Efficacy of antiarrhythmic drugs in patients with arrhythmogenic right ventricular disease. Results in patients with inducible and noninducible ventricular tachycardia

Long-Term Follow-Up Data on Flecainide Use as an Antiarrhythmic in Arrhythmogenic Right Ventricular Cardiomyopathy: A Multicenter Study

BACKGROUND

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy associated with a high risk of ventricular arrhythmia (VA). Several animal models have been used to postulate a therapeutic role of the inhibition of the ryanodine 2 receptor via the use of flecainide for this disease. Clinical data describing its use are scarce, however, especially in patients without implantable cardioverter-defibrillators or with left ventricular (LV) involvement.

OBJECTIVES

This study sought to report safety and effectiveness long-term, multicenter data on the impact of flecainide therapy on arrhythmic outcomes in patients with a definite diagnosis of ARVC.

METHODS

Patients with definite ARVC receiving flecainide at 12 academic institutions were enrolled in the study. Baseline was defined as the time of flecainide initiation. Premature ventricular complex burdens, nonsustained ventricular tachycardia (NSVT) rates, and sustained VA yearly/rates were collected and compared while on and off flecainide. Side effects and flecainide discontinuation were tracked. Analyses were performed in the overall cohort as well as stratifying for genotype (gene positive vs negative; plakohpillin-2 [PKP-2] vs non PKP-2) and for LV involvement.

RESULTS

A total of 191 patients (37.9 ± 13.7 years; 69.0% male; 89.0% probands; 59.2% having implantable cardioverter-defibrillators; 33.0% with prior VA; 43.5% PKP-2+; LV ejection fraction 55.9 ± 7.3%; right ventricular ejection fraction 44.5 ± 10.5% at baseline) were enrolled, with 66 patients (34.6%) showing LV involvement. The median dose of flecainide was 200 mg/d [150-200 mg/d], with 166 patients (86.9%) also taking a beta-blocker. The median follow-up time on flecainide was 4.2 years [1.9-6.3 years]. Flecainide was well tolerated, with a low (7.9%) discontinuation rate. After flecainide initiation, a significant reduction in the 24-hour premature ventricular complex burden and in the rate of nonsustained ventricular tachycardia was observed (2,190 vs 418; P < 0.001; 35.1% vs 21.5%; P = 0.003). For patients with prior VA events, a significant reduction in the amount of VA episodes/y (1.1 [0.4-1.6] episodes/y vs 0 [0-0.3] episodes/y; P < 0.001) was observed. These safety and effectiveness findings were consistent across genotype subgroups, as well as in patients with and without LV involvement.

CONCLUSIONS

Flecainide use had a favorable safety profile and was associated with an observed to a significant reduction in arrhythmic burden in patients with ARVC, irrespective of the underlying genotype or LV involvement.

Arrhythmogenic Right Ventricular Cardiomyopathy: A Comprehensive Review

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

Coonar A, Gimeno JR, Lazaros G, Lerakis S, Mestroni L, Papadopoulos G, Pecchia L, Prandi FR, Syrris P, Cadrin-Turigny J, Vasilakis A, Saffitz JE, Gaetano Thiene S, Elliott PM, Kaski JP, McKenna WJ, Bossone E, Limongelli G, Tsatsopoulou A. Naxos Disease and Related Cardio-Cutaneous Syndromes

Naxos disease is a rare autosomal recessive condition combining arrhythmogenic right ventricular cardiomyopathy, woolly hair, and palmoplantar keratoderma. The first identified causative variant was in the gene encoding the desmosomal protein plakoglobin. Naxos disease exhibits fibro-fatty myocardial replacement with immunohistological abnormalities in cardiac protein and signaling pathways, highlighting the role of inflammation and potential anti-inflammatory treatments. Childhood cutaneous signs precede cardiac features, which are diagnosed by familial and genetic evaluation, electrocardiography and cardiac imaging. Disease progression necessitates holistic care with risk management and lifestyle adjustments, often needing treatment for arrhythmia and heart failure. Similar phenotypes have been linked to desmoplakin and rarely desmocollin2 gene variants, highlighting the importance of familial and genetic evaluation. This document summarizes current knowledge on Naxos disease and related cardiocutaneous syndromes and initiates an international endeavor to collect and study all global cases, aiming to improve understanding, treatment, and patient care through shared data and research.

