740-2 The Impact of Heart Rate on Cerebral Blood Flow in Patients with Chronic Fatigue, Dizziness and Episodic Weakness After Implantation of Permanent Pacing Devices

Introduction: In a large study with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) patients, we showed that 86% had symptoms of orthostatic intolerance in daily life and that 90% had an abnormal reduction in cerebral blood flow (CBF) during a standard tilt test. A standard head-up tilt test might not be tolerated by the most severely affected bed-ridden ME/CFS patients. Sitting upright is a milder orthostatic stress. The present study examined whether a sitting test, measuring cerebral blood flow by extracranial Doppler, would be sufficient to provoke abnormal reductions in cerebral blood flow in severe ME/CFS patients. Methods and results: 100 severe ME/CFS patients were studied, (88 females) and were compared with 15 healthy controls (HC) (13 females). CBF was measured first while seated for at least one hour, followed by a CBF measurement in the supine position. Fibromyalgia was present in 37 patients. Demographic data as well as supine heart rate and blood pressures were not different between ME/CFS patients and HC. Heart rate and blood pressure did not change significantly between supine and sitting both in patients and HC. Supine CBF was not different between patients and HC. In contrast, absolute CBF during sitting was lower in patients compared to HC: 474 (96) mL/min in patients and 627 (89) mL/min in HC; p < 0.0001. As a result, percent CBF reduction while seated was −24.5 (9.4)% in severe ME/CFS patients and −0.4 (1.2)% in HC (p < 0.0001). In the ten patients who had no orthostatic intolerance complaints in daily life, the CBF reduction was −2.7 (2.1)%, which was not significantly different from HC (p = 0.58). The remaining 90 patients with orthostatic intolerance complaints had a −26.9 (6.2)% CBF reduction. No difference in CBF parameters was found in patients with and without fibromyalgia. Patients with a previous diagnosis of postural orthostatic tachycardia syndrome (POTS) had a significantly larger CBF reduction compared with those without POTS: 28.8 (7.2)% vs. 22.3 (9.7)% (p = 0.0008). Conclusions: A sitting test in severe ME/CFS patients was sufficient to provoke a clinically and statistically significant mean CBF decline of 24.5%. Patients with a previous diagnosis of POTS had a larger CBF reduction while seated, compared to patients without POTS. The magnitude of these CBF reductions is similar to the results in less severely affected ME/CFS patients during head-up tilt, suggesting that a sitting test is adequate for the diagnosis of orthostatic intolerance in severely affected patients.

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Cerebral blood flow and heart rate variability predict fatigue severity in patients with chronic fatigue syndrome

Brain Imaging and Behavior ◽

10.1007/s11682-018-9897-x ◽

2018 ◽

Vol 13 (3) ◽

pp. 789-797 ◽

Cited By ~ 9

Author(s):

Jeff Boissoneault ◽

Janelle Letzen ◽

Michael Robinson ◽

Roland Staud

Keyword(s):

Heart Rate ◽

Blood Flow ◽

Heart Rate Variability ◽

Cerebral Blood Flow ◽

Chronic Fatigue Syndrome ◽

Chronic Fatigue ◽

Fatigue Syndrome ◽

Fatigue Severity

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The Impact of Sevoflurane and Propofol Anesthesia on Cerebral Blood Flow in Pediatric Open Cardiac Surgery, a Comparative Randomized Study

Anaesthesia & Critical Care Medicine Journal ◽

10.23880/accmj-16000165 ◽

2019 ◽

Vol 4 (4) ◽

Author(s):

Hani I Taman

Keyword(s):

Blood Flow ◽

Cardiac Surgery ◽

Cerebral Blood Flow ◽

Randomized Study ◽

The Impact

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The preponderance of initial orthostatic hypotension in postural tachycardia syndrome

Journal of Applied Physiology ◽

10.1152/japplphysiol.00540.2020 ◽

2020 ◽

Vol 129 (3) ◽

pp. 459-466

Author(s):

Julian M. Stewart ◽

Archana Kota ◽

Mary Breige O’Donnell-Smith ◽

Paul Visintainer ◽

Courtney Terilli ◽

...

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Blood Flow ◽

Heart Rate Variability ◽

Cerebral Blood Flow ◽

Orthostatic Hypotension ◽

Pressure Recovery ◽

Postural Tachycardia Syndrome ◽

Postural Tachycardia ◽

Initial Orthostatic Hypotension

Significant initial orthostatic hypotension (IOH) occurs in ~50% of postural tachycardia syndrome (POTS) patients and 13% of controls. Heart rate and blood pressure recovery are prolonged in IOH sustaining lightheadedness; IOH is more prevalent and severe in POTS. Altered cerebral blood flow and cardiorespiratory regulation are more prevalent in POTS. Altered heart rate variability and baroreflex gain may cause nearly instantaneous lightheadedness in POTS. IOH alone fails to confer a strong probability of POTS.

