Low frequency component in systolic arterial pressure variability in patients with persistent atrial fibrillation

2009 ◽  
Vol 151 (2) ◽  
pp. 147-153 ◽  
Author(s):  
Luca Mainardi ◽  
Valentina Corino ◽  
Sebastiano Belletti ◽  
Paolo Terranova ◽  
Federico Lombardi
Keyword(s):  
Atrial Fibrillation ◽  
Arterial Pressure ◽  
Low Frequency ◽  
Systolic Arterial Pressure ◽  
Persistent Atrial Fibrillation ◽  
Frequency Component ◽  
Arterial Pressure Variability

scholarly journals Physiological Sympathetic Activation Reduces Systemic Inflammation: Role of Baroreflex and Chemoreflex

2021 ◽  
Vol 12 ◽  
Author(s):  
Fernanda Brognara ◽  
Jaci Airton Castania ◽  
Alexandre Kanashiro ◽  
Daniel Penteado Martins Dias ◽  
Helio Cesar Salgado
Keyword(s):  
Nervous System ◽  
Arterial Pressure ◽  
Systemic Inflammation ◽  
Inflammatory Responses ◽  
Low Frequency ◽  
Systolic Arterial Pressure ◽  
Sympathetic Activation ◽  
Bilateral Carotid Occlusion ◽  
Bilateral Carotid ◽  
Reflex Activation

Baroreflex and chemoreflex act through the autonomic nervous system, which is involved with the neural regulation of inflammation. The present study reports the effects of reflex physiological sympathetic activation in endotoxemic rats using bilateral carotid occlusion (BCO), a physiological approach involving the baroreflex and chemoreflex mechanisms and the influence of the baroreceptors and peripheral chemoreceptors in the cardiovascular and systemic inflammatory responses. After lipopolysaccharide (LPS) administration, the arterial pressure was recorded during 360 min in unanesthetized rats, and serial blood samples were collected to analyze the plasma cytokine levels. BCO elicited the reflex activation of the sympathetic nervous system, providing the following outcomes: (I) increased the power of the low-frequency band in the spectrum of the systolic arterial pressure during the BCO period; (II) reduced the levels of pro-inflammatory cytokines in plasma, including the tumor necrosis factor (TNF) and the interleukin (IL)-1β; (III) increased the plasma levels of anti-inflammatory cytokine IL-10, 90 min after LPS administration. Moreover, selective baroreceptor or chemoreceptor denervation deactivated mechanosensitive and chemical sensors, respectively, and decreased the release of the LPS-induced cytokine but did not alter the BCO modulatory effects. These results show, for the first time, that physiological reflex activation of the sympathetic circuit decreases the inflammatory response in endotoxemic rats and suggest a novel function for the baroreceptors as immunosensors during the systemic inflammation.

Influences of neural mechanisms on heart period and arterial pressure variabilities in quadriplegic patients

1994 ◽  
Vol 266 (3) ◽  
pp. H1112-H1120 ◽  
Author(s):  
S. Guzzetti ◽  
C. Cogliati ◽  
C. Broggi ◽  
C. Carozzi ◽  
D. Caldiroli ◽  
...  
Keyword(s):  
Arterial Pressure ◽  
Spectral Component ◽  
Systolic Arterial Pressure ◽  
Neural Mechanisms ◽  
Heart Period ◽  
Recording Session ◽  
Sympathetic Modulation ◽  
Arterial Pressure Variability ◽  
Head Up Tilt ◽  
Vasomotor Activity

The heart period (R-R) variability power spectrum presents two components, at low (LF; approximately 0.10 Hz) and high (approximately 0.25 Hz) frequencies, whose reciprocal powers appear to furnish an index of sympathovagal interaction modulating heart rate. In addition, the LF component of the systolic arterial pressure variability spectrum furnishes a marker of sympathetic modulation of vasomotor activity. The contribution of spinal and supraspinal neural circuits to the genesis of these rhythmic oscillatory components remains largely unsettled. Therefore we performed spectral analysis of R-R and systolic arterial pressure variabilities in 15 chronic neurologically complete quadriplegic patients (QP) and in 15 control subjects during resting conditions, controlled respiration, and head-up tilt. At rest, in seven QP the LF component was undetectable in both cardiovascular variability spectra; in two QP this component was present only in R-R variability spectrum, whereas the remaining six showed a significantly reduced LF in both signals. In QP, the LF component, when present, underwent paradoxical changes with respect to controls, decreasing during tilt and increasing during controlled respiration. In five QP in whom the recording session was repeated after 6 mo, a significant increase in LF was observed in both variability spectra. These data confirm the finding that a disconnection of sympathetic outflow from supraspinal centers can cause the disappearance of the LF spectral component. However, LF presence in some QP supports the hypothesis of a spinal rhythmicity likely to be modulated by the afferent sympathetic activity.