Management of arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a disease characterised by fibrofatty replacement of the ventricular myocardium due to specific mutations, leading to ventricular arrhythmias and sudden cardiac death. Treating this condition can be challenging due to progressive fibrosis, phenotypic variations and small patient cohorts limiting the feasibility of conducting meaningful clinical trials. Although widely used, the evidence base for anti-arrhythmic drugs is limited. Beta-blockers are theoretically sound, yet their efficacy in reducing arrhythmic risk is not robust. Additionally, the impact of sotalol and amiodarone is inconsistent with studies reporting contradictory results. Emerging evidence suggests that combining flecainide and bisoprolol may be efficacious.Radiofrequency ablation has shown some potential in disrupting ventricular tachycardia circuits, with combined endo and epicardial ablation yielding better results which could be considered at the index procedure. In addition, stereotactic radiotherapy may be a future option that can decrease arrhythmias beyond simple scar formation by altering levels of Nav1.5 channels, Connexin 43 and Wnt signalling, potentially modifying myocardial fibrosis.Future therapies, such as adenoviruses and GSk3b modulation, are still in early-stage research. While implantable cardioverter-defibrillator implantation is a key intervention for reducing arrhythmic death, the risks of inappropriate shocks and device complications must be carefully considered.

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

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

Antiarrhythmic Drug Therapy in Arrhythmogenic Right Ventricular Cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a heritable progressive myocardial disorder that predisposes patients to ventricular arrhythmias and sudden cardiac death. Antiarrhythmic medications have an important role in reducing the frequency of ventricular arrhythmias and the morbidity associated with recurrent implantable cardioverter-defibrillator (ICD) shocks. Although several studies have examined the use of antiarrhythmic drugs in ARVC, these have been mostly retrospective in nature and inconsistent in their methodology, patient population and endpoints. Thus, current prescribing practices are largely based on expert opinion and extrapolation from other diseases. Herein, we discuss the major studies of the use of antiarrhythmics in ARVC, present the current approach employed at the Johns Hopkins Hospital and identify areas where further research is needed. Most notably, there is a great need for high-quality studies with consistent methodology and randomized controlled trial data into the use of antiarrhythmic drugs in ARVC. This would improve management of the condition and ensure antiarrhythmic prescribing is based on robust evidence.

Varied Presentation of Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy (ARVD/C): A Case Series

Arrhythmogenic right ventricular dysplasia (ARVD) is a genetically predisposed form of cardiomyopathy that mainly affects young individuals resulting in fatal ventricular arrhythmias leading to sudden cardiac death. ARVD has 50% of cases that involve both the right ventricle (RV) and left ventricle (LV), but only a small number of cases involve an isolated left ventricle. In this case series, five patients (four males and one female) with a diagnosis of ARVD presented to our center with varied clinical presentations across a wide range of age groups. The MRI of all five cases showed dilated right atrium (RA)/RV with right ventricular free wall dyskinesia. Two-dimensional (2D) MRI showed aneurysmal outpouching with diffuse free wall enhancement. Automated implantable cardioverter defibrillator (AICD) was implanted uneventfully in all five patients, and the patients were discharged with oral medications such as low-dose diuretics, beta-blockers, spironolactone, angiotensin-converting enzymes (ACE) inhibitors, amiodarone, and anxiolytics. Until now, the patients were doing well on follow-up visits. The therapeutic management of patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) has evolved over the years and continues to be an important challenge. To further improve risk stratification and treatment of patients, more information is needed on natural history, long-term prognosis, and risk assessment. Special attention should be focused on the identification of patients who would benefit from implantable cardioverter-defibrillator (ICD) implantation in comparison to pharmacological and other nonpharmacological approaches.

