Effects of interdialytic interval on heart rate variability in chronic hemodialysis patients: a cross-sectional study

Low-Frequency/High-Frequency Ratio Is a Predictor of Death and Hospitalization in Patients on Maintenance Hemodialysis: A Prospective Study

INTRODUCTION

This study aimed to evaluate the predictive value of the low-frequency/high-frequency (LF/HF) ratio in all causes of death and hospitalizations in maintenance hemodialysis (MHD) patients.

METHODS

This is a single-center prospective study with a 48-h electrocardiograph (ECG) recording. A total of 110 patients were enrolled in the study from October 1, 2021, to September 30, 2022. ECG recordings started before initiation of the hemodialysis (HD) session and lasted for 48 h, covering the intra- as well as inter-HD period. We divided our participants into two groups based on the median value of LF/HF, one of the frequency domain parameters of heart rate variability (HRV). Patients with LF/HF <1.33 were categorized as group A and those with LF/HF ≥1.33 were group B. The endpoint of the study was a composite event of death or hospitalization. We followed all patients until the composite endpoint or the end of the study on February 28, 2023. Multivariate Cox regression was used to assess the adjusted effect of LF/HF on the composite endpoint.

RESULTS

Patients in group A were older and the number of patients with diabetes was more than that of group B. With regards to the laboratory data, group A had lower serum creatinine and uric acid and higher ferritin and NT-ProBNP. In the index HD session, systolic blood pressure was higher but diastolic blood pressure was significantly lower in group A. During the median follow-up period of 8.8 (7.6-9.8) months, 27 hospitalizations and 10 deaths were documented. Increased LF/HF ratio was an independent protective factor of composite endpoint events (HR = 0.357, 95% CI: 0.162-0.790, p = 0.011).

CONCLUSION

Risks of mortality and hospitalizations are higher among HD patients having decreased LF/HF ratios. LF/HF in the 48-h recording can be considered as a prognostic factor for risk stratification in HD patients.

Arrhythmia and Heart Rate Variability during Long Interdialytic Periods in Patients on Maintenance Hemodialysis: Prospective Observational Cohort Study

Sudden cardiac death among hemodialysis patients is related to the hemodialysis schedule. Mortality is highest within 12 h before and after the first hemodialysis sessions of a week. We investigated the association of arrhythmia occurrence and heart rate variability (HRV) using an electrocardiogram (ECG) monitoring patch during the long interdialytic interval in hemodialysis patients. This was a prospective observational study with 55 participants on maintenance hemodialysis for at least six months. A patch-type ECG monitoring device was applied to record arrhythmia events and HRV during 72 h of a long interdialytic period. Forty-nine participants with sufficient ECG data out of 55 participants were suitable for the analysis. The incidence of supraventricular tachycardia and ventricular tachycardia did not significantly change over time. The square root of the mean squared differences of successive NN intervals (RMSSD), the proportion of adjacent NN intervals differing by >50 ms (pNN50), and high-frequency (HF) increased during the long interdialytic interval. The gap in RMSSD, pNN50, HF, and the low-frequency/high-frequency (LF/HF) ratio between patients with and without significant arrhythmias increased significantly over time during the long interdialytic interval. The daily changes in RMSSD, pNN50, HF, and the LF/HF ratio were more prominent in patients without significant arrhythmias than in those with significant arrhythmias. The electrolyte fluctuation between post-hemodialysis and subsequent pre-hemodialysis was not considered in this study. The study results suggest that the decreased autonomic response during interdialytic periods in dialysis patients is associated with poor cardiac arrhythmia events.