Histochemical studies of the myocardium and conduction system in acquired iron-storage disease.

The myocardium, all parts of the conduction system, and the S-A node contained iron in six patients with acquired iron-storage disease. The nerve fibers and ganglia contained negligible amounts. No correlation was demonstrated between the amount of histochemically demonstrated iron in the myocardium and conduction system, or the amount of transfused iron, or the amount of quantitatively analyzed myocardial iron and the presence of antemortem arrhythmias and conduction disturbances. The degree of scarring in the S-A node, A-V node, and bundle of His did not parallel the density of iron deposits in these structures. These observations support the theory that factors other than iron alone are responsible for the cardiac rhythm and conduction abnormalities associated with ironstorage disease.