The epithelial barrier theory and its associated diseases.

The prevalence of many chronic noncommunicable diseases has been steadily rising over the past six decades. During this time, over 350,000 new chemical substances have been introduced to the lives of humans. In recent years, the epithelial barrier theory came to light explaining the growing prevalence and exacerbations of these diseases worldwide. It attributes their onset to a functionally impaired epithelial barrier triggered by the toxicity of the exposed substances, associated with microbial dysbiosis, immune system activation, and inflammation. Diseases encompassed by the epithelial barrier theory share common features such as an increased prevalence after the 1960s or 2000s that cannot (solely) be accounted for by the emergence of improved diagnostic methods. Other common traits include epithelial barrier defects, microbial dysbiosis with loss of commensals and colonization of opportunistic pathogens, and circulating inflammatory cells and cytokines. In addition, practically unrelated diseases that fulfill these criteria have started to emerge as multimorbidities during the last decades. Here, we provide a comprehensive overview of diseases encompassed by the epithelial barrier theory and discuss evidence and similarities for their epidemiology, genetic susceptibility, epithelial barrier dysfunction, microbial dysbiosis, and tissue inflammation.

Novel plasma biomarkers predicting biventricular involvement in arrhythmogenic right ventricular cardiomyopathy.

BACKGROUND: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited heart muscle disease characterized by fibrofatty replacement of the myocardium and ventricular arrhythmias. Biventricular involvement in ARVC may lead to heart failure. This study aimed to investigate the role of plasma biomarkers soluble (s)ST2, Galectin-3 (Gal-3) and GDF-15 in predicting biventricular involvement and adverse outcomes in ARVC. METHODS AND RESULTS: ARVC patients from 2 independent cohorts, were studied. The Bejing (Chinese) cohort (n = 108) was the discovery cohort, whereas the Zurich (Swiss) cohort (n = 47) served as validation. All patients had a definite ARVC diagnosis at time of blood withdrawal. Biomarkers were independently correlated with NT-proBNP and left ventricular (LV)-function. ARVC patients with LV involvement had higher levels of sST2 and GDF-15 as compared to controls and patients with isolated right ventricle (RV) involvement. sST2 and GDF-15 were significantly correlated with late gadolinium enhancement in CMR and with adverse heart failure outcomes. Gal-3 was elevated in ARVC patients with and without LV involvement. The combined use of the three biomarkers (sST2, GDF-15 and NT-proBNP) showed the best performance in predicting LV involvement in both cohorts. Plasma drawn from the coronary arteries and coronary sinus indicated a transmyocardial elevation of sST2, but no transmyocardial gradient of GDF-15. After heart transplantation, both sST2 and GDF-15 returned to near-normal levels. CONCLUSION: Our study showed that sST2 and GDF-15 may predict biventricular involvement in ARVC. The combined use of sST2, GDF-15 and NT-proBNP showed the best prediction of biventricular involvement in ARVC.

Clinical predictors of left ventricular involvement in arrhythmogenic right ventricular cardiomyopathy.

AIM: The impact of clinical characteristics for predicting patterns of ventricular involvement in arrhythmogenic right ventricular cardiomyopathy (ARVC) are not well defined. The aims of this study were to characterize different patterns of ventricular involvement in patients with ARVC and to stratify them based on clinical characteristics exercise and underlying genetic mutations. METHODS: Sixty-four patients with definite ARVC from the Swiss ARVC Registry were enrolled. Right and left ventricular functions were assessed at baseline and most recent follow-up. All patients received genetic testing. Serum high-sensitivity cardiac Troponin T (hs-cTNT) and N-terminal of pro-brain natriuretic peptide (NT-proBNP) were determined at baseline. RESULTS: Thirty-five patients (55%) had isolated right ventricular (RV) involvement, 12 patients (19%) had biventricular (BiV) involvement at baseline and 17 patients (26%) had no left ventricular (LV) involvement at baseline, but revealed new onset LV involvement at mean follow-up of 7.5 years. Patients with BiV involvement at baseline harbored significantly more desmoplakin and multiple mutations and patients with new-onset LV involvement at follow-up frequently showed non-desmosomal mutations. Patients engaging in competitive sports more often showed LV involvement during follow-up. Baseline hs-cTNT and NT-proBNP levels were higher in patients developing BiV involvement. CONCLUSION: Multiple mutations are more common in ARVC patients with BiV involvement. Competitive exercise is associated with disease progression resulting in BiV involvement. Hs-cTNT and NT-proBNP are elevated in patients with BiV involvement and may help to identify ARVC patients at risk for developing BiV disease.

