Ultrastructural pathology of the heart in patients with beta-thalassaemia major.

Patients with beta-thalassaemia major frequently suffer from hypersiderosis which leads to hemochromatosis of major organs such as the heart and liver. Little information exists about the ultrastructural pathology of the human heart in beta-thalassaemia patients. Five Cypriot patients with elevated blood ferritin and intractable heart failure were investigated. Cardiac biopsies from these patients were studied by light and electron microscopy, as well as by X-ray microanalysis. Ultrastructural examination revealed the presence of disrupted myocytes showing loss of myofibers, dense nuclei, and a variable number of pleomorphic electron dense granules. These cytoplasmic granules or siderosomes consisted of iron-containing particles as confirmed by X-ray microanalysis. It is likely that the ultrastructural changes observed in myocytes of patients with beta-thalassaemia are largely due to iron deposition.