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

Abstract

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 hypothesised 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 right ventricular end-diastolic area (RVEDA) were assessed using transthoracic two-dimensional and speckle-tracking echocardiography during acute normobaric hypoxia (F iO 2 = 0.12) and sustained exposure (5-10 days) to hypobaric hypoxia (3800 m). 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,

Right Ventricular Response to Acute Hypoxia Exposure: A Systematic Review

“…Twelve studies explored effects of simulated altitude and included a total of 199 healthy adults (Huez et al, 2005 ; Kjaergaard et al, 2007 ; Reichenberger et al, 2007 ; Hanaoka et al, 2011 ; Pavelescu and Naeije, 2012 ; Boos et al, 2013 , 2016 ; Goebel et al, 2013 ; Netzer et al, 2017 ; Seccombe et al, 2017 ; Pezzuto et al, 2018 ; Ewalts et al, 2021 ). Study participants were exposed to various degrees of hypoxia from 9.9 to 12.5% fraction of inspired oxygen (FiO 2 ), which correspond to altitude levels ranging from 4,000 to 5,500 m. Altitude was simulated by either hypobaric or normobaric hypoxic chamber exposure or hypoxia breathing.…”

“…RV-S′ values remained unchanged in 4 studies (Huez et al, 2005 ; Kjaergaard et al, 2007 ; Pavelescu and Naeije, 2012 ; Pezzuto et al, 2018 ) and were increased in one study (Boos et al, 2013 ) or decreased in another study after 1 h hypoxia exposure (Netzer et al, 2017 ). RV-GLS was evaluated in 2 studies and showed opposite results (Goebel et al, 2013 ; Ewalts et al, 2021 ).…”

“…Seven of the studies reported at least one of the following RV morphology parameters: RV end diastolic area (RV-EDA), RV end systolic area (RV-ESA), RV basal diameter (RVD1), RV mid diameter (RVD2), RV longitudinal size (RVD3) (Huez et al, 2005 ; Kjaergaard et al, 2007 ; Pavelescu and Naeije, 2012 ; Netzer et al, 2017 ; Seccombe et al, 2017 ; Pezzuto et al, 2018 ; Ewalts et al, 2021 ). The most frequently evaluated RV morphology parameter RV-EDA was reported in 7 studies (Huez et al, 2005 ; Kjaergaard et al, 2007 ; Pavelescu and Naeije, 2012 ; Netzer et al, 2017 ; Seccombe et al, 2017 ; Pezzuto et al, 2018 ; Ewalts et al, 2021 ).…”

“…Morphology Huez et al, 2005Kjaergaard et al, 2007Reichenberger et al, 2007Hanaoka et al, 2011Pavelescu and Naeije, 2012Goebel et al, 2013Boos et al, 2013Boos et al, 2016Seccombe et al, 2017Netzer et al, 2017Pezzuto et al, 2018Ewalts et al, 2021 Indicates that the echocardiographic parameter was provided in the corresponding studies; empty cell indicate that the echocardiographic parameter is not provided in the corresponding studies.…”

“…Frontiers in Physiology | www.frontiersin.org et al, 2017). RV-GLS was evaluated in 2 studies and showed opposite results (Goebel et al, 2013;Ewalts et al, 2021).…”