Immunology of COVID-19: Mechanisms, clinical outcome, diagnostics, and perspectives-A report of the European Academy of Allergy and Clinical Immunology (EAACI).

With the worldwide spread of the novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) resulting in declaration of a pandemic by the World Health Organization (WHO) on March 11, 2020, the SARS-CoV-2-induced coronavirus disease-19 (COVID-19) has become one of the main challenges of our times. The high infection rate and the severe disease course led to major safety and social restriction measures worldwide. There is an urgent need of unbiased expert knowledge guiding the development of efficient treatment and prevention strategies. This report summarizes current immunological data on mechanisms associated with the SARS-CoV-2 infection and COVID-19 development and progression to the most severe forms. We characterize the differences between adequate innate and adaptive immune response in mild disease and the deep immune dysfunction in the severe multiorgan disease. The similarities of the human immune response to SARS-CoV-2 and the SARS-CoV and MERS-CoV are underlined. We also summarize known and potential SARS-CoV-2 receptors on epithelial barriers, immune cells, endothelium and clinically involved organs such as lung, gut, kidney, cardiovascular, and neuronal system. Finally, we discuss the known and potential mechanisms underlying the involvement of comorbidities, gender, and age in development of COVID-19. Consequently, we highlight the knowledge gaps and urgent research requirements to provide a quick roadmap for ongoing and needed COVID-19 studies.

An autoantibody identifies arrhythmogenic right ventricular cardiomyopathy and participates in its pathogenesis.

Aims: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is characterized by right ventricular myocardial replacement and life-threatening ventricular arrhythmias. Desmosomal gene mutations are sometimes identified, but clinical and genetic diagnosis remains challenging. Desmosomal skin disorders can be caused by desmosomal gene mutations or autoantibodies. We sought to determine if anti-desmosome antibodies are present in subjects with ARVC. Methods and results: We evaluated ARVC subjects and controls for antibodies to cardiac desmosomal cadherin proteins. Desmoglein-2 (DSG2), desmocollin-2, and N-cadherin proteins on western blots were exposed to sera, in primary and validation cohorts of subjects and controls, as well as the naturally occurring Boxer dog model of ARVC. We identified anti-DSG2 antibodies in 12/12 and 25/25 definite ARVC cohorts and 7/8 borderline subjects. Antibody was absent in 11/12, faint in 1/12, and absent in 20/20 of two control cohorts. Anti-DSG2 antibodies were present in 10/10 Boxer dogs with ARVC, and absent in 18/18 without. In humans, the level of anti-DSG2 antibodies correlated with the burden of premature ventricular contractions (r = 0.70), and antibodies caused gap junction dysfunction, a common feature of ARVC, in vitro. Anti-DSG2 antibodies were present in ARVC subjects regardless of whether an underlying mutation was identified, or which mutation was present. A disease-specific DSG2 epitope was identified. Conclusion: Anti-DSG2 antibodies are a sensitive and specific biomarker for ARVC. The development of autoimmunity as a result of target-related mutations is unique. Anti-DSG2 antibodies likely explain the cardiac inflammation that is frequently identified in ARVC and may represent a new therapeutic target.

Value of a novel 16-lead High-Definition ECG machine to detect conduction abnormalities in structural heart disease.