Ca2+ dysregulation in cardiac stromal cells sustains fibro-adipose remodeling in Arrhythmogenic Cardiomyopathy and can be modulated by flecainide

BACKGROUND

Cardiac mesenchymal stromal cells (C-MSC) were recently shown to differentiate into adipocytes and myofibroblasts to promote the aberrant remodeling of cardiac tissue that characterizes arrhythmogenic cardiomyopathy (ACM). A calcium (Ca2+) signaling dysfunction, mainly demonstrated in mouse models, is recognized as a mechanism impacting arrhythmic risk in ACM cardiomyocytes. Whether similar mechanisms influence ACM C-MSC fate is still unknown. Thus, we aim to ascertain whether intracellular Ca2+ oscillations and the Ca2+ toolkit are altered in human C-MSC obtained from ACM patients, and to assess their link with C-MSC-specific ACM phenotypes.

METHODS AND RESULTS

ACM C-MSC show enhanced spontaneous Ca2+ oscillations and concomitant increased Ca2+/Calmodulin dependent kinase II (CaMKII) activation compared to control cells. This is manly linked to a constitutive activation of Store-Operated Ca2+ Entry (SOCE), which leads to enhanced Ca2+ release from the endoplasmic reticulum through inositol-1,4,5-trisphosphate receptors. By targeting the Ca2+ handling machinery or CaMKII activity, we demonstrated a causative link between Ca2+ oscillations and fibro-adipogenic differentiation of ACM C-MSC. Genetic silencing of the desmosomal gene PKP2 mimics the remodelling of the Ca2+ signalling machinery occurring in ACM C-MSC. The anti-arrhythmic drug flecainide inhibits intracellular Ca2+ oscillations and fibro-adipogenic differentiation by selectively targeting SOCE.

CONCLUSIONS

Altogether, our results extend the knowledge of Ca2+ dysregulation in ACM to the stromal compartment, as an etiologic mechanism of C-MSC-related ACM phenotypes. A new mode of action of flecainide on a novel mechanistic target is unveiled against the fibro-adipose accumulation in ACM.

Longitudinal Prediction of Ventricular Arrhythmic Risk in Patients With Arrhythmogenic Right Ventricular Cardiomyopathy

BACKGROUND

The arrhythmogenic right ventricular cardiomyopathy (ARVC) risk calculator stratifies risk for incident sustained ventricular arrhythmias (VA) at the time of ARVC diagnosis. However, included risk factors change over time, and how well the ARVC risk calculator performs at follow-up is unknown.

METHODS

This was a retrospective analysis of patients with definite ARVC and without prior sustained VA. Risk factors for VA including age, nonsustained ventricular tachycardia, premature ventricular complex burden, T-wave inversions on electrocardiogram, cardiac syncope, right ventricular function, therapeutic medication use, and exercise intensity were assessed at the time of 2010 Task Force Criteria based ARVC diagnosis and upon repeat evaluations. Changes in these risk factors were analyzed over 5-year follow-up. The 5-year risk of VA was predicted longitudinally using (1) the baseline ARVC risk calculator prediction, (2) the ARVC risk prediction calculated using updated risk factors, and (3) time-varying Cox regression. Discrimination and calibration were assessed in comparison to observed VA event rates.

RESULTS

Four hundred eight patients with ARVC experiencing 132 primary VA events were included. Matched comparison of risk factors at baseline versus at 5 years of follow-up revealed decreased burdens of premature ventricular complexes (-1200/day) and nonsustained ventricular tachycardia (-14%). Presence of significant right ventricular dysfunction and number of T-wave inversions on electrocardiogram were unchanged. Observed risk for VA decreased by 13% by 5 years follow-up. The baseline ARVC risk calculator's ability to predict 5-year VA risk worsened during follow-up (C statistics, 0.83 at diagnosis versus 0.68 at 5 years). Both the updated ARVC risk calculator (C statistics of 0.77) and time-varying Cox regression model (C statistics, 0.77) had strong discrimination. The updated ARVC risk calculator overestimated 5-year VA risk by an average of +6%.

