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Miki K, Ikegame S, Yoshimoto M. Regional Differences in Sympathetic Nerve Activity Are Generated by Multiple Arterial Baroreflex Loops Arranged in Parallel. Front Physiol 2022; 13:858654. [PMID: 35444564 PMCID: PMC9014290 DOI: 10.3389/fphys.2022.858654] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 03/15/2022] [Indexed: 11/13/2022] Open
Abstract
In this review, by evaluating the responses during freezing, rapid eye movement (REM) sleep, and treadmill exercise, we discuss how multiple baroreflex loops arranged in parallel act on different organs to modulate sympathetic nerve activity (SNA) in a region-specific and coordinated manner throughout the body. During freezing behaviors, arterial pressure (AP) remains unchanged, heart rate (HR) persistently decreases, renal SNA (RSNA) increases, and lumbar SNA (LSNA) remains unchanged. The baroreflex curve for RSNA shifts upward; that for LSNA remains unchanged; and that for HR shifts to the left. These region-specific changes in baroreflex curves are responsible for the region-specific changes in RSNA, LSNA, and HR during freezing. The decreased HR could allow the heart to conserve energy, which is offset by the increased RSNA caused by decreased vascular conductance, resulting in an unchanged AP. In contrast, the unchanged LSNA leaves the muscles in readiness for fight or flight. During REM sleep, AP increases, RSNA and HR decrease, while LSNA is elevated. The baroreflex curve for RSNA during REM sleep is vertically compressed in comparison with that during non-REM sleep. Cerebral blood flow is elevated while cardiac output is decreased during REM sleep. To address this situation, the brain activates the LSNA selectively, causing muscle vasoconstriction, which overcomes vasodilation of the kidneys as a result of the decreased RSNA and cardiac output. Accordingly, AP can be maintained during REM sleep. During treadmill exercise, AP, HR, and RSNA increase simultaneously. The baroreflex curve for RSNA shifts right-upward with the increased feedback gain, allowing maintenance of a stable AP with significant fluctuations in the vascular conductance of working muscles. Thus, the central nervous system may employ behavior-specific scenarios for modulating baroreflex loops for differential control of SNA, changing the SNA in a region-specific and coordinated manner, and then optimizing circulatory regulation corresponding to different behaviors.
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Affiliation(s)
- Kenju Miki
- Autonomic Physiology Laboratory, Faculty of Life Science and Human Technology, Nara Women's University, Kita-Uoya Nishimachi, Nara, Japan
| | - Shizuka Ikegame
- Autonomic Physiology Laboratory, Faculty of Life Science and Human Technology, Nara Women's University, Kita-Uoya Nishimachi, Nara, Japan
| | - Misa Yoshimoto
- Autonomic Physiology Laboratory, Faculty of Life Science and Human Technology, Nara Women's University, Kita-Uoya Nishimachi, Nara, Japan
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Xu L, Cao X, Wang R, Duan Y, Yang Y, Hou J, Wang J, Chen B, Xue X, Zhang B, Ma H, Sun C, Guo F. Clinical Features of Patients Undergoing the Head-Up Tilt Test and Its Safety and Efficacy in Diagnosing Vasovagal Syncope in 4,873 Patients. Front Cardiovasc Med 2022; 8:781157. [PMID: 35097001 PMCID: PMC8790085 DOI: 10.3389/fcvm.2021.781157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 12/20/2021] [Indexed: 11/17/2022] Open
Abstract
Background: The head-up tilt test (HUTT) is a useful diagnostic tool in patients with suspected vasovagal syncope (VVS). Objectives: We aimed to investigate the direct drug-potentiated HUTT in patients with recurrent syncope or precursor syncope and to assess the diagnostic value of the direct drug-potentiated HUTT. Methods: The medical history and direct drug-potentiated HUTT records of patients who complained of syncope or precursor syncope and who visited The Xianyang Central Hospital from January 2016 to December 2020 were retrospectively reviewed. Results: A total of 4,873 patients (age = 43.8 ± 17.6 years; male = 2,064 [42.4%]) were enrolled in our study. Overall, 2,343 (48.1%) showed positive responses as follows: 1,260 (25.9%) with the mixed type, 34 (0.7%) with the cardioinhibitory type, 580 (11.9%) with the vasodepressor type, 179 (3.7%) with postural tachycardia syndrome (POTS), and 290 (6.0%) with orthostatic hypotension (OH). The study showed that prior to syncope or near-syncope symptoms, patients first presented an increase in heart rate (HR), followed by decreases in blood pressure (BP) and HR successively. Among the patients in the syncope group, the sensitivity of the HUTT was 65.9%, which was significantly higher than a sensitivity of 44.8% for patients in the non-syncope group (P < 0.01). The sensitivity of the HUTT was higher for females than males in both the syncope group (52.6% in males and 77.9% in females, P < 0.01) and the non-syncope group (36.5% in males and 50.6% in females, P < 0.01). Within the four age groups (<20, 21–40, 41–60, and >60 years old), the sensitivities were 74.7%, 67.7%, 45.6%, and 31.2%, respectively. And all gender, age and symptom (whether suffered from a syncope or not) significantly affected the positive responses of HUTT. There were two adverse events and no deaths during the HUTT in this study. Conclusion: The direct drug-potentiated HUTT is a safe and highly sensitive tool with which to diagnose VVS. Patients with precursor syncope symptoms without syncope should undergo a HUTT, especially young females presenting with weakness and sweating, which can decrease the probability of a misdiagnosis or a missed diagnosis.
