Parathyroid hormone and calcium behavior in advanced congestive heart failure.

Parathyroid hormone (PTH) regulates the content of calcium and thus exerts an effect on myocardial function. Abnormal secretion of PTH has been sporadically reported to be associated with depressed mechanical performance of the heart muscle. In the present study, we first measured PTH levels at baseline in 27 consecutive patients with advanced congestive heart failure (LVEF: 17 +/- 9%): five patients (18.5%) revealed elevated PTH levels, one case of hypoparathyroidism was discovered. Furthermore, nine unselected patients underwent symptom-limited exercise stress test leading to an increase in mean pulmonary artery pressure from 25.6 +/- 15 at baseline to 41.2 +/- 18 mm Hg at peak exercise. In contrast to observations in healthy subjects, in heart failure patients both mean PTH and blood calcium concentrations did not change significantly during peak exercise or recovery. Moreover, patients with the lowest left-ventricular ejection fraction showed a decrease in PTH during maximal stress. We conclude that abnormal baseline PTH secretion is common in patients with advanced congestive heart failure. More importantly, these studies show that PTH release is depressed under stress conditions, possibly indicating a dysfunction of the parathyroid gland in severe heart failure.