Tesi sul tema "Arrhythogenic Right Ventricular Cardiomyopathy"

Les cardiomyopathies arythmogènes (CMA) sont une famille de pathologies cardiaques d’origine génétique dont la principale conséquence est le risque d’arythmie ventriculaires pouvant conduire à la mort subite cardiaque. Les CMA présentent une variété de phénotypes constamment en évolution incluant des modifications structurelles cachées nécessitant une évaluation multiparamétrique. L’imagerie par résonance magnétique cardiaque (IRMC) est essentielle à leur évaluation, compte tenu de l'identification croissante des formes de CMA biventriculaires et touchant le ventricule gauche (VG) de manière prédominante. La tomodensitométrie cardiaque (TDMC), bien que moins établie, présente une utilité potentielle comme outil complémentaire ou alternatif. Dans cette thèse, nous avons profité de notre large cohorte de patients porteur d’une CMA pour poursuivre trois objectifs permettant d'étendre les limites de l'imagerie cardiaque pour le diagnostic et la caractérisation fonctionnelle des CMA. Premièrement, nous avons développé et évalué un nouveau paramètre d’IRMC de suivi de textures intégrant les dynamiques longitudinales et radiales du ventricule droit (VD), qui s'est avéré efficace pour distinguer les patients atteint de CMA, en particulier ceux qui manquent de critères structurels majeurs, des sujets sains, impliquant qu'une analyse bidimensionnelle de la dynamique VD est essentielle pour saisir la physiologie complexe des CMA. Deuxièmement, nous avons décrit les caractéristiques à l’IRMC de la CMA liée aux variants pathogéniques dans Desmoplakine (DSP), une entité spécifique associée à un pronostic particulièrement défavorable au sein de la vaste diversité des CMA, et pour la première fois les avons comparées à celles trouvées dans d’autres formes de CMA avec atteinte du VG. Nous avons constaté que la présence d'un rehaussement tardif diffus s'étendant au-delà du VG inferolatéral associée à un rapport de volume VG-VD en fin de systole ≥ 0,8 pourrait être considérée comme indicatrice d'une forte probabilité pré-test génétique de CMA liée à DSP. Troisièmement, à travers une étude multimodalité, nous avons montré qu'il y avait généralement une faible concordance spatiale entre le substrat arythmogène et les anomalies morpho-fonctionnelles ou la graisse VD, à un niveau segmentaire. Ce résultat ouvre la voie à une intégration de données électrophysiologiques dans les critères diagnostics des CMA et suggère que l'imagerie cardiaque en pratique courante ne peut pas exclure de manière fiable la présence d'un substrat arythmogène à un certaine localisation du VD. Des améliorations déterminantes sont actuellement entreprises pour augmenter l'impact et la généralisabilité des trois ensembles de résultats
Arrhythmogenic cardiomyopathies (ACM) constitute a spectrum of genetically-determined cardiac diseases of which the main consequence are ventricular arrhythmias potentially leading to sudden cardiac death. Arrhythmogenic cardiomyopathies have a diverse range of clinical-imaging phenotypes, and a continuously evolving landscape including concealed structural changes requiring multiparametric assessment. Cardiac magnetic resonance (CMR) is central in their evaluation, given the growing identification of biventricular and left-ventricular(LV)-predominant ACM variants. Multidetector computed tomography (MDCT), while not as established, offers potential utility as either an adjunct or alternative tool. In this thesis, we took advantage on our large ACM cohort to pursue three aims able to extend the boundaries of cardiac imaging for ACM diagnosis and functional characterization. First, we developed and evaluated a novel feature-tracking CMR parameter that integrates both longitudinal and radial right ventricular (RV) dynamics, which was effective in distinguishing ACM patients, particularly those lacking major structural criteria, from healthy subjects, implying that a two-dimensional representation of RV dynamics is crucial to capture the complex physiology of ACM. Second, we described the CMR features of Desmoplakin (DSP)-related ACM, a specific entity associated with particularly worse outcomes amidst the wide diversity of ACMs, and for the first time compared them to those found in ACM with LV involvement. We found that the presence of diffuse late gadolinium enhancement extending beyond the inferolateral LV combined with an end-systolic LV-to-RV volume ratio ≥0.8 may be considered as indicative of a high pre-genetical test results likelihood for DSP-ACM. Third, through a transversal multimodality study, we showed there was overall a low spatial concordance between the arrhythmogenic substrate and morpho-functional abnormalities or RV fat, at a segmental level. This finding paves the way for an integration of EP data into ACM diagnostic criteria and suggest that routine practice cardiac imaging cannot reliably exclude the presence of an EP substrate in a given RV location. Determinant improvements are currently being undertaken to increase the impact and generalizability of the three sets of results

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited heart disease, where sudden cardiac death in young seemingly healthy persons may be the first symptom. There is a need for more sensitive and accurate diagnostic methods to detect signs of disease, at an early stage and in relatives of affected individuals. The aim of this thesis is the evaluation of new non-invasive modalities in assessment of right ventricular (RV) volume and function with focus on patients with ARVC. Clinical and non-invasive follow-up of fifteen patients with ARVC during a mean period of 8 years permitted the evaluation of disease progression. RV volume analysis by magnetic resonance imaging relies on short axis (SA) views. A new axially rotated modality acquisition was tested and its feasibility in assessment of RV volume was evaluated. This acquisition seems to be able to improve the assessment of RV volume and function by reducing the uncertainty in defining the basal slice of the RV. A third study concentrated on analysis of RV regional and general function by echocardiography, using tissue Doppler imaging as well as two dimensional (2D) longitudinal strain based on speckle tracking in patients with ARVC, their first degree relatives and in healthy subjects. 2D strain showed a good feasibility in analysis of the RV function in relatives and controls but less in ARVC patients probably due to the progressive myocardial cell death with fibro-fatty replacement of the RV wall. In order to detect and follow up echocardiographic changes an index was developed combining dimensional and functional parameters for the left and for the right ventricle. Advances in the molecular genetics of ARVC have provided new insights into the understanding of the disease. Hitherto, 9 candidate genes have been identified. A new mutation in the plakophilin 2 gene was detected in a three generation family. The clinical phenotype related to this mutation was investigated. The studies have evaluated and developed methods for studying the right ventricle with special emphasis on ARVC. With the ultimate goal of preventing sudden death in ARVC, a combination of genetic testing and improved diagnostic methods may create an improved algorithm for risk stratification and selection to prophylactic treatment.

Includes bibliographical references (leaves 71-79).
It has been shown that all forms of cardiomyopathy, including the dilated, hypertrophic, restrictive, and right ventricular arrhythmogenic forms, are found in African populations. Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a rare muscle disease characterised by fibrofatty replacement of the right ventricular myocardium, leading to electrical instability and eventual heart failure. Dilated cardiomyopathy (DCM) is a disease characterised by a reduction in ventricular wall thickness which leads to reduced contractility and impaired ventricular function. Mutations that cause ARVC have been reported in five desmosomal and three non-desmosomal genes.

Cardiomyopathy accounts for 20-30% of acute heart failure cases in adult Africans. Several types of cardiomyopathy have been identified; this study focused primarily on the genetic causes of arrhythmogenic right ventricular cardiomyopathy (ARVC). Many genes are implicated in ARVC pathogenesis, but many remain to be identified. We investigated a South African family (ACM2) with autosomal dominant ARVC, for whom the genetic cause of disease was unknown. Extensive genetic analysis was previously performed using genome-wide linkage analysis, but no disease-causing genetic variant was identified. We subsequently performed candidate gene screening of the phospholamban (PLN) gene, genome-wide copy number variant (CNV) analysis and whole exome sequencing to identify the causal genetic variant. The ACM2 family harboured no disease-causing PLN variants. However, on screening all cardiomyopathy cases in our registry (ARVC, dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy and peripartum cardiomyopathy), we identified a known pathogenic PLN variant (c.25C>T; p.R9C) in a DCM family of European descent. This variant was reported in an American DCM family of European descent. Haplotype analysis revealed independent variant origins in these families. CNV analysis revealed no disease-causing variants in the ACM2 family. Whole exome sequencing of two affected ACM2 family members revealed 38 variants shared by these individuals. Variants were verified in family members and population controls by high resolution melt analysis and Sanger sequencing, and by bioinformatics analysis to predict variant pathogenicity. A novel N-cadherin (CDH2) c.686A>C (p.Q229P) variant segregated with ARVC in the ACM2 family and was bioinformatically predicted to be deleterious. An additional pathogenic CDH2 variant (c.1219G>A (p.D407N)) was identified in another individual with ARVC after screening 85 cases. These CDH2 variants were absent in normal population controls. Furthermore, alterations in Cdh2 are known to cause cardiomyopathy in rodent models. Taken together, these findings support the causal role of N-cadherin gene variants in human cardiomyopathy.

