forms with early biventricular involvement and left-dominant subtypes with predominant LV involvement. Typical symptoms include palpitations, arrhythmic (pre)syncope and sudden cardiac arrest due to ventricular arrhythmias, which typically occur in athletes. At later stages, heart failure may occur. Diagnosis is established with the 2010 Task Force Criteria (TFC). Modern imaging tools are crucial for ACM diagnosis, including both echocardiography and cardiac magnetic resonance imaging for detecting functional and structural alternations. Of note, structural findings often become visible after electrical alterations, such as premature ventricular beats, ventricular fibrillation (VF) and ventricular tachycardia (VT). 12-lead ECG is important to assess for depolarisation and repolarisation abnormalities, including T-wave inversions as the most common ECG abnormality. Family history and the detection of causative mutations, mostly affecting the desmosome, have been incorporated in the TFC, and stress the importance of cascade family screening. Differential diagnoses include idiopathic right ventricular outflow tract (RVOT) VT, sarcoidosis, congenital heart disease, myocarditis, dilated cardiomyopathy, athlete's heart, Brugada syndrome and RV infarction. Therapeutic strategies include restriction from endurance and competitive sports, β-blockers, antiarrhythmic drugs, heart failure medication, implantable cardioverter-defibrillators and endocardial/epicardial catheter ablation.

Fetal arrhythmogenic right ventricular cardiomyopathy with double mutations in TMEM43

We herein describe a fetal case of arrhythmogenic right ventricular cardiomyopathy (ARVC) with double mutations in transmembrane protein 43 (TMEM43). RV aneurysm and ventricular arrhythmia were detected during the fetal period. After birth, electrocardiogram showed frequent premature ventricular contractions (PVC) of left bundle branch block morphology and epsilon waves in the right-sided chest leads. Echocardiography also indicated RV aneurysm with regionally decreased systolic function. PVC disappeared after treatment with amiodarone and mexiletin. Mutations in TMEM43, which was recently identified as the causative gene of ARVC type 5, were also confirmed in the present patient and in the patient's mother, and they were therefore diagnosed with ARVC. The present case confirms that symptoms of ARVC can emerge during the fetal period. Pediatricians need to keep in mind the possibility of ARVC when they encounter patients with RV aneurysm and arrhythmia.

Arrhythmogenic Right Ventricular Cardiomyopathy - Antiarrhythmic Therapy

Arrhythmogenic right ventricular cardiomyopathy is an inherited disorder characterised by progressive replacement of ventricular myocardium by fibrofatty tissue that predisposes patients to ventricular arrhythmias, heart failure and sudden death. Treatment focuses on slowing disease progression, decreasing the burden of arrhythmias and preventing sudden cardiac death through placement of implantable cardioverter-defibrillators (ICDs), catheter ablation and the use of antiarrhythmic medication. Although only ICDs have been demonstrated to affect patient mortality, antiarrhythmic medications are important adjuncts in reducing patient morbidity and inappropriate ICD therapy. Of the individual antiarrhythmic agents available, sotalol, beta-blockers and amiodarone appear to be most effective in arrhythmia suppression. Calcium-channel blockers may be effective in selected patients. For patients who are refractory to single agent therapy, combination therapy may be considered with the most effective combinations being sotalol + flecainide and amiodarone + beta-blockers.

The spectrum of epidemiology underlying sudden cardiac death

Sudden cardiac death (SCD) from cardiac arrest is a major international public health problem accounting for an estimated 15%-20% of all deaths. Although resuscitation rates are generally improving throughout the world, the majority of individuals who experience a sudden cardiac arrest will not survive. SCD most often develops in older adults with acquired structural heart disease, but it also rarely occurs in the young, where it is more commonly because of inherited disorders. Coronary heart disease is known to be the most common pathology underlying SCD, followed by cardiomyopathies, inherited arrhythmia syndromes, and valvular heart disease. During the past 3 decades, declines in SCD rates have not been as steep as for other causes of coronary heart disease deaths, and there is a growing fraction of SCDs not due to coronary heart disease and ventricular arrhythmias, particularly among certain subsets of the population. The growing heterogeneity of the pathologies and mechanisms underlying SCD present major challenges for SCD prevention, which are magnified further by a frequent lack of recognition of the underlying cardiac condition before death. Multifaceted preventative approaches, which address risk factors in seemingly low-risk and known high-risk populations, will be required to decrease the burden of SCD. In this Compendium, we review the wide-ranging spectrum of epidemiology underlying SCD within both the general population and in high-risk subsets with established cardiac disease placing an emphasis on recent global trends, remaining uncertainties, and potential targeted preventive strategies.