An 11 week old female infant with congenitally malformed eyes died from intractable cardiac arrhythmia. The heart showed extensive oncocytic transformation of myocytes, and this distinctive cardiomyopathy affected the conduction system. Oncocytes were found also in endocrine (pituitary, thyroid) and exocrine (submandibular, sublingual, minor salivary) glands. There is morphologic evidence that the lesions were caused early in gestation, possibly by a viral infection such as rubella.