Introduction Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic heart muscle disease characterized by electrical instability leading to ventricular arrhythmias and sudden cardiac death. The hallmark pathological lesion of ARVC is the transmural loss of the myocardium of the right ventricular (RV) free wall with replacement by fibro-fatty tissue. Three-dimensional electroanatomic voltage mapping (EVM) by CARTO system (Biosense-Webster, Diamond Bar, California) allows identification and characterization of low-voltage regions, i.e. "electroanatomical scars" (EAS), which in patients with ARVC correspond to areas of fibro-fatty replacement. Although the technique has been demonstrated to enhance the accuracy for diagnosing ARVC, its value for arrhythmic risk stratification remains to be established. Furthermore, the clinical utility of EVM for scar quantification and risk assessment is limited by its invasive nature, low availability and high costs. Thus, in daily clinical practice there is the need of a non-invasive test such as 12-lead electrocardiogram (ECG) for prediction of the amount of RV myocardial scar lesion and assessment of arrhythmic risk. Previous studies demonstrated an association between ECG repolarization/depolarization abnormalities and RV mechanical dilation/dysfunction. In fact, T wave inversion in right pericardial leads is the most common ECG abnormality of ARVC. However, the presence of T wave inversion in leads V1-V3, known as persistence of the juvenile pattern of repolarization, may also be observed in about 3% of healthy adults. The current perspective is that, at variance with healthy subjects, right precordial NTWs persist with exercise in ARVC patients. However, this view is not supported by systematic scientific data. Objective In this work, we aimed to further study some of the electrocardiographic features of ARVC. First, we assessed the prognostic value of EAS detected by EVM and its correlation with various non-invasive characteristics of ARVC, including abnormalities detected by surface ECG. Second, we studied the exercise-induced changes in right precordial negative T waves in patients with ARVC and in a group of healthy young individuals with persistence of the juvenile repolarization pattern Methods and results We first studied 69 consecutive ARVC patients (47 males; median age 35 years [28-45]) who underwent electrophysiological study and both bipolar and unipolar EVM. The extent of confluent bipolar (<1.5 mV) and unipolar (<6.0 mV) low-voltage electrograms was estimated using the CARTO-incorporated area calculation software. Fifty-three patients (77%) showed ≥1 RV electroanatomic scars with an estimated burden of bipolar versus unipolar low voltage areas of 24.8% (7.2-31.5) and 64.8% (39.8-95.3), respectively (P=0.009). In the remaining patients with normal bipolar EVM (n=16; 23%), the use of unipolar EVM unmasked ≥1 region of low-voltage electrogram affecting 26.2% (11.6-38.2) of RV wall. During a median follow-up of 41 (28-56) months, 19 (27.5%) patients experienced arrhythmic events. At multivariate analysis, the only independent predictor was the bipolar low-voltage electrogram burden (hazard ratio=1.6 per 5%; 95% confidence interval, 1.2-1.9; P<0.001). Patients with normal bipolar EVM had an uneventful clinical course. Then we further analyzed a subgroup including 49 patients [38 males, median age 35 years] with ARVC and an abnormal EVM by CARTO system. At univariate analysis, the presence of epsilon waves, the degree of RV dilation, the severity of RV dysfunction and the extent of negative T-waves correlated with RV-EAS% area. At multivariate analysis, the extent of negative T-waves remained the only independent predictor of RV-EAS% area (B=4.4, 95%CI 1.3-7.4, p=0.006) and correlated with the arrhythmic event-rate during follow-up (p=0.03). In a different cohort, we assessed the prevalence and relation to the clinical phenotype of exercise-induced right precordial negative T wave changes in 35 ARVC patients (19 males, mean age 22.2±6.2 years). Forty-one healthy individuals with right-precordial negative T waves served as controls. At peak of exercise, negative T waves persisted in 3 ARVC (9%) patients, completely normalized in 12 (34%) and partially reverted in 20 (57%). ARVC patients with or without negative T waves normalization showed a similar clinical phenotype. The overall prevalence of right precordial T-waves changes during exercise (normalization plus partial reversal) did not differ between ARVC patients and controls (92% versus 88%, p=1.0), while there was a statistically non significant trend towards a higher prevalence of complete normalization in controls (59% versus 34%, p=0.06). Conclusion In conclusion, our results showed that the extent of bipolar RV endocardial low-voltage area was a powerful predictor of arrhythmic outcome in ARVC independently of arrhythmic history and RV dilatation/dysfunction. A normal bipolar EVM characterized a low-risk subgroup of ARVC patients. Patients with abnormal ECG have a more severe RV EAS involvement, which is proportional to the extent of T wave inversion across ECG 12-leads and a higher arrhythmic risk. The absence of negative T waves characterizes a low-risk subgroup of ARVC patients with a more favorable clinical course because of a low rate of arrhythmic events. The results also showed that exercise-induced changes of negative T waves were unrelated to ARVC phenotypic manifestations and were of limited value for the differential diagnosis between ARVC and benign persistence of the juvenile repolarization pattern
Introduzione La cardiomiopatia aritmogena del ventricolo destro (CAVD) è una patologia genetica del muscolo cardiaco caratterizzata da instabilità elettrica che può portare a aritmie ventricolari e morte improvvisa. Dal punto di vista patologico, la CAVD si caratterizza per una progressiva perdita di tessuto miocardico della parete libera del ventricolo destro (VD) con sostituzione fibro-adiposa. Il mapaggio elettroanatomico tridimensionale (endocardial voltage mapping, EVM) col sistema CARTO (Biosense-Webster, Diamond Bar, California) consente di identificare e caratterizzare aree di basso-voltaggio, dette "cicatrici elettroanatomiche" (CEA), che in pazienti affetti da CAVD corrispondono ad aree di sostituzione fibro-adiposa. Nonostante la tecnica abbia dimostrato di migliorare l"accuratezza per la diagnosi di CAVD, il suo valore per la stratificazione del rischio aritmico rimane da dimostrate. Inoltre, l"utilità dell"EVM per la quantificazione della cicatrice e la valutazione del rischio è limitata dalla natura invasiva, bassa disponibilità ed alti costi. Quindi, nella pratica clinica quotidiana è auspicabile la disponibilità di un esame non-invasivo, come l"elettrocardiogramma (ECG), per la stima dell'estensione della CEA e la stratificazione del rischio aritmico. Studi precedenti hanno dimostrato un"associazione tra la presenza di anomalie della ripolarizzazione o della depolarizzazione all"ECG e l"entità della dilatazione e della disfunzione del VD. In particolare, l"inversione delle onde T nelle derivazioni precordiali destre V1-V3 è uno dei segni distintivi della CAVD. Tuttavia, lo stesso segno ECG può essere riscontrato come "persistenza del pattern giovanile di ripolarizzazione" fino al 3% degli adulti sani. La prospettiva attuale è che le T negative persistano con l'esercizio nei pazienti con CAVD ma non nei soggetti sani. Tuttavia, questa idea non è supportata da dati scientifici. Obbiettivo L"obbiettivo dell"attività di ricerca è stato quello di caratterizzare ulteriormente alcune delle caratteristiche ECG della CAVD. Inizialmente, abbiamo valutato il valore prognostico della CEA all"EVM e la sua correlazione con vari esami non invasivi, in particolare l"ECG. In secondo luogo, abbiamo studiato le modificazioni indotte dall"esercizio nella T negative nelle derivazioni precordiali destre in un gruppo di pazienti con CAVD ed in un gruppo di soggetti sani con "persistenza del pattern giovanile di ripolarizzazione". Metodi e risultati Sono stati studiati 69 pazienti consecutivi affetti da CAVD (47 maschi, età mediana 35 [28-45] anni) che sono stati sottoposti a studio elettrofisiologico endocavitario con mappa di voltaggio unipolare e bipolare. L"estensione delle aree contenenti elettrogrammi di basso voltaggio bipolari (<1.5 mV) e/o unipolari (<6.0 mV) è stata stimata usando un software incorporato nel sistema CARTO. Cinquantatre pazienti (77%) mostravano ≥1 CEA con un"estensione pari a 24.8% (7.2-31.5) dell"estensione del VD alla mappa bipolare e del 64.8% (39.8-95.3) alla mappa unipolare (p=0.009). Nei rimanenti 16 pazienti con mappa bipolare normale, la mappa unipolare è risultata alterata con un"estensione delle lesioni pari al 26.2% (11.6-38.2) del VD. Nel corso di un follow-up medio di 41 (28-56) mesi, 19 (27.5%) pazienti hanno avuto un evento aritmico maggiore. All'analisi multivariata, l'unico predittore indipendente di eventi aritmici è risultata l'estensione della CEA alla mappa di voltaggio bipolare (hazard ratio=1.6 per 5%; intervallo di confidenza 95%: 1.2-1.9; P<0.001). I pazienti con mappa di voltaggio bipolare negativa hanno avuto un follow-up privo di eventi. Successivamente, abbiamo analizzato un sottogruppo di 49 pazienti (38 maschi, età mediana 35 anni) con CAVD e mappa di voltaggio bipolare positiva. All'analisi univariata, la presenza di onde epsilon, il grado di dilatazione del VD, la severità della disfunzione del VD e l'estensione delle T negative all'ECG correlavano con l'estensione della CEA alla mappa bipolare. All'analisi multivariata, l'estensione delle onde T negative è rimasta l'unico predittore di estensione della CEA (B=4.4, 95%CI 1.3-7.4, p=0.006). Questo parametro si è inoltre dimostrato correlare con il rischio di eventi aritmici durante il follow-up (p=0.03). In una coorte differente, abbiamo valutato il comportamento durante test da sforzo delle T negative nelle derivazioni precordiali destre V1-V4 in 35 pazienti con CAVD (19 maschi, età media 22.2"±6.2 anni) ed in 41 controlli appaiati per età e sesso con benigna "persistenza del pattern giovanile di ripolarizzazione". Al picco dell'esercizio, le onde T negative persistevano in 3 (9%) pazienti con CAVD, normalizzavano completamente in 12 (34%) e normalizzavano parzialmente in 20 (57%). I pazienti affetti da CAVD con e senza normalizzazione delle onde T durante l'esercizio mostravano un fenotipo simile. La prevalenza di normalizzazione (parziale o completa) delle onde T era simile nei pazienti e nei controlli (92% e 88%, p=1,0), mentre si è notato un trend non significativo verso una più alta prevalenza di normalizzazione completa nei controlli sani rispetto ai pazienti con CAVD (59% e 34%, p=0,06). Conclusioni In conclusione, i nostri risultati hanno mostrato che l'estensione della CEA bipolare alla mappa di voltaggio del VD è un potente predittore di rischio aritmico nei pazienti con CAVD, indipendentemente dalla storia aritmica e dal grado di disfunzione/dilatazione del VD. Una mappa di voltaggio bipolare normale caratterizza una popolazione di pazienti con CAVD a basso rischio. Abbiamo inoltre dimostrato che l'estensione della CEA bipolare può essere stimata dall'estensione delle anomalie della ripolarizzazione (T negative) all'ECG. I pazienti che non mostrano T negative all'ECG dimostrano un basso rischio aritmico. Infine, abbiamo dimostrato che il comportamento delle T negative nelle derivazioni precordiali destre V1-V3 non è un utile strumento di diagnosi differenziale tra CAVD e benigna "persistenza del pattern giovanile di ripolarizzazione"

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a heritable disorder characterised by progressive degeneration of the right ventricular myocardium, arrhythmias and an increased risk of sudden death at a young age. Fourteen chromosomal loci have been linked to ARVC and nine disease genes have been identified. Linkage analysis of a South African family was previously performed at ARVC loci 1 to 6. ARVC loci 1 to 5 were excluded as disease loci in this family based on lack of evidence for linkage. However, a peak lod score of 2.93 was obtained for the ARVC-6 locus which is highly suggestive of linkage. Subsequently another locus (ARVC-7) and five ARVC disease genes (ARVC loci 8 to 12) have been reported. The aim of this project was to identify the disease gene that causes ARVC in this family.

Includes bibliographical references (leaves 84-90).
Heart failure is a major public health problem throughout the world. In South Africa 17% of mortality is attributed to cardiovascular disease (CVD). Heart failure may be either ischemic or non-ischemic in origin. A significant proportion of non-ischemic heart failur is due to cardiomyopathy. There are currently five types of cardiomyopathy recognised, of which arrhythmogenic right ventricular cardiomyopathy (ARVC) is one. ARVC is familial in 30 to 50% of cases and it is inherited in an autosomal dominant or an autosomal recessive manner. Twelve chromosomal loci have been linked to ARVC and six genes have been identified. In 2004 Asano and colleagues reported a mouse model of ARVC that established LAMRI and CBX5 as candidate genes for the human form of ARVC.

Background: Endocardial voltage mapping (EVM) identifies low-voltage right ventricular (RV) areas, which may represent the electroanatomic scar substrate of life-threatening tachyarrhythmias. We prospectively assessed the prognostic value of EVM in a consecutive series of patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). Methods: We studied 69 consecutive ARVC patients [47 males; median age 35 years(28-45)] who underwent electrophysiological study and both bipolar and unipolar EVM. The extent of confluent bipolar (<1.5mV) and unipolar (<6.0mV) low-voltage electrograms was estimated using the CARTO-incorporated area calculation software. Results: Fifty-three patients (77%) showed ≥1 RV electroanatomic scars with an estimated burden of bipolar vs unipolar low-voltage areas of 24.8% (7.2-31.5) and 64.8% (39.8-95.3), respectively (P=0.009). In the remaining patients with normal bipolar-EVM (n=16;23%), the use of unipolar EVM unmasked ≥1 region of low-voltage electrogram affecting 26.2% (11.6-38.2) of RV wall. During a median follow-up of 41 (28-56) months, 19(27.5%) patients experienced arrhythmic events, such as sudden death (n=1), appropriate ICD interventions (n=7), or sustained ventricular tachycardia (n=11). Univariate predictors of arrhythmic outcome included previous cardiac arrest or syncope (HR=3.4; 95%CI:1.4-8.8; P=0.03) and extent of bipolar low-voltage areas (HR=1.7 per 5%; 95%CI=1.5-2; P<0.001), while the only independent predictor was the bipolar low-voltage electrogram burden (HR=1.6 per 5%; 95% CI:1.2-1.9; P<0.001). Patients with normal bipolar-EVM had an uneventful clinical course. Conclusions: The extent of bipolar RV endocardial low-voltage area was a powerful predictor of arrhythmic outcome in ARVC, independently of history and RV dilatation/dysfunction. A normal bipolar-EVM characterized a low-risk subgroup of ARVC patients.
Introduzione: Il mappaggio elettroanatomico mediante sistema CARTO permette di identificare e quantificare aree di basso voltaggio del ventricolo destro che corrispondono a cicatrici elettroanatomiche, substrato di aritmie ventricolari pericolose per la vita. Lo scopo dello studio era di valutare, in modo prospettico, il valore prognostico del mappaggio elettroanatomico in una coorte di pazienti affetti da Cardiomiopatia Aritmogena del Ventricolo Destro. Materiali e Metodi: La popolazione di studio includeva 69 pazienti (47maschi; età mediana 35 anni; 28-35) affetti da Cardiomiopatia Aritmogena del Ventricolo Destro. Tutti i pazienti sono stati sottoposti ad un completo work up clinico che includeva: elettrocardiogramma, ecocardiografia, cateterismo cardiaco, studio elettrofisiologico e mappaggio elettroanatomico del ventricolo destro, utilizzando sia mappe bipolari sia unipolari. L’estensione degli elettrogrammi confluenti di basso voltaggio bipolari (<1.5 mV) e unipolari (<6.0 mV) è stata stimata usando un software incorporato nel sistema CARTO. Risultati: In cinquantatre pazienti (77%) è stata riscontrata ≥1 regione cicatriziale a carico del ventricolo destro con una percentuale stimata di aree di basso voltaggio bipolari e unipolari rispettivamente di 24.8% (7.2-31.5) e 64.8 (39.8-95.3), rispettivamente (P=0.009). In tutti pazienti con una normale mappa bipolare (n= 16; 23%) l’utilizzo del mappaggio unipolare ha identificato ≥1 regione con elettrogrammi di basso voltaggio che interessava il 26.2% (11.6-38.2) del ventricolo destro. Durante un follow-up di 41 (28-56) mesi 19 (27.5%) pazienti subirono eventi aritmici maggiori, quali morte improvvisa (n=1), intervento appropriato dell’ICD (n=7), o tachicardia ventricolare sostenuta (n=11). All’analisi univariata i predittori dell’outcome aritmico includevano: sincope (HR=3.4; 95%CI: 1.4-8.8; P=0.03), e l’estensione delle aree di basso voltaggio bipolare (HR=1.7 per 5%; 95%CI: 1.5-2; P<0.001). All’analisi multivariata, l’unico predittore indipendente risultava l’estensione delle aree di basso voltaggio al mappaggio bipolare (HR=1.6 per 5%;95% CI:1.2-1.9; P<0.001). Tutti i pazienti con un mappaggio bipolare normale presentavano un decorso clinico privo di eventi aritmici. Conclusioni: l’estensione delle aree endocardiche di basso voltaggio nel ventricolo destro risulta essere un potente predittore di eventi aritmici maligni nella Cardiomiopatia Aritmogena del Ventricolo Destro indipendentemente dalla storia clinica e dalla dilatazione/disfunzione del ventricolo destro. La presenza di un normale mappaggio elettroanatomico bipolare rapprestanta un sottogruppo di pazienti affetti da Cardiomiopatia Aritmogena del Ventricolo Destro a basso rischio aritmico.

