Arrhythmogenic right ventricular cardiomyopathy : Evolving from unique clinical features to a complex pathophysiological concept

Arrhythmogenic right ventricular cardiomyopathy (ARVC), an inherited heart muscle disease, is characterized by a progressive replacement of viable, in its classic form predominantly right ventricular myocardium by fibro-fatty tissue. These pathological alterations may provide the substrate for the occurrence of life-threatening ventricular tachyarrhythmias, heart failure, and sudden cardiac death. The clinical course in this young patient population is highly variable, diagnostic algorithms complex, and individualized treatment strategies yet to be refined. Molecular genetic analyses have revealed both heterozygous and compound mutations in genes encoding for desmosomal proteins that are an integral part of the intercellular architecture. However, its diagnostic and prognostic impact remains to be elucidated. Over time, other genetic (i.e., non-desmosomal) and non-genetic causes (phenocopies) have been identified, and biventricular and left dominant manifestations (ALVC) are known. Based on a qualitative scoring system, initially published in 1994, diagnostic criteria were revised and substantiated by quantitative criteria in 2010 followed by a critical appraisal 9 years later. In 1995, ARVC was included in the classification of cardiomyopathies of the World Health Organization but was recently proposed to be subsumed in a broader concept termed "arrhythmogenic cardiomyopathy" (AC). This review provides an update on the clinical diagnosis and differential diagnoses of ARVC as well as our current understanding of the underlying pathogenesis, and it sheds light on new efforts in risk stratification.