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Affiliation(s)
- Lingping Xu
- Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China.,Department of Cardiovascular Medicine, The Xianyang Central Hospital, Xianyang, China
| | - Xiangqi Cao
- Stroke Centre and Department of Neurology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Rui Wang
- Department of Cardiovascular Medicine, The Xianyang Central Hospital, Xianyang, China
| | - Yichao Duan
- Department of Cardiovascular Medicine, The Xianyang Central Hospital, Xianyang, China
| | - Ye Yang
- Department of Cardiovascular Medicine, The Xianyang Central Hospital, Xianyang, China
| | - Junlong Hou
- Department of Cardiovascular Medicine, The Xianyang Central Hospital, Xianyang, China
| | - Jing Wang
- Department of Cardiovascular Medicine, The Xianyang Central Hospital, Xianyang, China
| | - Bin Chen
- Department of Cardiovascular Medicine, The Xianyang Central Hospital, Xianyang, China
| | - Xianjun Xue
- Department of Cardiovascular Medicine, The Xianyang Central Hospital, Xianyang, China
| | - Bo Zhang
- Department of Cardiovascular Medicine, The Xianyang Central Hospital, Xianyang, China
| | - Hua Ma
- Department of Cardiovascular Medicine, The Xianyang Central Hospital, Xianyang, China
| | - Chaofeng Sun
- Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Fengwei Guo
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
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Cardioinhibitory syncope: from pathophysiology to treatment—should we think on cardioneuroablation? J Interv Card Electrophysiol 2020; 59:441-461. [DOI: 10.1007/s10840-020-00758-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 04/23/2020] [Indexed: 02/07/2023]
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Abstract
OBJECTIVE Most of the research on vasovagal reactions has focused on the contributions of cardiovascular activity to the development of symptoms. However, other research suggests that additional mechanisms like hyperventilation may contribute to the process. The goal of the present investigation was to examine the influences of cardiovascular and respiratory variables on vasovagal symptoms. METHODS This study was part of a randomized controlled trial investigating the effects of behavioral techniques on the prevention of vasovagal reactions in blood donors. Data from the no-treatment control group were analyzed. The final sample was composed of 160 college and university students. Observational and self-report measures of symptoms were obtained. Physiological variables were measured mainly using respiratory capnometry. RESULTS Although respiration rate remained stable throughout donation, change in end-tidal carbon dioxide was associated with requiring treatment for a reaction during donation (odds ratio = 0.57, 95% confidence interval [CI] = 0.41 to 0.79, p = .001) and self-reported symptoms measured in the postdonation period using the Blood Donation Reactions Inventory (β = -0.152, 95% CI = -0.28 to -0.02, t = -2.32, p = .022). Individuals with higher levels of predonation anxiety displayed larger decreases in end-tidal carbon dioxide throughout the procedure (F(2,236) = 3.64, p = .043, ηp = 0.030). Blood Donation Reactions Inventory scores were related to changes in systolic (β = -0.022, 95% CI = -0.04 to -0.004, t = -2.39, p = .019) and diastolic blood pressure (β = -0.038, 95% CI = -0.06 to -0.02, t = -4.03, p < .001). CONCLUSIONS Although the vasovagal reaction has traditionally been viewed as a primarily cardiovascular event, the present results suggest that hyperventilation also plays a role in the development of vasovagal symptoms.