BACKGROUND: Depolarization abnormalities are hardly detectable by standard 12-lead electrocardiogram (ECG) in some patients. OBJECTIVE: To evaluate the value of the 16-lead High-Definition (HD)-ECG machine to record conduction abnormalities including Epsilon waves in patients with structural heart disease. METHODS: Tracings with 12-lead ECG, 16-lead HD-ECG, and signal-averaged ECG were studied. RESULTS: (1) Case of severe coronary artery disease (CAD): On 16-lead HD-ECG, a tiny intra-QRS signal was noted in lead III, a prolonged P wave in lead II, and fragmentation on top of lead aVL and lead aVF. Proper automatic measurement of the prolonged P wave measuring 190 ms was noted. Signal-averaging by 16-lead HD-ECG in lead III showed the intra-QRS fragmentation and P wave prolongation of 180 ms. (2) First patient with arrhythmogenic right ventricular dysplasia (ARVD): Standard 12-lead ECG indicated Epsilon waves in lead III, V2, V3, and inverted T waves in V1-V3. 16-lead HD-ECG indicated QRS prolongation in lead II, III, aVL, aVF, V2, V3 as opposed to V6, and low amplitudes of QRS complexes in V4R and V3R as a new possible sign of ARVD. Notches in lead V2, widening of QRS complexes in all precordial leads, but shorter QRS in V8-V9 are also considered as a potential new diagnostic sign of ARVD. (3) Second ARVD patient: Notches at the end of the QRS in lead III and a negative initial deflection of the QRS in V1 and V2 were detected by standard 12-lead ECG. On 16-lead HD-ECG, a more pronounced QRS fragmentation was visible. CONCLUSION: 16-lead HD-ECG in both CAD and ARVD seems to be more sensitive than 12-lead ECG to record electrocardiographic abnormalities.

Sex hormones affect outcome in arrhythmogenic right ventricular cardiomyopathy/dysplasia: from a stem cell derived cardiomyocyte-based model to clinical biomarkers of disease outcome.

AIMS: Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is characterized by fibrofatty infiltration of the myocardium and ventricular arrhythmias that may lead to sudden cardiac death. It has been observed that male patients develop the disease earlier and present with more severe phenotypes as compared to females. Thus, we hypothesized that serum levels of sex hormones may contribute to major arrhythmic cardiovascular events (MACE) in patients with ARVC/D. METHODS AND RESULTS: The serum levels of five sex hormones, sex hormone-binding globulin, high sensitivity troponin T, pro-brain natriuretic peptide, cholesterol, triglycerides, insulin, and glucose were measured in 54 ARVC/D patients (72% male). Twenty-six patients (48%) experienced MACE. Total and free testosterone levels were significantly increased in males with MACE as compared to males with a favourable outcome, whereas estradiol was significantly lower in females with MACE as compared to females with a favourable outcome. Increased testosterone levels remained independently associated with MACE in males after adjusting for age, body mass index, Task Force criteria, ventricular function, and desmosomal mutation status. Furthermore, an induced pluripotent stem cell-derived ARVC/D cardiomyocyte model was used to investigate the effects of sex hormones. In this model, testosterone worsened and estradiol improved ARVC/D-related pathologies such as cardiomyocyte apoptosis and lipogenesis, strongly supporting our clinical findings. CONCLUSIONS: Elevated serum testosterone levels in males and decreased estradiol levels in females are independently associated with MACE in ARVC/D, and directly influence disease pathology. Therefore, determining the levels of sex hormones may be useful for risk stratification and may open a new window for preventive interventions.

Arrhythmogenic right ventricular cardiomyopathy: implications of next-generation sequencing in appropriate diagnosis.

