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Cerebral Oximetry in Syncope and Syndromes of Orthostatic Intolerance
Cerebral autoregulation is crucial for maintaining cerebral blood flow and perfusion. In recent years, the importance of cerebral oxygenation in syncope and orthostatic intolerance (OI) has received increased attention. Cerebral tissue oxygenation can be measured by using near-infrared spectroscopy...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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Frontiers Media S.A.
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6886369/ https://www.ncbi.nlm.nih.gov/pubmed/31824964 http://dx.doi.org/10.3389/fcvm.2019.00171 |
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author | Kharraziha, Isabella Holm, Hannes Bachus, Erasmus Ricci, Fabrizio Sutton, Richard Fedorowski, Artur Hamrefors, Viktor |
author_facet | Kharraziha, Isabella Holm, Hannes Bachus, Erasmus Ricci, Fabrizio Sutton, Richard Fedorowski, Artur Hamrefors, Viktor |
author_sort | Kharraziha, Isabella |
collection | PubMed |
description | Cerebral autoregulation is crucial for maintaining cerebral blood flow and perfusion. In recent years, the importance of cerebral oxygenation in syncope and orthostatic intolerance (OI) has received increased attention. Cerebral tissue oxygenation can be measured by using near-infrared spectroscopy (NIRS), which determines the ratio of oxygenated hemoglobin to total hemoglobin in cerebral tissue. NIRS is non-invasive technology using near-infrared light, which displays real-time cerebral tissue oxygenation. Normal values of cerebral tissue oxygenation in healthy subjects are 60 to 80%. Head-up tilt test (HUT) offers the opportunity to observe the haemodynamic changes precipitating syncope and is, today, the standard method for the evaluation of syncope and orthostatic intolerance syndromes. In previous studies where NIRS was applied during HUT, a significant decrease in cerebral tissue oxygenation both prior to and during loss-of-consciousness in vasovagal syncope (VVS) has been observed. Interestingly, cerebral tissue oxygenation appears to decrease even before haemodynamic changes can be observed. Apart from VVS, cerebral tissue oxygenation decreases during orthostatic provocation in patients with orthostatic hypotension (OH) and postural orthostatic tachycardia syndrome (POTS), in the latter even in the absence of hypotension. Importantly, decline of cerebral tissue oxygenation in VVS and POTS during HUT may not correlate with hemodynamic changes. In this mini review, we summarize the current knowledge of the application of cerebral oximetry in syncope and orthostatic intolerance syndromes, discuss its likely value as a clinical diagnostic tool and also emphasize its potential in the understanding of the relevant pathophysiology. |
format | Online Article Text |
id | pubmed-6886369 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | Frontiers Media S.A. |
record_format | MEDLINE/PubMed |
spelling | pubmed-68863692019-12-10 Cerebral Oximetry in Syncope and Syndromes of Orthostatic Intolerance Kharraziha, Isabella Holm, Hannes Bachus, Erasmus Ricci, Fabrizio Sutton, Richard Fedorowski, Artur Hamrefors, Viktor Front Cardiovasc Med Cardiovascular Medicine Cerebral autoregulation is crucial for maintaining cerebral blood flow and perfusion. In recent years, the importance of cerebral oxygenation in syncope and orthostatic intolerance (OI) has received increased attention. Cerebral tissue oxygenation can be measured by using near-infrared spectroscopy (NIRS), which determines the ratio of oxygenated hemoglobin to total hemoglobin in cerebral tissue. NIRS is non-invasive technology using near-infrared light, which displays real-time cerebral tissue oxygenation. Normal values of cerebral tissue oxygenation in healthy subjects are 60 to 80%. Head-up tilt test (HUT) offers the opportunity to observe the haemodynamic changes precipitating syncope and is, today, the standard method for the evaluation of syncope and orthostatic intolerance syndromes. In previous studies where NIRS was applied during HUT, a significant decrease in cerebral tissue oxygenation both prior to and during loss-of-consciousness in vasovagal syncope (VVS) has been observed. Interestingly, cerebral tissue oxygenation appears to decrease even before haemodynamic changes can be observed. Apart from VVS, cerebral tissue oxygenation decreases during orthostatic provocation in patients with orthostatic hypotension (OH) and postural orthostatic tachycardia syndrome (POTS), in the latter even in the absence of hypotension. Importantly, decline of cerebral tissue oxygenation in VVS and POTS during HUT may not correlate with hemodynamic changes. In this mini review, we summarize the current knowledge of the application of cerebral oximetry in syncope and orthostatic intolerance syndromes, discuss its likely value as a clinical diagnostic tool and also emphasize its potential in the understanding of the relevant pathophysiology. Frontiers Media S.A. 2019-11-22 /pmc/articles/PMC6886369/ /pubmed/31824964 http://dx.doi.org/10.3389/fcvm.2019.00171 Text en Copyright © 2019 Kharraziha, Holm, Bachus, Ricci, Sutton, Fedorowski and Hamrefors. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. |
spellingShingle | Cardiovascular Medicine Kharraziha, Isabella Holm, Hannes Bachus, Erasmus Ricci, Fabrizio Sutton, Richard Fedorowski, Artur Hamrefors, Viktor Cerebral Oximetry in Syncope and Syndromes of Orthostatic Intolerance |
title | Cerebral Oximetry in Syncope and Syndromes of Orthostatic Intolerance |
title_full | Cerebral Oximetry in Syncope and Syndromes of Orthostatic Intolerance |
title_fullStr | Cerebral Oximetry in Syncope and Syndromes of Orthostatic Intolerance |
title_full_unstemmed | Cerebral Oximetry in Syncope and Syndromes of Orthostatic Intolerance |
title_short | Cerebral Oximetry in Syncope and Syndromes of Orthostatic Intolerance |
title_sort | cerebral oximetry in syncope and syndromes of orthostatic intolerance |
topic | Cardiovascular Medicine |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6886369/ https://www.ncbi.nlm.nih.gov/pubmed/31824964 http://dx.doi.org/10.3389/fcvm.2019.00171 |
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