Prevalence of congenital cardiac anomalies at high altitude.

The effect of high altitude on the prevalence of congenital heart disease was tested by examining 1,116 school children at four study sites in the People's Republic of China. Sites ranged in altitude from sea level to 4,500 m above sea level. Children were screened by physical examination, and an echocardiogram and electrocardiogram were performed on each child suspected of having a cardiac anomaly.

Pulmonary pressure, cardiac output, and arterial oxygen saturation during exercise at high altitude and at sea level.

The response elicited by exercise on pulmonary pressure, cardiac output, and arterial oxygen saturation in 35 lifetime residents of high altitude has been studied at high altitude (14,900 feet above sea level), and 22 residents of low altitude have been studied at sea level. A procedure combining cardiac catheterization, arterial cannulation, and spirometry was carried out. The exercise was moderate and was performed in supine position using a bicycle ergometer, the work load being 300 kg-m/min/m2 and the average increase of the oxygen uptake being 4.