Long-Term Microgravity Exposure Increases ECG Repolarization Instability Manifested by Low-Frequency Oscillations of T-Wave Vector
Ventricular arrhythmias and sudden cardiac death during long-term space missions are a major concern for space agencies. Long-duration spaceflight and its ground-based analog head-down bed rest (HDBR) have been reported to markedly alter autonomic and cardiac functioning, particularly affecting vent...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2019-12-01
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| Series: | Frontiers in Physiology |
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| Online Access: | https://www.frontiersin.org/article/10.3389/fphys.2019.01510/full |
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| author | Saúl Palacios Enrico G. Caiani Federica Landreani Juan Pablo Martínez Juan Pablo Martínez Esther Pueyo Esther Pueyo |
| author_facet | Saúl Palacios Enrico G. Caiani Federica Landreani Juan Pablo Martínez Juan Pablo Martínez Esther Pueyo Esther Pueyo |
| author_sort | Saúl Palacios |
| collection | DOAJ |
| description | Ventricular arrhythmias and sudden cardiac death during long-term space missions are a major concern for space agencies. Long-duration spaceflight and its ground-based analog head-down bed rest (HDBR) have been reported to markedly alter autonomic and cardiac functioning, particularly affecting ventricular repolarization of the electrocardiogram (ECG). In this study, novel methods are developed, departing from previously published methodologies, to quantify the index of Periodic Repolarization Dynamics (PRD), an arrhythmic risk marker that characterizes sympathetically-mediated low-frequency oscillations in the T-wave vector. PRD is evaluated in ECGs from 42 volunteers at rest and during an orthostatic tilt table test recorded before and after 60-day –6° HDBR. Our results indicate that tilt test, on top of enhancing sympathetic regulation of heart rate, notably increases PRD, both before and after HDBR, thus supporting previous evidence on PRD being an indicator of sympathetic modulation of ventricular repolarization. Importantly, long-term microgravity exposure is shown to lead to significant increases in PRD, both when evaluated at rest and, even more notably, in response to tilt test. The extent of microgravity-induced changes in PRD has been associated with arrhythmic risk in prior studies. An exercise-based, but not a nutrition-based, countermeasure is able to partially reverse microgravity-induced effects on PRD. In conclusion, long-term exposure to microgravity conditions leads to elevated low-frequency oscillations of ventricular repolarization, which are potentiated following sympathetic stimulation and are related to increased risk for repolarization instabilities and arrhythmias. Tested countermeasures are only partially effective in counteracting microgravity effects. |
| first_indexed | 2024-12-19T04:20:20Z |
| format | Article |
| id | doaj.art-d7aba3a402cf41849bbe0bcc74fc689e |
| institution | Directory Open Access Journal |
| issn | 1664-042X |
| language | English |
| last_indexed | 2024-12-19T04:20:20Z |
| publishDate | 2019-12-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Physiology |
| spelling | doaj.art-d7aba3a402cf41849bbe0bcc74fc689e2022-12-21T20:36:10ZengFrontiers Media S.A.Frontiers in Physiology1664-042X2019-12-011010.3389/fphys.2019.01510493791Long-Term Microgravity Exposure Increases ECG Repolarization Instability Manifested by Low-Frequency Oscillations of T-Wave VectorSaúl Palacios0Enrico G. Caiani1Federica Landreani2Juan Pablo Martínez3Juan Pablo Martínez4Esther Pueyo5Esther Pueyo6BSICoS Group, Aragón Institute of Engineering Research, IIS Aragón, Universidad de Zaragoza, Zaragoza, SpainDipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, ItalyDipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, ItalyBSICoS Group, Aragón Institute of Engineering Research, IIS Aragón, Universidad de Zaragoza, Zaragoza, SpainCIBER en Bioingeniería, Biomateriales y Nanomedicina, Madrid, SpainBSICoS Group, Aragón Institute of Engineering Research, IIS Aragón, Universidad de Zaragoza, Zaragoza, SpainCIBER en Bioingeniería, Biomateriales y Nanomedicina, Madrid, SpainVentricular arrhythmias and sudden cardiac death during long-term space missions are a major concern for space agencies. Long-duration spaceflight and its ground-based analog head-down bed rest (HDBR) have been reported to markedly alter autonomic and cardiac functioning, particularly affecting ventricular repolarization of the electrocardiogram (ECG). In this study, novel methods are developed, departing from previously published methodologies, to quantify the index of Periodic Repolarization Dynamics (PRD), an arrhythmic risk marker that characterizes sympathetically-mediated low-frequency oscillations in the T-wave vector. PRD is evaluated in ECGs from 42 volunteers at rest and during an orthostatic tilt table test recorded before and after 60-day –6° HDBR. Our results indicate that tilt test, on top of enhancing sympathetic regulation of heart rate, notably increases PRD, both before and after HDBR, thus supporting previous evidence on PRD being an indicator of sympathetic modulation of ventricular repolarization. Importantly, long-term microgravity exposure is shown to lead to significant increases in PRD, both when evaluated at rest and, even more notably, in response to tilt test. The extent of microgravity-induced changes in PRD has been associated with arrhythmic risk in prior studies. An exercise-based, but not a nutrition-based, countermeasure is able to partially reverse microgravity-induced effects on PRD. In conclusion, long-term exposure to microgravity conditions leads to elevated low-frequency oscillations of ventricular repolarization, which are potentiated following sympathetic stimulation and are related to increased risk for repolarization instabilities and arrhythmias. Tested countermeasures are only partially effective in counteracting microgravity effects.https://www.frontiersin.org/article/10.3389/fphys.2019.01510/fullmicrogravityperiodic repolarization dynamics (PRD)ventricular repolarizationautonomous nervous systemelectrocardiogram (ECG) processingtilt table test |
| spellingShingle | Saúl Palacios Enrico G. Caiani Federica Landreani Juan Pablo Martínez Juan Pablo Martínez Esther Pueyo Esther Pueyo Long-Term Microgravity Exposure Increases ECG Repolarization Instability Manifested by Low-Frequency Oscillations of T-Wave Vector Frontiers in Physiology microgravity periodic repolarization dynamics (PRD) ventricular repolarization autonomous nervous system electrocardiogram (ECG) processing tilt table test |
| title | Long-Term Microgravity Exposure Increases ECG Repolarization Instability Manifested by Low-Frequency Oscillations of T-Wave Vector |
| title_full | Long-Term Microgravity Exposure Increases ECG Repolarization Instability Manifested by Low-Frequency Oscillations of T-Wave Vector |
| title_fullStr | Long-Term Microgravity Exposure Increases ECG Repolarization Instability Manifested by Low-Frequency Oscillations of T-Wave Vector |
| title_full_unstemmed | Long-Term Microgravity Exposure Increases ECG Repolarization Instability Manifested by Low-Frequency Oscillations of T-Wave Vector |
| title_short | Long-Term Microgravity Exposure Increases ECG Repolarization Instability Manifested by Low-Frequency Oscillations of T-Wave Vector |
| title_sort | long term microgravity exposure increases ecg repolarization instability manifested by low frequency oscillations of t wave vector |
| topic | microgravity periodic repolarization dynamics (PRD) ventricular repolarization autonomous nervous system electrocardiogram (ECG) processing tilt table test |
| url | https://www.frontiersin.org/article/10.3389/fphys.2019.01510/full |
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