biostudies-literatureUnknown34(1)Grabov ENational Institute of Neurological Disorders and Stroke<h4>Purpose</h4>Orthostasis increases the variability of continuously recorded blood pressure (BP). Low-frequency (LF) BP oscillations (Mayer waves) in this setting are related to the vascular-sympathetic baroreflex. Mechanisms of increased high-frequency (HF) BP oscillations at the periodicity of respiration during orthostasis have received less research attention. A previously reported patient with post-neurosurgical orthostatic hypotension (OH) and vascular-sympathetic baroreflex failure had large tilt-evoked, breathing-driven BP oscillations, suggesting that such oscillations can occur independently of vascular-sympathetic baroreflex modulation. In the present study we assessed effects of orthostasis on BP variability in the frequency domain in patient cohorts with or without OH.<h4>Methods</h4>Power spectral analysis of systolic BP variability was conducted on recordings from 73 research participants, 42 with neurogenic OH [13 pure autonomic failure, 14 Parkinson's disease (PD) with OH, 12 parkinsonian multiple system atrophy, and 3 status post-brainstem neurosurgery] and 31 without OH (control group of 16 healthy volunteers and 15 patients with PD lacking OH), before, during, and after 5' of head-up tilt at 90 degrees from horizontal. The data were log transformed for statistical testing.<h4>Results</h4>Across all subjects, head-up tilting increased HF power of systolic BP variability (p = 0.001), without a difference between the neurogenic OH and control groups. LF power during orthostasis was higher in the control than in the OH groups (p = 0.009).<h4>Conclusions</h4>The results of this observational cohort study confirm those based on our case report and lead us to propose that even in the setting of vascular-sympathetic baroreflex failure orthostasis increases HF power of BP variability.Clinical autonomic research : official journal of the Clinical Autonomic Research Society125-135https://www.ebi.ac.uk/biostudies/studies/S-EPMC10944440biostudies-literatureTilt-evoked, breathing-driven blood pressure oscillations: Independence from baroreflex-sympathoneural function.PMC10944440Grabov ESullivan PGoldstein DSWang SfalseTilt-evoked, breathing-driven blood pressure oscillations: Independence from baroreflex-sympathoneural function.<h4>Purpose</h4>Orthostasis increases the variability of continuously recorded blood pressure (BP). Low-frequency (LF) BP oscillations (Mayer waves) in this setting are related to the vascular-sympathetic baroreflex. Mechanisms of increased high-frequency (HF) BP oscillations at the periodicity of respiration during orthostasis have received less research attention. A previously reported patient with post-neurosurgical orthostatic hypotension (OH) and vascular-sympathetic baroreflex failure had large tilt-evoked, breathing-driven BP oscillations, suggesting that such oscillations can occur independently of vascular-sympathetic baroreflex modulation. In the present study we assessed effects of orthostasis on BP variability in the frequency domain in patient cohorts with or without OH.<h4>Methods</h4>Power spectral analysis of systolic BP variability was conducted on recordings from 73 research participants, 42 with neurogenic OH [13 pure autonomic failure, 14 Parkinson's disease (PD) with OH, 12 parkinsonian multiple system atrophy, and 3 status post-brainstem neurosurgery] and 31 without OH (control group of 16 healthy volunteers and 15 patients with PD lacking OH), before, during, and after 5' of head-up tilt at 90 degrees from horizontal. The data were log transformed for statistical testing.<h4>Results</h4>Across all subjects, head-up tilting increased HF power of systolic BP variability (p = 0.001), without a difference between the neurogenic OH and control groups. LF power during orthostasis was higher in the control than in the OH groups (p = 0.009).<h4>Conclusions</h4>The results of this observational cohort study confirm those based on our case report and lead us to propose that even in the setting of vascular-sympathetic baroreflex failure orthostasis increases HF power of BP variability.2024-01-01T00:00:00Z2024 Feb2025-04-04T20:18:16.321Z2025-04-04T20:18:16.321ZS-EPMC109444403844636210.1007/s10286-024-01022-7