General relation between variance-time curve and power spectral density for point processes exhibiting 1/f? ?-fluctuations, with special reference to heart rate variability

1995 ◽  
Vol 73 (3) ◽  
pp. 255-263
Author(s):  
Rainer Scharf ◽  
Malte Meesmann ◽  
Jan Boese ◽  
Dante R. Chialvo ◽  
K.-D. Kniffki
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Spectral Density ◽  
Special Reference ◽  
Power Spectral Density ◽  
Point Processes ◽  
General Relation ◽  
Time Curve ◽  
Power Spectral

scholarly journals Power spectral analysis of heart rate in hypothyroidism

2000 ◽  
pp. 327-333 ◽  
Author(s):  
V Cacciatori ◽  
ML Gemma ◽  
F Bellavere ◽  
R Castello ◽  
ME De Gregori ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Spectral Analysis ◽  
Spectral Density ◽  
Cardiovascular System ◽  
Power Spectral Density ◽  
Power Spectral Analysis ◽  
Control Subjects ◽  
Power Spectral ◽  
Hypothyroid Patients

OBJECTIVE: The aim of the present study was to evaluate the impact of hypothyroidism on the autonomic regulation of the cardiovascular system by analysing separately sympathetic and parasympathetic influences on the heart. DESIGN: In seven newly diagnosed untreated hypothyroid patients we analysed power spectral density of heart rate cyclic variations at rest, while lying, and while standing. The same protocol was repeated after the induction of stable euthyroidism by levothyroxine (L-T(4)) treatment. The results were also compared with those obtained from seven age-, sex- and body mass index-matched control subjects. METHODS: Heart rate variability was evaluated by autoregressive power spectral analysis (PSA). This method allows reliable quantification of low frequency (LF) and high frequency (HF) components of the heart rate power spectral density. These are considered to be under mainly sympathetic and purely parasympathetic control respectively. In addition, heart rate variations during deep breathing, lying to standing, and Valsalva's manoeuvre were assessed. RESULTS: PSA showed a sharp reduction in the HF (parasympathetic) component in hypothyroid subjects compared with controls (lying, 29.4+/-5.4 vs 47.7+/-6.3 normalized units (NU) (means +/- s.e.m.), P<0.05; standing, 14.0+/-3.5 vs 32.1+/-3.6NU, P<0.005). Conversely, the LF (mainly sympathetic) component was higher in hypothyroid subjects than in controls (lying, 61.6+/-6.4 vs 45.4+/-6.7 NU; standing, 71.7+/-8.0 vs 53.1+/-5.6NU), this difference being significant in the standing position. Hence, the LF/HF ratio, which is considered an index of sympathovagal balance, was increased in hypothyroid subjects while both lying (2.75+/-0.6 vs 1.16+/-0.3; P<0.05) and standing (10.0+/-3.7 vs 1.85+/-0.3; P<0. 02). Total heart rate variability, expressed as total power spectral density, was lower in hypothyroid patients than in control subjects, this difference being significant in the lying position (574+/-126 vs 2302+/-994ms(2), P<0.05). In patients re-examined after L-T(4) therapy, complete normalization of cardiovascular parameters was observed (LF/HF ratio, lying, 1.26+/-0.4; standing, 2.56+/-0.8, both P<0.01 vs baseline values). The response to conventional cardiovascular autonomic tests was not significantly different between hypothyroid patients and healthy controls, and did not change in patients after therapy. CONCLUSIONS: These results suggest that, contrary to the clinical picture, thyroid hormone deficiency is associated with an increased sympathetic influence on the autonomic cardiovascular system. The changes in sympathetic function could be explained by a secondary adaptation to an altered cardiovascular responsiveness.

The Comparisons of Heart Rate Variability and Perceived Exertion During Simulated Cycling with Various Viewing Devices

2008 ◽  
Vol 17 (6) ◽  
pp. 575-583 ◽  
Author(s):  
Shih-Fong Huang ◽  
Po-Yi Tsai ◽  
Wen-Hsu Sung ◽  
Chih-Yung Lin ◽  
Tien-Yow Chuang
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Spectral Density ◽  
Power Spectral Density ◽  
Perceived Exertion ◽  
Low Frequency ◽  
Control Group ◽  
Threshold Intensity ◽  
Power Spectral ◽  
Significant Difference

