Institute of Cardiovascular Diseases of PLA, the Second Affiliated Hospital, Third Military Medical University (Army Medical University), Chongqing, China.
Department of Cardiology, the Second Affiliated Hospital, Third Military Medical University (Army Medical University), Chongqing, China.
PLoS One. 2021 Feb 18;16(2):e0247107. doi: 10.1371/journal.pone.0247107. eCollection 2021.
High altitude exposure induces overload of right-sided heart and may further predispose to supraventricular arrhythmia. It has been reported that atrial mechanical dyssynchrony is associated with atrial arrhythmia. Whether high altitude exposure causes higher right atrial (RA) dyssynchrony is still unknown. The aim of study was to investigate the effect of high altitude exposure on right atrial mechanical synchrony.
In this study, 98 healthy young men underwent clinical examination and echocardiography at sea level (400 m) and high altitude (4100 m) after an ascent within 7 days. RA dyssynchrony was defined as inhomogeneous timing to peak strain and strain rate using 2D speckle-tracking echocardiography.
Following high altitude exposure, standard deviation of the time to peak strain (SD-TPS) [36.2 (24.5, 48.6) ms vs. 21.7 (12.9, 32.1) ms, p<0.001] and SD-TPS as percentage of R-R' interval (4.6 ± 2.1% vs. 2.5 ± 1.8%, p<0.001) significantly increased. Additionally, subjects with higher SD-TPS (%) at high altitude presented decreased right ventricular global longitudinal strain and RA active emptying fraction, but increased RA minimal volume index, which were not observed in lower group. Multivariable analysis showed that mean pulmonary arterial pressure and tricuspid E/A were independently associated with SD-TPS (%) at high altitude.
Our data for the first time demonstrated that high altitude exposure causes RA dyssynchrony in healthy young men, which may be secondary to increased pulmonary arterial pressure. In addition, subjects with higher RA dyssynchrony presented worse RA contractile function and right ventricular performance.
高海拔暴露会导致右心负荷过重，进而易患房性心律失常。已有研究报道心房机械不同步与房性心律失常相关。高海拔暴露是否会导致更高的右心房（RA）不同步尚不清楚。本研究旨在探讨高海拔暴露对右心房机械同步性的影响。
本研究纳入 98 名健康年轻男性，在 7 天内快速上升至海拔 4100 米后，于海平面（400 米）和高海拔（4100 米）进行临床检查和超声心动图检查。使用二维斑点追踪超声心动图，通过峰应变和应变率的不均匀达峰时间来定义 RA 不同步。
高海拔暴露后，峰应变的标准差（SD-TPS）[36.2（24.5，48.6）ms 比 21.7（12.9，32.1）ms，p<0.001]和 TPS 作为 R-R'间期的百分比（4.6±2.1%比 2.5±1.8%，p<0.001）显著增加。此外，在高海拔时具有更高的 SD-TPS（%）的患者，右心室整体纵向应变和 RA 主动排空分数降低，但 RA 最小容积指数增加，而在较低组中未观察到这些变化。多变量分析表明，平均肺动脉压和三尖瓣 E/A 与高海拔时的 SD-TPS（%）独立相关。
本研究首次表明，高海拔暴露会导致健康年轻男性的 RA 不同步，这可能是肺动脉高压增加所致。此外，RA 不同步较高的患者 RA 收缩功能和右心室功能更差。
