Exercise Testing in Asymptomatic Gene Carriers Exposes a Latent Electrical Substrate of Arrhythmogenic Right Ventricular Cardiomyopathy

The differentiation of the competitive athlete with physiologic cardiac remodeling from the athlete with cardiomyopathy

There are currently 5 million active high school, collegiate, professional, and master athletes in the United States. Regular intense exercise by these athletes can promote structural, electrical and functional remodeling of the heart, which is termed the "athlete's heart." In addition, regular intense exercise can lead to pathological adaptions that promote or worsen cardiac disease. Many of the athletes in the United States seek medical care. Consequently, physicians must be aware of the normal cardiac anatomy and physiology of the athlete, the differentiation of the normal athlete heart from the athlete with cardiomyopathy, and the contemporary care of the athlete with a cardiomyopathy. In athletes with persistent cardiovascular symptoms, investigations should include a detailed history and physical examination, an ECG, a transthoracic echocardiogram, and in athletes in whom the diagnosis is uncertain, a maximal exercise stress test or a continuous ECG recording, and cardiac magnetic resonance imaging or cardiac computed tomography angiography when definition of the coronary anatomy or characterization of the aorta and the aortic great vessels is indicated. This article discusses the differentiation of the normal athlete with physiologic cardiac remodeling from the athlete with hypertrophic, dilated or arrhythmogenic ventricular cardiomyopathy (ACM). The ECG changes in trained athletes that are considered normal, borderline, or abnormal are listed. In addition, the normal echocardiographic measurements for athletes who consistently participate in endurance, power, combined or heterogeneous sports are enumerated and discussed. Algorithms are listed that are useful in the diagnosis of trained athletes with borderline or abnormal echocardiographic measurements suggestive of cardiomyopathies along with the major and minor criteria for the diagnosis of ACM in athletes. Thereafter, the treatment of athletes with hypertrophic, dilated, and arrhythmogenic right ventricular cardiomyopathies are reviewed. The distinction between physiologic changes and pathologic changes in the hearts of athletes has important therapeutic and prognostic implications. Failure by the physician to correctly diagnose an athlete with hypertrophic cardiomyopathy, dilated cardiomyopathy, or ACM, can lead to the sudden cardiac arrest and death of the athlete during training or sports competition. Conversely, an incorrect diagnosis by a physician of cardiac pathology in a normal athlete can lead to an unnecessary restriction of athlete training and competition with resultant significant emotional, psychological, financial, and long-term health consequences in the athlete.

Prognostic Electrocardiographic Signs in Arrhythmogenic Cardiomyopathy

Arrhythmogenic cardiomyopathy (ACM) is a rare cardiac disease, characterized by the progressive replacement of myocardial tissue with fibrous and fatty deposits. It can involve both the right and left ventricles. It is associated with the development of life-threatening arrhythmias and culminates in sudden cardiac death. Electrocardiography (ECG) has emerged as a pivotal tool, offering diagnostic insights and prognostic information. The specific ECG abnormalities observed in ACM not only contribute to early detection but also hold the key to the prediction of the likelihood of severe complications. The recognition of these nuanced ECG manifestations has become imperative for clinicians as it guides them in the formulation of tailored therapeutic strategies that address both the present symptoms and the potential future risks.

Biallelic PKP2 loss of function variants are associated with a lethal perinatal-onset biventricular dilated cardiomyopathy with excessive trabeculations and ventricular septal defects

Homozygous plakophilin-2 (PKP2) variants have been identified as a cause of a lethal form of dilated cardiomyopathy with excessive trabeculations (DCM-ET) in three cases. We report three more cases from two families with homozygous pathogenic PKP2 variants and perinatal-onset, lethal DCM-ET. Identification of the genetic abnormalities played a key role in decision-making and family counselling in these cases. This case series supports the published evidence that biallelic loss of function PKP2 variants cause a lethal, perinatal-onset cardiomyopathy.

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.

Investigation of the cardiac effects of exercise testing on apparently healthy Boxer dogs

BACKGROUND

Holter electrocardiographic monitoring is a cornerstone of diagnostic testing for arrhythmogenic cardiomyopathy (ACM) in Boxer dogs, but physical activity during monitoring is not controlled. In humans, exercise testing (ExT) can identify latent tachyarrhythmias associated with cardiomyopathy, and exercise increases serum cardiac troponin-I concentrations ([hs-cTnI]). These effects have not yet been investigated in Boxer dogs.

HYPOTHESIS/OBJECTIVES

Subjecting Boxer dogs to brief, moderate-intensity ExT can identify changes in Holter recordings and [hs-cTnI] compared to baseline results.

ANIMALS

Thirty overtly healthy, client-owned Boxer dogs.

METHODS

Prospective interventional study. Dogs underwent baseline diagnostic testing including 24-hour Holter monitoring and [hs-cTnI], followed by brief ExT (accompanied, brisk stair-climbing and -descending for <5 minutes).

RESULTS

Eleven dogs (37%) had >100 premature ventricular complexes (PVCs)/24 hours at baseline (3), ExT (3), or both (5). After ExT, these dogs had more PVCs/24 hours and greater increases in [hs-cTnI] compared to those with ≤100 PVCs/24 hours. Dogs with the striatin mutation had more PVCs/24 hours and a greater increase in [hs-cTnI] after ExT than did dogs without the striatin mutation.

CONCLUSIONS AND CLINICAL IMPORTANCE

Exercise testing may improve the binary classification of Boxer dogs with or without ACM by increasing the number of PVCs and [hs-cTnI] in affected dogs to a greater degree than in unaffected dogs. This effect also is associated with presence or absence of the striatin mutation. Exercise should be a controlled variable when screening Boxer dogs for ACM.