AIMS: To evaluate potential differences in the genetic profile of cases with 'definite', 'borderline', and 'possible' arrhythmogenic right ventricular cardiomyopathy (ARVC) phenotype by 2010 task force criteria using a custom genetic panel after whole-exome analysis. METHODS AND RESULTS: We performed whole-exome sequencing in 14 cases with the clinical diagnosis ARVC using an 'Illumina HighSeq 2000' system. We presented our initial results focused on 96 known cardiomyopathy and channelopathy genes. According to the 2010 task force criteria, 7/14 cases (50%) were classified as 'definite' phenotype, 4/14 (29%) were 'borderline', and 3/14 (21%) were diagnosed with the 'possible' phenotype. Nine out of 14 patients (64%) were males, and all were Caucasians, with an average age at genetic diagnosis of 50 ± 15 years. Among the seven cases with the 'definite' phenotype, six (86%) had a putative desmosomal mutation, while none of the seven patients with a 'possible' or borderline task force classification phenotype hosted putative mutations in desmosomal genes. Four (57%) of them had rare variants in other dilated cardiomyopathy (DCM) genes. CONCLUSIONS: Most of the patients with 'definite' ARVC phenotype by task force 2010 host mutations in desmosomal genes. Weaker ARVC phenotypes host variants/mutations in other DCM genes and result in a disease spectrum, including DCM or phenocopies of ARVC.

Electrocardiographic features of disease progression in arrhythmogenic right ventricular cardiomyopathy/dysplasia.

BACKGROUND: Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is considered a progressive cardiomyopathy. However, data on the clinical features of disease progression are limited. The aim of this study was to assess 12-lead surface electrocardiographic (ECG) changes during long-term follow-up, and to compare these findings with echocardiographic data in our large cohort of patients with ARVC/D. METHODS: Baseline and follow-up ECGs of 111 patients from three tertiary care centers in Switzerland were systematically analyzed with digital calipers by two blinded observers, and correlated with findings from transthoracic echocardiography. RESULTS: The median follow-up was 4 years (IQR 1.9-9.2 years). ECG progression was significant for epsilon waves (baseline 14% vs. follow-up 31%, p = 0.01) and QRS duration (111 ms vs. 114 ms, p = 0.04). Six patients with repolarization abnormalities according to the 2010 Task Force Criteria at baseline did not display these criteria at follow-up, whereas in all patients with epsilon waves at baseline these depolarization abnormalities also remained at follow-up. T wave inversions in inferior leads were common (36% of patients at baseline), and were significantly associated with major repolarization abnormalities (p = 0.02), extensive echocardiographic right ventricular involvement (p = 0.04), T wave inversions in lateral precordial leads (p = 0.05), and definite ARVC/D (p = 0.05). CONCLUSIONS: Our data supports the concept that ARVC/D is generally progressive, which can be detected by 12-lead surface ECG. Repolarization abnormalities may disappear during the course of the disease. Furthermore, the presence of T wave inversions in inferior leads is common in ARVC/D.

IgG4 production is confined to human IL-10-producing regulatory B cells that suppress antigen-specific immune responses.

BACKGROUND: IL-10-producing regulatory B cells suppress immune responses, and lack of these cells leads to exacerbated symptoms in mouse models of chronic inflammation, transplantation, and chronic infection. IgG4 is a blocking antibody isotype with anti-inflammatory potential that is induced in human high-dose antigen tolerance models. OBJECTIVE: We sought to characterize human inducible IL-10-secreting B regulatory 1 (BR1) cells and to investigate their immunoregulatory capacity through suppression of cellular immune responses and production of anti-inflammatory immunoglobulins. METHODS: Highly purified IL-10-secreting B cells were phenotypically and functionally characterized by means of whole-genome expression analysis, flow cytometry, suppression assay, and antibody production. B cells specific for the major bee venom allergen phospholipase A2 (PLA) were isolated from beekeepers who displayed tolerance to bee venom antigens and allergic patients before and after specific immunotherapy. RESULTS: Human IL-10+ BR1 cells expressed high surface CD25 and CD71 and low CD73 levels. Sorting of CD73-CD25+CD71+ B cells allowed enrichment of human BR1 cells, which produced high levels of IL-10 and potently suppressed antigen-specific CD4+ T-cell proliferation. IgG4 was selectively confined to human BR1 cells. B cells specific for the major bee venom allergen PLA isolated from nonallergic beekeepers show increased expression of IL-10 and IgG4. Furthermore, the frequency of IL-10+ PLA-specific B cells increased in allergic patients receiving allergen-specific immunotherapy. CONCLUSION: Our data show the characterization of IL-10+ BR1 cells and in vivo evidence for 2 essential features of allergen tolerance: the suppressive B cells and IgG4-expressing B cells that are confined to IL-10+ BR1 cells in human subjects.

