A patient has long standing severe hemolytic anemia characterized by hypochromic cells. Electrophoresis studies demonstrate a near complete absence of beta chains. Several years later, the patient develops cardiac failure. Intracardiac deposition of which of the following would be most likely to contribute to the cardiac failure?

The disease is beta thalassemia major, which is a severe haemolytic anemia characterized by a failure to produce the beta chains of hemoglobin (some HbF, the fetal form of hemoglobin, is produced). The excess alpha chains are insoluble, leading to intra- and extravascular hemolysis. These patients require large numbers of transfusions, and iron overload with resulting secondary hemochromatosis can contribute to eventual cardiac failure. The hea is also damaged by the chronic high output state needed to compensate for the anemia. Calcium deposition is seen in damaged tissues and states with high serum calcium, such as hyperparathyroidism. Magnesium, potassium, and sodium are highly soluble and do not usually precipitate in tissues. Ref: Weatherall D.J. (2010). Chapter 47. The Thalassemias: Disorders of Globin Synthesis. In J.T. Prchal, K. Kaushansky, M.A. Lichtman, T.J. Kipps, U. Seligsohn (Eds), Williams Hematology, 8e.