scholarly journals Cross-Spectral Analysis of Electrocardiographic and Nostril Airflow Signals Identifies Two Respiratory Frequencies of Heart Rate Modulation

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Wan-An Lu ◽  
Jui-Feng Lin ◽  
Chen-Hsu Wang ◽  
Yung-Sheng Chen ◽  
Ying-Hua Shieh ◽  
...  
Keyword(s):  
Heart Rate ◽  
Spectral Analysis ◽  
High Frequency ◽  
Healthy Subjects ◽  
Low Frequency ◽  
High Frequency Power ◽  
Very Low Frequency ◽  
The Cross ◽  
Low Frequency Power ◽  
Frequency Power

Respiration is known to be a significant modulator of heart rate, and the high-frequency component in the power spectrum of heart rate variability (HRV) is believed to be caused mainly by respiration. To investigate the effect of respiration on heart rate, cross-spectral analysis of electrocardiographic (ECG) and nostril airflow signals was performed in healthy subjects to find the common features of ECG and respiration. Forty-two healthy subjects were included in this study. The autospectra of respective ECG and nostril airflow signals and the cross-spectra of ECG and nostril airflow signals were obtained and compared with the corresponding conventional HRV measures. We found that there were two spectral peaks at around 0.03 Hz and 0.3 Hz in the autospectrum of nostril airflow and the cross-spectrum of ECG and nostril airflow. In addition, the cross-spectral normalized high-frequency power (nHFPcs) was significantly larger than that of conventional HRV, while the cross-spectral normalized very low-frequency power (nVLFPcs), normalized low-frequency power (nLFPcs), and low-/high-frequency power ratio (LHRcs) were significantly lower than those of the conventional HRV. The cross-spectral nLFPcs and LHRcs had positive correlations with their corresponding HRV measures. We conclude that cross-spectral analysis of ECG and nostril airflow signals identifies two respiratory frequencies at around 0.03 Hz and below and around 0.3 Hz and can yield significantly enhanced nHFPcs and significantly suppressed nVLFPcs, as compared to their counterparts in conventional HRV. Both very low-frequency and high-frequency components of HRV are caused in part or mainly by respiration.

Cardiovascular variability after arousal from sleep: time-varying spectral analysis

2003 ◽  
Vol 95 (4) ◽  
pp. 1394-1404 ◽  
Author(s):  
Anna Blasi ◽  
Javier Jo ◽  
Edwin Valladares ◽  
Barbara J. Morgan ◽  
James B. Skatrud ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
High Frequency ◽  
Low Frequency ◽  
Sleep Time ◽  
Respiratory Pattern ◽  
Time Varying ◽  
High Frequency Power ◽  
Low Frequency Power ◽  
Frequency Power

We performed time-varying spectral analyses of heart rate variability (HRV) and blood pressure variability (BPV) recorded from 16 normal humans during acoustically induced arousals from sleep. Time-varying autoregressive modeling was employed to estimate the time courses of high-frequency HRV power, low-frequency HRV power, the ratio between low-frequency and high-frequency HRV power, and low-frequency power of systolic BPV. To delineate the influence of respiration on HRV, we also computed respiratory airflow high-frequency power, the modified ratio of low-frequency to high-frequency HRV power, and the average transfer gain between respiration and heart rate. During cortical arousal, muscle sympathetic nerve activity and heart rate increased and returned rapidly to baseline, but systolic blood pressure, the ratio between low-frequency and high-frequency HRV power, low-frequency HRV power, the modified ratio of low-frequency to high-frequency HRV power, and low-frequency power of systolic BPV displayed increases that remained above baseline up to 40 s after arousal. High-frequency HRV power and airflow high-frequency power showed concommitant decreases to levels below baseline, whereas the average transfer gain between respiration and heart rate remained unchanged. These findings suggest that 1) arousal-induced changes in parasympathetic activity are strongly coupled to respiratory pattern and 2) the sympathoexcitatory cardiovascular effects of arousal are relatively long lasting and may accumulate if repetitive arousals occur in close succession.