Clinical experience of pulmonary vein isolation via single transseptal puncture in atrial fibrillation patients: Comprehensive characterization and follow-up.

BACKGROUND: Atrial fibrillation is the most commonly observed cardiac rhythm disorder. Pulmonary vein isolation (PVI) is an effective treatment option to maintain sinus rhythm. This study evaluates the safety, efficacy, clinical outcomes and radiation exposures using a standardized single transseptal puncture (STP)-strategy. METHODS: We analyzed data from patients who underwent our STP-ablation technique with transesophageal echocardiography (TEE) guidance at a university hospital and a regional tertiary health center in Switzerland between January 1, 2017, and May 30, 2022. Collected data included demographics, symptoms, echocardiography results, procedural details, complications and outcomes. Mean follow-up time was 21.4 ± 16 months. RESULTS: The study population included 304 patients with a median age of 67 years, who had at least one ablation using our STP-approach. Among these, 248 (82 %) patients underwent de novo PVI with this technique. Ablation was successful in all patients with isolation of all pulmonary veins, with an average procedure duration of 120 min and an average fluoroscopy time of 3 min, resulting in a mean X-ray dose of 252 cGy × cm2. TEE guidance was performed in 235 (95 %) patients. During the first intervention, 17 complications occurred in 13 patients (5 %). After the first PVI, 135 (54 %) patients experienced no recurrence during the follow-up period. The one-year recurrence rate for atrial fibrillation requiring therapy was 30 %. CONCLUSION: Our STP- approach demonstrated comparable success rates to traditional methods, with similar procedural durations, low radiation exposure and a low complication rate. Therefore, this method may offer procedural, economic and safety benefits without compromising efficacy or safety.

Right heart strain in arrhythmogenic right ventricular cardiomyopathy: implications for cardiovascular outcome.

AIMS: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is characterized by progressive myocardial dysfunction and associated with an increased risk of major cardiovascular (CV) events. To determine right heart strain (ventricular and atrial global longitudinal strain (RVGLS and RAGLS) in patients with definite ARVC and its association with adverse events during follow-up. METHODS AND RESULTS: RVGLS and RAGLS were analysed in focused right heart apical views from 70 patients using TomTec ImageArena and association with a composite endpoint was determined (sustained ventricular arrhythmia and cardiovascular death). Over a median follow-up duration of 4.9 years, 26 (37%) patients met the endpoint. RVGLS was significantly impaired in the event group (-11.5 [-13.3 to -10.2] %) vs. the no-event group (-15.8 [-17.1 to -14.5] %, P < 0.001), and so was RAGLS (22.8 [21.4-27.4] % vs. 31.5 [25.1-39.6] %, respectively, P < 0.001). In Cox regression, RVGLS (HR 1.36, P < 0.001) and RAGLS (HR 0.92, P = 0.002) were associated with a higher risk of adverse events. In multivariable Cox regression models, RVGLS and RAGLS remained independent of and were incremental to age, gender, and conventional RV parameters, and model fitness was improved when RVGLS and RAGLS were applied together rather than alone. CONCLUSION: RVGLS and RAGLS are more impaired in patients with adverse events and associated with adverse events independent of age, gender, and conventional RV parameters. When RVGLS and RAGLS are applied together, prediction models are improved suggesting that right heart strain may form part of the echocardiographic routine protocol in patients with ARVC.

