Assessment of ventricular repolarization instability in terms of T-wave alternans induced by head-down bed-rest immobilization

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OBJECTIVE: To assess the effects of different durations of simulated microgravity exposure on ventricular repolarization (VR) in terms of T-wave alternans (TWA) as well as to test whether an increase in VR heterogeneity could be detected once normal gravity was restored. APPROACH: A total of 63 healthy volunteers were recruited in several head-down bed-rest (HDBR) experiments in the context of the European Space Agency bed-rest strategy. TWA is evaluated during the night period using ambulatory ECG recordings, before, during and after long- (60 d), mid- (21 d) and short- (5 d) duration HDBR by the long-term averaging technique. MAIN RESULTS: 5-21 d of exposure to simulated microgravity by means of the HDBR model do not lead to a significant increase of cardiac electrical instability in healthy myocardial substrates up to the point of eliciting TWA on the surface ECG. However, TWA indices increased after long-term HDBR exposure, once normal gravity was re-established, indicative of incipient electrical instability on VR at the conclusion of 60 d of HDBR. SIGNIFICANCE: The results of this work underline the importance of focusing future research on immediate effects after long-term microgravity exposure, both simulated by HDBR or from space mission scenarios, once partial gravity conditions are re-established. A deeper insight in the understanding of human body reactions in these scenarios results crucial in the design of future long-duration spaceflight missions, to mitigate any potential risk that can limit astronaut's performance.


  • Alba Martín-Yebra
  • Violeta Monasterio
  • Federica Landreani
  • Pablo Laguna
  • Juan Pablo Martínez
  • Enrico G. Caiani
Externa organisationer
  • Lund University
  • University of Zaragoza
  • San Jorge University
  • Polytechnic University of Milan
  • CIBER Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN)

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Miljömedicin och yrkesmedicin
  • Medicinsk laboratorie- och mätteknik
TidskriftPhysiological Measurement
Utgåva nummer10
StatusPublished - 2019 okt 30
Peer review utfördJa
Externt publiceradJa