The value of the 12-lead electrocardiogram in the prediction of sudden cardiac death

Sudden cardiac death (SCD) can be caused by several clinical conditions, overt or misconceived, which recognize different pathophysiologies determining the development of fatal arrhythmic events. In the various forms of structural heart disease such as ischaemic heart disease, cardiomyopathies (e.g. hypertrophic cardiomyopathy, dilated cardiomyopathy, and arrhythmogenic cardiomyopathy), channelopathies (e.g. long-QT syndrome, congenital short QT, Brugada syndrome, early repolarization (ER) syndrome, and idiopathic ventricular fibrillation) but also in the apparently healthy subject, the 12-lead electrocardiogram (ECG) has proved, over the years, to be a reliable and readily available method for stratifying the risk of adverse arrhythmic events and consequently SCD. Several electrocardiographic markers have been shown to be associated with adverse outcomes in different types of patients. Although with different sensitivity and specificity in each clinical condition, depolarization abnormalities, such as QRS fragmentation, Q waves, QRS duration, left posterior fascicular block, low QRS voltage, and left ventricular hypertrophy and similarly repolarization abnormalities as ER pattern, T wave alternans, QT interval, and QT dispersion, have shown significant efficacy in predicting SCD. Despite the advancement of techniques especially in the field of imaging, the correct interpretation of the 12-lead ECG remains, therefore, an effective tool for assessing the possible prognostic outcome in terms of arrhythmic risk and SCD in different types of patients.

Biventricular Arrhythmogenic Cardiomyopathy Associated with a Novel Heterozygous Plakophilin-2 Early Truncating Variant

Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) is a hereditary condition that can cause sudden cardiac death in young, frequently athletic individuals under the age of 35 due to malignant arrhythmias. Competitive and endurance exercise may hasten the onset and progression of ARVC, leading to right ventricular dysfunction and potentially fatal ventricular arrhythmias earlier in life. In this article, we present a novel, pathogenic, early truncating heterozygous variant in the PKP2 gene that causes biventricular arrhythmogenic cardiomyopathy and affects a family, of which the only member with the positive phenotype is a competitive endurance athlete.

Electrocardiographic phenotype of exercise-induced arrhythmogenic cardiomyopathy: A retrospective observational study

Introduction

The right ventricle can be susceptible to pathologic alterations with exercise. This can cause changes to the ECG. Our aim was to identify the electrocardiographic phenotype of exercise induced (ExI) arrhythmogenic cardiomyopathy (ACM).

Methods

A retrospective analysis of ECGs at rest, peak exercise and 1 min of recovery in four groups of individuals was performed: Arrhythmogenic Cardiomyopathy with genetic confirmation (Gen-ACM; n = 16), (genetically negative) ExI-ACM (n = 15), control endurance athletes (End; n = 16) and sedentary individuals (Sed; n = 16). The occurrence of ventricular arrhythmias (VA) and, at each stage, QRS duration, Terminal Activation Delay (TAD), the ratio of the sum of the QRS durations in the right precordials (V1-V3) over that in the left precordials (V4-V6; R/L duration ratio), the presence of complete RBBB and T-wave inversion (TWI) beyond lead V2 were evaluated.

Results

At rest, complete RBBB was exclusively found in Gen-ACM (6%) and ExI-ACM (13%). No epsilon waves were identified. TWI beyond V2 was uniquely present in Gen-ACM (73%) and ExI-ACM (38%; p < 0.001). VA was present in Gen-ACM (88%); ExI-ACM (80%), End (25%) and Sed (19%; p < 0.001). The presence of R/L duration ratio of >1.2 and TAD ≥ 55 ms were not significantly different over the four groups (p = 0.584 and p = 0.218, respectively). At peak exercise the most striking finding was a significant decrease of the R/L duration ratio in individuals with ACM, which was the result of lateral precordial QRS prolongation.

Conclusion

ExI-ACM shares important ECG-features with Gen-ACM, suggesting a similar underlying pathogenesis regardless of the presence or absence of desmosomal mutations.

Arrhythmogenic Right Ventricular Cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) encompasses a group of conditions characterized by right ventricular fibrofatty infiltration, with a predominant arrhythmic presentation. First described in the late 1970s and early 1980s, it is now frequently recognized to have biventricular involvement. The prevalence is ∼1:2,000 to 1:5,000, depending on geographic location, and it has a slight male predominance. The diagnosis of ARVC is determined on the basis of fulfillment of task force criteria incorporating electrophysiological parameters, cardiac imaging findings, genetic factors, and histopathologic features. Risk stratification of patients with ARVC aims to identify those who are at increased risk of sudden cardiac death or sustained ventricular tachycardia. Factors including age, sex, electrophysiological features, and cardiac imaging investigations all contribute to risk stratification. The current management of ARVC includes exercise restriction, β-blocker therapy, consideration for implantable cardioverter-defibrillator insertion, and catheter ablation. This review summarizes our current understanding of ARVC and provides clinicians with a practical approach to diagnosis and management.

Changes in Exercise Capacity and Ventricular Function in Arrhythmogenic Right Ventricular Cardiomyopathy: The Impact of Sports Restriction during Follow-Up

(1) Background: Physical exercise has been suggested to promote disease progression in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). We aimed to investigate the exercise performance and ventricular function of ARVC patients during follow-up, while taking into account their adherence to exercise restriction recommendations. (2) Methods: This retrospective study included 49 patients (33 male, 67%) who had an exercise test at baseline and after 4.2 ± 1.6 years. Of the 49 ARVC patients, 27 (55%) were athletes, while 22 (45%) were non-athletes. Of the athletes, 12 (44%) continued intensive sports activity (non-adherent), while 15 (56%) stopped intensive physical activity upon recommendation (adherent). The maximum workload in Watts (W), percentage of the target workload (W%), and double product (DP) factor were measured for all patients. (3) Results: The non-adherent cohort had a significant decrease in physical performance (W at baseline vs. follow-up, p = 0.012; W% at baseline vs. follow-up, p = 0.025; DP-factor at baseline vs. follow-up, p = 0.012) over time. Left ventricular (LV) function (LV ejection fraction at baseline vs. follow-up, p = 0.082) showed a decreasing trend in the non-adherent cohort, while the performance of the adherent cohort remained at a similar level. (4) Conclusions: If intensive sports activities are not discontinued, exercise capacity and left ventricular function of athletes with ARVC deteriorates during follow-up. All patients with ARVC need to strictly adhere to the recommendation to cease intense sports activity in order to halt disease progression.

