Rao Mingyue, Li Jiabei, Qin Jun, Zhang Jihang, Gao Xubin, Yu Shiyong, Yu Jie, Chen Guozhu, Xu Baida, Li Huijie, Rao Rongsheng, Huang Lan, Jin Jun
Institute of Cardiovascular Diseases of PLA, Third Military Medical University, Chongqing 400037, China; Department of Cardiology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
Institute of Cardiovascular Diseases of PLA, Third Military Medical University, Chongqing 400037, China.
PLoS One. 2015 Jan 28;10(1):e0116936. doi: 10.1371/journal.pone.0116936. eCollection 2015.
The purpose of this study was to observe left ventricular function during acute high-altitude exposure in a large group of healthy young males.
A prospective trial was conducted in Szechwan and Tibet from June to August, 2012. By Doppler echocardiography, left ventricular function was examined in 139 healthy young Chinese men at sea level; within 24 hours after arrival in Lhasa, Tibet, at 3700 m; and on day 7 following an ascent to Yangbajing at 4400 m after 7 days of acclimatization at 3700 m. The resting oxygen saturation (SaO2), heart rate (HR) and blood pressure (BP) were also measured at the above mentioned three time points.
Within 24 hours of arrival at 3700 m, the HR, ejection fraction (EF), fractional shortening (FS), stroke volume (SV), cardiac output (CO), and left ventricular (LV) Tei index were significantly increased, but the LV end-systolic dimension (ESD), end-systolic volume (ESV), SaO2, E/A ratio, and ejection time (ET) were significantly decreased compared to the baseline levels in all subjects. On day 7 at 4400 m, the SV and CO were significantly decreased; the EF and FS Tei were not decreased compared with the values at 3700 m; the HR was further elevated; and the SaO2, ESV, ESD, and ET were further reduced. Additionally, the E/A ratio was significantly increased on day 7 but was still lower than it was at low altitude.
Upon acute high-altitude exposure, left ventricular systolic function was elevated with increased stroke volume, but diastolic function was decreased in healthy young males. With higher altitude exposure and prolonged acclimatization, the left ventricular systolic function was preserved with reduced stroke volume and improved diastolic function.
本研究旨在观察一大群健康年轻男性在急性高原暴露期间的左心室功能。
2012年6月至8月在四川和西藏进行了一项前瞻性试验。通过多普勒超声心动图，对139名健康中国年轻男性在海平面时、抵达西藏拉萨（海拔3700米）后24小时内以及在海拔3700米适应7天后上升至海拔4400米的羊八井7天后的左心室功能进行了检查。还在上述三个时间点测量了静息血氧饱和度（SaO2）、心率（HR）和血压（BP）。
在抵达海拔3700米的24小时内，所有受试者的心率、射血分数（EF）、缩短分数（FS）、每搏量（SV）、心输出量（CO）和左心室（LV）Tei指数均显著增加，但左心室收缩末期内径（ESD）、收缩末期容积（ESV）、SaO2、E/A比值和射血时间（ET）与基线水平相比显著降低。在海拔4400米的第7天，SV和CO显著降低；EF和FS Tei与在海拔3700米时的值相比没有降低；心率进一步升高；SaO2、ESV、ESD和ET进一步降低。此外，E/A比值在第7天显著增加，但仍低于低海拔时的值。
在急性高原暴露时，健康年轻男性的左心室收缩功能随着每搏量增加而升高，但舒张功能降低。随着海拔升高和适应时间延长，左心室收缩功能得以保留，每搏量减少，舒张功能改善。
