Key result
Head-down bed rest simulating microgravity significantly altered the linear dependency of ventricular repolarization variability driven by heart rate variability, specifically for Tpe (p<0.05).
Why the study?
Does microgravity simulation via head-down bed rest alter the linear relationship between heart rate variability and ventricular repolarization variability?
Does microgravity simulation via head-down bed rest alter the linear relationship between heart rate variability and ventricular repolarization variability?
p-value: p=<0.05
Microgravity simulation via head-down bed rest alters ventricular repolarization variability, specifically showing a reduced recovery capacity for Tpe repolarization variability to restore its linear dependency to heart rate.
Simulated microgravity alters Tpe repolarization-heart rate coupling; hypothesis-generating for arrhythmia risk in spaceflight.
Features extracted from heart rate variability (HRV) have allowed to classify several cardiac disorders. In this work, the linear relationship between HRV and ventricular repolarization variability is studied as a possible feature for stratifying risk of cardiac arrhythmias under weightlessness conditions. Three VR beat-to-beat indexes extracted from ECG signals as QT, QT p (QRS onset to T wave peak) and T pe (peak to end of T wave) were measured. ARARX modeling was used to estimate the VR variability fraction driven by HRV. Head down bed rest as microgravity Earth-based test increased the linear dependency of VR variability driven by HRV. Furthermore, in a pairwise comparison between PRE and POST conditions showed significant differences (p-values <; 0.05) for T pe variability contents. These results evidence a reduced recovery capacity for the T pe re-polarization variability to restore its linear dependency values to HR in the first moments at the end of BR.
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Bolea et al. (2013) studied Microgravity simulation. Head-down bed rest (microgravity simulation) vs. PRE condition (baseline) was evaluated on Tpe variability contents (linear dependency of ventricular repolarization variability driven by HRV) (p=<0.05). Head-down bed rest simulating microgravity significantly altered the linear dependency of ventricular repolarization variability driven by heart rate variability, specifically for Tpe (p<0.05).
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