How does hypoparathyroidism lead to the development of cardiomyopathy?
The mechanisms6 for the development of cardiomyopathy in patients with hypoparathyroidism include hypocalcaemia (the most important), hypomagnesaemia, decreased levels of circulating parathormone, other metabolic changes due to hypoparathyroid state and coexisting myocardial disease. Calcium plays an important role in myocardial function. As sarcoplasmic reticulum is unable to sequester a sufficient quantity of calcium ion to initiate contraction a supplemental extra-cellular source of calcium ions is required. The strength of the contraction is influenced by the magnitude of influx of extra-cellular calcium. At renal level, a rise in cytosolic free calcium level in renal tubular cells will promote natriuresis.7 Conversely, a fall in cytosolic calcium may increase renal sodium reabsorbtion. Thus sodium retention during hypocalcaemia may be a factor in the pathogenesis of cardiac failure. The resolution of congestive cardiac failure associated with hypoparathyroidism with treatment of t