Sympathovagal modulation during immersion in a virtual environment is an important influence on human performance of a task. The aim of this study is to investigate sympathovagal modulation using heart rate variability and perceived exertion during exercise in a virtual reality (VR) environment. Sixteen young healthy volunteers were tested while using a stationary bicycle and maintained at an anaerobic threshold intensity for exercise sessions of approximately 10 min duration. Four randomized viewing alternatives were provided including desktop monitor, projector, head mounted device (HMD), and no simulation display. The “no simulation display” served as the control group. A quick ramp exercise test was conducted and maintained at an anaerobic threshold intensity for each session to evaluate power spectral density and rating of perceived exertion (RPE). The sampled heart rate data were rearranged by cubic spline interpolation into power spectrums spanning the ultra-low frequency (ULF) to high frequency (HF) range. A significant difference was found between the no-display and projector groups for total power (TP) and very low frequency (VLF) components. In particular, there was a significant difference when comparing HMD and no-display exercise RPE curves within 6 min of cycling and at the termination of the exercise. A significant difference was also achieved in projector vs. control group comparison at the termination of the exercise. Our results indicate that the use of HMD and the projected VR during cycling can reduce the TP and VLF power spectral density through a proposed decrease in the renin-angiotensin system, with the implication that this humoral effect may enable anaerobic exercise for longer durations through a reduction in sympathetic tone and subsequent increased blood flow to the muscles.

scholarly journals The Effect of Sleeping Position on Heart Rate Variability in Newborns

2020 ◽  
Author(s):  
Petja Fister ◽  
Manca Nolimal ◽  
Helena Lenasi ◽  
Matjaž Klemenc
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Spectral Density ◽  
Power Spectral Density ◽  
Gestational Age ◽  
Supine Position ◽  
Total Power ◽  
Sleeping Position ◽  
Power Spectral ◽  
Term Newborns

Abstract Background : Lower heart rate variability (HRV) in a newborn might represent a risk factor for unfavourable outcome, a longer recovery after illness, and a sudden infant death. Our aim was to determine whether the newborn’s sleeping position is associated with HRV. Methods : We performed a prospective clinical study in 46 hospitalized cardiorespiratory stable term newborns. During sleeping, we measured the parameters of HRV in four body positions (supine, supine with tilt, prone, prone with tilt). Results : The TP (total power spectral density) was significantly higher when lying supine in comparison to prone (p = 0,048) and to prone with tilt (p = 0,046). The HF (high frequency of power spectral density) in the supine position without tilt tended to be higher compared to prone without tilt (p > 0,05). The LF (low frequency power) was significantly higher when lying supine compared to prone, both without tilt (p = 0,018). TP and HF showed a positive correlation with gestational age (p = 0.044 and p = 0.036, respectively). Conclusions : In term newborns, sleeping position is associated with HRV. Higher TP and HF were found in the supine position, which might reflect better ANS stability. Gestational age positively correlated with TP and HF power, but only in supine position.

scholarly journals The Effect Of Sleeping Position On Heart Rate Variability In Newborns

2020 ◽  
Author(s):  
Petja Fister ◽  
Manca Nolimal ◽  
Helena Lenasi ◽  
Matjaž Klemenc
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Spectral Density ◽  
Power Spectral Density ◽  
Gestational Age ◽  
Supine Position ◽  
Total Power ◽  
Sleeping Position ◽  
Power Spectral ◽  
Term Newborns

Abstract Background : Lower heart rate variability (HRV) in a newborn might represent a risk factor for unfavourable outcome, a longer recovery after illness, and a sudden infant death. Our aim was to determine whether the newborn’s sleeping position is associated with HRV. Methods : We performed a prospective clinical study in 46 hospitalized cardiorespiratory stable term newborns. During sleeping, we measured the parameters of HRV in four body positions (supine, supine with tilt, prone, prone with tilt). Results : The TP (total power spectral density) was significantly higher when lying supine in comparison to prone (p = 0,048) and to prone with tilt (p = 0,046). The HF (high frequency of power spectral density) in the supine position without tilt tended to be higher compared to prone without tilt (p > 0,05). The LF (low frequency power) was significantly higher when lying supine compared to prone, both without tilt (p = 0,018). TP and HF showed a positive correlation with gestational age (p = 0.044 and p = 0.036, respectively). Conclusions : In term newborns, sleeping position is associated with HRV. Higher TP and HF were found in the supine position, which might reflect better ANS stability. Gestational age positively correlated with TP and HF power, but only in supine position.