Challenges and pitfalls during CRT implantation in patients with persistent left superior vena cava.

BACKGROUND: Persistent left superior vena cava (PLSVC) is a rare venous anomaly, affecting 0.3-0.5% of the general population. Cardiac resynchronization therapy (CRT) implantation in patients with PLSVC is challenging due to a complex anatomy. Moreover, data on CRT implantation in this patient population is scarce. Our aim was to report a series of patients with PLSVC and CRT implantation focusing on challenges and pitfalls. METHODS: Electronic medical databases on patients with CRT implantation at the University Heart Centers in Zurich, Switzerland, and Lübeck, Germany, were screened for individuals with a PLSVC. Clinical and demographic characteristics as well as procedural data were reported in all patients. RESULTS: This study presents six cases with a median age of 66 years. CRT implantation was successful in five patients, leading to a reduced QRS duration and improved left ventricular ejection fraction. Atrial fibrillation, ischemic cardiomyopathy, valvular heart disease, and dilated cardiomyopathy were observed in this group as underlying conditions. Specialized tools, such as active fixation left ventricular leads, were utilized. One patient experienced major complications. CONCLUSIONS: This case series shows that although challenging, conventional endovascular CRT implantation is feasible in PLSVC patients. Specialized tools for visualization and fixation may help. Our experiences highlight the importance of preprocedural evaluation of the anatomy and precise intervention planning.

PBX/Knotted 1 homeobox-2 (PKNOX2) is a novel regulator of myocardial fibrosis.

Much effort has been made to uncover the cellular heterogeneities of human hearts by single-nucleus RNA sequencing. However, the cardiac transcriptional regulation networks have not been systematically described because of the limitations in detecting transcription factors. In this study, we optimized a pipeline for isolating nuclei and conducting single-nucleus RNA sequencing targeted to detect a higher number of cell signal genes and an optimal number of transcription factors. With this unbiased protocol, we characterized the cellular composition of healthy human hearts and investigated the transcriptional regulation networks involved in determining the cellular identities and functions of the main cardiac cell subtypes. Particularly in fibroblasts, a novel regulator, PKNOX2, was identified as being associated with physiological fibroblast activation in healthy hearts. To validate the roles of these transcription factors in maintaining homeostasis, we used single-nucleus RNA-sequencing analysis of transplanted failing hearts focusing on fibroblast remodelling. The trajectory analysis suggested that PKNOX2 was abnormally decreased from fibroblast activation to pathological myofibroblast formation. Both gain- and loss-of-function in vitro experiments demonstrated the inhibitory role of PKNOX2 in pathological fibrosis remodelling. Moreover, fibroblast-specific overexpression and knockout of PKNOX2 in a heart failure mouse model induced by transverse aortic constriction surgery significantly improved and aggravated myocardial fibrosis, respectively. In summary, this study established a high-quality pipeline for single-nucleus RNA-sequencing analysis of heart muscle. With this optimized protocol, we described the transcriptional regulation networks of the main cardiac cell subtypes and identified PKNOX2 as a novel regulator in suppressing fibrosis and a potential therapeutic target for future translational studies.

Transseptal Puncture Guided by Three-Dimensional Electroanatomical Mapping: Early Experience Using a Simplified Approach in Adults with Congenital Heart Disease.

AIMS: The widespread use of three-dimensional (3D) mapping systems and echocardiography in the field of cardiac electrophysiology has made it possible to perform transseptal punctures (TSP) with low or no fluoroscopy. However, such attempts in adults with congenital heart disease (ACHD) who have previously undergone surgical or interventional treatment are limited. Therefore, we sought to explore the feasibility and safety of an approach to perform zero- or low-fluoroscopy TSP in ACHD patients undergoing left atrial cardiac ablation procedures. METHODS AND RESULTS: This study included 45 ACHD patients who underwent TSP for ablation of left-sided tachycardias (left atrium or pulmonary venous atrium). Computed tomography (CT) of the heart was performed in all patients prior to ablation. 3D mapping of the right-sided heart chambers before TSP was used to superimpose the registered anatomy, which was subsequently used for the mapping-guided TSP technique. TSP was performed with zero-fluoroscopy in 27 patients, and the remaining 18 patients had a mean fluoroscopy exposure of 315.88 ± 598.43 µGy.m2 and a mean fluoroscopy duration of 1.9 ± 5.4 min. No patient in this cohort experienced TSP-related complications. CONCLUSION: Our study describes a fluoroscopy-free or low-dose fluoroscopy approach for TSP in ACHD patients undergoing catheter ablation of left-sided tachyarrhythmias who had been previously treated surgically or interventionally due to congenital heart defects. By superimposing 3D electroanatomic mapping with cardiac CT anatomy, this protocol proved to be highly effective, feasible and safe.

A Novel Heterozygous Desmoplakin Variant Causes Cardiocutaneous Syndrome with Arrhythmogenic Cardiomyopathy and Palmoplantar Keratosis.

Cardiocutaneous syndrome (CCS) is often caused by genetic variants in desmoplakin (DSP) in the presence of thick calluses on the hands and soles of the feet (palmoplantar keratoderma) in combination with arrhythmogenic cardiomyopathy. In this case report, we describe a 58-year-old man presenting with a history of cardiomyopathy with recurrent sustained ventricular tachycardia and palmoplantar keratosis. The cardiological evaluation showed biventricular cardiomyopathy, and repeated genetic testing identified a novel DSP variant. Repeated genetic testingis clinically meaningful in patients with a high probability of a specific inherited cardiac disease, such as CCS, particularly if molecular screening has been performed in the pre-NGS era with an incomplete NGS panel or outdated technology as presented in this case report.

Electroanatomical voltage mapping with contact force sensing for diagnosis of arrhythmogenic right ventricular cardiomyopathy.

BACKGROUND: Three-dimensional electroanatomical mapping (EAM) can be helpful to diagnose arrhythmogenic right ventricular cardiomyopathy (ARVC). Yet, previous studies utilizing EAM have not systematically used contact-force sensing catheters (CFSC) to characterize the substrate in ARVC, which is the current gold standard to assure adequate tissue contact. OBJECTIVE: To investigate reference values for endocardial right ventricular (RV) EAM as well as substrate characterization in patients with ARVC by using CFSC. METHODS: Endocardial RV EAM during sinus rhythm was performed with CFSC in 12 patients with definite ARVC and 5 matched controls without structural heart disease. A subanalysis for the RV outflow tract (RVOT), septum, free-wall, subtricuspid region, and apex was performed. Endocardial bipolar and unipolar voltage amplitudes (BVA, UVA), signal characteristics and duration as well as the impact of catheter orientation on endocardial signals were also investigated. RESULTS: ARVC patients showed lower BVA vs. controls (p = 0.018), particularly in the subtricuspid region (1.4, IQR:0.5-3.1 vs. 3.8, IQR:2.5-5 mV, p = 0.037) and RV apex (2.5, IQR:1.5-4 vs. 4.3,IQR:2.9-6.1 mV, p = 0.019). BVA in all RV regions yielded a high sensitivity and specificity for ARVC diagnosis (AUC 59-78%, p < 0.05 for all), with the highest performance for the subtricuspid region (AUC 78%, 95% CI:0.75-0.81, p < 0.001, negative predictive value 100%). A positive correlation between BVA and an orthogonal catheter orientation (46°-90°:r = 0.106, p < 0.001), and a negative correlation between BVA and EGM duration (r = -0.370, p < 0.001) was found. CONCLUSIONS: EAM using CFSC validates previous bipolar cut-off values for normal endocardial RV voltage amplitudes. RV voltages are generally lower in ARVC as compared to controls, with the subtricuspid area being commonly affected and having the highest discriminatory power to differentiate between ARVC and healthy controls. Therefore, EAM using CFSC constitutes a promising tool for diagnosis of ARVC.

