scholarly journals Artifacts in dependency structures of Portapres® signals

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Marko Mozetić ◽  
Tamara Škorić ◽  
Jelena Antelj ◽  
Katarina Otašević ◽  
Branislav Milovanović ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Baroreflex Sensitivity ◽  
Pulse Interval ◽  
Signal Acquisition ◽  
Non Invasive ◽  
Complex Procedure ◽  
Sequence Method ◽  
Copula Density ◽  
Spontaneous Baroreflex ◽  
Dependency Structures

Portapres® is a unique device that reliably accomplishes a challenging task of continuous and non-invasive recording ofblood pressure (BP) waveforms in moving subjects. The complex procedure of Portapres® signal acquisition includes periodic changesof cuffed fingers to avoid pain and stress, as well as the blood pressure correction due to the increasing and decreasing elevation of armposture. Due to these procedures, the recorded waveforms are corrupted. The aim of this paper is to analyze the influence of inevitableartifacts on parameters obtained from the blood pressure waveforms. The analyzed waveforms are obtained from healthy volunteers atBezanija Kosa Hospital, Belgrade. The parameters include systolic blood pressure (SBP) and pulse interval (PI) extracted byBeatscope® software. The interrelationship of SBP and PI signals forms a major cardiovascular feedback – baroreflex. It can beanalyzed using the sequence method for spontaneous baroreflex sensitivity, but the tools that reveal more profound dependencystructures include cross-approximate and cross-sample entropy, as well as the copula structures. The influence of artifacts, inevitable inPortapres® signals, is the main goal of this study. The analyses revealed that automatic artifact correction induced no significantchanges considering the statistical moments and the baroreflex sensitivity; the same applies to the copula density and rank tests. Theentropy analysis, however, turned out to be extremely sensitive so its implementation in Portapres® signal analysis is not recommended.

Critical Appraisal of Indices for the Assessment of Baroreflex Sensitivity

1997 ◽  
Vol 36 (04/05) ◽  
pp. 246-249 ◽  
Author(s):  
P. Castiglioni ◽  
G. Mancia ◽  
G. Parati ◽  
A. Pedotti ◽  
M. Di Rienzo
Keyword(s):  
Blood Pressure ◽  
Baroreflex Sensitivity ◽  
Critical Appraisal ◽  
Spectral Estimation ◽  
Respiratory Frequency ◽  
Pulse Interval ◽  
Alpha Coefficient ◽  
Before And After ◽  
Reliable Parameter ◽  
Spontaneous Baroreflex

Abstract:The sequence technique and the spectral estimation of the alpha coefficient are currently employed for the assessment of “spontaneous” baroreflex sensitivity (BRS). The comparison of performance and effectiveness of these techniques is obtained by the analysis of systolic blood pressure (SBP) and pulse interval (PI) tracings recorded in conscious cats before and after baroreceptor denervation. Results indicate that (1) the average BRS estimates obtained by the sequence technique and by the alpha coefficient at the respiratory frequency are similar, (2) the alpha coefficients computed at the respiratory frequency tend to be higher than alpha coefficients estimated at 0.1 Hz, and (3) in spite of what is traditionally claimed, the PI-SBP coherence does not seem to represent a reliable parameter to enhance the specificity of the spectral estimate, because coherence values often remain above the 0.5 threshold also after baroreceptor denervation.

Applicability of recent methods used to estimate spontaneous baroreflex sensitivity to resting mice

2008 ◽  
Vol 294 (1) ◽  
pp. R142-R150 ◽  
Author(s):  
Dominique Laude ◽  
Véronique Baudrie ◽  
Jean-Luc Elghozi
Keyword(s):  
Baroreflex Sensitivity ◽  
Low Frequency ◽  
Pulse Interval ◽  
Arterial Baroreflex ◽  
Baroreflex Control ◽  
Spectral Estimates ◽  
Sequence Method ◽  
Highly Correlated ◽  
Spontaneous Baroreflex ◽  
Sequence Techniques

Short-term blood pressure (BP) variability is limited by the arterial baroreflex. Methods for measuring the spontaneous baroreflex sensitivity (BRS) aim to quantify the gain of the transfer function between BP and pulse interval (PI) or the slope of the linear relationship between parallel BP and PI changes. These frequency-domain (spectral) and time-domain (sequence) techniques were tested in conscious mice equipped with telemetric devices. The autonomic relevance of these indexes was evaluated using pharmacological blockades. The significant changes of the spectral bandwidths resulting from the autonomic blockades were used to identify the low-frequency (LF) and high-frequency (HF) zones of interest. The LF gain was 1.45 ± 0.14 ms/mmHg, with a PI delay of 0.5 s. For the HF gain, the average values were 2.0 ± 0.19 ms/mmHg, with a null phase. LF and HF bands were markedly affected by atropine. On the same 51.2-s segments used for cross-spectral analysis, an average number of 26.4 ± 2.2 slopes were detected, and the average slope in resting mice was 4.4 ± 0.5 ms/mmHg. Atropine significantly reduced the slopes of the sequence method. BRS measurements obtained using the sequence technique were highly correlated to the spectral estimates. This study demonstrates the applicability of the recent methods used to estimate spontaneous BRS in mice. There was a vagal predominance in the baroreflex control of heart rate in conscious mice in the present conditions.

