title: The forgotten role of central volume in low frequency oscillations of heart rate variability.
abstract: The hypothesis that central volume plays a key role in the source of low frequency (LF) oscillations of heart rate variability (HRV) was tested in a population of end stage renal disease patients undergoing conventional hemodialysis (HD) treatment, and thus subject to large fluid shifts and sympathetic activation. Fluid overload (FO) in 58 chronic HD patients was assessed by whole body bioimpedance measurements before the midweek HD session. Heart Rate Variability (HRV) was measured using 24-hour Holter electrocardiogram recordings starting before the same HD treatment. Time domain and frequency domain analyses were performed on HRV signals. Patients were retrospectively classified in three groups according to tertiles of FO normalized to the extracellular water (FO/ECW%). These groups were also compared after stratification by diabetes mellitus. Patients with the low to medium hydration status before the treatment (i.e. 1st and 2nd FO/ECW% tertiles) showed a significant increase in LF power during last 30 min of HD compared to dialysis begin, while no significant change in LF power was seen in the third group (i.e. those with high pre-treatment hydration values). In conclusion, several mechanisms can generate LF oscillations in the cardiovascular system, including baroreflex feedback loops and central oscillators. However, the current results emphasize the role played by the central volume in determining the power of LF oscillations.
authors: Department of Electronics, Information and Bioengineering (DEIB), Politecnico di Milano, Italy.
authors: Manuela
authors: M
authors: Ferrario
authors: Fresenius Medical Care R&D, Bad Homburg, Germany.
authors: Ulrich
authors: U
authors: Moissl
authors: San Bortolo Hospital, Vicenza, Italy.
authors: Francesco
authors: F
authors: Garzotto
authors: San Bortolo Hospital, Vicenza, Italy.
authors: Dinna N
authors: DN
authors: Cruz
authors: Fresenius Medical Care R&D, Bad Homburg, Germany.
authors: Ciro
authors: C
authors: Tetta
authors: Department of Electronics, Information and Bioengineering (DEIB), Politecnico di Milano, Italy.
authors: Maria G
authors: MG
authors: Signorini
authors: San Bortolo Hospital, Vicenza, Italy.
authors: Claudio
authors: C
authors: Ronco
authors: Fresenius Medical Care R&D, Bad Homburg, Germany.
authors: Aileen
authors: A
authors: Grassmann
authors: Department of Electronics, Information and Bioengineering (DEIB), Politecnico di Milano, Italy.
authors: Sergio
authors: S
authors: Cerutti
authors: L. Sacco Hospital, Università degli Studi, Milan, Italy.
authors: Stefano
authors: S
authors: Guzzetti
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D001810:Blood Volume; D059347:Cardio-Renal Syndrome / Q000503:physiopathology* / Q000628:therapy; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis