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  Disease summary:

  
  
  
  
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    Arrhythmogenic right ventricular cardiomyopathy (ARVC), formerly referred to as arrhythmogenic right ventricular dysplasia (ARVD), is a heart muscle disease predominantly affecting the right ventricle.

    
    
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    Pathologically, the central feature is a progressive replacement of right ventricular myocardium with fibrofatty tissue.

    
    
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    Clinically, affected individuals present with palpitations, syncope, or sudden death as a result of ventricular arrhythmias, such as ventricular tachycardia or fibrillation, with symptomatic heart failure usually only in later stages.

    
    
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    While the majority of patients do not present with sudden cardiac death, ARVC may account for 10% to 20% of sudden cardiac death in individuals younger than age 35.

    
    
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    The prevalence of ARVC is estimated to be 1 case per 1000 to 5000 of the general population.

  
  

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  Hereditary basis:

  
  
  
  
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    ARVC is familial in 30% to 50% of cases with onset usually in the second to fifth decades of life with males being three times more likely than females to manifest the phenotype.

    
    
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    The disease most commonly exhibits an autosomal dominant pattern of inheritance with reduced penetrance; however, rare autosomal recessive forms have also been described.

    
    
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    ARVC is a genetically heterogeneous condition with eight genes and four additional genetic loci have been identified thus far. A large proportion of known mutations occur in genes encoding structural proteins of the desmosome.

  
  

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  Differential diagnosis:

  
  
  
  
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    When arrhythmias or sudden death are present, other inherited cardiac rhythm disorders should be considered including catecholaminergic polymorphic ventricular tachycardia, hereditary idiopathic ventricular tachycardia, Brugada syndrome, long QT syndrome, and short QT syndrome (Table 20-1).

    
    
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    When heart failure is present, other inherited cardiomyopathies should be considered including: dilated cardiomyopathy, hypertrophic cardiomyopathy, and left ventricular noncompaction.

    
    
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    A major nongenetic diagnosis to consider is idiopathic right ventricular outflow tract tachycardia, which can also cause the ventricular tachycardia with left bundle branch pattern seen in ARVC.

    
    
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    Naxos syndrome, a rare autosomal recessive condition includes palmoplantar keratosis and wooly hair in addition to ARVC.

  
  

The diagnosis of ARVC is based on 1994 guidelines from an international ARVC task force and are based on the presence or absence of major and minor criteria (Table 20-2)