[Comparitive [Comparative] study of the indexes of pulmonary arterial pressure of healthy children at different altitudes by Doppler echocardiography].

Objective: Reduced oxygen availability at a high altitude is associated with increased pulmonary arterial pressure (PAP). With the altitude goes up the change of PAP in healthy children is still not clear. The difference of PAP in native Tibetan and Han children at a high altitude are also not clear.