Aging of modulation of heart rate

1987 ◽  
Vol 253 (4) ◽  
pp. H874-H877 ◽  
Author(s):  
D. C. Shannon ◽  
D. W. Carley ◽  
H. Benson
Keyword(s):  
Heart Rate ◽  
Supine Position ◽  
High Frequency ◽  
Low Frequency ◽  
Standing Position ◽  
Total Power ◽  
High Frequency Power ◽  
Sinus Arrhythmia ◽  
Low Frequency Power ◽  
Frequency Power

We postulated that measurements of autonomically mediated fluctuations in heart rate might provide a quantitative probe of biological aging. We used power spectrum analysis of instantaneous heart rate while 33 male subjects matched their breathing to a metronome at 15 breaths/min. Measurements were made in supine and standing position. Total power and its two major components, high- and low-frequency power, declined with age in both positions but at different rates. High-frequency power that represents parasympathetically mediated respiratory sinus arrhythmia declined linearly in supine position only in subjects 9-28 yr with a slope of -0.796, which was significantly different from zero at P = 0.0007. The absolute value of high-frequency power in standing position was approximately 60% of that in supine, a difference that was statistically significant (P = 0.01). Low-frequency power that represents beta-adrenergically mediated heart rate fluctuations, especially in standing position, declined linearly to 62 yr of age (P = 0.0001). Mean heart rate increased 17.2 beats/min, and diastolic blood pressure increased 8 mmHg in the entire group in the standing compared with supine position. There were no significant differences in these changes above and below 30 yr of age. We conclude that the influence of the two major mechanisms that modulate heart rate decline at significantly different rates with aging.

Elevated heart rate variability in physically active postmenopausal women: a cardioprotective effect?

1996 ◽  
Vol 271 (2) ◽  
pp. H455-H460 ◽  
Author(s):  
K. P. Davy ◽  
N. L. Miniclier ◽  
J. A. Taylor ◽  
E. T. Stevenson ◽  
D. R. Seals
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Postmenopausal Women ◽  
High Frequency ◽  
Low Frequency ◽  
Total Power ◽  
High Frequency Power ◽  
Fat Percentage ◽  
Physically Active ◽  
Frequency Power

Coronary heart disease (CHD) and cardiac sudden death (CSD) incidence accelerates after menopause, but the incidence is lower in physically active versus less active women. Low heart rate variability (HRV) is a risk factor for CHD and CSD. The purpose of the present investigation was to test the hypothesis that HRV at rest is greater in physically active compared with less active postmenopausal women. If true, we further hypothesized that the greater HRV in the physically active women would be closely associated with an elevated spontaneous cardiac baroreflex sensitivity (SBRS). HRV (both time and frequency domain measures) and SBRS (sequence method) were measured during 5-min periods of controlled frequency breathing (15 breaths/min) in the supine, sitting, and standing postures in 9 physically active postmenopausal women (age = 53 +/- 1 yr) and 11 age-matched controls (age = 56 +/- 2 yr). Body weight, body mass index, and body fat percentage were lower (P < 0.01) and maximal oxygen uptake was higher (P < 0.01) in the physically active group. The standard deviation of the R-R intervals (time domain measure) was higher in all postures in the active women (P < 0.05) as were the high-frequency, low-frequency, and total power of HRV. SBRS also was higher (P < 0.05) in the physically active women in all postures and accounted for approximately 70% of the variance in the high-frequency power of HRV (P < 0.05). The results of the present investigation indicate that physically active postmenopausal women demonstrate higher levels of HRV compared with age-matched, less active women. Furthermore, SBRS accounted for the majority of the variance in the high-frequency power of HRV, suggesting the possibility of a mechanistic link with cardiac vagal modulation of heart rate. Our findings may provide insight into a possible cardioprotective mechanism in physically active postmenopausal women.

scholarly journals Very Low Frequency Power of Heart Rate Variability is a Powerful Predictor of Clinical Prognosis in Patients With Congestive Heart Failure

2004 ◽  
Vol 68 (4) ◽  
pp. 343-347 ◽  
Author(s):  
Mitsuyoshi Hadase ◽  
Akihiro Azuma ◽  
Kan Zen ◽  
Satoshi Asada ◽  
Tatsuya Kawasaki ◽  
...  
Keyword(s):  
Heart Failure ◽  
Heart Rate ◽  
Congestive Heart Failure ◽  
Heart Rate Variability ◽  
Low Frequency ◽  
Powerful Predictor ◽  
Clinical Prognosis ◽  
Very Low Frequency ◽  
Low Frequency Power ◽  
Frequency Power

Reproducibility of Heart Rate Variability Measures in Patients with Chronic Heart Failure

1996 ◽  
Vol 91 (4) ◽  
pp. 391-398 ◽  
Author(s):  
Piotr Ponikowski ◽  
Massimo Piepoli ◽  
Aham A. Amadi ◽  
Tuan Peng Chua ◽  
Derek Harrington ◽  
...  
Keyword(s):  
Heart Failure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Chronic Heart Failure ◽  
Time Domain ◽  
Low Frequency ◽  
Variation Coefficient ◽  
Very Low Frequency ◽  
Low Frequency Power ◽  
Frequency Power

