Graded vascular autonomic control versus discontinuous cardiac control during gradual upright tilt

Bahjaoui‐Bouhaddi, Malika; Cappelle, Sylvie; Henriet, M T; Dumoulin, Gilles; Wolf, Jean‐Pierre; Regnard, Jacques

doi:10.1016/s0165-1838(99)00068-5

Cited by 24 publications

(19 citation statements)

References 25 publications

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“…As for the Kubios indices, a clear angulation change (of at least 45°) was needed to reach the significance level. This is in accordance with a clear-cut, rather than gradual switching in control of cardiac activity during graded orthostatism [19,36].…”

Section: Discussionsupporting

confidence: 88%

“…On a second visit, they performed a passive tilttest on a tilt-table to graduate the orthostatic stress [19] to assess the within-subject sensitivity of the analysis. With CODESNA_HRV, 4 durations for the HRV analysis were compared during this passive tilttest to evaluate whether changing the duration of the period analysed would have an effect on the indices.…”

Section: Overviewmentioning

confidence: 99%

“…After 15 min in the supine position, data acquisition was initiated and the control subjects were then tilted at angles chosen to graduate the orthostatic stress. Inclination of the tilt table was set for 8 min at each of the following angles, in a random order: 0°, 30°, 45° and 60° [19].…”

Section: Tilt-testsmentioning

confidence: 99%

“…Hence, a stable period of 300 sec [13,17,28,19] was chosen for comparisons between the two programmes. On the contrary, the duration of the analysis is claimed to have no real effect on the indexes with CODESNA_HRV.…”

Section: Hrv Analysismentioning

confidence: 99%

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CODESNA_HRV, a new tool to assess the activity of the autonomic nervous system from heart rate variability

Mourot¹

2018

Phys Med Rehabil Res

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Section: Discussionsupporting

confidence: 88%

Section: Overviewmentioning

confidence: 99%

Section: Tilt-testsmentioning

confidence: 99%

Section: Hrv Analysismentioning

confidence: 99%

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CODESNA_HRV, a new tool to assess the activity of the autonomic nervous system from heart rate variability

Mourot¹

2018

Phys Med Rehabil Res

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“…This indicates that the relation between BP, sympathetic activity, and respiration changes during orthostatic load and cannot completely be explained by models created during baseline conditions. Indeed, some evidence suggests that the properties of the cardiac baroreflex (HR-BP relation) change during upright tilt (1,33), but limited information about the sympathetic branch of the baroreflex has been reported during tilt. The results of the current model should be interpreted with caution, however, since a model will always have greater predictive value when its coefficients are reoptimized during each condition, as is the case here.…”

