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Heart rate variability and baroreflex sensitivity abnormalities in Guillain-Barré syndrome: a pilot study

Tan CY, Shahrizaila N, Yeoh KY, Goh KJ, Tan MP

Clin Auton Res, 2019 06;29(3):339-348.
PMID: 29654380 DOI: 10.1007/s10286-018-0525-z

OBJECTIVE: The current study aimed to investigate autonomic dysfunction in Guillain-Barré syndrome (GBS) patients and describe the results of computational heart rate variability (HRV)/baroreflex sensitivity (BRS) and autonomic challenge tests.
METHODS: GBS patients were consecutively recruited and the results were compared to age- and gender-matched healthy controls. A series of autonomic function tests including computation-dependent tests (power spectrum analysis of HRV and BRS at rest) and challenge maneuvers (deep breathing, eyeball compression, active standing, the Valsalva maneuver, sustained handgrip, and the cold pressor test) were performed.
RESULTS: Ten GBS patients (six men; mean age = 40.1 ± 13.9 years) and ten gender- and age-matched healthy controls were recruited. The mean GBS functional grading scale at disease plateau was 3.4 ± 1.0. No patients required intensive care unit admission or mechanical ventilation. Low-frequency HRV (p = 0.027), high-frequency HRV (p = 0.008), and the total power spectral density of HRV (p = 0.015) were significantly reduced in patients compared to controls. The mean up slope (p = 0.034), down slope (p = 0.011), and total slope (p = 0.024) BRS were significantly lower in GBS patients. The diastolic rise in blood pressure in the cold pressor test was significantly lower in GBS patients compared to controls (p = 0.008).
INTERPRETATION: Computation-dependent tests (HRV and BRS) were more useful for detecting autonomic dysfunction in GBS patients, whereas the cold pressor test was the only reliable challenge test, making it useful as a bedside measure of autonomic function in GBS patients.

Matched MeSH terms: Baroreflex/physiology*
Fulltext Comparison of high-fat style diet-induced dysregulation of baroreflex control of renal sympathetic nerve activity in intact and ovariectomized female rats: Renal sympathetic nerve activity in high-fat style diet fed intact and ovariectomized female rats

Sucedaram Y, Johns EJ, Husain R, Sattar MA, Abdulla M, Khalilpourfarshbafi M, et al.

Exp Biol Med (Maywood), 2020 05;245(9):761-776.
PMID: 32212858 DOI: 10.1177/1535370220915673

IMPACT STATEMENT: Over activation of renal sensory nerve in obesity blunts the normal regulation of renal sympathetic nerve activity. To date, there is no investigation that has been carried out on baroreflex regulation of renal sympathetic nerve activity in obese ovarian hormones deprived rat model, and the effect of renal denervation on the baroreflex regulation of renal sympathetic nerve activity. Thus, we investigated the role of renal innervation on baroreflex regulation of renal sympathetic nerve activity in obese intact and ovariectomized female rats. Our data demonstrated that in obese states, the impaired baroreflex control is indistinguishable between ovarian hormones deprived and non-deprived states. This study will be of substantial interest to researchers working on the impact of diet-induced hypertension in pre- and postmenopausal women. This study provides insight into health risks amongst obese women regardless of their ovarian hormonal status and may be integrated in preventive health strategies.

Matched MeSH terms: Baroreflex/physiology*
Renal denervation restores the baroreflex control of renal sympathetic nerve activity and heart rate in Wistar-Kyoto rats with cisplatin-induced renal failure

Khan SA, Sattar MA, Rathore HA, Abdulla MH, Ud Din Ahmad F, Ahmad A, et al.

Acta Physiol (Oxf), 2014 Mar;210(3):690-700.
PMID: 24438102 DOI: 10.1111/apha.12237

There is evidence that in chronic renal failure, the sympathetic nervous system is activated. This study investigated the role of the renal innervation in suppressing high- and low-pressure baroreflex control of renal sympathetic nerve activity and heart rate in cisplatin-induced renal failure.

Matched MeSH terms: Baroreflex/physiology*
Fulltext A cardiovascular mathematical model of graded head-up tilt

Lim E, Chan GS, Dokos S, Ng SC, Latif LA, Vandenberghe S, et al.

PLoS One, 2013;8(10):e77357.
PMID: 24204817 DOI: 10.1371/journal.pone.0077357

A lumped parameter model of the cardiovascular system has been developed and optimized using experimental data obtained from 13 healthy subjects during graded head-up tilt (HUT) from the supine position to [Formula: see text]. The model includes descriptions of the left and right heart, direct ventricular interaction through the septum and pericardium, the systemic and pulmonary circulations, nonlinear pressure volume relationship of the lower body compartment, arterial and cardiopulmonary baroreceptors, as well as autoregulatory mechanisms. A number of important features, including the separate effects of arterial and cardiopulmonary baroreflexes, and autoregulation in the lower body, as well as diastolic ventricular interaction through the pericardium have been included and tested for their significance. Furthermore, the individual effect of parameter associated with heart failure, including LV and RV contractility, baseline systemic vascular resistance, pulmonary vascular resistance, total blood volume, LV diastolic stiffness and reflex gain on HUT response have also been investigated. Our fitted model compares favorably with our experimental measurements and published literature at a range of tilt angles, in terms of both global and regional hemodynamic variables. Compared to the normal condition, a simulated congestive heart failure condition produced a blunted response to HUT with regards to the percentage changes in cardiac output, stroke volume, end diastolic volume and effector response (i.e., heart contractility, venous unstressed volume, systemic vascular resistance and heart rate) with progressive tilting.

Matched MeSH terms: Baroreflex/physiology