Use of recombinant human parathyroid hormone in hypocalcemic cardiomyopathy.

Hypocalcemia secondary to hypoparathyroidism is a rare cause of congestive heart failure. However, its early recognition and treatment lead to significant improvement in cardiac function. We report a middle-aged woman presenting with symptoms of heart failure with a serum calcium level of 3.7 mg/dl and a serum inorganic phosphate level of 17.6 mg/dl 22 years after subtotal thyroidectomy. Besides calcium and calcitriol supplementation, she was the first patient with severe hypocalcemic cardiomyopathy to be given off-label recombinant human parathyroid hormone (PTH) because of an elevated serum calcium-phosphate product. We discuss the management and outcome of the patient and then present a brief review of similar previously reported cases. We also describe the pivotal role of calcium ion and the potential role of PTH in maintaining myocardial contractility, effective natriuresis, and possible pathogenic mechanisms contributing to heart failure secondary to hypocalcemia and hypoparathyroidism.