1. In patients with chronic heart failure, heart rate variability is reduced with relative preservation of very-low-frequency power (< 0.04 Hz). Heart rate variability has been measured without acceptable information on its stability and the optimal recording periods for enhancing this reproducibility. 2. To this aim and to establish the optimal length of recording for the evaluation of the very-low-frequency power, we analysed 40, 20, 10 and 5 min ECG recordings obtained on two separate occasions in 16 patients with chronic heart failure. The repeatability coefficient and the variation coefficient were calculated for the heart rate variability parameters, in the time-domain (mean RR, SDRR and pNN50), and in the frequency-domain: very low frequency (< 0.04 Hz), low frequency (0.04–0.15 Hz), high frequency (0.15–0.40 Hz), total power (0–0.5 Hz). 3. Mean RR remained virtually identical over time (variation coefficient 8%). The reproducibility of time-domain (variation coefficient 25–139%) and of spectral measures (variation coefficient 45–111%) was very low. The stability of the heart rate variability parameters was only apparently improved after square root and after log transformation. 4. Very-low-frequency values derived from 5 and 10 min intervals were significantly lower than those calculated from 40 and 20 min intervals (P < 0.005). Discrete very-low-frequency peaks were detected in 11 out of 16 patients on the first 40, 20 and 10 min recording, but only in seven out of 16 when 5 min segments were analysed. 5. The reproducibility of both time or frequency-domain measures of heart rate variability in patients with chronic heart failure may vary significantly. Square root or log-transformed parameters may be considered rather than absolute units in studies assessing the influence of management on heart rate variability profile. Recordings of at least 20 min in stable, controlled conditions are to be recommended to optimize signal acquisition in patients with chronic heart failure, if very-low-frequency power in particular is to be studied.

Coarse-graining spectral analysis: new method for studying heart rate variability

1991 ◽  
Vol 71 (3) ◽  
pp. 1143-1150 ◽  
Author(s):  
Y. Yamamoto ◽  
R. L. Hughson
Keyword(s):  
Heart Rate ◽  
Time Series ◽  
Heart Rate Variability ◽  
Spectral Analysis ◽  
High Frequency ◽  
Low Frequency ◽  
Scale Invariant ◽  
Very Low Frequency ◽  
Frequency Components ◽  
Harmonic Components

Heart rate variability (HRV) spectra are typically analyzed for the components related to low- (less than 0.15 Hz) and high- (greater than 0.15 Hz) frequency variations. However, there are very-low-frequency components with periods up to hours in HRV signals, which might smear short-term spectra. We developed a method of spectral analysis suitable for selectively extracting very-low-frequency components, leaving intact the low- and high-frequency components of interest in HRV spectral analysis. Computer simulations showed that those low-frequency components were well characterized by fractional Brownian motions (FBMs). If the scale invariant, or self-similar, property of FBMs is considered a new time series (x′) was constructed by sampling only every other point (course graining) of the original time series (x). Evaluation of the cross-power spectra between these two (Sxx′) showed that the power of the FBM components was preserved, whereas that of the harmonic components vanished. Subtraction of magnitude of Sxx from the autopower spectra of the original sequence emphasized only the harmonic components. Application of this method to HRV spectral analyses indicated that it might enable one to observe more clearly the low- and high-frequency components characteristic of autonomic control of heart rate.

scholarly journals Heart Rate Variability during Face Cooling in Concussed Adolescents

Neurology ◽  
2019 ◽  
Vol 93 (14 Supplement 1) ◽  
pp. S8.1-S8
Author(s):  
Mohammad Haider ◽  
Charles Wilber ◽  
Kaitlin Viera ◽  
Itai Bezherano ◽  
John Leddy
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
High Frequency ◽  
Low Frequency ◽  
High Frequency Power ◽  
Clinical Recovery ◽  
Face Cooling ◽  
Ratio Measure ◽  
Frequency Power ◽  
Mean Heart Rate

ObjectiveWe measured heart rate variability (HRV) during physiological stimuli in acutely concussed adolescents (CX) and after clinical recovery, and compared with healthy controls (HC).BackgroundConcussion is associated with autonomic dysfunction. Face Cooling (FC) triggers the trigeminal nerve to evoke transient increases in cardiac parasympathetic (PNS) activity.Design/Methods11 CX (14.8 ± 0.9 years, 6 male, 7 days since injury) and 11 HC (16.1 ± 1.1 years, 9 male) participated. We calculated mean heart rate (HR), standard deviation of root mean square (RMSSD, measure of PNS tone) and low-frequency to high-frequency power ratio (LF/HF ratio, measure of sympathetic [SNS] tone) at rest and 3-minute FC test.ResultsCX at Visit 1 and 2 had significantly lesser increase in HR (p = 0.02) and RMSSD (p = 0.038) than HC on FC.ConclusionsThese data show that acutely concussed participants have an attenuated PNS response to physiological stimuli which continues after clinical recovery.