The Risk of Sudden Unexpected Cardiac Death in Children: Epidemiology, Clinical Causes, and Prevention

"Sudden unexplained death (SUD) is a tragic event for both the family and community, particularly when it occurs in young individuals. Sudden cardiac death (SCD) represents the leading form of SUD and is defined as an unexpected event without an obvious extracardiac cause, occurring within 1 hour after the onset of symptoms. In children, the main causes of SCD are inherited cardiac disorders, whereas coronary artery diseases (congenital or acquired), congenital heart diseases, and myocarditis are rare. The present review examines the current state of knowledge regarding SCD in children, discussing the epidemiology, clinical causes, and prevention strategies."

Facts and Gaps in Exercise Influence on Arrhythmogenic Cardiomyopathy: New Insights From a Meta-Analysis Approach

Arrhythmogenic cardiomyopathy (ACM) is a genetic cardiac condition characterized by fibrofatty myocardial replacement, either at the right ventricle, at the left ventricle, or with biventricular involvement. Ventricular arrhythmias and heart failure represent its main clinical features. Exercise benefits on mental and physical health are worldwide recognized. However, patients with ACM appear to be an exception. A thorough review of the literature was performed in PubMed searching for original papers with the terms “ARVC AND sports/exercise” and “sudden cardiac death AND sports/exercise.” Additional papers were then identified through other sources and incorporated to the list. All of them had to be based on animal models or clinical series. Information was structured in a regular format, although some data were not available in some papers. A total of 34 papers were selected and processed regarding sports-related sudden cardiac death, pre-clinical models of ACM and sport, and clinical series of ACM patients engaged in sports activities. Eligible papers were identified to obtain pooled data in order to build representative figures showing the global incidence of the most important causes of sudden cardiac death in sports and the global estimates of life-threatening arrhythmic events in ACM patients engaged in sports. Tables and figures illustrate their major characteristics. The scarce points of controversy were discussed in the text. Fundamental concepts were summarized in three main issues: sports may accelerate ACM phenotype with either structural and/or arrhythmic features, restriction may soften the progression, and these rules also apply to phenotype-negative mutation carriers. Additionally, remaining gaps in the current knowledge were also highlighted, namely, the applicability of those fundamental concepts to non-classical ACM phenotypes since left dominant ACM or non-plakophillin-2 genotypes were absent or very poorly represented in the available studies. Hopefully, future research endeavors will provide solid evidence about the safest exercise dose for each patient from a personalized medicine perspective, taking into account a big batch of genetic, epigenetic, and epidemiological variables, for instance, in order to assist clinicians to provide a final tailored recommendation.

Prevalence and clinical correlates of exercise-induced ventricular arrhythmias in arrhythmogenic right ventricular cardiomyopathy

Exercise has a deleterious effect on the phenotypic expression of arrhythmogenic right ventricular cardiomyopathy (ARVC) and increases the risk of sudden death. The aim of the study was to determine the prevalence and correlates of exercise-induced arrhythmias during exercise tolerance test (ETT) in patients with ARVC. Between 2010 and 2019, 30 (47% males, mean age 42 ± 12 years) consecutive patients with a definite diagnosis of ARVC underwent a full genotypic and phenotypic characterization at our center. Exercise-induced arrhythmic response (EIAR) was defined by the development of complex or repetitive ventricular arrhythmias after stage 2 of exercise. A heart rate ≥ 85% of predicted was achieved by 23 (77%) patients. In 16 (53%) cases, a desmosomal pathogenic variant was found [most commonly PKP2 (n = 7) and DSP (n = 3)]. In 12 (40%) cases, an EIAR was observed. In 2 (6%) patients, ETT was interrupted due to the onset of ventricular tachycardia (sustained with a LBBB/inferior axis pattern in one case, and non-sustained LBBB/superior axis pattern in the other). Mean body surface area (BSA)-indexed left ventricular (LV) end-diastolic volumes (EDV) were higher in the EIAR group (92 ± 12 ml/m² vs 80 ± 7 ml/m², p = 0.002), as well as right ventricular EDV/BSA (110 ± 18 ml/m² vs 91 ± 27 ml/m², p = 0.04). Subepicardial/mid-wall LV late gadolinium enhancement (LGE) was more common in the EIAR group (67% vs 22%, p = 0.01). ARVC patients commonly exhibit exercise-induced ventricular arrhythmias. Patients with more significant RV remodeling and LV involvement (based on the presence of LV dilatation and LGE) appear more susceptible to exercise-induced arrhythmias.

Generation of human induced pluripotent stem cell line EURACi006-A and its isogenic gene-corrected line EURACi006-A-1 from an arrhythmogenic cardiomyopathy patient carrying the c.1643delG PKP2 mutation

Arrhythmogenic Cardiomyopathy (ACM) is a rare genetic cardiac disease predominantly associated with mutations in genes of the desmosomes and characterized by arrhythmia and fibro-fatty replacement of the myocardium. We generated human induced pluripotent stem cells (hiPSCs) from one patient affected by ACM carrying the heterozygous c.1643delG (p.G548VfsX15) PKP2 mutation and then corrected the mutation using CRISPR/Cas9 technology. Both original and corrected hiPSC lines showed typical morphology of pluripotent cells, expressed pluripotency markers, displayed a normal karyotype, and differentiated towards the three germ layers. This isogenic hiPSC pair can be used to study the role of the c.1643delG PKP2 mutation in vitro.

Progressive cardiac arrhythmias and ECG abnormalities in the Huntington's disease BACHD mouse model

Huntington's disease (HD) is a dominantly inherited neurodegenerative disease. There is accumulating evidence that HD patients have increased prevalence of conduction abnormalities and compromised sinoatrial node function which could lead to increased risk for arrhythmia. We used mutant Huntingtin (mHTT) expressing bacterial artificial chromosome Huntington's disease mice to determine if they exhibit electrocardiogram (ECG) abnormalities involving cardiac conduction that are known to increase risk of sudden arrhythmic death in humans. We obtained surface ECGs and analyzed arrhythmia susceptibility; we observed prolonged QRS duration, increases in PVCs as well as PACs. Abnormal histological and structural changes that could lead to cardiac conduction system dysfunction were seen. Finally, we observed decreases in desmosomal proteins, plakophilin-2 and desmoglein-2, which have been reported to cause cardiac arrhythmias and reduced conduction. Our study indicates that mHTT could cause progressive cardiac conduction system pathology that could increase the susceptibility to arrhythmias and sudden cardiac death in HD patients.