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Harrison JM, Gilchrist PT, Corovic TS, Bogetti C, Song Y, Bacon SL, Ditto B. Respiratory and hemodynamic contributions to emotion-related pre-syncopal vasovagal symptoms. Biol Psychol 2017; 127:46-52. [PMID: 28456564 DOI: 10.1016/j.biopsycho.2017.04.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Revised: 04/10/2017] [Accepted: 04/22/2017] [Indexed: 02/05/2023]
Abstract
Vasovagal reactions are conventionally understood as resulting from systemic changes in cardiovascular activity; however, there exists a complementary perspective focused on specific changes in cerebral vasoconstriction associated with hyperventilation-induced hypocapnia. The present study investigated the role of cardiovascular and respiratory activity in self-reported pre-syncopal vasovagal reactions to a surgery video in a sample of 49 healthy women. Participants who indicated more previous real-life episodes of dizziness reported experiencing significantly more symptoms in the laboratory consistent with a vasovagal response. They also showed lower total peripheral resistance and higher pre-ejection period in general, suggesting lower sympathetic nervous system activity. Significant decreases in end-tidal carbon dioxide (PETCO2) occurred during the surgery video among susceptible participants, without significant increases in respiration rate. Further, participants who experienced reductions from the neutral video in PETCO2, systolic blood pressure, or both, reported vasovagal symptoms during the surgery video. The results suggest that patterns of respiration associated with decreases in PETCO2 may contribute to vasovagal symptoms reported in non-clinical groups as well as those with blood-injection-injury phobia and are associated with susceptibility to dizziness.
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Affiliation(s)
- Johanna M Harrison
- Laboratory for Cardiovascular Psychophysiology, Department of Psychology, McGill University, 1205 Ave. Docteur Penfield, Montreal, Quebec, H3A 1B1, Canada.
| | - Philippe T Gilchrist
- Wolfson College, University of Cambridge, Cambridge CB3 9BB, United Kingdom; MRC/BHF Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Strangeways Research Laboratory, 2 Wort's Causeway, Cambridge, CB1 8RN, United Kingdom
| | - Tiana S Corovic
- Laboratory for Cardiovascular Psychophysiology, Department of Psychology, McGill University, 1205 Ave. Docteur Penfield, Montreal, Quebec, H3A 1B1, Canada
| | - Curtis Bogetti
- Laboratory for Cardiovascular Psychophysiology, Department of Psychology, McGill University, 1205 Ave. Docteur Penfield, Montreal, Quebec, H3A 1B1, Canada
| | - Yuqing Song
- Laboratory for Cardiovascular Psychophysiology, Department of Psychology, McGill University, 1205 Ave. Docteur Penfield, Montreal, Quebec, H3A 1B1, Canada
| | - Simon L Bacon
- Department of Exercise Science, Concordia University, 7141 Sherbrooke St. West, Montreal, Quebec, H4 B 1R6, Canada
| | - Blaine Ditto
- Laboratory for Cardiovascular Psychophysiology, Department of Psychology, McGill University, 1205 Ave. Docteur Penfield, Montreal, Quebec, H3A 1B1, Canada
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Chu W, Wang C, Lin P, Li F, Wu L, Xie Z. Transient aphasia: a rare complication of head-up tilt test. Neurol Sci 2014; 35:1127-32. [DOI: 10.1007/s10072-014-1664-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 01/28/2014] [Indexed: 11/30/2022]
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Karbasi-Afshar R, Saburi A, Shahmari A, Khosravi A. Sub-Lingual Spray Versus Pearl of TNG as A Provocative Agent for Tilt Table Test. J Clin Diagn Res 2013; 7:2250-2. [PMID: 24298489 DOI: 10.7860/jcdr/2013/5494.3483] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 08/12/2013] [Indexed: 12/22/2022]
Abstract
OBJECTIVE The aim of this study was to determine the false positive ratio of Tilt Table Test (TTT) result by using TNG spray (Sub-lingual; SL) as compared to TNG pearl in patients referred to military service. MATERIAL AND METHODS This was a prospective study. It was conducted on 110 cases referred for military service, expressed vasovagal symptoms. We divided the subjects into three groups; first Group (60 cases) used TNG pearl for provoking syncope in TTT, Group 2 (50 cases) and Group 3 (control cases) used TNG spray in the same dose (0.4 mg). RESULTS In the first step of tilt study, 10%, and 8% of subjects had fainted on not using provoking drug in cases and controls, respectively. After using the drugs, 36.6%, 96% and 18% showed positive results in pearl, spray and the control groups, respectively (p<0.05). CONCLUSION Rather than pearl group, a 40 minute tilt using TNG spray showed significant higher positive results, which may be incorrectly positive. Using this form of TNG seems not useful for distinguishing and diagnosing vasovagal shocks, especially in subjects referred for military service capacity. For constant evidence, a cross-over clinical trial study is required, involving suspected cases divided into two groups, who both will be examined with spray and pearl.
