Quantification of Autonomic Nervous Activity During Hemodialysis

Variations over time in autonomic nervous activity due to differences in ultrafiltration rate will be evaluated by measuring heart rate variability in hemodialysis patients without blood pressure variations during HD session. The subjects will be divided into 3 groups, those with UFR \< 10 ml/hr/kg; ≥10 ml/hr/kg but ≤ 15 ml/hr/kg; and \>15 ml/hr/kg, and Holter ECG are recorded continuously during HD session using frequency analysis of RR intervals.