CONCLUSIONS

Risk factors for VA in ARVC are dynamic, and overall risk for incident sustained VA decreases during follow-up. Up-to-date risk factor assessment improves VA risk stratification.

Pharmacologic Management for Ventricular Arrhythmias: Overview of Anti-Arrhythmic Drugs

Ventricular arrhythmias (Vas) are a life-threatening condition and preventable cause of sudden cardiac death (SCD). With the increased utilization of implantable cardiac defibrillators (ICD), the focus of VA management has shifted toward reduction of morbidity from VAs and ICD therapies. Anti-arrhythmic drugs (AADs) can be an important adjunct therapy in the treatment of recurrent VAs. In the treatment of VAs secondary to structural heart disease, amiodarone remains the most well studied and current guideline-directed pharmacologic therapy. Beta blockers also serve as an important adjunct and are a largely underutilized medication with strong evidentiary support. In patients with defined syndromes in structurally normal hearts, AADs can offer tailored therapies in prevention of SCD and improvement in quality of life. Further clinical trials are warranted to investigate the role of newer therapeutic options and for the direct comparison of established AADs.

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.

Arrhythmogenic right ventricular cardiomyopathy in the pediatric population

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

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

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

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

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

Safety and efficacy of flecainide associated with beta-blockers in arrhythmogenic right ventricular cardiomyopathy

AIMS

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy associated with a high risk of ventricular arrhythmia (VA). Current guidelines recommend beta-blockers as first-line medical therapy and if ineffective, sotalol or amiodarone. We describe our experience, as a tertiary centre for ARVC, with the effectiveness and tolerance of flecainide in addition to beta-blockers to prevent VA in ARVC.

METHODS AND RESULTS

We retrospectively included 100 consecutive ARVC patients who received flecainide with beta-blockers between May 1999 and November 2017. Treatment persistence and related side effects were assessed, as was VA-free survival on treatment, 24-h Holter monitoring and programmed ventricular stimulation (PVS) off- and on-treatment. Tolerance was good, with 10% flecainide discontinuations (lack of efficacy in six, atrial fibrillation in one, and side effects in three). No Brugada-induced electrocardiography pattern on flecainide or haemodynamic impairment was reported. Premature ventricular contraction burden at 24-h Holter monitoring was significantly decreased under treatment [median 415 (interquartile range, IQR 97-730) vs. 2370 (1572-3400) at baseline, P < 0.0001, n = 46]. Among the 33 patients with PVS under treatment, PVS was positive in 40% on-treatment vs. 94% off-treatment (P < 0.001). During a median follow-up of 47 months (IQR 23-73), 22 patients presented sustained VA on treatment, corresponding to an event rate of 5% [95% confidence interval (CI) (0.6-9)] at 1 year and 25% [95% CI (14-35)] at 5 years under treatment. No patient died.

CONCLUSION

This study suggests that flecainide and beta-blockers association is complementary to implantable cardioverter-defibrillator and catheter ablation and is safe for treating persistent symptomatic VA in patients with ARVC.

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

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

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

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

Antiarrhythmic therapy and risk of cumulative ventricular arrhythmias in arrhythmogenic right ventricle cardiomyopathy

OBJECTIVES

The aim of our study was to investigate the benefit of antiarrhythmic drugs (AAD) - beta-blockers, sotalol or amiodarone - in a cohort of Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) patients with long-term longitudinal follow up.

BACKGROUND

AAD are prescribed in ARVC to prevent ventricular arrhythmias and control symptoms. However, there are no controlled clinical trials and knowledges regarding the efficacy of AAD in ARVC are limited.

METHODS

The study population included 123 patients with definite diagnosis of ARVC and ≥ 2 clinical evaluations. The primary outcome was a composite of sudden cardiac death (SCD)/recurrent major ventricular arrythmias (MVA): sudden cardiac arrest, sustained ventricular tachycardia (VT) and appropriate implantable cardioverter defibrillator interventions, including recurrent events in patients with >1 MVA. Time to first event (SCD or MVA) was considered as secondary composite endpoint.