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Affiliation(s)
- Reza Karbasi-Afshar
- Faculty of Medicine & Cardiovascular Research Center, Department of Cardiovascular Diseases, Baqiyatallah University of Medical Sciences , Tehran, Iran
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Miki K, Yoshimoto M. Reprint of "Sympathetic nerve activity during sleep, exercise, and mental stress". Auton Neurosci 2013; 175:70-5. [DOI: 10.1016/j.autneu.2013.04.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 12/18/2012] [Accepted: 12/26/2012] [Indexed: 10/27/2022]
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Sympathetic nerve activity during sleep, exercise, and mental stress. Auton Neurosci 2013; 174:15-20. [DOI: 10.1016/j.autneu.2012.12.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 12/18/2012] [Accepted: 12/26/2012] [Indexed: 11/18/2022]
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Yoshimoto M, Yoshida I, Miki K. Functional role of diverse changes in sympathetic nerve activity in regulating arterial pressure during REM sleep. Sleep 2011; 34:1093-101. [PMID: 21804671 DOI: 10.5665/sleep.1168] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES This study aimed to investigate whether REM sleep evoked diverse changes in sympathetic outflows and, if so, to elucidate why REM sleep evokes diverse changes in sympathetic outflows. MEASUREMENTS Male Wistar rats were chronically implanted with electrodes to measure renal (RSNA) and lumbar sympathetic nerve activity (LSNA), electroencephalogram, electromyogram, and electrocardiogram, and catheters to measure systemic arterial and central venous pressure; these parameters were measured simultaneously and continuously during the sleep-awake cycle in the same rat. RESULTS REM sleep resulted in a step reduction in RNSA by 36.1% ± 2.7% (P < 0.05), while LSNA increased in a step manner by 15.3% ± 2% (P < 0.05) relative to the NREM level. Systemic arterial pressure increased gradually (P < 0.05), while heart rate decreased in a step manner (P < 0.05) during REM sleep. In contrast to REM sleep, RSNA, LSNA, systemic arterial pressure, and heart rate increased in a unidirectional manner associated with increases in physical activity levels in the order from NREM sleep, quiet awake, moving, and grooming state. Thus, the relationship between RSNA vs. LSNA and systemic arterial pressure vs. heart rate observed during REM sleep was dissociated compared with that obtained during the other behavioral states. CONCLUSIONS It is suggested that the diverse changes in sympathetic outflows during REM sleep may be needed to increase systemic arterial pressure by balancing vascular resistance between muscles and vegetative organs without depending on the heart.
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Affiliation(s)
- Misa Yoshimoto
- Department of Environmental Health, Life Science and Human Technology, Nara Women's University, Kita-Uoya Nishimachi, Nara, Japan.
