Fatal "iron heart" in an adolescent: biochemical and ultrastructural aspects of the heart.

Histochemical and ultrastructural aspects of the heart were investigated in an adolescent with fatal congestive heart failure resulting from exogenous hemochromatosis. Extensive iron deposits were found in all four chambers, papillary muscles, and the conduction system. These deposits were most prominent over the outer third of the left ventricular myocardium, with no significant difference between deposits in the middle and inner thirds. Quantitative analysis of iron from different chambers and all zones of the left ventricular myocardium confirmed the aforementioned pattern of iron distribution. Iron deposits in sinoauricular and atrioventricular nodes were similar to those in the right atrial myocardium. Degenerative changes and fibrosis were minimal. Ultrastructural studies showed that intracytoplasmic iron deposition followed a perinuclear, paranuclear, or diffuse pattern. In addition, some iron was consistently present in the nucleus and mitochondria. It is postulated that the presence of iron in the mitochondria may adversely affect the cellular enzyme system; this could provide a biochemical basis for myocardial dysfunction in patients with acquired iron-storage disease.