2020 APHRS/HRS expert consensus statement on the investigation of decedents with sudden unexplained death and patients with sudden cardiac arrest, and of their families

This international multidisciplinary document intends to provide clinicians with evidence-based practical patient-centered recommendations for evaluating patients and decedents with (aborted) sudden cardiac arrest and their families. The document includes a framework for the investigation of the family allowing steps to be taken, should an inherited condition be found, to minimize further events in affected relatives. Integral to the process is counseling of the patients and families, not only because of the emotionally charged subject, but because finding (or not finding) the cause of the arrest may influence management of family members. The formation of multidisciplinary teams is essential to provide a complete service to the patients and their families, and the varied expertise of the writing committee was formulated to reflect this need. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by Class of Recommendation and Level of Evidence. The recommendations were opened for public comment and reviewed by the relevant scientific and clinical document committees of the Asia Pacific Heart Rhythm Society (APHRS) and the Heart Rhythm Society (HRS); the document underwent external review and endorsement by the partner and collaborating societies. While the recommendations are for optimal care, it is recognized that not all resources will be available to all clinicians. Nevertheless, this document articulates the evaluation that the clinician should aspire to provide for patients with sudden cardiac arrest, decedents with sudden unexplained death, and their families.

Role of Exercise as a Modulating Factor in Arrhythmogenic Cardiomyopathy

PURPOSE OF REVIEW

The review addresses the role of exercise in triggering ventricular arrhythmias and promoting disease progression in arrhythmogenic cardiomyopathy (AC) patients and gene-mutation carriers, the differential diagnosis between AC and athlete's heart and current recommendations on exercise activity in AC.

RECENT FINDINGS

AC is an inherited heart muscle disease caused by genetically defective cell-to-cell adhesion structures (mainly desmosomes). The pathophysiological hallmark of the disease is progressive myocyte loss and replacement by fibro-fatty tissue, which creates the substrates for ventricular arrhythmias. Animal and human studies demonstrated that intense exercise, but not moderate physical activity, may increase disease penetrance, worsen the phenotype, and favor life-threatening ventricular arrhythmias. It has been proposed that in some individuals prolonged endurance sports activity may in itself cause AC (so-called exercise-induced AC). The studies agree that intense physical activity should be avoided in patients with AC and healthy gene-mutation carriers. However, low-to-moderate intensity exercise does not appear detrimental and these patients should not be entirely deprived from the many health benefits of physical activity.

Actionable secondary findings in arrhythmogenic right ventricle cardiomyopathy genes: impact and challenge of genetic counseling

Background

Comprehensive genetic analysis yields in a higher diagnostic rate but also in a higher number of secondary findings (SF). American College of Medical Genetics and Genomics (ACMG) published a list of 59 actionable genes for which disease causing sequence variants are recommended to be reported as SF including 27 genes linked to inherited cardiovascular disease (CVD) such as arrhythmia syndromes, cardiomyopathies and vascular and connective tissue disorders. One of the selected conditions represented in the actionable gene list is the arrhythmogenic right ventricle cardiomyopathy (ARVC), an inherited heart muscle disease with a particularly high risk of sudden cardiac death (SCD). Since clinical symptoms are frequently absent before SCD, a genetic finding is a promising option for early diagnosis and possible intervention. However, the variant interpretation and the decision to return a SF is still challenging.

Methods

To determine the frequency of medically actionable SF linked to CVD we analyzed data of 6,605 individuals who underwent high throughput sequencing for noncardiac diagnostic requests. In particular, we critically assessed and classified the variants in the ARVC genes: DSC2, DSG2, DSP, PKP2 and TMEM43 and compared our findings with the population-based genome Aggregation Database (gnomAD) and ARVC-afflicted individuals listed in ClinVar and ARVC database.

Results

1% (69/6,605) of tested individuals carried pathogenic SF in one of the 27 genes linked to CVD, of them 13 individuals (0.2%) carried a pathogenic SF in a ARVC gene. Overall, 582 rare variants were identified in all five ARVC genes, 96% of the variants were missense variants and 4% putative LoF variants (pLoF): frameshift, start/stop-gain/loss, splice-site. Finally, we selected 13 of the 24 pLoF variants as pathogenic SF by careful data interpretation.

Conclusions

Since SF in actionable ARVC genes can allow early detection and prevention of disease and SCD, detected variant must undergo rigorous clinical and laboratory evaluation before it can be described as pathogenic and returned to patients. Returning a SF to a patient should be interdisciplinary, it needs genetic counselling and clinicians experienced in inherited heart disease.

Exercise restores dysregulated gene expression in a mouse model of arrhythmogenic cardiomyopathy

AIMS

Arrhythmogenic cardiomyopathy (ACM) is a myocardial disease caused mainly by mutations in genes encoding desmosome proteins ACM patients present with ventricular arrhythmias, cardiac dysfunction, sudden cardiac death, and a subset with fibro-fatty infiltration of the right ventricle predominantly. Endurance exercise is thought to exacerbate cardiac dysfunction and arrhythmias in ACM. The objective was to determine the effects of treadmill exercise on cardiac phenotype, including myocyte gene expression in myocyte-specific desmoplakin (Dsp) haplo-insufficient (Myh6-Cre:DspW/F) mice.

METHODS AND RESULTS

Three months old sex-matched wild-type (WT) and Myh6-Cre:DspW/F mice with normal cardiac function, as assessed by echocardiography, were randomized to regular activity or 60 min of daily treadmill exercise (5.5 kJ work per run). Cardiac myocyte gene expression, cardiac function, arrhythmias, and myocardial histology, including apoptosis, were analysed prior to and after 3 months of routine activity or treadmill exercise. Fifty-seven and 781 genes were differentially expressed in 3- and 6-month-old Myh6-Cre:DspW/F cardiac myocytes, compared to the corresponding WT myocytes, respectively. Genes encoding secreted proteins (secretome), including inhibitors of the canonical WNT pathway, were among the most up-regulated genes. The differentially expressed genes (DEGs) predicted activation of epithelial-mesenchymal transition (EMT) and inflammation, and suppression of oxidative phosphorylation pathways in the Myh6-Cre:DspW/F myocytes. Treadmill exercise restored transcript levels of two-third (492/781) of the DEGs and the corresponding dysregulated transcriptional and biological pathways, including EMT, inflammation, and secreted inhibitors of the canonical WNT. The changes were associated with reduced myocardial apoptosis and eccentric cardiac hypertrophy without changes in cardiac function.

