Autonomic dysfunction in uremia assessed by heart rate variability

Abstract

Decreased heart rate variability is an independent risk factor for cardiac mortality in hemodialysis patients. Our aim was to determine whether it is already present in uremic children and young adults on hemodialysis and following renal transplantation. Twenty-two hemodialysis patients [age 17.2 years (median, quartiles 13.0-22.6)], 22 transplant patients [18.4 years (14.4-21.2)], and 29 healthy controls [16.4 years (15.7-21.1)] were examined. Heart rate and its high (HF) and low (LF) frequency variability were measured in the supine position for 10 min. High and low frequency variability was significantly reduced, whereas heart rate and LF/HF ratio was significantly elevated in both patient groups compared with controls. There was a clear-cut difference between the dialyzed and the transplanted groups based on the HF variability, with the lowest values in the dialysis group ( P<0.01). LF and LF/HF data did not allow us to distinguish between the patient groups. In conclusion, heart rate variability in the HF range is a sensitive tool for detecting cardiovascular autonomic dysfunction that is already present in children and adolescents with impaired kidney function.

The Subjective Sleep Quality and Heart Rate Variability in Hemodialysis Patients

“…34 A reduction of HRV in ESRD patients has been demonstrated in some earlier reports, [19][20][21]35 whereas some other groups reported increased LF power. 36 This discrepancy may be related to clinical or methodological differences.…”

“…The reasons for these changes are unexplained but may be suspected due to the fact that the HD patients nearly have abnormal autonomic function. [19][20][21]34 Also, another reason is that autonomic function fluctuates depending on sleep dynamics when non-REM sleep is accompanied by an augmentation of parasympathetic tone with depression of sympathetic activity, and REM sleep shows reverse change. 26,27 The autonomic function is even synchronized with REM/non-REM ultradian sleep rhythm.…”

“…17,18 The spectral analysis of heart rate variability (HRV) has been proven to be a potent, noninvasive, sensitive, and reproducible tool for the diagnosis of cardiovascular autonomic dysfunction in ESRD. [19][20][21] It is well established that HRV can be divided into total power (TP, 0-0.5 Hz), high-frequency power (HF, 0.15-0.40 Hz), low-frequency power (LF, 0.04-0.15 Hz), and very-low-frequency power (VLF, 0.003-0.04 Hz) components. 22 The HF component is equivalent to respiratory sinus arrhythmia and is thought to reflect vagal control of heart rate.…”

Efeito do exercício aeróbico durante as sessões de hemodiálise na variabilidade da frequência cardíaca e na função ventricular esquerda em pacientes com doença renal crônica

“…3,12,17,18 The HRV reduction in patients with CKD is considered a risk factor for the occurrence of cardiac arrhythmias, and is associated with a higher cardiovascular mortality. 4,5 Cashion et al 19 , assessing hemodialysis patients by use of 24-hour Holter to study HRV in the time and frequency domains for a period of two years, have reported that the reduction in the SDNN, LF, and LF/HF parameters predicted cardiovascular death, especially sudden death.…”

“…In that population, the reduction in HRV associated with injury to the parasympathetic system due to the structural impairment of arteries or the functional alterations of the autonomic nervous system secondary to uremic toxins. [18][19][20] The increase in HRV in patients with CKD has been observed with kidney transplantation and the practice of exercise programs. 10,11,21,22 The present study did not show an increase in the HRV assessed in the time and frequency domains after 12 weeks of aerobic training.…”