Evolution and triggers of defibrillator shocks in patients with arrhythmogenic right ventricular cardiomyopathy.

INTRODUCTION: Implantable cardioverter-defibrillators (ICDs) can prevent sudden cardiac death due to ventricular arrhythmias in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). The aim of our study was to assess the cumulative burden, evolution and potential triggers of appropriate ICD shocks during long-term follow-up, which may help to reduce and further refine individual arrhythmic risk in this challenging disease. METHODS: This retrospective cohort study included 53 patients with definite ARVC according to the 2010 Task Force Criteria from the multicentre Swiss ARVC Registry with an implanted ICD for primary or secondary prevention. Follow-up was conducted by assessing all available patient records from patient visits, hospitalisations, blood samples, genetic analysis, as well as device interrogation and tracings. RESULTS: Fifty-three patients (male 71.7%, mean age 43±2.2 years, genotype positive 58.5%) were analysed during a median follow-up of 7.9 (IQR 10) years. In 29 (54.7%) patients, 177 appropriate ICD shocks associated with 71 shock episodes occurred. Median time to first appropriate ICD shock was 2.8 (IQR 3.6) years. Long-term risk of shocks remained high throughout long-term follow-up. Shock episodes occurred mainly during daytime (91.5%, n=65) and without seasonal preference. We identified potentially reversible triggers in 56 of 71 (78.9%) appropriate shock episodes, the main triggers representing physical activity, inflammation and hypokalaemia. CONCLUSION: The long-term risk of appropriate ICD shocks in patients with ARVC remains high during long-term follow-up. Ventricular arrhythmias occur more often during daytime, without seasonal preference. Reversible triggers are frequent with the most common triggers for appropriate ICD shocks being physical activity, inflammation and hypokalaemia in this patient population.

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.

Tissue Doppler echocardiography and outcome in arrhythmogenic right ventricular cardiomyopathy.

AIMS: This study aimed at investigating whether tissue Doppler imaging (TDI) is associated with adverse events in arrhythmogenic right ventricular cardiomyopathy (ARVC). METHODS AND RESULTS: Transthoracic echocardiography was performed in 72 patients with definite (n = 63) or borderline (n = 9) ARVC diagnosed according to the 2010 Task Force Criteria and included in the prospective Zurich ARVC registry. Myocardial peak systolic tissue velocity (S') was measured by TDI at lateral tricuspid (tricuspid S'), medial mitral (septal S'), and lateral mitral annulus (lateral S'). Association of echocardiographic parameters with outcome was assessed by univariable Cox regression. During a median follow-up of 4.9 ± 2.6 years, 6 (8.3%) patients died of cardiovascular cause or received heart transplantation and 21 (29.2%) patients developed sustained ventricular arrhythmia. Tricuspid, septal, and lateral S' were lower in patients who died (p = 0.001; p < 0.001; p = 0.008; respectively), while tricuspid and septal S' were lower in those with ventricular arrhythmia (p = 0.001; p = 0.008; respectively). There was a significant association of tricuspid, septal, and lateral S' with mortality (HR = 1.61, p = 0.011; HR = 2.15, p = 0.007; HR = 1.67, p = 0.017; respectively), while tricuspid and septal S' were associated with ventricular arrhythmia (HR = 1.20, p = 0.022; HR = 1.37, p = 0.004; respectively). Kaplan-Meier analyses demonstrated a higher freedom from mortality with tricuspid S' >8 cm/s (p = 0.001) and from ventricular arrhythmia with S' >10.5 cm/s (p = 0.021). CONCLUSIONS: This study demonstrates that TDI provides information on the ARVC phenotype, is associated with adverse events in ARVC patients, and differentiates between patients with and without adverse events.