scholarly journals Bispectral Index™ Alterations Have Associations with Autonomic Changes during Hypnosis in Trauma Center Researchers: A Formative Evaluation (Preprint)

2020 ◽  
Author(s):  
C. Michael Dunham ◽  
Amanda L. Burger ◽  
Barbara M. Hileman ◽  
Elisha A. Chance ◽  
Amy E. Hutchinson
Keyword(s):  
Respiratory Rate ◽  
Skin Conductance ◽  
High Frequency ◽  
Trauma Center ◽  
Formative Evaluation ◽  
Low Frequency ◽  
High Frequency Power ◽  
Interbeat Interval ◽  
Low Frequency Power ◽  
Frequency Power

BACKGROUND Hypnosis was induced to enhance reductions in Bispectral Index™ (BIS) values. OBJECTIVE Autonomic monitoring was used to assess physiologic relaxation and explore their associations with BIS values. METHODS Each session consisted of reading a 4-minute baseline neutral script and playing an 18-minute hypnosis tape to 3 researchers involved in the BIS neurofeedback study. In addition to BIS monitoring, autonomic monitoring was performed and included measures of electromyography, skin temperature, skin conductance, respiratory rate, expired carbon dioxide, and heart rate variability. The t-test, correlation analyses, and multivariate linear regression analyses were used in data analysis. RESULTS Hypnosis was associated with reductions in BIS (P<.001), electromyography (P<.001), respiratory rate (P<.001), skin conductance (P=.006), and very low frequency power (P=.04) and with increases in expired carbon dioxide (P<.001), skin temperature (P=.04), high frequency power (P<.001), and successive heart interbeat interval difference (P=.04) values. Decreased BIS values were associated with reduced electromyography measures (R=.76; P<.001), respiratory rate (R=.35; P=.004), skin conductance (R=.57; P<.001), and low frequency power (R=.32; P=.01) and with increased high frequency power (R=-.53; P<.001), successive heart interbeat interval difference (R=-.32; P=.009), and standard deviation of heart interbeat interval (R=-.26; P=.04) values. CONCLUSIONS Hypnosis appeared to induce mental and physical relaxation, enhance parasympathetic neural activation, and attenuate sympathetic nervous system activity, changes that were associated with BIS values. Findings of the preliminary formative evaluation suggest that the current hypnosis model may be useful for assessing autonomic physiological associations with changes in BIS values, thus motivating us to proceed with a larger investigation in trauma center nurses and physicians. CLINICALTRIAL None

Thermoregulation and Heart Rate Variability

1996 ◽  
Vol 90 (2) ◽  
pp. 97-103 ◽  
Author(s):  
Lee A. Fleisher ◽  
Steven M. Frank ◽  
Daniel I. Sessler ◽  
Christi Cheng ◽  
Takashi Matsukawa ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Frequency Band ◽  
Low Frequency ◽  
Skin Surface ◽  
Surface Cooling ◽  
Very Low Frequency ◽  
Core Cooling ◽  
Low Frequency Power ◽  
Frequency Power

1. Heart rate variability is modulated by multiple control systems, including autonomic and hormonal systems. Long-term variability, i.e. the very low-frequency band of the power spectra, has been postulated to reflect thermoregulatory vasomotor control, based upon thermal entrainment experiments. However, the relationship between thermoregulatory responses (vasoconstriction and shivering) and heart rate variability has not been studied. 2. We performed two distinct protocols in a series of human subjects. In the first protocol, core temperature was reduced by intravenous infusion of cold saline, while skin temperature was unchanged. The second protocol involved skin-surface warming and cooling until shivering developed. Power spectral analysis was performed using a fast Fourier transformation, and the area in three distinct band-widths was determined. 3. Very low-frequency power (0.0039–0.04 Hz) increased significantly in response to core cooling, peripheral vasoconstriction and shivering, while both very low- and low- (0.04–0.15 Hz) frequency power increased in response to skin-surface cooling. Heart rate decreased during core cooling-induced vasoconstriction, suggesting a direct thermal response, and increased in relation to the metabolic demands associated with shivering. 4. Our results suggest that very low-frequency power is modulated by thermal stimuli which result in core hypothermia and thermoregulatory activity, while skin-surface cooling without core hypothermia does not selectively modulate this frequency band.

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