RESULTS

Sixteen patients were taking AAD at baseline and 75 started at least one AAD during a median follow-up of 132 months [61-255]. A total of 37 patients experienced ≥1 MVA with a total count of 83 recurrent MVA. After adoption of a propensity score analysis, no AAD were associated with lower risk of recurrent MVA. However, if dosage of AAD was considered, beta-blockers at >50% target dose were associated with a significant reduction in the risk of MVA compared to patients not taking beta-blockers (HR 0.10, 95% CI 0.02-0.46, p = 0.004).

CONCLUSIONS

In a large cohort of ARVC patients with a long-term follow-up, only beta-blockers administrated at >50% target dose were associated with lower risk of SCD/recurrent MVA.

Deciphering DSC2 arrhythmogenic cardiomyopathy electrical instability: From ion channels to ECG and tailored drug therapy

BACKGROUND

Severe ventricular rhythm disturbances are the hallmark of arrhythmogenic cardiomyopathy (ACM), and are often explained by structural conduction abnormalities. However, comprehensive investigations of ACM cell electrical instability are lacking. This study aimed to elucidate early electrical myogenic signature of ACM.

METHODS

We investigated a 41-year-old ACM patient with a missense mutation (c.394C>T) in the DSC2 gene, which encodes desmocollin 2. Pathogenicity of this variant was confirmed using a zebrafish DSC2 model system. Control and DSC2 patient-derived pluripotent stem cells were reprogrammed and differentiated into cardiomyocytes (hiPSC-CM) to examine the specific electromechanical phenotype and its modulation by antiarrhythmic drugs (AADs). Samples of the patient's heart and hiPSC-CM were examined to identify molecular and cellular alterations.

RESULTS

A shortened action potential duration was associated with reduced Ca2+ current density and increased K+ current density. This finding led to the elucidation of previously unknown abnormal repolarization dynamics in ACM patients. Moreover, the Ca2+ mobilised during transients was decreased, and the Ca2+ sparks frequency was increased. AAD testing revealed the following: (1) flecainide normalised Ca2+ transients and significantly decreased Ca2+ spark occurrence and (2) sotalol significantly lengthened the action potential and normalised the cells' contractile properties.

CONCLUSIONS

Thorough analysis of hiPSC-CM derived from the DSC2 patient revealed abnormal repolarization dynamics, prompting the discovery of a short QT interval in some ACM patients. Overall, these results confirm a myogenic origin of ACM electrical instability and provide a rationale for prescribing class 1 and 3 AADs in ACM patients with increased ventricular repolarization reserve.

Arrhythmogenic Right Ventricular Cardiomyopathy in Pediatric Patients: An Important but Underrecognized Clinical Entity

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy characterized by fibrofatty infiltration of predominantly the right ventricular (RV) myocardium. Affected patients typically present as young adults with hemodynamically stable ventricular tachycardia, although pediatric cases are increasingly recognized. These young subjects often have a more severe phenotype with a high risk of sudden cardiac death (SCD) and progression toward heart failure. Diagnosis of ARVC is made by combining multiple sources of information as prescribed by the consensus-based Task Force Criteria. The description of Naxos disease, a fully penetrant autosomal recessive disorder that is associated with ARVC and a cutaneous phenotype of palmoplantar keratoderma and wooly hair facilitated the identification of the genetic cause of ARVC. At present, approximately 60% of patients are found to carry a pathogenic variant in one of five genes associated with the cardiac desmosome. The incomplete penetrance and variable expressivity of these variants however implies an important role for environmental factors, of which participation in endurance exercise is a strong risk factor. Since there currently is no definite cure for ARVC, disease management is directed toward symptom reduction, delay of disease progression, and prevention of SCD. This clinically focused review describes the spectrum of ARVC among children and adolescents, the genetic architecture underlying this disease, the cardio-cutaneous syndromes that led to its identification, and current diagnostic and therapeutic strategies in pediatric ARVC subjects.