CONCLUSION

Treadmill exercise restored transcript levels of the majority of dysregulated genes in cardiac myocytes, reduced myocardial apoptosis, and induced eccentric cardiac hypertrophy without affecting cardiac dysfunction in a mouse model of ACM. The findings suggest that treadmill exercise has potential beneficial effects in a subset of cardiac phenotypes in ACM.

Electrocardiographic features of arrhythmogenic right ventricular cardiomyopathy in school-aged children

It can be difficult to distinguish children with early-stage arrhythmogenic right ventricular cardiomyopathy (ARVC) from those with benign premature ventricular contraction (PVC). We retrospectively evaluated six school-aged children with ARVC and compared with those of 20 with benign PVC. The median age at initial presentation was 11.4 and 10.2 years in ARVC and benign PVC, respectively. None of the ARVC patients fulfilled the diagnostic criteria of ARVC at initial presentation. At ARVC diagnosis, the treadmill exercise test and Holter monitoring showed provoked PVC during exercise and pleomorphic PVC in all ARVC cases, respectively. During the observation period, terminal activation duration (TAD) was prolonged in all ARVC patients. In addition, ΔTAD (5.5 [3-10] ms) were significantly longer than those with benign PVC (p < 0.001). A new notched S-wave in V1 appeared in four (67%) ARVC patients, who had myocardial abnormalities in the right ventricle, and in zero benign PVC. Our electrocardiographic findings, such as provoked PVC during exercise, pleomorphic PVC, prolonged TAD, and a new notched S-wave in V1 could contribute to the early detection of ARVC in school-aged children.

2020 APHRS/HRS expert consensus statement on the investigation of decedents with sudden unexplained death and patients with sudden cardiac arrest, and of their families

This international multidisciplinary document intends to provide clinicians with evidence-based practical patient-centered recommendations for evaluating patients and decedents with (aborted) sudden cardiac arrest and their families. The document includes a framework for the investigation of the family allowing steps to be taken, should an inherited condition be found, to minimize further events in affected relatives. Integral to the process is counseling of the patients and families, not only because of the emotionally charged subject, but because finding (or not finding) the cause of the arrest may influence management of family members. The formation of multidisciplinary teams is essential to provide a complete service to the patients and their families, and the varied expertise of the writing committee was formulated to reflect this need. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by Class of Recommendation and Level of Evidence. The recommendations were opened for public comment and reviewed by the relevant scientific and clinical document committees of the Asia Pacific Heart Rhythm Society (APHRS) and the Heart Rhythm Society (HRS); the document underwent external review and endorsement by the partner and collaborating societies. While the recommendations are for optimal care, it is recognized that not all resources will be available to all clinicians. Nevertheless, this document articulates the evaluation that the clinician should aspire to provide for patients with sudden cardiac arrest, decedents with sudden unexplained death, and their families.

2019 HRS expert consensus statement on evaluation, risk stratification, and management of arrhythmogenic cardiomyopathy: Executive summary

Arrhythmogenic cardiomyopathy (ACM) is an arrhythmogenic disorder of the myocardium not secondary to ischemic, hypertensive, or valvular heart disease. ACM incorporates a broad spectrum of genetic, systemic, infectious, and inflammatory disorders. This designation includes, but is not limited to, arrhythmogenic right/left ventricular cardiomyopathy, cardiac amyloidosis, sarcoidosis, Chagas disease, and left ventricular noncompaction. The ACM phenotype overlaps with other cardiomyopathies, particularly dilated cardiomyopathy with arrhythmia presentation that may be associated with ventricular dilatation and/or impaired systolic function. This expert consensus statement provides the clinician with guidance on evaluation and management of ACM and includes clinically relevant information on genetics and disease mechanisms. PICO questions were utilized to evaluate contemporary evidence and provide clinical guidance related to exercise in arrhythmogenic right ventricular cardiomyopathy. Recommendations were developed and approved by an expert writing group, after a systematic literature search with evidence tables, and discussion of their own clinical experience, to present the current knowledge in the field. Each recommendation is presented using the Class of Recommendation and Level of Evidence system formulated by the American College of Cardiology and the American Heart Association and is accompanied by references and explanatory text to provide essential context. The ongoing recognition of the genetic basis of ACM provides the opportunity to examine the diverse triggers and potential common pathway for the development of disease and arrhythmia.

Mechanotransduction and Adrenergic Stimulation in Arrhythmogenic Cardiomyopathy: An Overview of in vitro and in vivo Models

Arrhythmogenic Cardiomyopathy (AC) is a rare inherited heart disease, manifesting with progressive myocardium degeneration and dysfunction, and life-threatening arrhythmic events that lead to sudden cardiac death. Despite genetic determinants, most of AC patients admitted to hospital are athletes or very physically active people, implying the existence of other disease-causing factors. It is recognized that AC phenotypes are enhanced and triggered by strenuous physical activity, while excessive mechanical stretch and load, and repetitive adrenergic stimulation are mechanisms influencing disease penetrance. Different approaches have been undertaken to recapitulate and study both mechanotransduction and adrenergic signaling in AC, including the use of in vitro cellular and tissue models, and the development of in vivo models (particularly rodents but more recently also zebrafish). However, it remains challenging to reproduce mechanical load stimuli and physical activity in laboratory experimental settings. Thus, more work to drive the innovation of advanced AC models is needed to recapitulate these subtle physiological influences. Here, we review the state-of-the-art in this field both in clinical and laboratory-based modeling scenarios. Specific attention will be focused on highlighting gaps in the knowledge and how they may be resolved by utilizing novel research methodology.