Changes in systolic arterial pressure variability are associated with the decreased aerobic performance of rats subjected to physical exercise in the heat

2017 ◽  
Vol 63 ◽  
pp. 31-40 ◽  
Author(s):  
Flávia C. Müller-Ribeiro ◽  
Samuel P. Wanner ◽  
Weslley H.M. Santos ◽  
Milene R. Malheiros-Lima ◽  
Ivana A.T. Fonseca ◽  
...  
Keyword(s):  
Physical Exercise ◽  
Arterial Pressure ◽  
Systolic Arterial Pressure ◽  
Aerobic Performance ◽  
Arterial Pressure Variability

scholarly journals Orthostatic Intolerance Is Independent of the Degree of Autonomic Cardiovascular Adaptation after 60 Days of Head-Down Bed Rest

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Jiexin Liu ◽  
Yongzhi Li ◽  
Bart Verheyden ◽  
Zhanghuang Chen ◽  
Jingyu Wang ◽  
...  
Keyword(s):  
Arterial Pressure ◽  
Orthostatic Intolerance ◽  
Low Frequency ◽  
Systolic Arterial Pressure ◽  
Bed Rest ◽  
Progressive Increase ◽  
Tilt Test ◽  
Sinus Arrhythmia ◽  
Before And After ◽  
Low Frequency Power

Spaceflight and head-down bed rest (HDBR) can induce the orthostatic intolerance (OI); the mechanisms remain to be clarified. The aim of this study was to determine whether or not OI after HDBR relates to the degree of autonomic cardiovascular adaptation. Fourteen volunteers were enrolled for 60 days of HDBR. A head-up tilt test (HUTT) was performed before and after HDBR. Our data revealed that, in all nonfainters, there was a progressive increase in heart rate over the course of HDBR, which remained higher until 12 days of recovery. The mean arterial pressure gradually increased until day 56 of HDBR and returned to baseline after 12 days of recovery. Respiratory sinus arrhythmia and baroreflex sensitivity decreased during HDBR and remained suppressed until 12 days of recovery. Low-frequency power of systolic arterial pressure increased during HDBR and remained elevated during recovery. Three subjects fainted during the HUTT after HDBR, in which systemic vascular resistance did not increase and remained lower until syncope. None of the circulatory patterns significantly differed between the fainters and the nonfainters at any time point. In conclusion, our data indicate that the impaired orthostatic tolerance after HDBR could not be distinguished by estimation of normal hemodynamic and/or neurocardiac data.

scholarly journals Cardiac output is not a significant source of low frequency mean arterial pressure variability

2013 ◽  
Vol 34 (9) ◽  
pp. 1207-1216 ◽  
Author(s):  
F Aletti ◽  
R L Hammond ◽  
J A Sala-Mercado ◽  
X Chen ◽  
D S O'Leary ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Low Frequency ◽  
Significant Source ◽  
Arterial Pressure Variability

Dose-response relationship of autonomic nervous system responses to individualized training impulse in marathon runners

2009 ◽  
Vol 296 (6) ◽  
pp. H1733-H1740 ◽  
Author(s):  
Vincenzo Manzi ◽  
Carlo Castagna ◽  
Elvira Padua ◽  
Mauro Lombardo ◽  
Stefano D'Ottavio ◽  
...  
Keyword(s):  
Nervous System ◽  
High Frequency ◽  
Baroreflex Sensitivity ◽  
Low Frequency ◽  
Systolic Arterial Pressure ◽  
Training Load ◽  
Recreational Athletes ◽  
Arterial Pressure Variability ◽  
Individualized Training ◽  
Training Impulse