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Reduced heart rate variability and lower cerebral blood flow associated with poor cognition during recovery following concussion

Autonomic Neuroscience ◽

10.1016/j.autneu.2019.04.004 ◽

2019 ◽

Vol 220 ◽

pp. 102548 ◽

Cited By ~ 6

Author(s):

Sushmita Purkayastha ◽

Benjamin Williams ◽

Megan Murphy ◽

Sydney Lyng ◽

Tonia Sabo ◽

...

Keyword(s):

Heart Rate ◽

Blood Flow ◽

Heart Rate Variability ◽

Cerebral Blood Flow ◽

Poor Cognition

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Hyperlipidemia Disrupts Cerebrovascular Reflexes and Worsens Ischemic Perfusion Defect

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.2013.38 ◽

2013 ◽

Vol 33 (6) ◽

pp. 954-962 ◽

Cited By ~ 26

Author(s):

Cenk Ayata ◽

Hwa Kyoung Shin ◽

Ergin Dileköz ◽

Dmitriy N Atochin ◽

Satoshi Kashiwagi ◽

...

Keyword(s):

Blood Flow ◽

Cerebral Blood Flow ◽

Apolipoprotein E ◽

Knockout Mice ◽

Perfusion Defect ◽

Laser Speckle ◽

Wild Type ◽

Apolipoprotein E Knockout Mice ◽

The Impact ◽

Cerebrovascular Reflexes

Hyperlipidemia is a highly prevalent risk factor for coronary and cervical atherosclerosis and stroke. However, even in the absence of overt atherosclerosis, hyperlipidemia disrupts endothelial and smooth muscle function. We investigated the impact of hyperlipidemia on resting-brain perfusion, fundamental cerebrovascular reflexes, and dynamic perfusion defect during acute focal ischemia in hyperlipidemic apolipoprotein E knockout mice before the development of flow-limiting atherosclerotic stenoses. Despite elevated blood pressures, absolute resting cerebral blood flow was reduced by 20% in apolipoprotein E knockout compared with wild type when measured by [14C]-iodoamphetamine technique. Noninvasive, high spatiotemporal resolution laser speckle flow imaging revealed that the lower autoregulatory limit was elevated in apolipoprotein E knockout mice (60 vs. 40 mm Hg), and cortical hyperemic responses to hypercapnia and functional activation were attenuated by 30% and 64%, respectively. Distal middle cerebral artery occlusion caused significantly larger perfusion defects and infarct volumes in apolipoprotein E knockout compared with wild type. Cerebrovascular dysfunction showed a direct relationship to the duration of high-fat diet. These data suggest that hyperlipidemia disrupts cerebral blood flow regulation and diminishes collateral perfusion in acute stroke in the absence of hemodynamically significant atherosclerosis.

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Adrenoceptor blockade modifies regional cerebral blood flow responses to hyperbaric hyperoxia: protection against CNS oxygen toxicity

Journal of Applied Physiology ◽

10.1152/japplphysiol.00540.2018 ◽

2018 ◽

Vol 125 (4) ◽

pp. 1296-1304 ◽

Cited By ~ 4

Author(s):

Heath G. Gasier ◽

Ivan T. Demchenko ◽

Sergei Yu Zhilyaev ◽

Alexander N. Moskvin ◽

Alexander I. Krivchenko ◽

...

Keyword(s):

