HP07: A 24-hour heart rate variability analysis in Tunisian patients under hemodialysis is an indicator of autonomic nervous system activity

Abstract

Heart rate variability (HRV) is a useful tool to evaluate autonomic nervous system activity in patients under hemodialysis (HD). The aim of the study was to evaluate the autonomic nervous system activity in Tunisian patients under HD using HRV analysis. Patients and methods: It was a prospective study including 27 patients under HD for at least 3 months. A Holter-ECG recording was realized for 48 hours. Time- and frequency-domain were analyzed. Statistical analysis were done using SPSS20. Results: The different HRV parameters were decreased. Only LF/HF ratio was increased indicating a deviation of the sympatico-vagal balance. The time-domain analysis showed a significant variation of the RR and the RMSSD during sleep-wake cycle. The latter parameters were increased during sleep. The frequency-domain analysis showed a significant increase in HF and LF during sleep. Nevertheless, LF/HF ratio decreased during sleep while the LF increased, however, without being significantly different. Conclusion: Our study showed an autonomic nervous system dysfunction in patients under HD. This dysfunction was characterized by a hyperactivation of the sympathetic system associated to a decreased parasympathetic activity. However, the physiological activation of the parasympathetic system during sleep was preserved. A HRV alteration is an independent cardiovascular risk factor.