PTH and dilated cardiomyopathy: Hypocalcemia is a rare but treatable and reversible cause of dilated cardiomyopathy and therefore should be investigated in all unexplained cases of severe left ventricular dysfunction.5, 6 Primary hypoparathyroidism (HPTP) is characterized by an abnormally low level of secretion of parathyroid hormone (PTH), a hormone that plays a key role in calcium homeostasis.