2019 HRS expert consensus statement on evaluation, risk stratification, and management of arrhythmogenic cardiomyopathy

Arrhythmogenic cardiomyopathy (ACM) is an arrhythmogenic disorder of the myocardium not secondary to ischemic, hypertensive, or valvular heart disease. ACM incorporates a broad spectrum of genetic, systemic, infectious, and inflammatory disorders. This designation includes, but is not limited to, arrhythmogenic right/left ventricular cardiomyopathy, cardiac amyloidosis, sarcoidosis, Chagas disease, and left ventricular noncompaction. The ACM phenotype overlaps with other cardiomyopathies, particularly dilated cardiomyopathy with arrhythmia presentation that may be associated with ventricular dilatation and/or impaired systolic function. This expert consensus statement provides the clinician with guidance on evaluation and management of ACM and includes clinically relevant information on genetics and disease mechanisms. PICO questions were utilized to evaluate contemporary evidence and provide clinical guidance related to exercise in arrhythmogenic right ventricular cardiomyopathy. Recommendations were developed and approved by an expert writing group, after a systematic literature search with evidence tables, and discussion of their own clinical experience, to present the current knowledge in the field. Each recommendation is presented using the Class of Recommendation and Level of Evidence system formulated by the American College of Cardiology and the American Heart Association and is accompanied by references and explanatory text to provide essential context. The ongoing recognition of the genetic basis of ACM provides the opportunity to examine the diverse triggers and potential common pathway for the development of disease and arrhythmia.

Epsilon wave: A review of historical aspects

The epsilon wave of the electrocardiogram (ECG) together with fragmented QRS (fQRS), the terminal conduction delay, incomplete right bundle branch block (IRBBB) and complete/advanced RBBB (CRBBB) of peripheral origin are part of a spectrum of ventricular depolarization abnormalities of arrhythmogenic cardiomyopathy(AC). Although the epsilon wave is considered a major diagnostic criterion for AC since 2010 (AC Task Force Criteria), its diagnostic value is limited because it is a sign of the later stage of the disease. It would be more appropriate to say that the epsilon wave is a “hallmark” of AC, but is of low diagnostic sensitivity. Although the epsilon wave has high specificity for AC, it can be present in other pathological conditions. In this update we will cover the nomenclature, association with disease states and electrocardiographic aspects of the epsilon wave.

Diagnosis of Arrhythmogenic Right Ventricular Cardiomyopathy: Progress and Pitfalls

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy that predominantly affects the right ventricle. With a prevalence in the range of 1:5000 to 1:2000 persons, ARVC is one of the leading causes of sudden cardiac death in young people and in athletes. Although early detection and treatment is important, the diagnosis of ARVC remains challenging. There is no single pathognomonic diagnostic finding in ARVC; rather, current international task force criteria specify diagnostic major and minor criteria in six categories: right ventricular imaging (including echocardiography and cardiac magnetic resonance imaging (MRI)), histology, repolarisation abnormalities, depolarisation and conduction abnormalities, arrhythmias and family history (including genetic testing). Combining findings from differing diagnostic modalities can establish a "definite", "borderline" or "possible" diagnosis of ARVC. However, there are limitations inherent in the current task force criteria, including the lack of specificity for ARVC; future iterations may be improved, for example, by enhanced imaging protocols able to detect subtle changes in the structure and function of the right ventricle, incorporation of electro-anatomical data, response to adrenergic challenge, and validated criteria for interpreting genetic variants.

Electrocardiographic Markers of Sudden Cardiac Death (Including Left Ventricular Hypertrophy)

Although the electrocardiograph (ECG) was invented more than 100 years ago, it remains the most commonly used test in clinical medicine. It is easy to perform, relatively cheap, and results are readily available. Interpretation, however, needs expertise and knowledge. New data, phenomenon, and syndromes are continually discovered by the ECG. It is important to differentiate between normal and abnormal ECGs first and then try to correlate the findings with clinical pathologies. Furthermore, the ECG is an integral part of the screening model for a variety of conditions such as channelopathies, athletes, preoperative risk profile, and remains the cardiologist's best friend.

Electrocardiographic differentiation of idiopathic right ventricular outflow tract ectopy from early arrhythmogenic right ventricular cardiomyopathy

AIMS

The differentiation between idiopathic right ventricular outflow tract (RVOT) arrhythmias and early arrhythmogenic right ventricular cardiomyopathy (ARVC) can be challenging. We aimed to assess whether QRS morphological features and coupling interval of ventricular ectopic beats (VEBs) can improve differentiation between the two conditions.

METHODS AND RESULTS

Twenty desmosomal-gene mutation carriers (13 females, mean age 43 years) with no or mild ARVC phenotypic expression and 33 age- and sex-matched subjects with idiopathic RVOT arrhythmias were studied. All patients exhibited isolated monomorphic VEBs with left bundle branch block/inferior axis morphology. The predictive value of ectopic QRS morphology and coupling interval was evaluated. Five ectopic QRS features were significantly more common in desmosomal-gene mutation carriers than in idiopathic RVOT-ventricular arrhythmia patients: maximal QRS duration >160 ms (60 vs. 27%, P = 0.02), intrinsicoid deflection time >80 ms (65 vs. 24%, P = 0.01), initial QRS slurring (40 vs. 12%, P = 0.04), QS pattern in lead V1 (90 vs. 36%, P < 0.001), and QRS axis >90° in limb leads (60 vs. 24%, P = 0.01). In the multivariate analysis, intrinsicoid deflection time >80 ms [odds ratio (OR) = 9.9], QS pattern in lead V1 (OR = 28), and QRS axis >90° (OR = 5.7) remained independent predictors of early ARVC. The coupling interval did not differ between the two groups.

CONCLUSIONS

In patients with RVOT VEBs and no major electrocardiographic or echocardiographic abnormalities, the ectopic QRS morphology aids in the differential diagnosis between idiopathic RVOT arrhythmias and early ARVC.

