Right ventricular dysplasia: Right and left ventricular involvement morphometrically evaluated

Right ventricular dysplasia (RVD) is a cardiac anomaly characterized by replacement of variable amounts of right ventricular myocardium by adipose tissue. This condition is believed to be a selective disorder involving extensively the right ventricle, but there are occasional reports of concomitant "minor" abnormalities of the left ventricle. The object of this report concerns a patient who died after heart transplantation because of an unsuspected RVD of the donor heart. We present a morphometric study of the heart in order to evaluate the distribution of the fat on both ventricles and to understand the structural basis of the heart failure. The results show that a large portion of the right ventricle is replaced by fat with a quite homogeneous distribution; the left ventricle is also largely replaced by adipose tissue that is primarily localized at the apex and decreases from the apex to the basis. The remodeling of the heart is attributable to a conspicuous increase in volume of the right ventricle associated with a normal number of myocytes that are longer than normal. For these reasons, according to Starling's law, the heart develops congestive failure.