Background: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy characterised by structural changes to mostly the right ventricle (RV) that predisposes to ventricular arrhythmias heart failure and sudden cardiac death. ARVC is diagnosed using the 2010 Task Force Criteria which include RV angiography (RVA) and cardiovascular magnetic resonance (CMR). There has been a dearth of studies to document the comparison of the performance of CMR and RVA, and none undertaken in Africa. The aim of this study was to compare CMR and RVA in the assessment of ARVC in the South African ARVC registry. Methods: The study is a retrospective analysis of definite, possible and borderline ARVC cases from the South African ARVC registry and the African Cardiomyopathy and Myocarditis Registry Program (IMHOTEP) that have both CMR and RVA data. RV end-systolic and diastolic volumes, RV ejection fractions and the presence of absence of structural abnormalities derived from RVA and CMR are compared. Sensitivity of CMR and RVA for the diagnosis of definite, possible and borderline ARVC was also calculated. Results: A total of 11 patients out of 62 from the registry met the inclusion criteria. The Spearman’s coefficient for RV end-systolic volume was 0.48 (p=0.12). The Spearman’s coefficient for RV enddiastolic volume was 0.28 (p=0.4). The Spearman’s coefficient for RV ejection fraction was 0.06 (p=0.85). CMR detected regional wall abnormalities in 4 out of 11 patients while RVA did not detect any regional wall abnormalities. Sensitivity of CMR and RVA for the diagnosis of definite, possible and borderline ARVC was 48% and 55%, respectively. Conclusions: We show that South African ARVC patients had poor correlation between CMR and RVA parameters, and CMR was also more likely to reveal RV free wall regional wall motion abnormalities.

Dissertação de Mestrado Integrado em Medicina Veterinária
Arrhythmogenic right ventricle cardiomyopathy (ARVC) is recognized in Boxers, cats and humans, is characterized clinically by ventricular tachyarrhythmias and histopathologically by fibrofatty replacement, mostly of the right ventricle. Affected dogs may have syncope, exercise intolerance or heart failure associated signs. ARVC is an inherited adult onset disorder that can lead to sudden death which can also be the first and single clinical sign. Ventricular premature complexes (VPC’s) with left bundle branch block morphology on the electrocardiogram (ECG) are typical for the disease. These VPCs can occur singly, in pairs, triplets or runs of ventricular tachycardia (VT). Routine ECG can be insensitive for the detection of ventricular arrhythmias when compared with a 24 hour Holter study. The antiarrhythmic drugs most commonly used are sotalol or mexiletine-atenolol association. A 24 hour Holter study should be repeated in order to evaluate the efficacy of treatment or detect a proarrhythmic effect. In this study, 4 out of 6 animals (66,6%) died suddenly, however owners refer an improvement in the animal’s quality of life once the treatment is initiated. The prognosis of this disease is guarded due to sudden death risk or heart failure development.
RESUMO - Cardiomiopatia Arritmogénica do Ventrículo Direito em Boxers – Estudo Retrospectivo (6 Casos) - A cardiomiopatia arritmogénica do ventrículo direito (CAVD) é uma patologia reconhecida em cães de raça Boxer, gatos e humanos, caracterizada clinicamente por taquiarritmias ventriculares e histopatologicamente por substituição fibro-adiposa, sobretudo do ventrículo direito. Os cães afectados podem apresentar síncope, intolerância ao exercício ou sinais associados a insuficiência cardíaca. CAVD é uma patologia hereditária do adulto com risco de morte súbita, que pode ser a primeira e única manifestação clínica da doença. Complexos ventriculares prematuros (CVP) com morfologia de bloqueio de ramo esquerdo são achados típicos da doença no electrocardiograma (ECG). Estes CVP podem ocorrer singularmente, em pares, em grupos de três ou em runs de taquicardia ventricular. Um ECG de rotina pode ser insensível na detecção das arritmias que normalmente são mais evidentes num estudo Holter de 24 horas. Os antiarritmicos mais frequentemente utilizados são o sotalol ou a associação mexiletinaatenolol. Para se avaliar a eficácia do tratamento e detectar um eventual efeito pro-arrítmico, um segundo Holter deve ser realizado. Neste estudo, 4 dos 6 animais (66,6%) morreram subitamente, porém, segundo os proprietários a qualidade de vida do animal melhorou com o tratamento. O prognóstico desta doença é reservado devido ao risco de morte súbita ou desenvolvimento de insuficiência cardíaca.

Introduction: Little is known about the molecular genetics of cardiomyopathy in Africans. Aims: to (I) determine the prevalence of desmosomal gene mutations in arrhythmogenic right ventricular cardiomyopathy (ARVC) and dilated cardiomyopathy (DCM) in desmosomal protein genes (i.e., plakophilin 2, desmocollin 2, desmoglein 2, and plakoglobin), (2) establish the presence of a founder effect in families with a recurrent mutation in the plakophilin 2 (PKP2) gene, (3) investigate whether single nucleotide polymorphisms found in desmosomal genes affect gene expression, and (4) search for new candidate genes for ARVC in families where no causal mutation was found in desmosomal protein genes. Methods: 177 participants with cardiomyopathy were screened for desmosomal gene mutations which were confumed by Sanger sequencing. The following methods were used: in the founder effect study we used haplotyping with microsatellite markers; for total gene expression we used real time polymerase chain reaction and allelic expression imbalance and exome sequencing was used for mutation screening in two siblings with severe early onset ARVC. To all novel variants identified prediction tools were used to predict the pathogenicity of the variant in uestion. Results: 21.5% of ARVC pro bands had a disease-causing mutation in one of four desmosomal genes; no disease-causing mutation was found in the 112 OCM index cases. A recurrent PKP2 mutation occurred on a common haplotype background in four white South African probands with cardiomyopathy. Investigation of a common PKP2 polymorphism had no effect on total gene expression nor was there evidence of allelic expression imbalance. Finally, rare mutations were found in PARVA and HMGXB3 by exome sequencing of two siblings.

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a genetic cardiac disease inherited as an autosomal dominant trait with incomplete penetrance and variable expressivity. Its main feature is the progressive substitution of the myocardium with fatty or fibro-fatty tissue, involving predominantly the right ventricle. Clinically, ARVC/D is characterized by ventricular arrhythmias, often associated with syncope and sudden cardiac death, especially in the young and athletes. Up to now, several disease genes have been identified, including 5 encoding desmosomal proteins. In this study, mutation screening for desmosomal genes performed in 80 consecutive unrelated Italian probands failed to detect mutation in about half of index cases, thus suggesting further genetic heterogeneity. On the basis of alphaT-catenin (a protein of cardiac area composita) cellular localization and function, mutation screening was then performed in CTNNA3 candidate gene in 76 affected subjects, negative for mutations in desmosomal genes. Four mutations have been detected. In vitro functional studies assessed the pathogenicity for two of them. For the first time mutations in CTNNA3 have been detected in a human disease. Particularly, the recurrence of pathogenic mutations in CTNNA3 gene in ARVC/D patients expands the concept of this disease beyond desmosomes
La cardiomiopatia aritmogena del ventricolo destro (ARVC/D) è una malattia genetica cardiaca, ereditata come carattere autosomico dominante a penetranza incompleta ed espressività variabile. La sua caratteristica principale è la progressiva sostituzione del miocardio del ventricolo destro con tessuto adiposo e/o fibroadiposo, con formazione di circuiti anatomici di rientro e conseguenti aritmie e morte improvvisa, specie nei giovani. Attualmente sono noti dieci geni malattia, di cui cinque sono codificanti per le proteine desmosomali. In questo studio, lo screening di mutazioni nei geni desmosomali eseguito in 80 pazienti affetti non ha evidenziato mutazioni in circa la metà dei casi, suggerendo la presenza di ulteriore eterogeneità genetica. In virtù della funzione e della localizzazione cellulare dell’alphaT-catenina (proteina dell’area composita), è stato svolto lo screening di mutazioni nel gene candidato CTNNA3 in 76 casi indice negativi per mutazioni nei geni desmosomali. Sono state identificate quattro variazioni. Studi funzionali in vitro hanno dimostrato la patogenicità per due di esse. Per la prima volta, mutazioni nel gene CTNNA3 sono state associate a una malattia umana. In particolare, la ricorrenza di mutazioni patogene nel gene CTNNA3 in pazienti ARVC/D estende il concetto di questa malattia oltre i desmosomi

