Impact of serum sodium on heart rate variability in Dialytic chronic renal patients

Objective: to analyze the influence of serum sodium (sNa) on heart rate variability (HRV) in chronic dialytic renal patients. Methods: cross-sectional study with comparative approach with subjects undergoing maintenance hemodialysis and a control group. Resting HRV, in time (TD) and frequency domain (FD) analysis, and evaluation of biochemical markers of renal function were performed.The volunteers were allocated into three groups: normotremia dialysis group (NDG), hyponatremia dialysis group (HDG) and a control group (CG). Results: the sample consisted of 32 volunteers, being CG = 10, NDG = 14 and HDG = 8 participants. For the biochemical variables of renal function, there was a difference between CG vs NDG and HDG (p = 0.001). HRV analysis in TD showed that HDG presented a reduction in SDNN (p = 0.002) and rMSSD (p = 0.005) indices compared to CG. For the NN50 index, NDG and HDG presented significant differences in relation to the CG (p = 0.010 and p = 0.001 respectively).While in FD there was a reduction in the high frequency and low frequency band (p = 0.037 and p = 0.007 respectively) in HDG compared to CG. Conclusion: In dialysis patients there is a reduction in HRV, especially in those with hyponatremia.