Comparison of the ratio of the early diastolic filling velocity to the late diastolic filling velocity (E/A ratio) in 139 lowlanders at the altitudes of 500 m, 3700 m and 4400 m.

At the elevated altitudes, the E/A ratio decreased, though it increased on day 7 at 4400 m compared with the ratio observed at 3700 m. (Note: **P<0.01, compared with 500 m; ^##P<0.01, compared with 3700 m.)