Introduction: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiac disease characterized by fibrofatty replacement of myocardial tissue and high incidence of serious ventricular tachyarrhythmias. To date, ten disease-genes have been identified, five of which encoding desmosomal proteins (PKP2, DSP, DSG2, DSC2 and JUP). Aim of the study: The study described in the present thesis aimed at determining the spectrum and prevalence of desmosomal mutations in 80 Italian unrelated index cases. Moreover, the identification of novel disease loci and genes in three ARVC families was attempted by integrating different approaches, including genome-wide linkage study, Copy Number Variations (CNVs) analysis, and exome-sequencing. Methods: Mutation screening of the desmosomal ARVC genes was performed by Denaturing High-Performance Liquid Chromatography (DHPLC) and direct sequencing. In order to map novel loci and, possibly, to identify novel genes, genome-wide linkage study and CNVs analysis was performed in three independent families with recurrence of ARVC, showing no mutations in any of the desmosomal genes. In addition, in Family #2 and in Family #3 a combined strategy of linkage analysis and exome sequencing was adopted to identify novel ARVC genes. Results: Mutation screening of five desmosomal ARVC genes in 80 Italian probands identified single point mutations in 32.5% of cases and multiple mutations in 12.5%. No mutations were identified in the remaining 55% of probands. The genes most frequently involved were PKP2, DSP and DSG2. Among the index cases negative for point mutations in the desmosomal genes, three belong to independent families with recurrence of ARVC. Assuming a further genetic heterogeneity in these families, a genome-wide scan was performed in order to identify novel loci and genes. In Family #1, a CNV involving a desmosomal ARVC gene was identified in all affected family members. In Family #2, a novel ARVC locus was mapped on chromosome 19 by linkage analysis. Finally, in Family #3, a possible novel candidate gene for ARVC was detected by a combined strategy of linkage analysis and exome-sequencing. Discussion: In the present study, genetic screening of five desmosomal ARVC genes in 80 Italian probands identified causative mutations in 45% of cases, mainly involving the “big3” genes PKP2, DSP, and DSG2, according to data reported in literature. Genetic analysis of available family members confirmed the high heterogeneity in the clinical expression of ARVC mutations even among relatives. Mutation screening of desmosomal genes failed to detect causative mutations in more than 50% of index cases, suggesting that additional and still unknown genes could be involved. In this perspective, a genome-wide scan was performed in three large ARVC families, showing no mutations in any of the desmosomal genes. In Family #1, a CNV was identified in a desmosomal ARVC gene, highlighting the importance of complementing the conventional mutation screening in ARVC genes with other approaches able to detect possible structural variations. In Family #2, genome-wide linkage results provided strong evidence for a novel ARVC locus on chromosome 19, highlighting the soundness of this strategy for identifying susceptibility regions in large, highly informative families and providing the basis for the identification of a novel disease gene. Finally, in Family #3, exome-sequencing identified a novel putative candidate gene for ARVC. Identification of novel ARVC genes is of great importance for understanding the molecular pathogenesis of this disease, as well as for increasing the power of genetic screening and developing successful targeted therapies
Introduzione: La Cardiomiopatia Aritmogena del Ventricolo Destro (ARVC) è una malattia ereditaria del muscolo cardiaco caratterizzata dalla progressiva perdita e sostituzione fibro-adiposa dei cardiomiociti che costituiscono la parete libera delventricolo destro. Tale disomogeneità del tessuto cardiaco altera la normale conduzione dell'impulso elettrico, determinando l'insorgenza di aritmie che occasionalmente portano a fibrillazione ventricolare e morte improvvisa per arresto cardiaco, soprattutto nei giovani e negli atleti. Attualmente, sono noti 10 geni implicati nella determinazione genetica dell’ARVC e cinque di questi codificano per proteine costituenti il desmosoma cardiaco: Placofilina-2 (PKP2), Desmoplachina (DSP), Desmogleina-2 (DSG2), Desmocollina-2 (DSC2) e Placoblobina (JUP). Scopo dello studio: Lo studio descritto nella presente tesi mira a valutare la prevalenza e lo spettro di mutazioni nei cinque geni ARVC desmosomali in un gruppo di 80 casi indice Italiani, non imparentati tra loro. Inoltre, in tre grandi famiglie con ricorrenza di casi ARVC e in cui non sono state identificate mutazioni nei geni desmosomali, è stata effettuata un'analisi genome-wide integrando diversi approcci, quali studio di linkage, analisi di Copy Number Variations (CNVs) e sequenziamento dell’esoma. Metodi: Lo screening per la ricerca di mutazioni nei cinque geni ARVC desmosomali ha coinvolto 80 casi indice ed è stato effettuato tramite analisi DHPLC (Denaturing High-Performance Liquid Chromatography) e sequenziamento diretto del DNA.I soggetti appartenenti a ciascuna delle tre famiglie selezionate per l'analisi genome-wide sono stati genotipizzati utilizzando un pannello di marcatori ad alta densità che include più di 370.000 polimorfismi di singolo nucleotide (SNPs) (Illumina HumanCNV370-Duo BeadChip). In ciascuna famiglia è stato effettuato uno studio di linkage ed un’analisi di CNVs. Inoltre, Nella Famiglia #2 e nella #3 l'identificazione del gene malattia è stata tentata integrando i risultati dello studio di linkage con i dati ottenuti dal sequenziamento dell'esoma di due soggetti affetti. Risultati: L'analisi delle sequenze codificanti dei geni PKP2, DSP, DSG2, DSC2 e JUP in 80 casi indice Italiani ha permesso di identificare mutazioni singole nel 32.5% dei casi e mutazioni multiple nel 12.5%. Il 55% dei probandi non è risultato portatore di alcuna mutazione nei geni desmosomali. La maggior parte delle mutazioni ha coinvolto i geni PKP2, DSP, DSG2, confermando i dati riportati in letteratura. Tra i casi indice in cui non sono state identificate mutazioni nei geni desmosomali, tre appartengono a famiglie indipendenti con ricorrenza di casi ARVC. In ognuna di queste famiglie è stata effettuata un'analisi genome-wide allo scopo di identificare nuovi loci e geni malattia. Nella Famiglia #1 è stata identificata una CNV che coinvolge uno dei geni ARVC desmosomali noti e co-segrega con il fenotipo patogeno. Nella Famiglia #2, l’analisi di linkage ha permesso di identificare un nuovo locus ARVC sul cromosoma 19. Infine, nella Famiglia #3 è stato identificato un nuovo potenziale gene candidato per l’ARVC. Discussione: L’analisi genetica delle sequenze codificanti dei cinque geni ARVC desmosomali, in un gruppo di 80 probandi italiani, ha permesso di identificare mutazioni nel 45% dei casi, confermando il prevalente coinvolgimento dei tre geni PKP2, DSP e DSG2, in accordo con i dati riportati in letteratura. L'analisi genetica dei familiari dei probandi ha confermato la penetranza incompleta e l'espressività variabile della malattia, anche all'interno della stessa famiglia. L'assenza di mutazioni in più del 50% dei casi suggerisce il coinvolgimento di altri geni nella determinazione genetica dell'ARVC. In quest' ottica, un'analisi genome-wide è stata effettuata in tre famiglie con ricorrenza di casi ARVC e in cui non sono state individuate mutazioni nei geni desmosomali. Nella Famiglia #1, l’identificazione di una CNV in uno dei geni ARVC desmosomali, presente in tutti i soggetti affetti, sottolinea l'importanza di associare alle metodiche tradizionali utilizzate per lo screening di mutazioni puntiformi approcci che permettano di identificare eventuali variazioni strutturali presenti nel genoma. Nella Famiglia #2, l'analisi di linkage ha fornito una significativa evidenza dell'esistenza di un nuovo locus ARVC sul cromosoma 19, fornendo le basi per l'identificazione di nuovi geni. Infine, nella Famiglia #3, il sequenziamento dell'esoma di due soggetti affetti ha identificato un nuovo gene come un possibile candidato per l'ARVC

Mutation analysis of the recognized ARVC genes and of further candidate genes was performed on a large cohort of ARVC patients. Several novel mutations were identified and three further desmosomal genes were linked to the disease: plakophilin2, desmocollin2 and desmoglein2. Heart and skin samples from ARVC patients were subjected to microscopic examination and immunohistochemistry to study the effect of the newly-identified mutations on the structure of cell adhesion complexes.;The functional effects of a particular novel mutation were thoroughly examined in vitro. S39_K40insS is the first dominant ARVC-causing plakoglobin mutation to be reported. Yeast-two hybrid analysis was used to investigate the effect of S39_K40insS on the proteins interactions established by plakoglobin. A HEK293 cell line stably expressing the mutant protein was generated and used to study the effects of S39_K40insS on desmosomal structure, cell proliferation, cell death, subcellular localization and expression levels of proteins involved in adhesion and signalling and cellular responses to defined mechanical load. A recombinant adenovirus expressing the mutant protein was generated and used to transfect neonatal rat ventricular cardiomyocytes, whose behaviour and responses were subsequently analysed. The functional consequences of S39_K40insS were compared with those of PK215del2, a previously reported recessive plakoglobin mutation known to underlie Naxos disease, a syndromic form of ARVC.;These results point towards novel mechanisms of disease pathogenesis, that apart from weakened cell-cell adhesion involve altered protein turnover kinetics and defects in signalling pathways. Similar studies should improve our understanding of ARVC and provide a more accurate diagnostic algorithm.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetically determined heart muscle disorder that presents clinically with ventricular arrhythmias, heart failure, and sudden death. The pathological process consists of progressive loss of ventricular myocardium with fibro-fatty replacement. Right ventricle is mostly involved, but presentation of the disease with predominantly left ventricular involvement has been reported. ARVC is typically inherited as a dominant disease, although recessive variants exist and the involvement of family members often can only be detected by molecular genetic analysis (low penetrance of mutations). Genetic studies over the last few years have offered insight into the potential causes of ARVC. Early works demonstrated substantial genetic heterogeneity, and at least 12 independent loci and 7 disease-genes have now been identified. These findings also implicated desmosomal proteins or proteins involved in desmosomal function as candidate causes of the disorder. In the present study Perp was investigated as a candidate gene for ARVC because of its possible role in cell-cell adhesion, as a structural constituent of desmosomes or as a protein playing an yet unknown role in desmosome assembly. After PERP human cardiac expression was tested and confirmed, 90 ARVC index cases were screened for PERP mutations by DHPLC analysis and direct sequencing. Two variations G59R in exon1 and c.1091C>T in 3'UTR were detected in two patients, in whom a mutation in a known ARVC gene was previously identified. The missense variation G59R was detected in 1 control out of 250 screened and the variation c.1091C>T was identified in 2 controls out of 192 screened. Moreover these two novel variants involved respectively a highly conserved amino acid and a highly conserved nucleotide. Interestingly index cases, carrying two mutations (one in PERP gene and one in a known ARVC gene), showed a more severe phenotype than family members carriers for only one of these variations. It is impossible to establish whether these single PERP mutations might lead to ARVC determination, but on the other hands, in patients carrying a pathogenic mutation in a different gene involved in ARVC, PERP mutations might worsen the clinical phenotype. The idea that ARVC is due to desmosomal dysfunction was strengthened by two recent studies that reported mutations in the desmosomal desmocollin-2 (DSC2) gene as the cause of ARVC. During the present study six different DSC2 mutations were identified in seven out of sixty-four ARVC unrelated Italian index cases. Two nucleotide substitutions (c.-92G>T and c.3241A>T) in 5' and 3' UTR regions were detected in two different index cases. Neither of the nucleotide changes were found in 300 chromosomes from the same population, but to exclude that these mutations could correspond to rare polymorphisms the size of the control group should be increased to 500. Moreover in order to test whether this UTR mutations could affect the expression levels of DSC2 gene, specific in vitro functional studies are needed. Another nucleotide substitution (c.348A>G) absent among 500 control chromosomes, was detected in exon 3; although this mutation corresponds to a synonymous variation (Q116Q), it has been demonstrated that it creates a cryptic splice site, leading to a deletion of 9 nucleotides. Although skipping of 9bp in the mutant transcript doesn't alter the reading frame of DNA sequence, at protein level it leads to loss of three amino acids very conserved among species. This mutation mapped on a region important for maturation of the protein. Two heterozygous point substitutions c.304G>A and c.1034T>C were detected in other two patients. Both nucleotide changes was never found in 250 unrelated controls (500 control chromosomes). Variations c.304G>A in exon 3 and c.1034T>C in exon 8 result in predicted p.E102K and p.I345T amino acid substitutions. The mutated amino acids had completely different physico-chemical properties when compared to the wild type. Both these changes occurred in a residue highly conserved among species and are located in protein regions involved on DSC2 adhesion function. The sixth mutation c.2687_2688insGA in exon 17 was detected in two different patients and in six control subjects, suggesting the possibility of a polymorphism. This mutation would affect the C terminus of DSC2a, precisely the ICS domain, by altering 4 aa residues before a termination codon is prematurely introduced. The change occurred in the last five aa residues of the protein, which are non conserved among mammals, in contrast with the high conservation of the upstream region. The final part of this thesis work was focused on the analysis of potential pathogenic effects of the last three DSC2 mutations described above in cultured cardiomyocytes. Once human cDNAs coding for wild type, two polymorphic variants and mutant proteins were obtained, constructs containing also GFP protein were expressed by transient transfection of HL-1 cell line. In transfected HL-1 cells, wild type protein and the two polymorphic variants were detected in the cell membrane, into cell-cell contact regions since co-localised with the endogenous desmoglein which was marked with a monoclonal dsg antibody. In contrast the three mutant proteins were almost exclusively distributed throughout the cytoplasm with very scarce cell membrane localisation, affecting the normal localisation of DSC2 and suggesting the potential pathogenic effect of the mutations.

ARVC is a cardiac disease associated with ventricular cardiomyocyte fibro-fatty replacement and sudden death. It presents with incomplete penetrance and variable clinical expression. Desmoplakin (DP) and plakoglobin (PG) gene mutations were previously identified. This study aimed: to identify desmosomal (DS) gene mutations in an ARVC cohort by DNA sequencing study the gene transmission and disease expression in affected families and determine functional implications of three identified mutations (A733fsX740PKP-2, S140FPKP-2 and Q273fsX288DP) using wild-type and mutant cDNA plasmid cloning and cell line protein expressions. Eight PKP-2 mutations were identified of which four were novel: frame-shifts disrupting Armadillo domains (ARM) 4, 5 and 8, and a non-sense disrupting ARM 2. One missense and two frame-shift novel DP mutations occurred. Pedigree analysis showed incomplete gene penetrance and variable ARVC expression. Stable cells over-expressing A733fsX740PKP-2 showed increased cellular adhesion and apoptosis following mechanical stretch recovery, and absence of cell junction Connexin-43 (Cx43) protein without significant change in cell-input resistance. Desmosomal lengths were statistically unaltered, but intermittent pale DS coupling occurred. Truncated PKP-2 showed reduced PG interaction. Stable cells over-expressing S140FPKP-2 showed no differences in cell proliferation, adhesion, apoptosis following mechanical stretch recovery, and in cell junction Cx43 protein localization. DS lengths, however, were significantly increased, and missense PKP-2 showed reduced p-catenin interaction. Stable cells over-expressing Q273fsX288 DP showed reduced DS widths, vimentin filament retraction, and lower monolayer adhesion. PG and PKP-2 interacted normally with truncated DP. Altered DS morphologies featured prominently in all three mutant protein expressions. Reduced inter-protein interactions of truncated and missense PKP-2 proteins with PG and p-catenin respectively suggests PG and p-catenin signalling may be affected. Q273fsX288DP expression lacking DP distal domains correlated with loss of DS filament association. These data suggests that expression of mutant desmosomal proteins leads to abnormal DS formation, thus providing the substrate for arrhythmia and cardiomyopathy.

Includes bibliographical references.
Arrhythmogenic right ventricular cardiomyopathy / dysplasia (ARVC/D) is a genetic disease causing fibro-fatty replacement of the right ventricular myocardium, resulting in cardiac arrhythmias and sudden death. Part of the diagnostic work up for these patients includes a biopsy of the endocardium which has historically been difficult to interpret and of limited value in the early stages of disease. This study will focus on novel immunohistochemical stains of the cardiac desmosomes. These will be used to try to aid in the early diagnosis of ARVC.