scholarly journals The Effect of Sleeping Position on Heart Rate Variability in Newborns

2020 ◽  
Author(s):  
Petja Fister ◽  
Manca Nolimal ◽  
Helena Lenasi ◽  
Matjaž Klemenc
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Spectral Density ◽  
Power Spectral Density ◽  
Gestational Age ◽  
Supine Position ◽  
Total Power ◽  
Sleeping Position ◽  
Power Spectral ◽  
Term Newborns

Abstract Background : Lower heart rate variability (HRV) in a newborn might represent a risk factor for unfavourable outcome, a longer recovery after illness, and a sudden infant death. Our aim was to determine whether the newborn’s sleeping position is associated with HRV. Methods : We performed a prospective clinical study in 46 hospitalized cardiorespiratory stable term newborns. During sleeping, we measured the parameters of HRV in four body positions (supine, supine with tilt, prone, prone with tilt). Results : The TP (total power spectral density) was significantly higher when lying supine in comparison to prone (p = 0,048) and to prone with tilt (p = 0,046). The HF (high frequency of power spectral density) in the supine position without tilt tended to be higher compared to prone without tilt (p > 0,05). The LF (low frequency power) was significantly higher when lying supine compared to prone, both without tilt (p = 0,018). TP and HF showed a positive correlation with gestational age (p = 0.044 and p = 0.036, respectively). Conclusions : In term newborns, sleeping position is associated with HRV. Higher TP and HF were found in the supine position, which might reflect better ANS stability. Gestational age positively correlated with TP and HF power, but only in supine position.

scholarly journals An Application of The Lomb-Scargle Periodogram To Investigate Heart Rate Variability During Haemodialysis

2020 ◽  
Author(s):  
Jill Stewart ◽  
Paul Stewart ◽  
Thomas Walker ◽  
Latha Gullapudi ◽  
Tarek Eldehni ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Spectral Analysis ◽  
Spectral Density ◽  
Power Spectral Density ◽  
Circulatory System ◽  
False Alarm Probability ◽  
Process Time ◽  
Processing Methods ◽  
Power Spectral

<div><div><div><p>Objective: Short-term cardiovascular compensatory responses to perturbations in the circulatory system caused by haemodialysis can be investigated by spectral analysis of heart rate variability. This could provide an important variable for categorising individual patients response to haemodialysis leading to a more personalised treatment. However, data obtained over a four-hour haemodialysis treatment is significant in volume and subject to artefacts that can compromise its analysis.</p><p>Methods: The Lomb-Scargle Periodogram can provide a robust method of generating power spectral density estimates for large, irregularly sampled and noisy data sets obtained in clinical settings, provided that careful attention is given to frequency limits. The effect of different pre-processing methods on the resulting power spectrum is explored with simulated and real heart rate variability data.</p><p>Results: Common pre-processing methods for correcting individual artefacts in heart rate records, such as interpolation, are unreliable as they act as non-linear low-pass filters and distort the resulting spectral analysis. These distortions are present, but less apparent within patient data and can mislead clinical interpretations.</p><p>Conclusion: It is more appropriate to exclude suspect data points than to edit them prior to spectral analysis via the Lomb- Scargle periodogram, and where required, de-noise the entire heart rate signal by empirical mode decomposition. The use of a False Alarm Probability metric can help establish whether spectral estimates are valid</p><p>Significance: Methods established to pre-process time-invariant data prior to power spectral density estimation fail when used in conjunction with the Lomb-Scargle method.</p></div></div></div>

scholarly journals The Effect Of Sleeping Position On Heart Rate Variability In Newborns

2019 ◽  
Author(s):  
Petja Fister ◽  
Manca Nolimal ◽  
Helena Lenasi ◽  
Matjaž Klemenc
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Spectral Density ◽  
Power Spectral Density ◽  
Supine Position ◽  
Total Power ◽  
Sudden Infant ◽  
Prospective Clinical Study ◽  
Sleeping Position ◽  
Power Spectral