Change in spontaneous baroreflex control of pulse interval during heat stress in humans

2003 ◽  
Vol 95 (5) ◽  
pp. 1789-1798 ◽  
Author(s):  
Kichang Lee ◽  
Dwayne N. Jackson ◽  
Douglas L. Cordero ◽  
Takeshi Nishiyasu ◽  
Jochen K. Peters ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heat Stress ◽  
Stroke Volume ◽  
Linear Relationship ◽  
Baroreflex Sensitivity ◽  
Pulse Interval ◽  
Baroreflex Control ◽  
Arterial Blood ◽  
Transfer Function Analysis ◽  
Spontaneous Baroreflex

Spontaneous baroreflex control of pulse interval (PI) was assessed in healthy volunteers under thermoneutral and heat stress conditions. Subjects rested in the supine position with their lower legs in a water bath at 34°C. Heat stress was imposed by increasing the bath temperature to 44°C. Arterial blood pressure (Finapres), PI (ECG), esophageal and skin temperature, and stroke volume were continuously collected during each 5-min experimental stage. Spontaneous baroreflex function was evaluated by multiple techniques, including 1) the mean slope of the linear relationship between PI and systolic blood pressure (SBP) with three or more simultaneous increasing or decreasing sequences, 2) the linear relationship between changes in PI and SBP (ΔPI/ΔSBP) derived by using the first differential equation, 3) the linear relationship between changes in PI and SBP with simultaneously increasing or decreasing sequences (+ΔPI/+ΔSBP or -ΔPI/-ΔSBP), and 4) transfer function analysis. Heat stress increased esophageal temperature by 0.6 ± 0.1°C, decreased PI from 1,007 ± 43 to 776 ± 37 ms and stroke volume by 16 ± 5 ml/beat. Heat stress reduced baroreflex sensitivity but increased the incidence of baroreflex slopes from 5.2 ± 0.8 to 8.6 ± 0.9 sequences per 100 heartbeats. Baroreflex sensitivity was significantly correlated with PI or vagal power ( r2 = 0.45, r2 = 0.71, respectively; P < 0.05). However, the attenuation in baroreflex sensitivity during heat stress appeared related to a shift in autonomic balance (shift in resting PI) rather than heat stress per se.

scholarly journals Implantation of Combined Telemetric ECG and Blood Pressure Transmitters to Determine Spontaneous Baroreflex Sensitivity in Conscious Mice

10.3791/62101 ◽  
2021 ◽  
Author(s):  
René D. Rötzer ◽  
Verena F. Brox ◽  
Konstantin Hennis ◽  
Stefan B. Thalhammer ◽  
Martin Biel ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Baroreflex Sensitivity ◽  
Spontaneous Baroreflex

Effects of aging on 24-h dynamic baroreceptor control of heart rate in ambulant subjects

1995 ◽  
Vol 268 (4) ◽  
pp. H1606-H1612 ◽  
Author(s):  
G. Parati ◽  
A. Frattola ◽  
M. Di Rienzo ◽  
P. Castiglioni ◽  
A. Pedotti ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Systolic Blood Pressure ◽  
Baroreflex Sensitivity ◽  
Regression Line ◽  
Domain Analysis ◽  
Pulse Interval ◽  
Alpha Coefficient ◽  
Baroreflex Control ◽  
Effects Of Aging

The effects of aging on the dynamic modulation of baroreflex sensitivity over 24 h was assessed in eight elderly (mean age +/- SD, 63.9 +/- 3.2 yr) and in eight young (23.9 +/- 6.1 yr) mild or moderate essential hypertensive patients, who were subject to a 24-h intra-arterial (Oxford technique) blood pressure recording in ambulatory conditions. The sensitivity of baroreflex control of the heart rate was dynamically assessed by quantifying 1) the slope of the regression line between pulse interval (the reciprocal of heart rate) and systolic blood pressure changes over spontaneously occurring hypertension-bradycardia or hypotension-tachycardia sequences (time domain analysis) and 2) the ratio between spectral-powers of pulse interval and systolic blood pressure around 0.1 Hz (alpha-coefficient: frequency domain analysis). The 24-h average sequence slope was lower in old than in young individuals (4.4 +/- 0.5 vs. 9.9 +/- 1.3 and 4.8 +/- 0.7 vs. 8.4 +/- 1.4 ms/mmHg for hypertension-bradycardia and hypotension-tachycardia sequences, respectively; P < 0.05 for both). Similar results were obtained by using the alpha-coefficient approach. The marked nighttime increase in baroreflex sensitivity observed in young individuals was much less evident in the elderly. Thus 24-h baroreflex sensitivity is markedly impaired by aging. The impairment becomes manifest also as an inability to increase baroreflex sensitivity at night.