Introduction - Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is an inherited heart muscle disorder that primarily affects the right ventricular myocardium early in the course of disease with later-onset left ventricular involvement. Clinically, it is characterized by ventricular arrhythmias of right ventricular origin, as noted by ventricular tachycardia with a left bundle branch block morphology, commonly associated with syncope or sudden cardiac death in particular in teenagers and in young adults. To date, mutations in 7 genes, including 5 encoding desmosomal proteins, Junctional plakoglobin (JUP), Desmoplakin (DSP), Plakophilin-2 (PKP2), Desmoglein-2 (DSG2) and Desmocollin-2 (DSC2), have been identified in ARVC/D patients. The study of genetically engineered mice models of ARVC/D, generated through transgenesis and gene targeting, recapitulates the pathogenic characteristics of the disease. Methods - The study involved a cohort of 110 unrelated consecutive index cases and their available family members. Clinical diagnosis of ARVC/D was based on major and minor criteria established by an international Task Force. Mutation screening in four desmosomal protein genes (PKP2, DSP, DSG2 and DSC2) was performed by denaturing high-performance liquid chromatography (DHPLC) and direct sequencing in ARVC/D index cases. Desmin (DES) and plakophilin-4 (PKP4) candidate genes were screened in 80 ARVC/D index cases, by DHPLC and direct sequencing as well. In order to generate a knock-in mouse carrying a targeted mutation in DSG2, the mouse dsg2 gene was isolated from the l FIX II 129/SVJ library. A 7041bp genomic fragment was subcloned in the targeting vector, and three nucleotide mutations (G105R, N271S, and K299E) were introduced in mouse dsg2 exons 4, 7, and 8 by site-directed mutagenesis. Neomycin resistance cassette (Neo) and Thymidine kinase cassette (TK) were cloned in the targeting vector, thus allowing positive-negative selection of the recombination events. Results - Analysis of coding sequences of PKP2, DSP, DSG2 and DSC2 genes was performed on genomic DNA of 110 ARVC/D index cases. One PKP2 mutation was detected in 16 probands (14.6%), one DSP mutation in 11 (10.0%), one DSG2 mutation in 8 (7.3%), and one DSC2 mutation in 3 subjects (2.7%). Compound or double heterozygosity was identified in 14 probands (12.7%). Available family members of 19 index cases were screened for the detected mutations and clinical investigation showed that clinical expression of ARVC/D mutations is heterogeneous even among relatives, ranging from a complete lack of symptoms and/or clinical manifestations to severe disease phenotype. According with the hypothesis that ARVC/D is due to desmosomal defects, DES and PKP4 genes were screened in 80 ARVC/D probands. Two variations (K241E and c.736-11A>G) were detected in DES gene in two subjects. Three PKP4 variations (c.245+101A>G, A479A, and P797P) were detected in three subjects. None of the nucleotide changes was found in 300 control subjects from the same population. To establish a cause and effect relationship between DSG2 mutations and ARVC/D, a knock-in mouse model will be generated. A dsg2 genomic fragment was cloned in the targeting vector that will be used; by site-directed mutagenesis three dsg2 pathogenic mutations (G105R, N271S, and K299E) were introduced; also Neo and TK cassettes were cloned. After linearization, the vector will be transfected into the murine embryonic stem cells. Discussion - ARVC/D is a recognized cause of sudden cardiac death, which may be prevented by timely detection and intervention. Since mutations causing ARVC/D have been identified so far in genes encoding desmosomal proteins, this cardiomyopathy might be considered as "a disease of the desmosome". Mutation screening of the four desmosomal genes PKP2, DSP, DSG2 and DSC2 in 110 ARVC/D unrelated individuals allowed successful genotyping of 52 (47.3%). Emerging data suggest that an important minority of ARVC/D patients are compound heterozygous or double heterozygous (12.7%). Clinical comparison of patients carrying single and multiple mutations showed no significant differences in terms of electrocardiographic and structural abnormalities, major events and disease expression. The only significant difference was that patients carrying DSG2 mutations were found older at diagnosis and at the time of major arrhythmic symptoms than DSP and PKP2 carriers. On the ground of these data, it is impossible to clinically differentiate different forms of ARVC/D due to mutations in different genes. Since no causing mutations have been identified in more than 50% of patients, additional components of the desmosome-intermediate filament complex and associated proteins were considered the primary candidates disease-genes. The coding regions of DES and PKP4 genes were screened in 80 ARVC/D index cases. Most of the detected nucleotide changes were intronic and synonymous variations that do not change the sequence of the gene product, but might affect splicing (by activating a cryptic splice site). On the basis of present data, it is not possible to exclude the involvement of these genes in the pathogenesis of ARVC/D; thus, mutation screening in ARVC/D genes on DNA of probands should be planned only on the basis of relative prevalence of mutations in different genes. The identification of the primary genetic causes of ARVC/D has opened the possibility to generate animal models where the events underlying the pathophysiology of this disease can be studied in detail. Gene transfer technology allows the creation of specific mutant genotypes in animals thereby increasing their chance of resembling human diseases at the genetic and phenotypic levels. The generated targeting vectors will be transfected into the murine embryonic stem cells to create a DSG2 knock-in mouse model. In perspective, such models should prove useful for investigating cellular mechanisms involved in the molecular pathogenesis of ARVC/D and for assessing the effects of selected pharmacological treatments.

Introduction: Cardiomyopathy is an endemic disease in Africa that is a major contributor to the clinical syndrome of heart failure. The various forms of cardiomyopathies pose a great challenge in Africa for many reasons, including the difficulty of diagnosis and the scarcity of interventions such as heart transplantations in resource-poor environments. The aetiology of the cardiomyopathies had been unknown but various genetic abnormalities associated with cardiomyopathy have been unraveled. A previous whole exome sequencing project conducted in the United Kingdom (UK) had identified parvin alpha (PARVA) as a candidate gene in a South African family, ACM 8, with several members affected with arrhythmogenic right ventricular cardiomyopathy (ARVC). Hypothesis: We hypothesize that PARVA harbors novel genetic mutations that cause ARVC and other forms of cardiomyopathy. Aim: To screen the PARVA gene for mutations in a large panel of probands with ARVC and other cardiomyopathies and to validate the whole exome sequencing results obtained in the UK on a different sequencing platform. Methods and Results: We investigated the ACM 8 family with three affected individuals (two severely affected children and the mother) for whom the genetic cause of the disease was unknown. Genetic analysis was previously performed at Newcastle in the UK using whole exome sequencing on an Illumina platform. In this analysis, the PARVA c.392A>T variant was identified as a possible cause of ARVC in this family. We expanded on this work by using high resolution melt (HRM) analysis and Sanger sequencing to screen all the available ACM 8 family members to determine segregation of the PARVA c.392A>T variant within this family. We observed that the phenotypic variability seen within this family cannot be explained by the PARVA c.392A>T variant alone and called into question the causative role of PARVA within this family We also screened the cardiomyopathy cohort consisting of 180 probands diagnosed with ARVC, dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM) and restrictive cardiomyopathy (RCM) in the Cardiovascular Genetics Laboratory. No definitive evidence of pathogenic PARVA variants was found any of the cardiomyopathy probands screened. We subsequently performed whole exome sequencing on this family to validate the UK findings ( Ion Torrent platform). We found that both affected individuals were homozygous for the PKP2 c.1162C>T mutation. PKP2 is a gene known to cause ARVC, and the c.1162C>T mutation has been described as a founder mutation for autosomal dominant ARVC families of Afrikaner decent in South Africa. Conclusion: While this study set out to validate the whole exome sequencing experiments conducted in family ACM 8 in the UK, we instead found the causal variant to be the previously reported PKP2 c.1162C>T mutation. We also explored the possibility of PARVA as a causal gene for ARVC but no pathogenic PARVA mutations were identified.

Introduction: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a progressive form of inherited heart muscle disease characterized by ventricular arrhythmias and sudden cardiac death. Often the pathogenesis is linked to deleterious mutations in the desmosomal gene plakophilin-2 (PKP2). We extended investigations of the pathogenic PKP2 c.1162C>T founder mutation which had previously been reported to occur within four 'unrelated' probands (6.2%) who selfidentified as Afrikaners and who also carried a common haplotype. Common evolutionary history suggests common haplotypes are linked to a common founder and today the Afrikaner populations are a unique ethnic group in South Africa identified with various founder effects for a range of heritable disorders. Aim: This study aimed to identify the common founder using genealogical and molecular methods for the PKP2 c.1162C>T mutation in ARVC families of Afrikaner descent in South Africa. Methods and results: DNA was collected from 46 participants (7 probands and 39 relatives) from the ARVC Registry of South Africa. Probands and relatives were screened for the PKP2 c.1162C>T mutation using High Resolution Melt and Sanger sequencing. The genetic results indicated that 65.2% (30/46) of the family members harbored this mutation. High Resolution Melt, Sanger sequencing and microsatellite typing were used to create a haplotype which encompassed the c.1162C>T mutation and three microsatellite markers (M1, D12S1692 and M2) spanning the PKP2 gene. A common haplotype emerged that segregated amongst all of the affected members of the seven Afrikaner families. Genealogical tracing went back, through multiple generations, into the implicated ancestral lines of the present day Afrikaner families. Four of the seven families attained their 17th century progenitors. Through genealogical analyses of the two largest families, ACM 19 and ACM 38, we identified 116 couples which we reduced to ten candidate South African founder couples who were then subjected to further analyses. After the ACM 12 family was added to the analysis there were five candidate founder couples. Unfortunately, the ACM 71 family did not progress past the 20th century due to tracing difficulties associated with poor record keeping of mixed ancestry data in South Africa and hence, could not be linked back to any other family tree without finding ACM71.5's grandparents. Additionally, ACM 8 and 57 families were recent finds and completion of their genealogical tracing still has to done. Conclusions: Our genetic data showed that not only were 30/46 individuals positive for the PKP2 c.1162C>T mutation but that all 30 individuals also shared the same common haplotype. Our preliminary genealogy tracing data suggests that the PKP2 c.1162C>T mutation segregates at a higher frequency in the Afrikaner population possibly due to a founder effect. The genealogical evidence supports the hypothesis that the PKP2 c.1162C>T mutation is a founder mutation and that descendants of the common founders are at risk of developing ARVC. At least three more families need to be recruited to make a clear conclusion and achieve genealogical evidence based saturation, ideally, a common founder.

Background: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiac disorder characterised by structural and functional abnormalities of the right ventricle with or without left ventricular involvement. In 1994, Task Force criteria (TFC) were proposed for the diagnosis of ARVC and were found to be highly specific but lacked sensitivity. In 2010, revised TFC were proposed to increase sensitivity and facilitate diagnosis in those with subtle phenotypes. Purpose: Many participants of ARVC registries have been enrolled using the 1994 TFC and not re-analysed using the 2010 TFC. We retrospectively compared the utility of both TFC for the diagnosis of mutation-positive probands in the IMHOTEP (The African Cardiomyopathy and Myocarditis Registry Program) study with the aim of identifying diagnostic changes that may have clinical impact. Method: 162 participants with the suspicion of ARVC were referred between May 2003 and May 2018 to our ARVC registry. 150 cases were reviewed using the same ECG and imaging data to fulfil both TFC, and were re-classified by a diagnostic panel at Groote Schuur Hospital, Cape Town. Results: Sixty-eight participants were diagnosed with ARVC by the diagnostic panel and included into the registry; 14/68 participants with ARVC were found to be mutation-positive. Eighty-two participants were found to have an alternative diagnosis or insufficient criteria and were excluded from the ARVC registry. Mutation-positive probands presented at a significantly younger age compared to the mutation-negative group (29 ± 14 years versus 39 ± 13 years, p=0.009), suggesting an earlier onset of ARVC. Common reasons for presentation in the mutation-positive cohort included palpitations (79%) and presyncope (64%), with Page 11 of 78 approximately twice the number of participants presenting with sustained ventricular tachycardia (VT) compared to mutation-negative participants (79% versus 47%, p=0.036). The diagnostic yield of the 2010 versus 1994 TFC (n=68) revealed more participants with a definite diagnosis, and less featuring in possible and no criteria categories. A 67% (n=8) change in diagnosis from 1994 borderline to 2010 definite, and an 88% (n=7) change from 1994 possible to 2010 borderline, were observed. Mutation-positive participants had a higher yield for definite ARVC when compared to mutation-negative participants. We subsequently analysed the contribution of each diagnostic modality at fulfilling TFC in our mutation-positive definite participants and found CMR contribution statistically significant, p=0.021. Conclusion: Our study found that mutation-positive probands were found to be younger, more likely to present with sustained VT, fulfilled a significantly larger number of major 2010 TFC than mutation-negative probands, and that the 2010 TFC for structural and repolarisation abnormalities were more useful in diagnosing ARVC compared to 1994 TFC. We found a significant evolution in classification between both TFC, suggesting that re-classification of participants recruited in traditional ARVC registries according to updated criteria is worthwhile.

