Etiopathogenesis of arrhythmogenic right ventricular dysplasia]

Arhythmogenic right ventricular dysplasia (ARVD) is a genetically determined cardiomyopathy with a dominant transmission mode and variable penetrance. Transdifferenciation of cardiomyocytes into adipocytes is likely to explain massive replacement of right ventricular and to a lesser extent left ventricular myocardium by adipose tissue. This phenomenon starts in the mediomural layers and extends into the epicardium. It can occur in the fetus, however youth and young adults are more frequently involved. Apoptosis defined as a programmed cell death, is likely to enhance adipogenesis and tiny fibrosis production. Inflammation can be superimposed on the genetically determined substrate and usually involves both ventricles. Myocarditis can be acute or chronic with interstitial or scar fibrosis, or active chronic. In some cases, left ventricular involvement can be as important as right ventricle, characterizing biventricular dysplasia. In Naxos disease, ARVD is associated with an ectodermic dysplasia. The transmission mode is recessive.