Heart Rate ◽

Blood Flow ◽

Cerebral Blood Flow ◽

Hyperbaric Oxygen ◽

Phase Ii ◽

Regional Cerebral Blood Flow ◽

Sympathetic Outflow ◽

Regional Cerebral Blood ◽

Epileptiform Discharges ◽

Drug Doses

Exposure to extreme hyperbaric oxygen (HBO2) >5–6 atmospheres absolute (ATA) produces baroreflex impairment, sympathetic hyperactivation, hypertension, tachycardia, and cerebral hyperemia, known as phase II, culminating in seizures. We hypothesized that attenuation of the effects of high sympathetic outflow would preserve regional cerebral blood flow (rCBF) and protect against HBO2-induced seizures. To explore this possibility, we tested four adrenoceptor antagonists in conscious and anesthetized rats exposed to HBO2at 5 and 6 ATA, respectively: phentolamine (nonselective α1and α2), prazosin (selective α1), propranolol (nonselective β1and β2), and atenolol (selective β1). In conscious rats, four drug doses were administered to rats before HBO2exposures, and seizure latencies were recorded. Drug doses that provided similar protection against seizures were administered before HBO2exposures in anesthetized rats to determine the effects of adrenoceptor blockade on mean arterial pressure, heart rate, rCBF, and EEG spikes. All four drugs modified cardiovascular and rCBF responses in HBO2that aligned with epileptiform discharges, but only phentolamine and propranolol effectively increased EEG spike latencies by ~20 and 36 min, respectively. When phentolamine and propranolol were delivered during HBO2at the onset of phase II, only propranolol led to sustained reductions in heart rate and rCBF, preventing the appearance of epileptiform discharges. The enhanced effectiveness of propranolol may extend beyond β-adrenoceptor blockade, i.e., membrane stability and reduced metabolic activity. These results indicate that adrenoceptor drug pretreatment will minimize the effects of excessive sympathetic outflow on rCBF and extend HBO2exposure time.NEW & NOTEWORTHY Blocking adrenergic receptors with phentolamine (nonselective α1and α2), prazosin (selective α1), propranolol (nonselective β1and β2), and atenolol (selective β1) modified cardiovascular and regional cerebral blood flow (rCBF) responses in hyperbaric oxygen (HBO2) at 6 atmospheres absolute (ATA); however, only phentolamine and propranolol extended EEG spike latencies. When these two agents were delivered at the onset of sympathetic hyperactivation, only propranolol reduced heart rate and rCBF throughout the exposure and prevented epileptiform discharges. These data validate the strong role of adrenergic control of cardiovascular function and rCBF in extreme HBO2and the potential use of antiadrenergic drugs to prevent seizures.

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Impact of blood pressure changes in cerebral blood perfusion of patients with ischemic Moyamoya disease evaluated by SPECT

Journal of Cerebral Blood Flow & Metabolism ◽

10.1177/0271678x20967458 ◽

2020 ◽

pp. 0271678X2096745

Author(s):

Zhao Liming ◽

Sun Weiliang ◽

Jia Jia ◽

Liang Hao ◽

Liu Yang ◽

...

Keyword(s):

Blood Pressure ◽

Blood Flow ◽

Cerebral Blood Flow ◽

Mean Arterial Pressure ◽

Arterial Pressure ◽

Moyamoya Disease ◽

Emission Computed Tomography ◽

Study Cohort ◽

Pressure Changes ◽

The Impact

Our aim was to determine the impact of targeted blood pressure modifications on cerebral blood flow in ischemic moyamoya disease patients assessed by single-photon emission computed tomography (SPECT). From March to September 2018, we prospectively collected data of 154 moyamoya disease patients and selected 40 patients with ischemic moyamoya disease. All patients underwent in-hospital blood pressure monitoring to determine the mean arterial pressure baseline values. The study cohort was subdivided into two subgroups: (1) Group A or relative high blood pressure (RHBP) with an induced mean arterial pressure 10–20% higher than baseline and (2) Group B or relative low blood pressure (RLBP) including patients with mean arterial pressure 10–20% lower than baseline. All patients underwent initial SPECT study on admission-day, and on the following day, every subgroup underwent a second SPECT study under their respective targeted blood pressure values. In general, RHBP patients showed an increment in perfusion of 10.13% (SD 2.94%), whereas RLBP patients showed a reduction of perfusion of 12.19% (SD 2.68%). Cerebral blood flow of moyamoya disease patients is susceptible to small blood pressure changes, and cerebral autoregulation might be affected due to short dynamic blood pressure modifications.

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Baroreceptor influence on postural changes in blood pressure and carotid blood flow

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1963.205.2.360 ◽

1963 ◽

Vol 205 (2) ◽

pp. 360-364 ◽

Cited By ~ 18

Author(s):

Francis L. Abel ◽

John H. Pierce ◽

Warren G. Guntheroth

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Blood Flow ◽

Cerebral Blood Flow ◽

Carotid Sinus ◽

Systemic Blood Pressure ◽

Systemic Blood ◽

Carotid Blood Flow ◽

Postural Changes ◽

Nembutal Anesthesia

The effects of 30° head-down and head-up tilting on mean systemic blood pressure, carotid blood flow, and heart rate were studied in 16 dogs under morphine and Nembutal anesthesia. The tilting procedure was further repeated after denervation of the carotid sinus and aortic arch baroreceptors and after administration of a dihydrogenated ergot alkaloid mixture (Hydergine). The results indicate that the drop in pressure in the head-down position is primarily due to baroreceptor activity and that the baroreceptors are necessary for compensatory vasoconstriction on head-up tilting. Carotid blood flow decreased in both tilted positions in the control animals; the possible relationship to cerebral blood flow is discussed.

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