Background. The diagnosis of fibrotic scar tissue in arrhythmogenic right ventricular cardiomyopathy (ARVC) and other cardiomyopathies is crucial as it forms the substrate for ventricular tachycardia (VT) and fibrillation (VT). Signal-averaged electrocardiography (SAECG) abnormalities are frequent in ARVC and in other cardiomyopathy-related ventricular arrhythmias. The correlation between cardiovascular magnetic resonance (CMR) late gadolinium enhancement (LGE) and parameters of SAECG in ARVC is not known. Method. Thirty-five patients [median age 32 years (IQR 25 – 46)] referred to the ARVC Registry at Groote Schuur Hospital were included in this retrospective study. SAECG was performed with high-amplification and filtered using bidirectional Butterworth filters between 40 and 250 Hz. A filtered averaged QRS (fQRS) was obtained and analysed for fQRS duration, low amplitude signal duration <40 mV (LAS40), and root-mean-square voltage in the last 40ms of the QRS (RMS40). LGE acquired at 5 to 20 minutes after intravenous administration of gadolinium (0.1mmol/kg to 0.2mmol/kg of body mass) was assessed. We evaluated the correlation between SAECG parameters and the presence of LGE. Results. Sixteen patients had definite ARVC, 5 had possible ARVC, 4 had idiopathic VT/VF, 2 had Athlete's heart, 1 had dilated cardiomyopathy (DCM), 1 had hypertrophic cardiomyopathy (HCM), 1 had SVT and 1 had pericardial constriction. LGE was present in 13 (81%) ARVC patients, 2 (40%) with possible ARVC, 1 (50%) with athlete's heart and in all patients with DCM and HCM. Patients with idiopathic VT/VF, pericardial constriction and supraventricular tachycardias had no myocardial LGE on CMR. Comparing patients with LGE and those without LGE on CMR, there were no differences in fQRS, (114ms [102.3 – 119] versus 111ms [99.5 -130], p = 0.608); LAS40 (34.5ms [16.8 - 40.8] versus 31ms [27.5 – 45], p = 0.566) and a RMS40 (23.5 µV [14.3 – 47.5] versus 33 µV [18.5 – 43.5], p= 0.621), respectively. LGE was present in 6 (60%) patients who had VT at presentation, in 9 (56%) with VT at baseline or follow-up and in all (2) patients who survived cardiac arrest. Three oneway analyses of variance (fQRS vs LGE, LAS40 vs LGE and RMS40 vs. LGE) confirmed that there was no correlation between LGE technique on CMR and SAECG for the detection of myocardial fibrosis in ARVC and other myocardial disorders: for fQRS F(1 , 33) = 1.47, p = 0.23,  2 = 0.02; for LAS40 F(1 , 33) =0.95, p = 0.34,  2 = 0.02 and for RMS40 F(1 , 33) = 0.36, p= 0.85,  2 = 0.02. Conclusion. In this study comparing assessment of myocardial fibrosis by LGE CMR and SAECG, there was no correlation between CMR and SAECG in detection of myocardial fibrosis in ARVC and other cardiovascular diseases.

An accumulation of sudden unexpected cardiac deaths (SUCD) occurred in young Swedish orienteers, most of whom were elite athletes. From 1979 to 1992 the incidence in 18 to 34 year old male elite orienteers ranked on the national level the same year as death was calculated to 30 (per 100,000), which represents a 20 to 40 fold increase from the expected rate. From 1989 to 1992, the incidence was 50. There were, however, no indications on any similar clusters of SUCD in other sports. A special program to alter behaviour in orienteers was implemented in 1992-1993, after which there have been no more cases of SUCD in orienteers below 35 years of age. A histopathological re-evaluation of 16 cases of SUCD revealed myocarditis in 75% of these cases. In parallel, four of those cases also had changes mimicing arrhythmogenic right ventricular cardiomyopathy (ARVC). The combination of an increased incidence and myocarditis suggested that infection may be a pathogenetic factor. A broad search for different microorganisms in archival sera from five cases and tissues from the autopsies in two of those cases revealed the only common finding that all had antibodies to Chlamydia pneumoniae. DNA from C. pneumoniae was detected in the lung and heart in one of two cases. The intimate contact with nature of orienteers suggested possible zoonotic/vectorborne pathogens. Bartonella is such a pathogen and known to cross-react with C. pneumoniae. The use of PCR to test for DNA from the gltA gene of Bartonella in the two formerly mentioned cases of SUCD, and in three additional cases, gave positive bands from the hearts in four cases and the lung in a fifth case. The PCR products were sequenced and found to be identical to B. henselae in three cases and almost identical to B. quintana in the remaining two cases. Four of the five cases had antibodies to Bartonella when using micro immunofluorescence test with the antigens B. henselae, B. quintana, and B. elizabethae. The total prevalence of antibodies to Bartonella was 31% in 1,136 elite orienteers vs. 6.8% in 322 healthy blood donors (p<0.001), suggesting widespread exposure in the elite. It is hypothesized that subacute or reactivated Bartonella infection has a pathogenetic role in SUCD in orienteers, and may be involved in the development of ARVC-like disease.

Introduction: Cardiac cell-cell junctions play important roles in maintaining cardiac integrity linking single cardiomyocytes into a single functioning syncytium. There are three main types of cell junctions in the heart: gap junctions (GJ), desmosomes (D) and adherens junctions (AJ). Mutations in the proteins which make-up these junctions are known to cause arrhythmogenic right ventricular cardiomyopathy (ARVC). Pathological features include progressive replacement of right ventricular cardiac muscle with fibrofatty tissue. This can lead to heart failure and life threatening arrhythmias. During normal development of the mammalian heart, protein components of AJ and D gradually fuse to form composite junctions at the intercalated discs, also called areae compositae (singular, area composita, AC). In contrast, the adult heart of lower vertebrates, including the zebrafish, may have few or no AC type junctions. The detailed structure of cardiomyocyte cell-cell junctions in the adult zebrafish heart remain poorly defined and their role in normal development, growth and response to injury have yet to be studied. This thesis will examine the hypothesis that localisation and distribution of myocardial cell-cell junction proteins are crucial in normal myocardial development and in endogenous cardiac regeneration and repair following injury. This will be achieved by understanding the normal development of cell-cell junction proteins in zebrafish from embryonic to adulthood. These findings will then be analysed in comparison to cell-cell junction proteins localisation and distribution in early and late mammalian (mouse and human) myocardium. Once a normal pattern of cell-cell junction proteins will be established, the localisation of cell-cell junction proteins in plakologbin mutant zebrafish model for cardiomyopathy will be studied to understand the distribution and localisation of these proteins in disease manifestation. This model will then be used to test if localisation of cell-cell junction proteins plays an important in cardiac repair following injury by using embryonic laser injury model, this will be further tested by drug intervention study to investigate underlying pathways such as Wnt signalling pathway. Methods: Myocardial cell-cell junctions were assessed using immunohistochemistry in embryonic, juvenile and adult zebrafish hearts and in foetal and adult human hearts. The Plakoglobin mutant zebrafish line (UAS:Gal-4:Plakoglobin Naxos; named as PGNx) was characterised using various functional and morphological assessments including histology, echocardiography and MRI scanning. Similar studies were undertaken in PGNx mutants at different developmental stages. A pharmacological intervention study, using a GSK-3 inhibitor, was carried out in PGNx mutants followed by cardiac structural and functional assessments. Laser-induced cardiac trauma was used to assess the response to injury and repair in normal and PGNx embryos following treatment with the GSK3 inhibitor drug. Results: Cell-cell junction patterning in the embryonic, juvenile and adult zebrafish heart shows a characteristic pearl string appearance of desmoplakin and β-catenin labelled distinct disc shaped AJ. Human foetal heart showed small distinct D and AJ, while the adult human heart had features consistent with AC type junctions. PGNx fish showed reduced ventricle ejection fraction, dilatation of the atrium, reduced amplitude of wall motion and ventricle relaxation velocity compared to age-matched controls. Echocardiography and MRI imaging confirmed severe atrial dilatation and restrictive ventricle physiology in adult fish. The cell-cell junction proteins were over-expressed in the zebrafish PG mutant (PGNx) hearts compared to age-matched controls. Drug studies using a GSK-3β inhibitor showed complete recovery of cardiac function and partial recovery of heart structure. Cardiac injury studies, using laser, showed failure of repair in PGNx embryos compared to age-matched controls. The GSK3 inhibitor failed to improve the functional response following heart laser injury. Conclusions: Cell-cell junctions are distributed abundantly around cardiomyocytes in the zebrafish heart during early development and into adulthood. In contrast to previous studies in adult mammalian heart, there was no evidence of AC type junctions in adult zebrafish cardiomyocytes. The mutant zebrafish line showed restrictive cardiac physiology and abnormal cardiac structure confirming the key role played by plakoglobin in the normal heart development. This is further supported by evidence showing failure of repair in PGNx mutant embryos after injury. Drug treatment with a GSK-3 inhibitor highlights a potentially novel therapeutic pathway for treatment of ARVC involving Wnt signalling.

Echocardiography is a well established technique when evaluating the size and function of the heart. One of the most common ways to measure the size of the right ventricle (RV) is to measure the RV outflow tract 1(RVOT1). Several ways to measure RVOT1 are described in the literature.These ways were compared with echocardiography on 27 healthy subjects.The result showed significant differences in RVOT1, depending on the way it was measured, concluding that the same site, method and body positionshould be used when comparing RVOT1 in the same subject over time.One parameter to evaluate the RV diastolic function (RVDF) is to measure the RV isovolumetric relaxation time (RV-IVRT), a sensitive marker ofRV dysfunction. There are different ways to measure this. In this thesis two ways of measuring RV-IVRT and their time intervals were compared in 20 patients examined with echocardiography. There was a significant difference between the two methods indicating that they are not measuring the same interval.Another way to assess the RVDF is to measure the maximal early diastolicvelocity (MDV) in the long-axis direction. MDV can be measured bydifferent methods, hence 29 patients were examined and MDV was measured according to two methods. There was a good correlation but a poor agreement between the two methods meaning that reference values cannot be used interchangeably.Takotsubo cardiomyopathy is characterized by apical wall motion abnormalities without coronary stenosis. The pathology of this condition remains unclear. To evaluate biventricular changes in systolic long-axisfunction and diastolic parameters in the acute phase and after recovery, 13 patients were included and examined with echocardiography at admission and after recovery. The results showed significant biventricular improvementof systolic long-axis function while most diastolic parameters remainedunchanged.