Influence of non-invasive measurements of arterial blood pressure in frequency and time-domain estimates of cardiac baroreflex sensitivity

2008 ◽  
Vol 26 (1) ◽  
pp. 76-82 ◽  
Author(s):  
Stephen Matthew Smith ◽  
Nilesh J Samani ◽  
Emily L Sammons ◽  
Wendy E Rathbone ◽  
John F Potter ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Time Domain ◽  
Baroreflex Sensitivity ◽  
Non Invasive ◽  
Arterial Blood

Smoking impairs baroreflex sensitivity in humans

1997 ◽  
Vol 273 (3) ◽  
pp. H1555-H1560 ◽  
Author(s):  
G. Mancia ◽  
A. Groppelli ◽  
M. Di Rienzo ◽  
P. Castiglioni ◽  
G. Parati
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Systolic Blood Pressure ◽  
Baroreflex Sensitivity ◽  
Pulse Interval ◽  
Average Systolic Blood Pressure ◽  
Carotid Baroreceptor ◽  
Baroreceptor Stimulation ◽  
Finger Blood Pressure ◽  
Carotid Baroreceptor Stimulation

In 10 healthy smokers, finger blood pressure was recorded continuously for 1 h in a supine control condition and for 1 h while smoking four cigarettes, one every 15 min. Smoking increased average systolic blood pressure (+19%, P < 0.01) and its variability and reduced pulse interval (reciprocal of heart rate, -22%, P < 0.01) and its variability. Baroreflex sensitivity, as assessed by the slope of spontaneous hypertension/bradycardia or hypotension/tachycardia sequences and by the alpha-coefficient (squared ratio between pulse interval and systolic blood pressure spectral powers at 0.1 Hz) was significantly decreased (P < 0.01) during smoking, whereas there were no effects of smoking on the reflex changes in pulse interval induced by carotid baroreceptor stimulation through a neck suction device. Sham smoking by a drinking straw had no effects on any of the above parameters. Thus, when assessed in the absence of laboratory maneuvers in daily life conditions, baroreflex sensitivity is markedly impaired by smoking. This impairment may contribute to the smoking-induced increase in blood pressure and heart rate as well as to the concomitant alterations in their variability.

Effects of Low-Intensity Exercise Conditioning on Blood Pressure, Heart Rate, and Autonomic Modulation of Heart Rate in Men and Women with Hypertension

2009 ◽  
Vol 11 (2) ◽  
pp. 129-143 ◽  
Author(s):  
Lien P.T. Hua ◽  
C. Ann Brown ◽  
Sylvia J.M. Hains ◽  
Marshall Godwin ◽  
Joel L. Parlow
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Diastolic Blood Pressure ◽  
Baroreflex Sensitivity ◽  
Autonomic Modulation ◽  
Men And Women ◽  
Low Intensity ◽  
Walking Program ◽  
Spontaneous Baroreflex ◽  
Low Intensity Exercise

Untreated hypertension increases cardiovascular risk 2-fold to 3-fold, leading to serious cardiovascular problems that include left ventricular hypertrophy, stroke, ischemic heart disease, myocardial infarction, vascular disease, renal disease, and death. Exercise conditioning is recommended as one of the initial treatments for hypertension. The purpose of this pretest—posttest study was to quantify the effects of a 12-week home-based low-intensity exercise conditioning (walking) program in hypertensive men and women on systolic and diastolic blood pressure, heart rate, and autonomic modulation of heart rate. A total of 20 mildly hypertensive men and women who were assigned to a structured exercise (walking) program were compared with a control group of 20 nonexercising mildly hypertensive participants. Electrocardiographic heart rate and R-R interval data and beat-by-beat arterial blood pressure data were collected continuously for 10 min with participants in the supine and standing postures and during low-intensity steady-state exercise. The results show that systolic and diastolic blood pressure and R-R interval decreased and spontaneous baroreflex sensitivity increased in the exercise group. The decline in blood pressure was significant statistically and clinically. The increase in spontaneous baroreflex sensitivity indicates that the ability of the cardiovascular system to respond rapidly to changing stimuli improved after the 12-week walking protocol. The low-intensity exercise conditioning program achieved a training effect in this population.

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