Heart Rate Variability Assessment Using Time–Frequency Analysis in Hypotensive and Non-Hypotensive Patients in Hemodialysis

Abstract

Intradialytic hypotension occurs in 10–30% of hemodialysis (HD) sessions. This phenomenon affects the cardiovascular system’s functions, which are reflected in the activity of the autonomic nervous system (ANS). To indirectly assess the ANS during HD, we analyzed the mean R–R intervals and the spectral power of heart rate variability (HRV) from 20 end-stage renal disease patients divided into hypotensive and non-hypotensive groups. The spectrotemporal analysis was accomplished using short-time Fourier transform with 10 min epochs of HRV overlapping by 40%. The spectral power was divided into three segments according to high frequency, low frequency, and very low frequency bandwidths and averaged to fit quadratic regression models. The analysis of the mean R–R intervals showed significant differences between the groups (p = 0.029). The power variation over time was significant in each spectral band (p ≪ 0.05). The average power, maximum power, and time when the peak was reached differed for each band and between groups, showing the ability to correctly identify the decompensation of the ANS and discriminate between hypotensive and non-hypotensive patients. Additionally, the changes in the sympathovagal ratio were not significant and very scattered for the hypotensive group (p = 0.23) compared to the non-hypotensive group, where the changes were significant (p ≪ 0.05) and much less scattered.

Heart rate detection method based on Ballistocardiogram signal of wearable device：Algorithm development and validation

“…Each method undergoes testing three times, and the comparison results are presented in Table 2 . And the average accuracy of the deep learning model mentioned in this paper can reach 99.33% higher than that of M1 (Time–Frequency Analysis) [ 34 ], M2 (ResNet-BiLSTM) [ 35 ], M3 (UNet-BiLSTM) [ 36 ], M4 (RNN) [ 31 ], M5 (LSTM) [ 24 ] and M6(GRU) [ 33 ], respectively, which reflects the advantages of the proposed model in the J-wave recognition task.…”

Correlation between Angiotensin Serum Levels and Very-Low-Frequency Spectral Power of Heart Rate Variability during Hemodialysis

“…Regarding the VLF band, this has been little studied because 5 min of HRV recording are not sufficient to capture it and estimate it with certainty [ 14 ]. Previous studies showed that the increase in intradialytic VLF is higher in patients who maintain a stable blood pressure compared to patients who develop intradialytic hypotension [ 15 , 19 ], suggesting the significant role of RAAS to preserve the hemodynamic stability.…”

“…The most common method to obtain HRV is through an electrocardiographic (ECG) recording, from which the time intervals between consecutive R waves are measured to form a time series called the HRV recording or R-R tachogram ( Figure 1 ). HRV assessment can be performed using time domain [ 10 ] or frequency domain analysis techniques [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. Spectral analysis of HRV is accepted as an indirect method to assess interactions between the ANS and the cardiovascular system.…”

“…Recent studies on the cardiovascular control in ESRD patients showed that VLF power increases during hemodialysis [ 16 ] and that such an increase in VLF is different in patients who maintain stable blood pressure compared to patients who develop intradialytic hypotension [ 15 , 19 ]. These results suggest that the RAAS may have a significant role in cardiovascular control to prevent sudden drops in systemic blood pressure.…”

“…also influenced by the respiratory rate; LF is associated with both SNS and PNS activities as well as the baroreflex activity; VLF is associated to hormonal, vasomotor, thermoregulatory and RAAS influences [10,21]. Recent studies on the cardiovascular control in ESRD patients showed that VLF power increases during hemodialysis [16] and that such an increase in VLF is different in patients who maintain stable blood pressure compared to patients who develop intradialytic hypotension [15,19]. These results suggest that the RAAS may have a significant role in cardiovascular control to prevent sudden drops in systemic blood pressure.…”