The arrhythmogenic right ventricular cardiomyopathy is a primitive disease caused by defects of the genes coding the proteins that keep the cardiomyocites jointed at cellular junctions (desmosomal disease), and it is characterized by the presence of structural alterations (fibrofatty infiltration with areas of surviving myocytes, typically located at the angles of the “triangle of dysplasia” at the infero-apical and infundibular walls) and functional alterations of the right ventricle, with related electric instability and ventricular arrhythmias, to the point of ventricle fibrillation, with a risk of sudden death. In fact, the development of fibrofatty scans, either diffused or regional, with adipose fibers replacement and dilation of the right ventricle, promotes the appearance of re-entry circuits which are the origin of ventricular arrhythmias. ARVC is a hereditary disease genetically determined, with dominant autosomic transmission, and with incomplete penetration. After carrying out a complete review of modern techniques used to evaluate cardiac function, the research focuses on the specific aspects of the disease from a forensic medicine perspective with particular emphasis – due to the disposition of the disease – on two basic tests: echocardiography and cardiovascular magnetic resonance (CMR). With regards to the forensic medicine aspects, and taking into consideration that the disease is one of the main causes of sudden cardiac death (SCD) in young athletes, prime aspects of medical professionals’ responsibility due to lack of a diagnosis of the disease are investigated, as well as the lack of prophylaxis of a malignant arrhythmia with implantable cardioverter defibrillator (ICD). Moreover, since effort is a possible trigger for ventricular arrhythmias in subjects affected by ARVC, possible responsibilities of physicians issuing certificates of sporting fitness are considered. Lastly, dealing with a pathology that affects primarily youth and frequently generates damages that have to be evaluated in a welfare context (“Social Medicine”), exact evaluation methods of the disability derived by such pathology are proposed (and this is just the most innovative aspect, since there are no other works of this kind in literature) for the two most important Italian health care and social security areas: the civil disability and INPS disability, and disability retirement
La cardiomiopatia aritmogena del ventricolo destro è una malattia primitiva del miocardio dovuta a difetti dei geni che codificano per le proteine che tengono adesi i cardiomiociti a livello delle giunzioni intercellulari (malattia del desmosoma), caratterizzata dalla presenza di alterazioni strutturali (atrofia miocardica progressiva con perdita dei miociti e sostituzione fibro-adiposa con aree in cui i miociti sono conservati, tipicamente localizzati nel “triangolo della displasia” a livello delle pareti infero-apicale e infundibolare) e funzionali del ventricolo destro, con instabilità elettrica e aritmie ipercinetiche ventricolari, anche maggiori, a rischio di morte improvvisa. Infatti, lo sviluppo di atrofia miocardica progressiva diffusa o segmentaria con sostituzione fibro-adiposa e dilatazione del ventricolo destro favorisce la comparsa di circuiti di rientro che sono all’origine delle aritmie ventricolari. La CAVD è una malattia ereditaria geneticamente determinata, a trasmissione autosomica dominante, a penetranza incompleta. Dopo avere fatto una rassegna completa delle moderne tecniche strumentali di valutazione della funzionalità cardiaca, soffermandosi soprattutto – stante la particolarità della malattia – su due esami fondamentali: l’ecocardiogramma e la risonanza magnetica cardiaca, la ricerca prende in esame gli aspetti peculiari della malattia dal punto di vista medico legale. Per quanto riguarda gli aspetti medico-legali, trattandosi di una delle cause principali di morte cardiaca improvvisa (SCD) nei giovani sportivi, si esaminano anzitutto gli aspetti di responsabilità professionale medica dovuta alla mancata diagnosi della malattia e alla mancata profilassi delle aritmie maligne mediante impianto di defibrillatore (ICD). Inoltre, poiché lo sforzo è uno dei trigger che possono determinare destabilizzazione del ritmo nei soggetti affetti da ARVC, si discute sulle eventuali responsabilità dei medici che rilasciano idoneità sportive. Infine, trattandosi di una patologia che interessa soprattutto l’età giovanile e che non infrequentemente determina un danno a persona da valutare in ambito di medicina sociale, si fanno (e questo è probabilmente l’aspetto più innovativo del lavoro, poiché in letteratura non esistono altre pubblicazioni su questo argomento) precise proposte di valutazione della menomazione derivata da tale patologia nei due più importanti ambiti assistenziali e previdenziali italiani: l’invalidità civile e l’invalidità pensionabile Inps.

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2018
A cardiomiopatia arritmogénica do ventrículo direito (ARVC) constitui uma doença hereditária do miocárdio caracterizada clinicamente por arritmia ventricular, insuficiência cardíaca, morte súbita cardíaca, assim como histologicamente por substituição progressiva do miocárdio ventricular direito por tecido fibroadiposo. A ARVC foi originalmente descrita como uma displasia devido à hipótese prevalente à altura de que esta patologia seria o resultado de um defeito durante o desenvolvimento embrionário do ventrículo direito. (1, 2) Atualmente, esta entidade clínica é reconhecida como uma cardiomiopatia, dada a substituição fibroadiposa gradual pós-natal intimamente relacionada com defeitos genéticos predominantemente associados aos desmossomas cardíacos. (3, 4) Recentemente, o termo cardiomiopatia arritmogénica tem sido usado para englobar o leque de variantes desta patologia em que o envolvimento do ventrículo esquerdo pode ser similar ou até mesmo maior do que as alterações verificadas no ventrículo direito. (5, 6) A prevalência estimada da ARVC varia entre 1 em 5000 até 1 em 1000 indivíduos em algumas regiões europeias. (7, 8) A ARVC é uma causa major de SCD em jovens e atletas, podendo esta ser a manifestação inicial da doença. (9, 10) Apesar da gravidade da ARVC, as abordagens terapêuticas modernas não impedem o seu desenvolvimento nem atrasam a progressão da doença, oferecendo unicamente medidas paliativas. (11) Este trabalho pretende rever o estado da arte relativo à ARVC, abordando esforços recentes para elucidar a sua patogénese, diagnóstico, tratamento e prevenção.
Arrythmogenic right ventricular cardiomyopathy (ARVC) is an inherited myocardial disease characterized clinically by ventricular arrhythmia, heart failure, sudden cardiac death (SCD), and histologically by progressive replacement of right ventricular muscle by fibrofatty tissue. ARVC was originally described as a dysplasia, as it was believed to be a developmental defect of the right ventricle. (1, 2) Currently, this clinical entity is recognized as a cardiomyopathy, as the adipose and fibrous replacement occurs gradually after birth, while being intimately related to genetic abnormalities mainly in cardiac desmosomes. (3, 4) Most recently, the term arryhtmogenic cardiomyopathy has also been used to broadly reflect variants of this condition where left ventricle involvement can be similar or even greater than right ventricular changes. (5, 6) ARVC’s estimated prevalence ranges from 1 in 5000 to 1 in 1000 individuals in some European regions. (7, 8) ARVC is a major cause of SCD in young people and athletes, and this fatal event may be the first manifestation of the disease. (9, 10) Despite ARVC’s severity, modern therapeutic approaches fail to prevent its development or to halt its progression, offering solely palliative measures. (11) This article aims to review the state of the art in arrythmogenic right ventricular cardiomyopathy, encompassing recent efforts to further our knowledge of its pathogenesis, diagnosis, treatment and prevention.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is characterized by a high incidence of lethal ventricular arrhythmias, fibrofatty replacement of myocardium, and can account for up to 20% of sudden cardiac death (SCD) cases in the young. Typically involving autosomal dominant transmission, germline mutations in genes encoding desmosomal proteins have been identified as a cause of ARVC, although the pathogenesis of the disease is still unclear. While early detection and treatment can provide a normal life expectancy for the majority of patients, with less than 10% progressing to overt right ventricular failure, low genetic penetrance and epigenetic modifiers (such as endurance exercise) can make the condition difficult to diagnose. Addressing this clinical challenge requires a better understanding of the defective molecular mechanisms that underlie the disease. To that end, the goal of this dissertation is to provide insight into the effects of ARVC-causing mutant proteins on the mechanical and signaling properties of cardiac myocytes. Using elastography and histological techniques, we begin by characterizing the structural and mechanical properties of the native right ventricular myocardium, particularly the right ventricular apex (RVA). Because the RVA is a key site for development of arrhythmias and a potential pacing target, a careful characterization of its structure and mechanical properties are essential for understanding its role in cardiac physiology. In the first section of this dissertation, we perform a systematic analysis of the structural features and mechanical strains in the heart, focusing on the RVA region. More than half of ARVC patients exhibit one or more mutations in genes encoding desmosomal proteins. This has led many investigators to suggest that ARVC is a "disease of the desmosome" in which defective cell-cell adhesion plays a critical pathogenic role, although direct evidence for this hypothesis is lacking. To gain greater insights into potential mechanisms by which desmosomal mutations cause ARVC, we next characterize biomechanical properties and responses to shear stress (motivated by our results in the previous section) in neonatal rat ventricular myocytes expressing two distinct mutant forms of the desmosomal protein plakoglobin which have been linked to ARVC in patients. We show that ARVC-causing mutations in plakoglobin lead to altered cellular distribution of plakoglobin, without alterations in cell mechanical properties or certain early signaling pathways. The identification of defective molecular mechanisms that are common across ARVC-patients remains a strategic area of research. Specifically, recent studies have investigated the mechanistic basis for different ARVC-causing mutations in hopes of identifying common defects in a signaling pathway - information that could be used to develop diagnostic tests or identify therapeutic targets. In the last section of this dissertation, we investigate the effects of mutant plakophilin-2 expression, and repeat key experiments performed in the previous section to identify common defects in mechanical and signaling properties. We identify a common, underlying defect in ARVC pathogenesis. Specifically, we show that disease-causing mutations across different desmosomal proteins can cause the cell to respond abnormally to mechanical shear stress with respect to plakoglobin trafficking.

Right ventricular dysfunction is under-recognized in veterinary medicine, and has relied more on qualitative signs of right-sided congestive failure, rather than on quantitative cardiac indices (Visser, Scansen, Schober, & Bonagura, 2015b). Haddad, Doyle, Murphy, and Hunt (2008a), and more recently Lang, Badano, Mor-Avi, Afilalo, Armstrong, Ernande et al. (2015) published studies that highlight the prognostic value of right heart assessment, not only in right heart diseases but also for diseases affecting the left heart diseases. According to de Madron, Chetboul, and Bussadori (2015), there are several diseases that affect the canine right heart, such as arrhythmogenic right ventricular cardiomyopathy, dilated cardiomyopathy, pulmonary hypertension and congenital malformation of the pulmonic and tricuspid valves. It is therefore important to use echocardiographic parameters with high feasibility and repeatability and low intra- and interobserver variability that efficiently quantify right ventricular function. With the evolution in echocardiographic examination and technology, new parameters have been studied and reference values become increasingly accessible for the veterinarian cardiologist. The aim of this thesis was to review the state of knowledge on the clinical applicability of echocardiography to assess right ventricular function, emphasizing the methodology for image acquisition, evaluated parameters, advantages and limitations of each technique, their prognostic value and applicability to the different clinical scenarios.
A disfunção ventricular direita está pouco reconhecida na Medicina Veterinária, e tem sido avaliada maioritariamente através de sinais qualitativos de insuficiência cardíaca congestiva direita em vez de índices cardíacos quantitativos (Visser et al., 2015b). Como Haddad et al. (2008a) e, mais recentemente Lang et al. (2015) demonstraram, a avaliação de função do coração direito tem grande valor prognóstico não só em patologia de coração direito como em patologia de coração esquerdo. Segundo de Madron et al. (2015), existem diversas patologias que afectam o coração direito canino, destacando-se a cardiomiopatia arritmogénica do ventrículo direito, cardiomiopatia dilatada, hipertensão pulmonar e malformações congénitas da válvula tricúspide e pulmonar. Deste modo, surgiu a necessidade de utilizar técnicas ecocardiográficas repetíveis com baixos valores de variabilidade inter e intra dependentes do observador que quantifiquem eficientemente a função do ventrículo direito e que sejam possíveis de executar em qualquer centro veterinário. Com a evolução da metodologia ecocardiográfica e da tecnologia disponível, novos parâmetros foram estudados e valores de referência para diferentes patologias estão disponíveis para cardiologistas veterinários Pretende-se com esta dissertação, efectuar uma revisão dos conhecimentos sobre a aplicabilidade clínica da ecocardiografia para estimar a função sistólica e diastólica ventricular direita, dando ênfase à metodologia de aquisição de imagem, parâmetros avaliados, vantagens e limitações das técnicas, aplicações em contexto clínico e valor prognóstico.

ABSTRACT 1 Background. With recognition of disease-causing genes in arrhythmogenic right ventricular cardiomyopathy, mutation analysis is being applied. Methods and Results. The role of genotyping in familial assessment for arrhythmogenic right ventricular cardiomyopathy was investigated, including the prevalence of mutations in known causal genes, the penetrance and expressivity in genotyped families, and the utility of the 2010 Task Force criteria in clinical diagnosis. Clinical and molecular genetic evaluation was performed in 210 first-degree and 45 second-degree relatives from 100 families. In 51 families, the proband was deceased. The living probands had a high prevalence of ECG abnormalities (89%) and ventricular arrhythmia (78%) and evidence of more severe disease than relatives. Definite or probable causal mutations were found in 58% of families and 73% of living probands, of whom 28% had an additional desmosomal variant (ie, mutation or polymorphism). Ninety-three relatives had a causal mutation; 33% fulfilled the 2010 criteria, whereas only 19% satisfied the 1994 version (P=0.03). An additional desmosomal gene variant was found in 10% and was associated with a 5-fold increased risk of developing penetrant disease (odds ratio, 4.7; 95% confidence interval, 1.1 to 20.4; P=0.04). Conclusions. Arrhythmogenic right ventricular cardiomyopathy is a genetically complex disease characterized by marked intrafamilial phenotype diversity. Penetrance is definition dependent and is greater with the 2010 criteria compared with the 1994 criteria. Relatives harboring >1 genetic variant had significantly increased risk of developing clinical disease, potentially an important determinant of the phenotypic heterogeneity seen within families with arrhythmogenic right ventricular cardiomyopathy. ABSTRACT 2 Aims. Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited heart muscle disease predominantly caused by mutations in desmosomal protein genes. Lamin A/C gene (LMNA) mutations are associated with dilated cardiomyopathy, conduction abnormalities and high incidence of sudden cardiac death. In this study we screened a large cohort of ARVC patients for LMNA mutations. Methods and Results. One hundred and eight patients from unrelated families with borderline (n= 27) or definite (n= 81) diagnosis of ARVC were genetically tested for five desmosomal genes and LMNA. Sixty-one (56.5 %) were positive for desmosomal gene mutations. Standard polymerase chain reaction (PCR) amplification of the 12 protein-coding LMNA exons was performed and mutational screening performed by direct sequencing. Four patients (4%) without desmosomal gene mutations carried LMNA variants. Three had severe RV involvement, and during follow-up three died (two suddenly and one from congestive heart failure); all three had conduction abnormalities on resting 12 lead ECG. Myocardial tissue from two patients showed myocyte loss and fibro-fatty replacement. In one of these, immunohistochemical staining with antibody to plakoglobin showed reduced/absent staining of the intercalated discs in the myocardium. Conclusion. LMNA mutations can be found in severe forms of ARVC. LMNA should be added to desmosomal genes when genetically testing patients with suspected ARVC, particularly when they also have ECG evidence for conduction disease.

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014
Syncope is a transverse symptom to all age groups with extensive differential diagnosis, and therefore, establishing an etiologic diagnosis is not always linear. Despite being mostly a benign symptom, it may be the only way of presentation of extremely debilitating diseases. One of the differential diagnoses of syncope is arrhythmogenic right ventricular cardiomyopathy. The arrhythmogenic right ventricular cardiomyopathy is a clinical entity of difficult diagnosis that manifests itself through ventricular arrhythmias associated with characteristic right ventricular changes (in an early stage limited to the right ventricle and, in a later stage biventricular). We present a case of a 23 year old with arrhythmogenic right ventricular cardiomyopathy that manifests itself in the form of transient loss of consciousness preceded by heart palpitations, during sport practice. With no previous history of disease, the patient suffers rapid progression of heart disease over 12 months, with the final diagnosis of arrhythmogenic right ventricular cardiomyopathy. In this paper, a theoretical analysis on arrhythmogenic right ventricular cardiomyopathy is performed, focusing the historical perspective of the disease, its clinical presentation and therapy, while tracking the clinical progress of the clinical case.
Síncope é um sintoma transversal a todas as faixas etárias com diagnóstico diferencial extenso e, por isso, estabelecer um diagnóstico etiológico nem sempre é linear. Apesar de ser maioritariamente um sintoma benigno, pode ser a única forma de apresentação de patologias extremamente debilitantes. Um dos diagnósticos diferenciais de síncope é a miocardiopatia arritmogénica do ventrículo direito. A miocardiopatia arritmogénica do ventrículo direito é uma entidade clínica de diagnóstico difícil que se manifesta por arritmias ventriculares associadas a alterações ventriculares direitas característica (numa fase inicial, limitadas ao ventrículo direito e, numa fase mais avançada, biventriculares). Apresenta-se um caso clínico de um jovem de 23 anos com miocardiopatia arritmogénica do ventrículo direito que se manifestou sob a forma de perda transitória de consciência precedida por quadro de palpitações, durante prática desportiva. Sem qualquer história de doença prévia, o doente sofreu rápida progressão de doença cardíaca ao longo de 12 meses, sendo o diagnóstico final de miocardiopatia arritmogénica do ventrículo direito. Neste trabalho, é feita uma abordagem teórica sobre miocardiopatia arritmogénica do ventrículo direito focando-se a perspectiva histórica da doença, a sua apresentação clínica e terapêutica, expondo-se paralelamente o desenrolar do caso clínico.

Hintergrund: Die gegenwärtigen Richtlinien zur Herzinsuffizienzbehandlung schenken der Beurteilung des rechten Ventrikels nur wenig Aufmerksamkeit, da nur begrenzte Daten zu Determinanten der rechtsventrikulären Funktion und den Mechanismen, die zu seiner Insuffizienz führen bzw. der Beziehung zu den Ergebnissen zur Verfügung stehen. Fragestellung: Es war die Aufgabe der Studie, die Prävalenz der rechtsventrikulären Dysfunktion (RVD) zu bestimmen, klinische und hämodynamische Korrelate zu identifizieren und die Beziehung zu kardialer Mortalität bei Herzinsuffizienz mit reduzierter linksventrikulärer Ejektionsfraktion (LVEF) hervorgerufen durch die nicht-ischämische Kardiomyopathie (NICM) einzuschätzen. Methoden: In dieser prospektiv angelegten Studie wurden 423 Patienten mit kardiovaskulärer Magnetresonanztomographie (CMR) untersucht. Zudem wurde bei 100 Patienten zeitnah zur CMR-Untersuchung eine Rechtsherzkatheteruntersuchung durchgeführt. Die kardiale Mortalität wurde als Studienendpunkt definiert. Ergebnisse: Während einer medianen Nachbeobachtungszeit von 6,2 Jahren (IQR: 2,9 bis 7,6) starben 101 (24 %) der Patienten aufgrund eines kardialen Versagens. Es stellte sich heraus, dass die rechtsventrikuläre Ejektionsfraktion (RVEF) ein starker Prädiktor für kardiale Mortalität nach Anpassung an Alter, NYHA-Klasse, systolischen Blutdruck, Herzfrequenz, Natrium und Kreatininserumspiegel, Myokardnarbe und linksventrikuläre Ejektionsfraktion (LVEF) ist. Patienten, die im Quintil mit der niedrigsten RVEF waren, hatten ein fast fünffach so hohes kardiales Mortalitätsrisiko im Vergleich zum höchsten Quintil (Hazard Ratio [95%-Konfidenzintervall (CI)]: 4,68 [2,43-9,02]; p<0,0001). Die RVEF hatte eine positive Korrelation zur LVEF (r=0,60; p=<0,0001), und eine umgekehrte Korrelation zum rechten Vorhofdruck (r=−0,32; p=0,001), mittleren pulmonalarteriellen Druck (r=−0,34, p=0,0005), transpulmonalen Gradienten (r=−0,28; p=0,006), aber keine mit dem pulmonalarteriellen Verschlussdruck (r=−0,15; p=0,13). In der multivariablen logistischen Regressionsanalyse des CMR und der klinischen und hämodynamischen Daten waren die LVEF (Odds Ratio [95%-CI]: 0,85 [0,78-0,92], p<0,0001), der transpulmonale Gradient (Odds Ratio [95%-CI]: 1,20 [1,09-1,32], p=0,0003) und der systolische Blutdruck (Odds Ratio [95%-CI]: 0,97 [0,94-0,99], p=0,02) die stärksten Prädiktoren für die RVD. Schlussfolgerungen: Die Untersuchung der RVEF mit CMR liefert wichtige prognostische Informationen unabhängig von etablierten Risikofaktoren bei Herzinsuffizienzpatienten. RVD steht in einer starken Verbindung mit beiden Kenngrößen der intrinsischen myokardialen Kontraktilität und der erhöhten Nachlast durch eine pulmonalvaskuläre Dysfunktion.:Inhaltsverzeichnis Abkürzungsverzeichnis 1 Einleitung 1.1 Einführung in die Problemstellung der vorliegenden Arbeit 1.2 Nicht-ischämische Kardiomyopathie 1.3 Die Bedeutung des rechten Ventrikels für die Entwicklung der Herzinsuffizienz 1.4 Magnetresonanztomographie als Untersuchungsmethode 1.4.1 Einführung in die CMR 1.4.2 Allgemeine Grundlagen der MRT 1.4.3 True Fast Imaging with Steady-State Precession (TrueFISP) 1.4.4 Turbo Fast Low-Angle Shot (Turbo-FLASH) 1.5 Rechtsherzkatheter als Standarduntersuchung 1.6 Ziele der Studie 2 Patienten und Methoden 2.1 Patientenpopulation 2.2 Untersuchungsprotokoll MRT 2.2.1 Untersuchungstechnik 2.2.2 Bildanalyse 2.3 Rechtsherzkatheteruntersuchung 2.4 Verlaufsuntersuchung 2.5 Statistische Analyse 3. Ergebnisse 3.1 Basischarakteristika 3.2 Ergebnisse der Nachfolgeuntersuchung 3.3 Zusammenhang zwischen rechtsventrikulärer Dysfunktion und kardialer Mortalität 3.4 Prädiktoren der kardialen Mortalität 3.5 Bestimmungsfaktoren der rechtsventrikulären Dysfunktion 4 Diskussion 4.1 Ergebnisdiskussion 4.2 Grenzen der Studie 4.3 Schlussfolgerungen der Diskussion 4.4 Perspektiven 4.4.1 Kompetenz bei der Patientenbehandlung und Fähigkeiten der Prozedur 4.4.2 Ausblick für die zukünftige Behandlung 5 Zusammenfassung 6 Literaturverzeichnis Abbildungsverzeichnis Tabellenverzeichnis Eidesstattliche Erklärungen Einhaltung der gesetzlichen Regeln Danksagung
Background: Current heart failure (HF) management guidelines place little emphasis on right ventricular (RV) assessment, due to limited available data on determinants of RV function and mechanisms leading to its failure, and relation to outcomes. Objective: To determine the prevalence of RV dysfunction (RVD), identify clinical and hemodynamic correlates, and assess the relation to cardiac mortality in HF with reduced left ventricular ejection fraction (LVEF) from non-ischemic cardiomyopathy (NICM). Methods: This study prospectively examined 423 patients with cardiovascular magnetic resonance (CMR). Right-heart catheterization was performed in 100 patients. The prespecified study endpoint was cardiac mortality. Results: During a median follow-up time of 6.2 years (IQR: 2.9 to 7.6) 101 (24%) patients died of cardiac causes. RVEF was a strong independent predictor of cardiac mortality after adjustment for age, HF functional class, systolic blood pressure, heart rate, serum sodium and creatinine levels, myocardial scar, and LVEF. Patients with the lowest quintile of RVEF had a near five-fold higher cardiac mortality risk compared to the highest quintile (hazard ratio [95% confidence interval (CI)]: 4.68 [2.43-9.02], p<0.0001). RVEF was positively correlated with LVEF (r=0.60, p=<0.0001), and inversely correlated with right atrial pressure (r=−0.32, p=0.001), mean pulmonary artery pressure (r=−0.34, p=0.0005), transpulmonary gradient, (r=−0.28, p=0.006) but not with pulmonary wedge pressure (r=−0.15, p=0.13). In multivariable logistic regression analysis of CMR, clinical, and hemodynamic data, LVEF, transpulmonary gradient, and systolic blood pressure were the strongest predictors of RVD (odds ratio [95% CI]: 0.85 [0.78-0.92], p<0.0001; 1.20 [1.09-1.32], p=0.0003; 0.97 [0.94-0.99], p=0.02, respectively). Conclusion: CMR assessment of RVEF provides important prognostic information independent of established risk factors in HF patients. RVD is strongly associated with both indices of intrinsic myocardial contractility and increased afterload from pulmonary vascular dysfunction.:Inhaltsverzeichnis Abkürzungsverzeichnis 1 Einleitung 1.1 Einführung in die Problemstellung der vorliegenden Arbeit 1.2 Nicht-ischämische Kardiomyopathie 1.3 Die Bedeutung des rechten Ventrikels für die Entwicklung der Herzinsuffizienz 1.4 Magnetresonanztomographie als Untersuchungsmethode 1.4.1 Einführung in die CMR 1.4.2 Allgemeine Grundlagen der MRT 1.4.3 True Fast Imaging with Steady-State Precession (TrueFISP) 1.4.4 Turbo Fast Low-Angle Shot (Turbo-FLASH) 1.5 Rechtsherzkatheter als Standarduntersuchung 1.6 Ziele der Studie 2 Patienten und Methoden 2.1 Patientenpopulation 2.2 Untersuchungsprotokoll MRT 2.2.1 Untersuchungstechnik 2.2.2 Bildanalyse 2.3 Rechtsherzkatheteruntersuchung 2.4 Verlaufsuntersuchung 2.5 Statistische Analyse 3. Ergebnisse 3.1 Basischarakteristika 3.2 Ergebnisse der Nachfolgeuntersuchung 3.3 Zusammenhang zwischen rechtsventrikulärer Dysfunktion und kardialer Mortalität 3.4 Prädiktoren der kardialen Mortalität 3.5 Bestimmungsfaktoren der rechtsventrikulären Dysfunktion 4 Diskussion 4.1 Ergebnisdiskussion 4.2 Grenzen der Studie 4.3 Schlussfolgerungen der Diskussion 4.4 Perspektiven 4.4.1 Kompetenz bei der Patientenbehandlung und Fähigkeiten der Prozedur 4.4.2 Ausblick für die zukünftige Behandlung 5 Zusammenfassung 6 Literaturverzeichnis Abbildungsverzeichnis Tabellenverzeichnis Eidesstattliche Erklärungen Einhaltung der gesetzlichen Regeln Danksagung