Histopathology of Familial Versus Nonfamilial Dilated Cardiomyopathy

Idiopathic dilated cardiomyopathy is most likely a heterogenous group of diseases characterized by ventricular dilatation and dysfunction. Approximately 20% of patients with idiopathic dilated cardiomyopathy have familial disease, which may be inapparent by review of the family history alone. It has been suggested that histopathologic features, particularly the presence of bizarrely shaped mitochondria, may be useful in distinguishing familial from nonfamilial disease. We investigated 57 patients with dilated cardiomyopathy, 13 familial and 43 nonfamilial or indeterminate. Pathologic examination of right endomyocardial biopsy specimens showed no significant differences between the familial, nonfamilial, or indeterminate groups by light microscopy or electron microscopy. We conclude that the distinction between familial and nonfamilial dilated cardiomyopathy cannot be made by histopathologic examination in most cases.