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A Four-Way Comparison of Cardiac Function with Normobaric Normoxia, Normobaric Hypoxia, Hypobaric Hypoxia and Genuine High Altitude
BACKGROUND: There has been considerable debate as to whether different modalities of simulated hypoxia induce similar cardiac responses. MATERIALS AND METHODS: This was a prospective observational study of 14 healthy subjects aged 22–35 years. Echocardiography was performed at rest and at 15 and 120...
Autores principales: | , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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Public Library of Science
2016
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4839767/ https://www.ncbi.nlm.nih.gov/pubmed/27100313 http://dx.doi.org/10.1371/journal.pone.0152868 |
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author | Boos, Christopher John O’Hara, John Paul Mellor, Adrian Hodkinson, Peter David Tsakirides, Costas Reeve, Nicola Gallagher, Liam Green, Nicholas Donald Charles Woods, David Richard |
author_facet | Boos, Christopher John O’Hara, John Paul Mellor, Adrian Hodkinson, Peter David Tsakirides, Costas Reeve, Nicola Gallagher, Liam Green, Nicholas Donald Charles Woods, David Richard |
author_sort | Boos, Christopher John |
collection | PubMed |
description | BACKGROUND: There has been considerable debate as to whether different modalities of simulated hypoxia induce similar cardiac responses. MATERIALS AND METHODS: This was a prospective observational study of 14 healthy subjects aged 22–35 years. Echocardiography was performed at rest and at 15 and 120 minutes following two hours exercise under normobaric normoxia (NN) and under similar PiO(2) following genuine high altitude (GHA) at 3,375m, normobaric hypoxia (NH) and hypobaric hypoxia (HH) to simulate the equivalent hypoxic stimulus to GHA. RESULTS: All 14 subjects completed the experiment at GHA, 11 at NN, 12 under NH, and 6 under HH. The four groups were similar in age, sex and baseline demographics. At baseline rest right ventricular (RV) systolic pressure (RVSP, p = 0.0002), pulmonary vascular resistance (p = 0.0002) and acute mountain sickness (AMS) scores were higher and the SpO(2) lower (p<0.0001) among all three hypoxic groups (GHA, NH and HH) compared with NN. At both 15 minutes and 120 minutes post exercise, AMS scores, Cardiac output, septal S’, lateral S’, tricuspid S’ and A’ velocities and RVSP were higher and SpO(2) lower with all forms of hypoxia compared with NN. On post-test analysis, among the three hypoxia groups, SpO(2) was lower at baseline and 15 minutes post exercise with GHA (89.3±3.4% and 89.3±2.2%) and HH (89.0±3.1 and (89.8±5.0) compared with NH (92.9±1.7 and 93.6±2.5%). The RV Myocardial Performance (Tei) Index and RVSP were significantly higher with HH than NH at 15 and 120 minutes post exercise respectively and tricuspid A’ was higher with GHA compared with NH at 15 minutes post exercise. CONCLUSIONS: GHA, NH and HH produce similar cardiac adaptations over short duration rest despite lower SpO(2) levels with GHA and HH compared with NH. Notable differences emerge following exercise in SpO(2,) RVSP and RV cardiac function. |
format | Online Article Text |
id | pubmed-4839767 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-48397672016-04-29 A Four-Way Comparison of Cardiac Function with Normobaric Normoxia, Normobaric Hypoxia, Hypobaric Hypoxia and Genuine High Altitude Boos, Christopher John O’Hara, John Paul Mellor, Adrian Hodkinson, Peter David Tsakirides, Costas Reeve, Nicola Gallagher, Liam Green, Nicholas Donald Charles Woods, David Richard PLoS One Research Article BACKGROUND: There has been considerable debate as to whether different modalities of simulated hypoxia induce similar cardiac responses. MATERIALS AND METHODS: This was a prospective observational study of 14 healthy subjects aged 22–35 years. Echocardiography was performed at rest and at 15 and 120 minutes following two hours exercise under normobaric normoxia (NN) and under similar PiO(2) following genuine high altitude (GHA) at 3,375m, normobaric hypoxia (NH) and hypobaric hypoxia (HH) to simulate the equivalent hypoxic stimulus to GHA. RESULTS: All 14 subjects completed the experiment at GHA, 11 at NN, 12 under NH, and 6 under HH. The four groups were similar in age, sex and baseline demographics. At baseline rest right ventricular (RV) systolic pressure (RVSP, p = 0.0002), pulmonary vascular resistance (p = 0.0002) and acute mountain sickness (AMS) scores were higher and the SpO(2) lower (p<0.0001) among all three hypoxic groups (GHA, NH and HH) compared with NN. At both 15 minutes and 120 minutes post exercise, AMS scores, Cardiac output, septal S’, lateral S’, tricuspid S’ and A’ velocities and RVSP were higher and SpO(2) lower with all forms of hypoxia compared with NN. On post-test analysis, among the three hypoxia groups, SpO(2) was lower at baseline and 15 minutes post exercise with GHA (89.3±3.4% and 89.3±2.2%) and HH (89.0±3.1 and (89.8±5.0) compared with NH (92.9±1.7 and 93.6±2.5%). The RV Myocardial Performance (Tei) Index and RVSP were significantly higher with HH than NH at 15 and 120 minutes post exercise respectively and tricuspid A’ was higher with GHA compared with NH at 15 minutes post exercise. CONCLUSIONS: GHA, NH and HH produce similar cardiac adaptations over short duration rest despite lower SpO(2) levels with GHA and HH compared with NH. Notable differences emerge following exercise in SpO(2,) RVSP and RV cardiac function. Public Library of Science 2016-04-21 /pmc/articles/PMC4839767/ /pubmed/27100313 http://dx.doi.org/10.1371/journal.pone.0152868 Text en © 2016 Boos et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. |
spellingShingle | Research Article Boos, Christopher John O’Hara, John Paul Mellor, Adrian Hodkinson, Peter David Tsakirides, Costas Reeve, Nicola Gallagher, Liam Green, Nicholas Donald Charles Woods, David Richard A Four-Way Comparison of Cardiac Function with Normobaric Normoxia, Normobaric Hypoxia, Hypobaric Hypoxia and Genuine High Altitude |
title | A Four-Way Comparison of Cardiac Function with Normobaric Normoxia, Normobaric Hypoxia, Hypobaric Hypoxia and Genuine High Altitude |
title_full | A Four-Way Comparison of Cardiac Function with Normobaric Normoxia, Normobaric Hypoxia, Hypobaric Hypoxia and Genuine High Altitude |
title_fullStr | A Four-Way Comparison of Cardiac Function with Normobaric Normoxia, Normobaric Hypoxia, Hypobaric Hypoxia and Genuine High Altitude |
title_full_unstemmed | A Four-Way Comparison of Cardiac Function with Normobaric Normoxia, Normobaric Hypoxia, Hypobaric Hypoxia and Genuine High Altitude |
title_short | A Four-Way Comparison of Cardiac Function with Normobaric Normoxia, Normobaric Hypoxia, Hypobaric Hypoxia and Genuine High Altitude |
title_sort | four-way comparison of cardiac function with normobaric normoxia, normobaric hypoxia, hypobaric hypoxia and genuine high altitude |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4839767/ https://www.ncbi.nlm.nih.gov/pubmed/27100313 http://dx.doi.org/10.1371/journal.pone.0152868 |
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