Therapie von Herzrhythmusstörungen mit Antiarrhythmika: kein Ende einer Ära

Antiarrhythmika sind eine Medikamentengruppe, die vor mehr als 100 Jahren eingeführt wurde. Jahrzehntelang wurden sie relativ breit und großzügig eingesetzt. Die Erkenntnis, dass proarrhythmische Effekte relativ häufig sind, und die Entwicklung neuer nicht medikamentöser Behandlungsalternativen (z. B. die Katheterablation bei Vorhofflimmern) haben dazu geführt, dass sich ihr klinischer Stellenwert in den letzten Jahren geändert hat. Schon seit Längerem wird das Ende der Antiarrhythmikaära prophezeit. In der Realität ergibt sich allerdings ein anderes Bild. Registerdaten zeigen, dass fast die Hälfte der Patienten mit Vorhofflimmern, die sich einer Katheterablation unterziehen, im weiteren Verlauf ein Antiarrhythmikum erhält. Eine unverändert wichtige Rolle spielen Antiarrhythmika (insbesondere Amiodaron) auch im Notfall und bei Patienten mit häufigen malignen ventrikulären Arrhythmien. Einen zunehmend relevanter werdenden Anwendungsbereich stellen angeborene Arrhythmien (langes-QT-Syndrom, Brugada-Syndrom, katecholaminerge polymorphe Kammertachykardien) dar. Antiarrhythmika gehören damit weiterhin zum Armamentarium des rhythmologisch orientierten Arztes. Es darf gehofft werden, dass neue Formen des EKG- und Patienten-Monitorings (z. B. Smartphone-EKGs) dazu betragen werden, die Überprüfung der Therapiewirksamkeit zu vereinfachen und die Therapiesicherheit zu optimieren.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

Propafenone-Induced QRS Widening in a Child With Arrhythmogenic Right Ventricular Cardiomyopathy: A Case Report and Literatures Review

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a rare cardiac disease in children, and can lead to sudden cardiac death (SCD). Propafenone is classI_C antiarrhythmic medication, and its side effects include cardiovascular compromise in the form of hypotension, bradycardia, ventricular dysrhythmias, QRS widening, and heart block. Propafenone has been reported causing QRS widening, but rarely in children. In this article, we presented a boy diagnosed with ARVC who meets diagnosis criteria based on typical symptoms, electrocardiograph (ECG), echocardiography (Echo), cardiac magnetic resonance imaging (CMRI), sudden death of first family member, and genetic mutation in desmosomal DSG2 gene. Antiarrhythmic drugs have been used for treating patients with ARVC, by eliminating or decreasing the occurring frequency of arrhythmias. As his ECG showed frequent premature ventricular contractions (PVC), he was prescribed with oral propafenone. One day after the drug treatment, he presented dizziness accompanied with significant QRS widening in ECG. His dizziness was improved when Propafenone dose was reduced, and resolved after sotalol replacement, with ECG recovered to nearly normal state of QRS. Propafenone may lead to QRS widening and increase the risk of ventricular tachycardia, and it may not reduce ARVC associated mortality. This report may serve as a precaution for clinicians when providing cares for ARVC patients.

Ventricular Arrhythmias

Ventricular tachycardia is commonly seen in medical practice. It may be completely benign or portend high risk for sudden cardiac death. Therefore, it is important that clinicians be familiar with and able to promptly recognize and manage ventricular tachycardia when confronted with it clinically. In many cases, curative therapy for a given ventricular arrhythmia may be provided after a thorough understanding of the underlying substrate and mechanism. In this article, the authors broadly review the current classification of the different ventricular arrhythmias encountered in medical practice, provide brief background regarding the different mechanisms, and discuss practical diagnosis and management scenarios.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

