Arrhythmogenic Right Ventricular Dysplasia (ARVD)

Updated: Sep 23, 2014
  • Author: Gyanendra K Sharma, MD, FACC, FASE; Chief Editor: Jeffrey N Rottman, MD  more...
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Overview

Background

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/ARVC) is an inherited cardiomyopathy characterized by structural and functional abnormalities in the right ventricle (RV) resulting in ventricular arrhythmias. [1] It is an important cause of sudden cardiac death (SCD) in young adults, accounting for 11% of all cases and 22% of cases among athletes. [2, 3]

ARVD was first described in 1977 and was included in the WHO classification of cardiomyopathies in 1996. [4] Since then, there have been significant advances in the understanding of its etiopathogenesis, diagnosis, and management. [5]

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Pathophysiology

The structural abnormalities in ARVD result from the fatty infiltration and fibrosis of the RV myocardium. This leads to progressive RV dilatation and dysfunction. The left ventricle (LV) is less commonly involved, and the septum is relatively spared. [6] However, in a cohort of 200 probands, Sen-Chowdhry et al found that LV involvement may even precede the onset of significant RV dysfunction. [7] The prognosis is worse in patients with LV involvement. [8]

The mechanisms for myocardial loss include the following:

  • Apoptosis (programmed cell death)
  • Inflammation, enhanced fibrosis, and loss of function
  • Fatty replacement of myocardium
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Etiology

ARVD is an inherited disorder, as it is already present in the fetus. Familial cases account for 30%-90% of cases. [9] In other cases, it may result from an acquired etiology such as viral infection (myocarditis) or unidentified inheritance. It is also likely that patients with a genetic predisposition are more likely to develop myocarditis.

The disease manifests more frequently in active individuals, when mechanical sheer stress can cause cell membrane damage, inflammation, and fibrosis in genetically predisposed RV.

Genetics

ARVD is considered a genetic disorder, as most cases are familial, and there is geographical clustering. The most common pattern of inheritance is autosomal dominance, with a variable penetrance ranging from 20%-35% of family members. [10, 11] People living in the Veneto region of Italy have a higher penetrance. The autosomal-recessive (Naxos disease) pattern of inheritance is localized to the Greek island of Naxos and is associated with palmoplantar keratosis and wooly hair. The genetic mutation occurs on chromosome 17q21, and penetrance is almost 100%. [12, 13]

Genetic abnormalities in ARVD are located on chromosomes 1, 2, 3, 6, 7, 10, 12, and 14. There is no single unique genetic abnormality, posing a challenge in evaluation of patients and families with suspected ARVD. The responsible genes include plakoglobin (JUP), desmoplakin (DSP), plakophilin-2 (PKP2), desmoglein-2 (DSG2), desmocollin-2 (DSC2), and others. [14, 15, 16]

The Heart Rhythm Society and the European Heart Rhythm Association have published a consensus statement on genetic testing for cardiomyopathies. [17]

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Epidemiology

Because of the diagnostic challenge, the exact incidence and prevalence of ARVD remains unknown, as clinically silent cases may go unrecognized. [18] It is estimated that it affects 1 in 1000-5000 population and is more common in individuals of Greek and Italian origin. [19]

In a cohort of 100 patients from the United States, the median age at presentation was 26 years, and 51% were males. The median time to diagnosis was one year from the initial presentation, and median survival in the entire cohort was 60 years. [20]

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Prognosis

ARVD is an important cause of sudden cardiac death in young adults, accounting for 11% of all cases and 22% of cases among athletes.

The prognosis is worse in patients with LV involvement

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