Identification of established arrhythmogenic right ventricular cardiomyopathy mutation in a patient with the contrasting phenotype of hypertrophic cardiomyopathy

Background

Advances in the nucleic acid sequencing technologies have ushered in the era of genetic-based “precision medicine”. Applications of the genetic discoveries to practice of medicine, however, are hindered by phenotypic variability of the genetic variants. The report illustrates extreme pleiotropic phenotypes associated with an established causal mutation for hereditary cardiomyopathy.

Case presentation

We report a 61-year old white female who presented with syncope and echocardiographic and cardiac magnetic resonance (CMR) imaging findings consistent with the diagnosis of hypertrophic cardiomyopathy (HCM). The electrocardiogram, however, showed a QRS pattern resembling an Epsilon wave, a feature of arrhythmogenic right ventricular cardiomyopathy (ARVC). Whole exome sequencing (mean depth of coverage of exons 178X) analysis did not identify a pathogenic variant in the known HCM genes but identified an established causal mutation for ARVC. The mutation involves a canonical splice accepter site (c.2146-1G > C) in the PKP2 gene, which encodes plakophillin 2. Sanger sequencing confirmed the mutation. PKP2 is the most common causal gene for ARVC but has not been implicated in HCM. Findings on echocardiography and CMR during the course of 4-year follow up showed septal hypertrophy and a hyperdynamic left ventricle, consistent with the diagnosis of HCM. However, neither baseline nor follow up echocardiography and CMR studies showed evidence of ARVC. The right ventricle was normal in size, thickness, and function and there was no evidence of fibro-fatty infiltration in the myocardium.

Conclusions

The patient carries an established pathogenic mutation for ARVC and a subtle finding of ARVC but exhibits the classic phenotype of HCM, a contrasting phenotype to ARVC. The case illustrates the need for detailed phenotypic characterization for patients with hereditary cardiomyopathies as well as the challenges physicians face in applying the genetic discoveries in practicing genetic-based “precision medicine”.

Electronic supplementary material

The online version of this article (doi:10.1186/s12881-017-0385-8) contains supplementary material, which is available to authorized users.

How to develop a clinic for sudden cardiac arrest survivors and families of non-survivors

The investigation of the aetiology of sudden cardiac arrest or death in a young person combines features of a traditional clinical medical examination with those of forensic medicine. Nuances of the immediate peri-event history, when available, can be paramount. New genetic tools have greatly improved the yield of such investigations, but they must be carefully interpreted by genetic specialists. The approach to surviving patients, their family members, and to family members of non-survivors is best achieved in a structured programme that includes all appropriate specialists and support personnel. As an example, this may include all appropriate paediatric and internal medicine specialists, a geneticist, a genetic counsellor, a clinical psychologist, nurse specialist(s), and a programme coordinator. This family-centred strategy affords the patient, if surviving, and all family members the necessary emotional and medical support while at the same time providing the necessary diagnostic and therapeutic approaches.

Murine Electrophysiological Models of Cardiac Arrhythmogenesis

Cardiac arrhythmias can follow disruption of the normal cellular electrophysiological processes underlying excitable activity and their tissue propagation as coherent wavefronts from the primary sinoatrial node pacemaker, through the atria, conducting structures and ventricular myocardium. These physiological events are driven by interacting, voltage-dependent, processes of activation, inactivation, and recovery in the ion channels present in cardiomyocyte membranes. Generation and conduction of these events are further modulated by intracellular Ca2+ homeostasis, and metabolic and structural change. This review describes experimental studies on murine models for known clinical arrhythmic conditions in which these mechanisms were modified by genetic, physiological, or pharmacological manipulation. These exemplars yielded molecular, physiological, and structural phenotypes often directly translatable to their corresponding clinical conditions, which could be investigated at the molecular, cellular, tissue, organ, and whole animal levels. Arrhythmogenesis could be explored during normal pacing activity, regular stimulation, following imposed extra-stimuli, or during progressively incremented steady pacing frequencies. Arrhythmic substrate was identified with temporal and spatial functional heterogeneities predisposing to reentrant excitation phenomena. These could arise from abnormalities in cardiac pacing function, tissue electrical connectivity, and cellular excitation and recovery. Triggering events during or following recovery from action potential excitation could thereby lead to sustained arrhythmia. These surface membrane processes were modified by alterations in cellular Ca2+ homeostasis and energetics, as well as cellular and tissue structural change. Study of murine systems thus offers major insights into both our understanding of normal cardiac activity and its propagation, and their relationship to mechanisms generating clinical arrhythmias.

Exercise testing for long-term follow-up in arrhythmogenic right ventricular cardiomyopathy

OBJECTIVES

We investigated arrhythmia, electrocardiography and physical work capacity (PWC) in the follow-up of ARVC.

DESIGN

Twenty-three patients (13 men; age 41±12years) fulfilling diagnostic criteria were re-investigated after at least five years.

RESULTS

Ventricular arrhythmia during exercise testing (ET) was present in 14 patients (61%) and showed variation between examinations. In eleven (48%), complex ventricular ectopic activity was observed at peak exercise or immediately thereafter. Mutations known to be pathogenic in ARVC were present in 13 patients (57%) of which 11 developed complex ventricular arrhythmia at ET. PWC at baseline was 190±66W (104±26%) decreasing to 151±61W (91±23%, p=0.008) after 10.7years.

CONCLUSION

The appearance of ventricular arrhythmia during exercise testing showed temporal variation but was frequent in patients with relevant genetic mutation. Physical exercise capacity decreased over time in patients with ARVC in excess to the age-related deterioration and regardless of medication.

2015 update on the diagnosis and management of arrhythmogenic right ventricular cardiomyopathy

PURPOSE OF REVIEW

This review will discuss the recent advances in the diagnosis and management of arrhythmogenic right ventricular cardiomyopathy (ARVC).