Abstract Background : Lower heart rate variability (HRV) in a newborn might represent a risk factor for unfavourable outcome, a longer recovery after illness, and a sudden infant death. Our aim was to determine whether the newborn’s sleeping position is associated with HRV. Methods : We performed a prospective clinical study in 46 hospitalized cardiorespiratory term stable newborns. During sleeping, we measured the parameters of HRV in four body positions (supine, supine with tilt, prone, prone with tilt). Results : The TP (total power spectral density) was significantly higher when lying supine in comparison to prone (p = 0,048) and to prone with tilt (p = 0,046). The HF (high frequency of power spectral density) in the supine position without tilt tended to be higher compared to prone without tilt (p > 0,05). The LF (low frequency power) was significantly higher when lying supine compared to prone, both without tilt (p = 0,018). TP and HF showed a positive correlation with postmenstrual age (PMA) (p = 0.044 and p = 0.036, respectively). Conclusions : In term newborns, sleeping position is associated with HRV. Higher TP and HF were found in the supine position, which might reflect better ANS stability. PMA positively correlated with TP and HF power, but only in supine position.

scholarly journals An Application of The Lomb-Scargle Periodogram To Investigate Heart Rate Variability During Haemodialysis

2020 ◽  
Author(s):  
Jill Stewart ◽  
Paul Stewart ◽  
Thomas Walker ◽  
Latha Gullapudi ◽  
Tarek Eldehni ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Spectral Analysis ◽  
Spectral Density ◽  
Power Spectral Density ◽  
Circulatory System ◽  
False Alarm Probability ◽  
Process Time ◽  
Processing Methods ◽  
Power Spectral

<div><div><div><p>Objective: Short-term cardiovascular compensatory responses to perturbations in the circulatory system caused by haemodialysis can be investigated by spectral analysis of heart rate variability. This could provide an important variable for categorising individual patients response to haemodialysis leading to a more personalised treatment. However, data obtained over a four-hour haemodialysis treatment is significant in volume and subject to artefacts that can compromise its analysis.</p><p>Methods: The Lomb-Scargle Periodogram can provide a robust method of generating power spectral density estimates for large, irregularly sampled and noisy data sets obtained in clinical settings, provided that careful attention is given to frequency limits. The effect of different pre-processing methods on the resulting power spectrum is explored with simulated and real heart rate variability data.</p><p>Results: Common pre-processing methods for correcting individual artefacts in heart rate records, such as interpolation, are unreliable as they act as non-linear low-pass filters and distort the resulting spectral analysis. These distortions are present, but less apparent within patient data and can mislead clinical interpretations.</p><p>Conclusion: It is more appropriate to exclude suspect data points than to edit them prior to spectral analysis via the Lomb- Scargle periodogram, and where required, de-noise the entire heart rate signal by empirical mode decomposition. The use of a False Alarm Probability metric can help establish whether spectral estimates are valid</p><p>Significance: Methods established to pre-process time-invariant data prior to power spectral density estimation fail when used in conjunction with the Lomb-Scargle method.</p></div></div></div>

scholarly journals The Effect of Sleeping Position on Heart Rate Variability in Newborns

2020 ◽  
Author(s):  
Petja Fister ◽  
Manca Nolimal ◽  
Helena Lenasi ◽  
Matjaž Klemenc
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Spectral Density ◽  
Power Spectral Density ◽  
Gestational Age ◽  
Supine Position ◽  
Total Power ◽  
Sleeping Position ◽  
Power Spectral ◽  
Term Newborns

Abstract Background : Lower heart rate variability (HRV) in a newborn might represent a risk factor for unfavourable outcome, a longer recovery after illness, and a sudden infant death. Our aim was to determine whether the newborn’s sleeping position is associated with HRV. Methods : We performed a prospective clinical study in 46 hospitalized cardiorespiratory stable term newborns. During sleeping, we measured the parameters of HRV in four body positions (supine, supine with tilt, prone, prone with tilt). Results : The TP (total power spectral density) was significantly higher when lying supine in comparison to prone (p = 0,048) and to prone with tilt (p = 0,046). The HF (high frequency of power spectral density) in the supine position without tilt tended to be higher compared to prone without tilt (p > 0,05). The LF (low frequency power) was significantly higher when lying supine compared to prone, both without tilt (p = 0,018). TP and HF showed a positive correlation with gestational age (p = 0.044 and p = 0.036, respectively). Conclusions : In term newborns, sleeping position is associated with HRV. Higher TP and HF were found in the supine position, which might reflect better ANS stability. Gestational age positively correlated with TP and HF power, but only in supine position.

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