OBJECTIVETo investigate the changes of the cardiac hemodynamics after acute high altitude exposure in healthy young males and the relationship with acute mountain sickness(AMS).

METHODSLeft ventricular function and oxyhemoglobin saturation (SaO2), heart rate (HR), blood pressure (BP) were measured in 218 healthy young males before and after high altitude exposure within 24 h respectively. According to the lake louise score criteria, the subjects were divided into two groups: acute mountain sickness group (AMS group) and non acute mountain sickness group (non-AMS group).

RESULTSHR, diastolic blood pressure (DBP), mean arterial pressure (MAP), left ventricular ejection fraction (LVEF), stroke volume (SV), stroke index (SI) cardiac output (CO), cardiac index (CI) were significantly increased upon acute high altitude exposure (P < 0.05). Whereas SaO2 and end-systolic volume (ESV) were significantly decreased (P < 0.05). In addition, HR, systolic blood pressure (SBP) and MAP in AMS group were significantly higher than those in non-AMS group (P < 0.05). But stroke index (SI) and end-diastolic volume (EDV) in AMS group were significantly lower than those in non-AMS group (P < 0.05).

CONCLUSIONCardiac function in healthy young males upon acute high altitude exposure was enhanced. EDV, HR and SI might become the indexes of predicting the acute mountain sickness in the future.