The influence of increased venous return on right ventricular dyssynchrony during acute and sustained hypoxemia

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Author
Ewalts, Michiel
Dawkins, Tony
Boulet, Lindsey
Thijssen, Dick
Stembridge, Mike
Date
2020-12-28Acceptance date
2020-12-19
Type
Article
Publisher
Wiley
ISSN
0958-0670
1469-445X (electronic)
Metadata
Show full item recordAbstract
Regional heterogeneity in timing of right ventricular (RV) contraction (RV dyssynchrony; RVD) occurs when pulmonary artery systolic pressure (PASP) is increased during acute hypoxia. Interestingly, RVD is not observed during exercise, a stimulus that increases both PASP and venous return. Therefore, we hypothesized that RVD in healthy humans is sensitive to changes in venous return, and examined whether (i) increasing venous return in acute hypoxia lowers RVD and (ii) if RVD is further exaggerated in sustained hypoxia, given increased PASP is accompanied by decreased ventricular filling at high altitude. RVD, PASP and RV end diastolic area (EDA) were assessed using transthoracic two‐dimensional and speckle‐tracking echocardiography during acute normobaric hypoxia (FiO2 = 0.12) and sustained exposure (5‐10 days) to hypobaric hypoxia (3800m). Venous return was augmented with lower body positive pressure at sea level (LBPP; +10 mmHg) and saline infusion at high altitude. PASP was increased in acute hypoxia (20±6 vs. 28±7, P<0.001) concomitant to an increase in RVD (18±7 vs. 38±10, P<0.001); however, the addition of LBPP during hypoxia decreased RVD (38±0 vs. 26±10, P<0.001). Sustained hypoxia increased PASP (20±4 vs. 26±5, P = 0.008) and decreased RV EDA (24±4 vs. 21±2, P = 0.042), with RVD augmented (14±5 vs. 31±12, P = 0.001). Saline infusion increased RV EDA (21±2 vs. 23 ± 3, P = 0.008) and reduced RVD (31±12 vs. 20±9, P = 0.001). In summary, an increase in PASP secondary to acute and sustained exposure to hypoxia augments RVD, which can be at least partly reduced via increased venous return.
Journal/conference proceeding
Experimental Physiology;
Citation
Ewalts, M., Dawkins, T., Boulet, L.M., Thijssen, D. and Stembridge, M. (2020) 'The influence of increased venous return on right ventricular dyssynchrony during acute and sustained hypoxemia', Experimental Physiology. https://doi.org/10.1113/EP088657
Description
Article published in Experimental Physiology available at https://doi.org/10.1113/EP088657
Sponsorship
Cardiff Metropolitan University (Grant ID: Cardiff Metropolian (Internal))
Collections
- Sport Research Groups [1083]
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