Spectral analysis of heart-rate variability showed that haemodynamically stable patients had a systematically greater LF/HF power ratio than unstable patients during haemodialysis.
Observational (n=30)
Does spectral analysis of heart-rate variability differentiate autonomic responses between haemodynamically stable and unstable patients during haemodialysis?
Spectral analysis of heart-rate variability demonstrates that reduced efficiency in autonomic control (lower LF/HF ratio) is associated with haemodynamic instability in patients undergoing haemodialysis.
Short-term autonomic response to haemodialysis-induced hypovolaemia was studied in 30 patients undergoing chronic haemodialysis by analysing power spectra of heart-period variability. Patients were classified as haemodynamically stable (15 patients) and unstable (15 patients) according to their past history of cardiovascular collapse during the treatment. Blood volume, systolic arterial pressure and heart period were measured during sessions that ended without the occurrence of collapse. 2. No significant differences were observed when comparing blood volume, heart rate and arterial pressure of stable and unstable patients during the dialysis, and the two groups could not be distinguished merely on the basis of these haemodynamic parameters. Conversely, spectral analysis of beat-to-beat heart-period variability showed markedly different power patterns: in stable patients power was mainly in the low-frequency (LF) band (0.06-0.15 Hz), whereas in unstable patients it was mainly in the high-frequency (HF) band (0.15-0.4 Hz). 3. The efficiency of the autonomic response to hypovolaemia was evaluated by the ratio between the powers in the LF and HF bands. Stable patients exhibited an LF/HF power ratio systematically greater than unstable patients during the entire dialysis, and on the basis of this index the two groups were clearly separated. 4. Results obtained with spectral analysis lead us to conclude that reduced efficiency in the autonomic control of cardiovascular functions could be the main cause of the haemodynamic instability of patients prone to collapse.
Cavalcanti et al. (Tue,) conducted a observational in Chronic haemodialysis (n=30). Spectral analysis of heart-rate variability vs. Haemodynamically stable vs unstable patients was evaluated on LF/HF power ratio. Spectral analysis of heart-rate variability showed that haemodynamically stable patients had a systematically greater LF/HF power ratio than unstable patients during haemodialysis.