Arrhythmogenic right ventricular dysplasia (ARVD) is an inherited cardiomyopathy characterized by ventricular arrhythmias and structural abnormalities of the right ventricle (RV). ARVD results from progressive replacement of right ventricular myocardium with fatty and fibrous tissue. The precise prevalence of ARVD in the United States has been estimated to be 1 in 5000 of the general population. Recent evidence has made it clear that ARVD is a disease of desmosomal dysfunction. The main management consideration concerns whether to implant an ICD. Catheter ablation of VT is a largely a paliative procedure that should not be considered as an appropriate strategy to eliminate VT or reduce sudden death risk. It is likely that the recent advances in the understanding of the pathophysiologic basis of this condition will result in more targeted treatment approaches in the future.
"The prevalence of ARVC/D is estimated at 1/5,000 and follows an autosomal dominant pattern of inheritance with reduced penetrance and variable clinical expression [3, 4]. At least 12 genetic variances are known, mainly in genes encoding for desmosomal proteins . A positive family history is present in 30–50% of cases . "
[Show abstract][Hide abstract] ABSTRACT: Histopathologic findings in arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) are replacement of the normal myocardium with fatty and fibrous elements with preferential involvement of the right ventricle. The right ventricular fibrosis can be visualised by post-gadolinium delayed enhancement inversion recovery imaging (DE imaging). We compared the image quality of three different gradient echo MRI sequences for short axis DE imaging of the right ventricle (RV). We retrospectively analysed MRI scans performed between February 2005 and December 2008 in 97 patients (mean age: 41.2 years, 67% men) suspected of ARVC/D. For DE imaging either a 2D Phase Sensitive (PSIR), a 2D (2D) or a 3D (3D) inversion recovery sequence was used in respectively 38, 32 and 27 MRI-examinations. The RV, divided in 10 segments, was assessed for image quality by two radiologists in random sequence. A consensus reading was performed if results differed between the two readings. Image quality was good in 24% of all segments in the 3D group, 66% in the 2D group and 79% in the PSIR group. Poor image quality was observed in 51% (3D), 10% (2D), and 2% (PSIR) of all segments. Exams were considered suitable for clinical use in 7% of exams in the 3D group, 75% of exams in the 2D group and 90% of exams of the PSIR group. Breathing-artifacts occurred in 22% (3D), 59% (2D) and 53% (PSIR). Motion-artifacts occurred in 56% (3D), 28% (2D) and 29% (PSIR). Post-gadolinium imaging using the PSIR sequence results in better and more consistent image quality of the RV compared to the 2D and 3D sequences.
The international journal of cardiovascular imaging 04/2011; 28(3):595-601. DOI:10.1007/s10554-011-9871-9 · 1.81 Impact Factor
"To date, ten different genes have been determined to be responsible for causing ARVC, including desmocollin, desmoglein, desmoplakin, plakophillin-2 (PKP2), plakoglobin, desmin, ZASP, Transmembrane Protein 43 (TP43), and Transforming Growth Factor β3 (TGF β3). For many of these genes, mutations have only been identified in a few pedigrees worldwide  or lead to “atypical” forms of ARVD. "
[Show abstract][Hide abstract] ABSTRACT: The intercalated disk (ID) is a complex structure that electromechanically couples adjoining cardiac myocytes into a functional syncitium. The integrity of the disk is essential for normal cardiac function, but how the diverse elements are assembled into a fully integrated structure is not well understood. In this study, we examined the assembly of new IDs in primary cultures of adult rat cardiac myocytes. From 2 to 5 days after dissociation, the cells flatten and spread, establishing new cell-cell contacts in a manner that recapitulates the in vivo processes that occur during heart development and myocardial remodeling. As cells make contact with their neighbors, transmembrane adhesion proteins localize along the line of apposition, concentrating at the sites of membrane attachment of the terminal sarcomeres. Cx43 gap junctions and ankyrin-G, an essential cytoskeletal component of voltage gated sodium channel complexes, were secondarily recruited to membrane domains involved in cell-cell contacts. The consistent order of the assembly process suggests that there are specific scaffolding requirements for integration of the mechanical and electrochemical elements of the disk. Defining the relationships that are the foundation of disk assembly has important implications for understanding the mechanical dysfunction and cardiac arrhythmias that accompany alterations of ID architecture.
BioMed Research International 05/2010; 2010:624719. DOI:10.1155/2010/624719 · 2.71 Impact Factor
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