[Parathyroid function in hypertrophic myocardiopathy]

It has been suggested that hypertrophic cardiomyopathy (HCM) may be associated with hyperparathyroidism. We evaluated parathyroid function in 15 patients with HCM and 14 patients with primary dilated cardiomyopathy (DCM), measuring different parameters of calcium metabolism (total serum calcium, ionized calcium, PTH, vitamin D metabolites, alkaline phosphatase, osteocalcin). As a group PTH levels were normal in HCM (intact PTH 3.9 +/- 1.6 pmol/l, midmolecular PTH 59 +/- 13 pmol/l and carboxyterminal PTH 0.6 +/- 0.4 ng/ml), but in 3 patients carboxyterminal PTH levels were persistently higher than normal, while all other parameters of calcium metabolism were normal. We conclude that parathyroid function is normal in patients with HCM, although some of them may have an abnormal secretion and/or metabolism of carboxyterminal PTH fragments, or a circulating substance the interferes with this PTH assay. Parathyroid function in DCM patients was normal, except in a patient who had hyperparathyroidism secondary to vitamin D deficiency.