In athletes, exercise training induces autonomic nervous system (ANS) adaptations that could be used to monitor training status. However, the relationship between training and ANS in athletes has been investigated without regard for individual training loads. We tested the hypothesis that in long-distance athletes, changes in ANS parameters are dose-response related to individual volume/intensity training load and could predict athletic performance. A spectral analysis of heart rate (HR), systolic arterial pressure variability, and baroreflex sensitivity by the sequences technique was investigated in eight recreational athletes during a 6-mo training period culminating with a marathon. Individualized training load responses were monitored by a modified training impulse (TRIMPi) method, which was determined in each athlete using the individual HR and lactate profiling determined during a treadmill test. Monthly TRIMPi steadily increased during the training period. All the ANS parameters were significantly and very highly correlated to the dose of exercise with a second-order regression model ( r2 ranged from 0.90 to 0.99; P < 0.001). Variance, high-frequency oscillations of HR variability (HRV), and baroreflex sensitivity resembled a bell-shaped curve with a minimum at the highest TRIMPi, whereas low-frequency oscillations of HR and systolic arterial pressure variability and the low frequency (LF)-to-high frequency ratio resembled an U-shaped curve with a maximum at the highest TRIMPi. The LF component of HRV assessed at the last recording session was significantly and inversely correlated to the time needed to complete the nearing marathon. These results suggest that in recreational athletes, ANS adaptations to exercise training are dose related on an individual basis, showing a progressive shift toward a sympathetic predominance, and that LF oscillations in HRV at peak training load could predict athletic achievement in this athlete population.

Altered Dynamics of the Circadian Relationship between Systemic Arterial Pressure and Cardiac Sympathetic Drive Early on in Mild Hypertension

1994 ◽  
Vol 86 (2) ◽  
pp. 209-215 ◽  
Author(s):  
S. Guzzetti ◽  
S. Dassi ◽  
M. Balsamà ◽  
G. B. Ponti ◽  
M. Pagani ◽  
...  
Keyword(s):  
Arterial Pressure ◽  
Neural Control ◽  
Mild Hypertension ◽  
Clinical Laboratory ◽  
Spectral Component ◽  
Low Frequency ◽  
Frequency Component ◽  
Regulatory Mechanisms ◽  
Non Invasive ◽  
Normotensive Subjects

1. This study was designed to test the hypothesis that simultaneous non-invasive assessment of the circadian variations in both intermittent arterial pressure and the continuous 24 h changes of spectral markers of cardiac neural control could provide new information on cardiovascular regulatory mechanisms, in hypertensive patients and normotensive subjects. To test this hypothesis we studied 18 subjects with mild hypertension and 11 normotensive subjects in whom we recorded simultaneously non-invasive intermittent arterial pressure and Holter electrocardiogram for 24 h. We also studied the same subjects during resting and standing conditions in the clinical laboratory. 2. The normalized power of the low-frequency (∼0.1 Hz) spectral component of R-R interval variability, considered mainly a marker of sympathetic drive to the sino-atrial node, was, at rest, significantly higher in the hypertensive than in the normotensive subjects, as already reported. Moreover, the values of the low-frequency component at rest recorded in the clinical laboratory were significantly correlated with those obtained from ambulatory recording during night rest. The decrease in the values of arterial pressure during the night-time was accompanied by a reduction in the power of the low-frequency component only in the case of normotensive subjects. Accordingly, the slope of the regression of the low-frequency component as a function of systolic arterial pressure during ambulatory recordings was steep in normotensive subjects and flat in hypertensive subjects. 3. The computer analysis of Holter recordings combined with ambulatory arterial pressure monitoring seems to provide a new method with which to quantify the early changes in cardiovascular regulatory mechanisms that could help to identify individuals at higher risk.

scholarly journals Influence of age and gender on the phase and strength of the relation between heart period and systolic blood pressure spontaneous fluctuations

2018 ◽  
Vol 124 (3) ◽  
pp. 791-804 ◽  
Author(s):  
Juliana C. Milan-Mattos ◽  
Alberto Porta ◽  
Natália M. Perseguini ◽  
Vinicius Minatel ◽  
Patricia Rehder-Santos ◽  
...  
Keyword(s):  
Arterial Pressure ◽  
Coherence Function ◽  
Low Frequency ◽  
Systolic Arterial Pressure ◽  
Progressive Increase ◽  
Heart Period ◽  
Baroreflex Control ◽  
And Gender ◽  
Spontaneous Fluctuations ◽  
Cardiovascular Variables