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Malignant Neurally-Mediated Syncope: Pathophysiology and Treatment. Am J Med Sci 2009; 337:476-9. [DOI: 10.1097/maj.0b013e3181a40a5b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Panerai RB. Transcranial Doppler for evaluation of cerebral autoregulation. Clin Auton Res 2009; 19:197-211. [PMID: 19370374 DOI: 10.1007/s10286-009-0011-8] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2008] [Accepted: 03/13/2009] [Indexed: 12/14/2022]
Abstract
Transcranial Doppler ultrasound (TCD) can measure cerebral blood flow velocity in the main intracranial vessels non-invasively and with high accuracy. Combined with the availability of non-invasive devices for continuous measurement of arterial blood pressure, the relatively low cost, ease-of-use, and excellent temporal resolution of TCD have stimulated the development of new techniques to assess cerebral autoregulation in the laboratory or bedside using a dynamic approach, instead of the more classical 'static' method. Clinical applications have shown consistent results in certain conditions such as severe head injury and carotid artery disease. Studies in syncopal patients revealed a more complex pattern due to aetiological non-homogeneity and methodological limitations mainly due to inadequate sample-size. Different analytical models to quantify autoregulatory performance have also contributed to the diversity of results in the literature. The review concludes with specific recommendations for areas where further validation and research are needed to improve the reliability and usefulness of TCD in clinical practice.
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Affiliation(s)
- Ronney B Panerai
- Medical Physics Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, UK.
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Postural tachycardia syndrome and reflex syncope: similarities and differences. J Pediatr 2009; 154:481-5. [PMID: 19324216 PMCID: PMC3810291 DOI: 10.1016/j.jpeds.2009.01.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Revised: 12/02/2008] [Accepted: 01/06/2009] [Indexed: 11/24/2022]
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Sorond FA, Serrador JM, Jones RN, Shaffer ML, Lipsitz LA. The sit-to-stand technique for the measurement of dynamic cerebral autoregulation. ULTRASOUND IN MEDICINE & BIOLOGY 2009; 35:21-9. [PMID: 18834658 PMCID: PMC2680703 DOI: 10.1016/j.ultrasmedbio.2008.08.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2008] [Revised: 07/16/2008] [Accepted: 08/01/2008] [Indexed: 05/08/2023]
Abstract
Measurement of cerebral autoregulation is important for the evaluation and management of a number of clinical disorders that affect cerebral blood flow. We currently lack simple bedside measures that mimic common physiologic stresses. Therefore, we evaluated a new sit-to-stand technique as an alternative method to the frequently-used thigh-cuff technique in healthy volunteers. Continuous middle cerebral artery (MCA) blood flow velocities (BFV) and arterial blood pressure (ABP) were measured in response to standing from a sitting position, or rapid thigh-cuff deflation in 24 healthy subjects (50 +/- 22 y). Autoregulatory index (ARI) was calculated as the BFV response for step changes in ABP using a second-order differential equation with a set of parameters that can be used to grade the performance of autoregulation. Of these 24 subjects, 30% could tolerate only two thigh-cuffs and refused to proceed with the third cuff, whereas none of our subjects had any difficulty with performing the three sit-to-stand trials. The two techniques produced similar changes in mean ABP, but the times to nadir of the blood pressure and BFV were significantly faster for the thigh-cuff. The mean group ARIs were similar between the two techniques. Although between-subjects variability was higher for sit-to-stand ARIs, the within-subject sit-to-stand ARI variability was small. Thus, for the assessment of cerebral autoregulation, the sit-to-stand procedure is well tolerated and produces ARI values that have low within-subject variability. The sit-to-stand technique appears to be a suitable measure of individual ARI values for inferring dynamic cerebral autoregulation.
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Affiliation(s)
- Farzaneh A Sorond
- Department of Neurology, Stroke Division, Brigham and Women's Hospital, Boston, MA 02115, USA.
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Abstract
Whatever the pathogenesis of syncope is, the ultimate common cause leading to loss of consciousness is insufficient cerebral perfusion with a critical reduction of blood flow to the reticular activating system. Brain circulation has an autoregulation system that keeps cerebral blood flow constant over a wide range of systemic blood pressures. Normally, if blood pressure decreases, autoregulation reacts with a reduction in cerebral vascular resistance, in an attempt to prevent cerebral hypoperfusion. However, in some cases, particularly in neurally mediated syncope, it can also be harmful, being actively implicated in a paradox reflex that induces an increase in cerebrovascular resistance and contributes to the critical reduction of cerebral blood flow. This review outlines the anatomic structures involved in cerebral autoregulation, its mechanisms, in normal and pathologic conditions, and the noninvasive neuroimaging techniques used in the study of cerebral circulation and autoregulation. An emphasis is placed on the description of autoregulation pathophysiology in orthostatic and neurally mediated syncope.
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