The correlation of heart rate variability with parathyroid hormone in hemodialysis patients with secondary hyperparathyroidism

Abstract

Introduction: Hyperparathyroidism (HPTH) which is often found in end stage of chronic renal disease patients replacedby hemodialysis (HD) may cause the cardiac autonomic neuropathy.

Method: Healthy subjects and HD patients categorized into two groups by parathyroid hormone (PTH) levels: highPTH group (H-PTH; PTH = 150 - 300 pg/mL) and ultra high PTH group (UH-PTH; PTH > 300 pg/mL) wereinvestigated. Frequency and time domains of heart rate variability (HRV) were analyzed. The frequencydomain parameters were then transformed by the fast Fourier transform and its normalized unit wascalculated in terms of natural logarithms (ln). The correlations between PTH concentration and eachparameter of HRV were analyzed by Pearson’s correlation.

Result: The results of the current study showed that frequency and time domains of UH-PTH were at lowestvalues. The values of lnTP (total power), lnLF (low frequency), LF/HF ratio (low frequency and highfrequency ratio), SDANN (standard deviation of the averages of N-N intervals in all 5-minute segments),SDNN (standard deviation of N-N intervals), TINN (triangular interpolation of N-N interval) and HRV index,were significantly lower in UH-PTH compared to H-PTH. Moreover, lnLF showed the highest negativecorrelation with lnPTH concentration. This correlation coefficient (r) was -0.633.

Discussion and Conclusion: The greatest reduction in LF and SDNN, and the highest negative correlation between lnLF and lnPTH indicated that the sympathetic nervous system was, at least in part, activated by hyperparathyroidism.It is suggested that PTH plays a role as an important uremic toxin which involves in the initiation ofcardiac sympathetic hyperactivity.

Key words: Frequency domain, Hemodialysis, Heart rate variability, Parathyroid hormone, Time domain