RECENT FINDINGS

Since the first detailed clinical description of the disease in 1982, we have learned much about the genetics, pathophysiology, diagnosis, and management of ARVC. We now appreciate that pathogenic mutations in desmosomal genes are the most common genetic finding. Although the right ventricle is mostly affected, left ventricular involvement is being increasingly recognized. Electrical instability precipitating sudden cardiac death often presents before structural abnormalities, and therefore early accurate diagnosis is of utmost importance. The broad spectrum of phenotypic variation, age-related penetrance, and lack of a definitive diagnostic test make the clinical diagnosis challenging. The diagnosis is made by fulfilling the 2010 Task Force criteria. Today, genetic testing and cardiac MRI play an important role in the diagnosis. Implantable cardioverter defibrillator implantation is the only lifesaving therapy available today for a subset of patients. In patients with recurrent ventricular arrhythmias, epicardial catheter ablation has demonstrated improved outcomes compared with endocardial ablation. Exercise restriction may delay the progression of disease.

SUMMARY

ARVC is predominantly associated with mutations in desmosomal genes with incomplete penetrance and variable expressivity. Ventricular electrical instability is the hallmark of ARVC, often occurring before structural abnormalities. Goals in the evaluation and management of ARVC are early diagnosis, risk stratification for sudden cardiac death, minimizing ventricular arrhythmias, and delaying the progression of disease.

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.

Exercise-induced Ventricular Tachycardia/Ventricular Fibrillation in the Normal Heart: Risk Stratification and Management

Exercise-induced ventricular tachycardia (VT) rarely occurs in the absence of organic heart disease. Idiopathic monomorphic VT has an excellent prognosis. The main aspect of the risk stratification process is recognizing subtle forms of organic heart disease, particularly arrhythmogenic right ventricular cardiomyopathy. Exercise-induced polymorphic VT is potentially malignant. Exercise-induced polymorphic VT has also been seen in mitral valve prolapse. Some patients with stable coronary disease, and even healthy athletes, sometimes have short bursts of polymorphic VT during exercise tests but these arrhythmias are usually not reproducible during repeated testing and have unknown long-term clinical significance.

Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia (ARVC/D): Review of 16 Pediatric Cases and a Proposal of Modified Pediatric Criteria

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a heritable cardiomyopathy characterized by fibro-fatty replacement of right ventricular myocardium. Diagnostic criteria, established in 1994 and modified in 2010, are based on predominately adult manifestations of ARVC/D. The goal of this paper is to review a single-center experience with pediatric ARVC/D and propose modifications of current diagnostic criteria to appropriately include pediatric ARVC/D. We identified 16 pediatric cases of ARVC/D from our tertiary care center. Patient demographics, presentation, course, genetic testing, and family history were reviewed. Sixteen patients were diagnosed with ARVC/D through the modified diagnostic criteria, genetic testing, and pathology. Five patients had positive family histories. Five patients presented with cardiac arrest, and six were found to have ventricular tachycardia. Two patients presented with heart failure. Six autopsies, six explanted hearts, and three biopsies found massive fibro-fatty infiltration of the right ventricular wall. Six patients underwent heart transplantation, and two have received automatic implantable cardioverter defibrillator. Two patients had identifiable genetic mutations previously noted in the literature. One patient had a novel mutation of a known ARVC/D gene. Many pediatric patients do not meet the current ARVC/D diagnostic criteria, resulting in delays in diagnosis and treatment. The current criteria need further revision to encompass pediatric manifestations of ARVC/D. In our opinion, pathological and clinical findings alone are sufficient for accurate diagnosis of pediatric ARVC/D. Creating modified pediatric criteria would facilitate prompt diagnosis and management of ARVC/D and facilitate structured research with the goal of improving outcomes.

Arrhythmogenic right ventricular cardiomyopathy, clinical manifestations, and diagnosis

This review aims to give an update on the pathogenesis, clinical manifestations, and diagnosis of arrhythmogenic right ventricular cardiomyopathy (ARVC). Arrhythmogenic right ventricular cardiomyopathy is mainly an autosomal dominant inherited disease linked to mutations in genes encoding desmosomes or desmosome-related proteins. Classic symptoms include palpitations, cardiac syncope, and aborted cardiac arrest due to ventricular arrhythmias. Heart failure may develop in later stages. Diagnosis is based on the presence of major and minor criteria from the Task Force Criteria revised in 2010 (TFC 2010), which includes evaluation of findings from six different diagnostic categories. Based on this, patients are classified as having possible, borderline, or definite ARVC. Imaging is important in ARVC diagnosis, including both echocardiography and cardiac magnetic resonance imaging for detecting structural and functional abnormalities, but importantly these findings may occur after electrical alterations and ventricular arrhythmias. Electrocardiograms (ECGs) and signal-averaged ECGs are analysed for depolarization and repolarization abnormalities, including T-wave inversions as the most common ECG alteration. Ventricular arrhythmias are common in ARVC and are considered a major diagnostic criterion if originating from the RV inferior wall or apex. Family history of ARVC and detection of an ARVC-related mutation are included in the TFC 2010 and emphasize the importance of family screening. Electrophysiological studies are not included in the diagnostic criteria, but may be important for differential diagnosis including RV outflow tract tachycardia. Further differential diagnoses include sarcoidosis, congenital abnormalities, myocarditis, pulmonary hypertension, dilated cardiomyopathy, and athletic cardiac adaptation, which may mimic ARVC.

Management of patients with Arrhythmogenic Right Ventricular Cardiomyopathy in the Nordic countries

OBJECTIVES

Diagnostics of patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) are complex, and based on the 2010 Task Force document including different diagnostic modalities. However, recommendations for clinical management and follow-up of patients with ARVC and their relatives are sparse. This paper aims to give a practical overview of management strategies, risk stratification, and selection of appropriate therapies for patients with ARVC and their family members.

DESIGN

This paper summarizes follow-up and treatment strategies in ARVC patients in the Nordic countries. The author group represents cardiologists who are actively involved in the Nordic ARVC Registry which was established in 2009, and contains prospectively collected clinical data from more than 590 ARVC patients from Denmark, Norway, Sweden, and Finland.

RESULTS

Different approaches of management and follow-up are required in patients with definite ARVC and in genetic-mutation-positive family members. Furthermore, ARVC patients with and without implantable cardioverter defibrillators (ICDs) require different follow-up strategies.

CONCLUSION

Careful follow-up is required in patients with ARVC diagnosis to evaluate the need of anti-arrhythmic therapy and ICD implantation. Mutation-positive family members should be followed regularly for detection of early disease and risk stratification of ventricular arrhythmias.