MSH: A congenital cardiomyopathy that is characterized by infiltration of adipose and fibrous tissue into the RIGHT VENTRICLE wall and loss of myocardial cells. Primary injuries usually are at the free wall of right ventricular and right atria resulting in ventricular and supraventricular arrhythmias.,NCI: A rare genetic disorder characterized by cardiomyopathy affecting the right ventricle. The heart tissue is replaced by fibrous and adipose tissues. It is characterized by ventricular arrhythmia and right ventricular dysfunction. It is a cause of sudden death.