Aging affects baroreflex regulation. The effect of senescence on baroreflex control was assessed from spontaneous fluctuations of heart period (HP) and systolic arterial pressure (SAP) through the HP-SAP gain, while the HP-SAP phase and strength are usually disregarded. This study checks whether the HP-SAP phase and strength, as estimated, respectively, via the phase of the HP-SAP cross spectrum (PhHP-SAP) and squared coherence function (K2HP-SAP), vary with age in healthy individuals and trends are gender-dependent. We evaluated 110 healthy volunteers (55 males) divided into five age subgroups (21–30, 31–40, 41–50, 51–60, and 61–70 yr). Each subgroup was formed by 22 subjects (11 males). HP series was extracted from electrocardiogram and SAP from finger arterial pressure at supine resting (REST) and during active standing (STAND). PhHP-SAP and K2HP-SAP functions were sampled in low-frequency (LF, from 0.04 to 0.15 Hz) and in high-frequency (HF, above 0.15 Hz) bands. Both at REST and during STAND PhHP-SAP(LF) showed a negative correlation with age regardless of gender even though values were more negative in women. This trend was shown to be compatible with a progressive increase of the baroreflex latency with age. At REST K2HP-SAP(LF) decreased with age regardless of gender, but during STAND the high values of K2HP-SAP(LF) were more preserved in men than women. At REST and during STAND the association of PhHP-SAP(HF) and K2HP-SAP(HF) with age was absent. The findings points to a greater instability of baroreflex control with age that seems to affect to a greater extent women than men. NEW & NOTEWORTHY Aging increases cardiac baroreflex latency and decreases the degree of cardiac baroreflex involvement in regulating cardiovascular variables. These trends are gender independent but lead to longer delays and asmaller degree of cardiac baroreflex involvement in women than in men, especially during active standing, with important implications on the tolerance to an orthostatic stressor.

Measuring baroreflex sensitivity from the gain function between arterial pressure and heart period

2002 ◽  
Vol 103 (1) ◽  
pp. 81-88 ◽  
Author(s):  
Gian Domenico PINNA ◽  
Roberto MAESTRI ◽  
Grzegorz RACZAK ◽  
Maria Teresa LA ROVERE
Keyword(s):  
Arterial Pressure ◽  
Frequency Band ◽  
Baroreflex Sensitivity ◽  
Low Frequency ◽  
Systolic Arterial Pressure ◽  
Normal Subjects ◽  
Heart Period ◽  
Gain Function ◽  
Limits Of Agreement ◽  
Spectral Technique

We tested an innovative approach for estimating baroreflex sensitivity (BRS) from the gain function between spontaneous oscillations of systolic arterial pressure (SAP) and heart period (HP). The major goal was to assess the practical implications of abandoning the classical coherence criterion (⩾0.5) as regards measurability of BRS, and agreement with values of BRS obtained using the phenylephrine test (Phe-BRS). We studied 19 normal subjects, 44 patients with a history of previous myocardial infarction (MI) and 45 patients with chronic heart failure (CHF). The experimental protocol included recording of SAP and HP for 10min of supine rest, and evaluation of Phe-BRS. From resting SAP and HP, the gain and coherence functions were computed. The new BRS index was obtained in all subjects by averaging the gain function over the whole low-frequency band (0.04-0.15Hz) (whole-band average BRS, WBA-BRS). WBA-BRS was 7.4 (5.8-10.8)ms/mmHg [median (25th-75th percentile)] in normal controls, 3.1 (1.4-5.4)ms/mmHg in MI patients (P<0.001 compared with normals) and 5.0 (3.2-6.9)ms/mmHg in CHF patients (P<0.01 compared with normals). Using the coherence criterion, BRS could be measured in only 43% and 49% of MI and CHF patients respectively, and the proportion of the low-frequency band contributing to the measurement was 21% (14-47%) and 29% (16-35%) respectively. The correlation between WBA-BRS and Phe-BRS was 0.47, 0.63 and 0.36 in the normal, MI and CHF groups respectively (all P<0.001). The relative bias of WBA-BRS was -5.2ms/mmHg (P<0.001) in normals, -1.4ms/mmHg (P = 0.004) in MI patients and -1.0ms/mmHg (P = 0.11) in CHF patients. The limits of agreement were -13 to 2.6, -7.4 to 4.6 and -9.3 to 7.3ms/mmHg in the normal, MI and CHF groups respectively. Thus the WBA-BRS method standardizes the computation of BRS among subjects, and dramatically increases its measurability in subjects with pathology compared with the classical spectral technique based on the coherence criterion. Compared with Phe-BRS, WBA-BRS tends to give negatively biased results. The correlation and the magnitude of the limits of agreement between the two methods are similar to those observed previously using coherence-based spectral methods.

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