Section: Predictive Modelmentioning

confidence: 99%

A simplified two-component model of blood pressure fluctuation

Brychta

Shiavi²,

Robertson³

et al. 2007

American Journal of Physiology-Heart and Circulatory Physiology

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September 29, 2006; doi:10.1152/ajpheart.00645.2006.-We propose a simple moving-average (MA) model that uses the low-frequency (LF) component of the peroneal muscle sympathetic nerve spike rate (LFspike rate) and the high-frequency (HF) component of respiration (HFResp) to describe the LF neurovascular fluctuations and the HF mechanical oscillations in systolic blood pressure (SBP), respectively. This method was validated by data from eight healthy subjects (23-47 yr old, 6 male, 2 female) during a graded tilt (15°increments every 5 min to a 60°angle). The LF component of SBP (LFSBP) had a strong baroreflex-mediated feedback correlation with LFspike rate (r ϭ Ϫ0.69 Ϯ 0.05) and also a strong feedforward relation to LFspike rate [r ϭ 0.58 Ϯ 0.03 with LFSBP delay () ϭ 5.625 Ϯ 0.15 s]. The HF components of spike rate (HFspike rate) and SBP (HFSBP) were not significantly correlated. Conversely, HFResp and HFSBP were highly correlated (r ϭ Ϫ0.79 Ϯ 0.04), whereas LFResp and LFSBP were significantly less correlated (r ϭ 0.45 Ϯ 0.08). The mean correlation coefficients between the measured and model-predicted LFSBP (r ϭ 0.74 Ϯ 0.03) in the supine position did not change significantly during tilt. The mean correlation between the measured and model-predicted HFSBP was 0.89 Ϯ 0.02 in the supine position. R 2 values for the regression analysis of the model-predicted and measured LF and HF powers indicate that 78 and 91% of the variability in power can be explained by the linear relation of LFspike rate to LFSBP and HFResp to HFSBP. We report a simple two-component model using neural sympathetic and mechanical respiratory inputs that can explain the majority of blood pressure fluctuation at rest and during orthostatic stress in healthy subjects. wavelet transform; blood pressure variability; Mayer waves; respiration; muscle sympathetic nerve activity VARIOUS RHYTHMIC OSCILLATIONS in human blood pressure (BP) have been proposed to reflect the action of different physiological mechanisms on BP regulation. For instance, it has been suggested that very low-frequency (VLF) trends (period Ͼ25 s, frequency Ͻ0.04 Hz) in BP represent the influence of hormonal regulation and thermoregulation and that high-frequency (HF, 0.15-0.4 Hz) fluctuations mark the effect of respiration on BP. A more hotly debated issue is the idea that low-frequency (LF, 0.04 -0.14 Hz) BP oscillations with a 10-s periodicity, generally referred to as Mayer waves, reflect sympathetically mediated vasomotor BP modulation. It has been proposed that the origin of these waves is a resonance phenomenon of the baroreflex pathway (12), and the LF power has been used as a marker of sympathetic activity (34,35,37), although this practice remains controversial (31, 48).Several lines of indirect evidence have been used to associate the oscillations in BP with oscillations in these other physiological rhythms. For example, physiological maneuvers have identified changes in the oscillatory patterns of sympathetic nerve activity and respiration that correspond to those in BP ...

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Six-month cardiovascular changes in cyclosporine-treated recipients of corneal grafts: serial baroreflex responses

et al. 2004

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Loss of autonomic cardiovascular homoeostasis is often suspected in hypertension that has developed after organ transplantation. We serially assessed autonomic cardiovascular control in eight patients in generally good condition who needed cyclosporine (CyA) treatment because of high risk of rejection in corneal transplantation. To this aim, we investigated the patients, before and while they were receiving CyA, for 1 week and at 1, 3 and 6 months. For each period, spontaneous baroreflex, blood pressure, heart rate and variability were assessed, as well as neuro-hormonal indicators, while the patients were in both supine and 60 degrees upright positions. After 1 week of treatment, patients showed increases in systolic, diastolic and pulse blood pressures (P<0.05) that were concomitant with a transient decrease in plasma noradrenaline (P<0.05), which, thereafter, resumed the range of baseline values for 6 months. After patients had received CyA treatment for 1 month, the total power of systolic blood pressure variability and its low-frequency component remained higher than before treatment (P<0.05). At 3 and 6 months, heart rate was decreased (P<0.001) when high-frequency power of RR variability and plasma atrial natriuretic peptide were increased (P<0.05). As plasma noradrenaline never exceeded the baseline range, the hypertensive effect of CyA was not likely to have resulted from sympathetic activation. Rather, the increase in systolic blood pressure variability, its low-frequency component and the pattern of pulse pressure changes, pointed to a direct vascular effect of CyA. The maintenance of a normal cardiac baroreflex function during 6 months of CyA treatment might be pivotal to the adaptive responses towards direct CyA effects.

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Graded vascular autonomic control versus discontinuous cardiac control during gradual upright tilt

Cited by 24 publications

References 25 publications

CODESNA_HRV, a new tool to assess the activity of the autonomic nervous system from heart rate variability

CODESNA_HRV, a new tool to assess the activity of the autonomic nervous system from heart rate variability

A simplified two-component model of blood pressure fluctuation

Six-month cardiovascular changes in cyclosporine-treated recipients of corneal grafts: serial baroreflex responses

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