Anti-arrhythmic therapy in patients with non-ischemic cardiomyopathy

Implantable cardiac defibrillators (ICD) are the foundation of therapy for the prevention of sudden cardiac death. While ICDs prevent SCD, they do not prevent the occurrence of ventricular arrhythmias which are usually symptomatic. Though catheter ablation has been successful in substrate modification of ventricular tachycardia in patients with ischemic cardiomyopathy, there is much less evidence to support its use in non-ischemic cardiomyopathy. Therefore, anti-arrhythmic drugs (AADs) are an essential adjunctive therapy for secondary prevention of ventricular arrhythmias in patients with non-ischemic cardiomyopathy. In patients with hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM), the prevalence of ventricular arrhythmias correlates with the volume of scar as characterized by late gadolinium enhancement. Beta-blockers forms the cornerstone of treatment to prevent ventricular arrhythmias in both HCM and DCM. Disopyramide is an important therapeutic option in HCM as it provides both negative inotropy which reduces obstruction as well as lass I anti-arrhythmic action. In DCM sotalol, through is combined beta-blocking and class III AD effects, significantly reduces the burden of ventricular arrhythmias. Though amiodarone is efficacious in the prevention of ventricular arrhythmias in both HCM and DCM, its use is limited by its side-effects profile. Evidence for AAD therapy for arrhythmogenic right ventricular dysplasia (ARVD) is limited by its low prevalence and lack of studies. ICDs have been shown to reduce SCD regardless of whether patients are receiving AAD therapy.

Does Sotalol Still Have a Role in the Management of Arrhythmias?

Despite proven effectiveness in treating tachyarrhythmias, sotalol is proarrhythmic and can cause torsades de pointes. Given the emergence of studies that show no benefit from rhythm control strategies in managing atrial fibrillation, as well as the introduction of nonpharmacological approaches to treating arrhythmias, we felt it necessary to ascertain if there was any role for sotalol given its side effects. Review of the literature regarding sotalol use in the prevention and treatment of supraventricular and ventricular tachyarrhythmias seems to show that more effective and safer agents and nonpharmacological alternatives are currently available. However, sotalol still seems to be useful in preventing supraventricular tachyarrhythmias postcardiac surgery and in reverting hemodynamically stable sustained ventricular tachycardias in the setting of coronary artery disease. Its role in the prevention of tachyarrhythmias in the setting of arrhythmogenic right ventricular cardiomyopathy requires further investigation.

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.

Right ventricular dysplasia: management and treatment in light of current evidence

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a rare cardiovascular disease that predisposes to ventricular arrhythmias potentially leading to sudden cardiac death (SCD). ARVC varies considerably with multiple clinical presentations, ranging from no symptoms to cardiac arrhythmias to SCD. ARVC prevalence is not well known, but the estimated prevalence in the general population is 1:5000. Diagnosis of ARVC can be made by using the Revised European Society of Cardiology criteria for ARVC that includes ventricular structural and functional changes, ECG abnormalities, arrhythmias, family and genetic factors. The management of ARVC is focused on prevention of lethal events such as SCD. Implantable cardioverter defibrillator placement is the only proven mortality benefit in treatment of ARVC. Other treatment strategies include medications such as beta blockers and antiarrhythmics, radiofrequency ablation, surgery, cardiac transplantation, and lifestyle changes. All these interventions help in symptomatic treatment but none of them have proved to decrease mortality rates. ARVC is a progressive disease that leads to SCD if not treated appropriately. Management of these diseases has been a challenge for physicians. With the advent of technology and many new drugs/devices under clinical investigation, this might change in the future. However, while advances in technologies have helped elucidate many aspects of these diseases, many mysteries still remain of this unique disease. With continued research, we can expect more cost-effective and patient-friendly drug therapies and ablation techniques to be developed in the near future.

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) in clinical practice

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is an inherited myocardial disease characterized by fibro-fatty replacement of the right ventricular myocardium, and associated with paroxysmal ventricular arrhythmias and sudden cardiac death (SCD). It is currently the second most common cause of SCD after hypertrophic cardiomyopathy in young people <35 years of age, causing up to 20% of deaths in this patient population. This condition has a male preponderance and is more commonly found in individuals of Italian and Greek descent. To date, there is no single diagnostic test for ARVC/D and the diagnosis is made based on clinical, electrocardiographic, and radiological findings according to the Revised 2010 Task Force Criteria. In this review, we will discuss the mainstay treatment which includes pharmacotherapy, implantable cardioverter-defibrillator insertion for abortion of sudden cardiac death, and in the advanced stages of the disease cardiac transplantation.

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.

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.