Abstract
Background
The trend of human migration to terrestrial high altitudes (HA) has been increasing over the years. However, the long-term impact of this migration on cardiac structure and function remains unclear. This prospective study aimed to investigate the changes in cardiac structure and function in healthy young male lowlanders following long-term migration to HA.
Methods
A total of 122 Chinese healthy young males were divided into two groups: those migrating to altitudes between 3600 meters and 4000 meters (low HA group, n = 65) and those migrating to altitudes between 4000 meters and 4700 meters (high HA group, n = 57). Traditional echocardiographic parameters were measured at sea level, one month, and one year after migration to HA.
Results
All four cardiac chamber dimensions, areas, and volumes decreased after both one month and one year of HA exposure. This reduction was more pronounced in the high HA group than in the low HA group. Bi-ventricular diastolic function declined after one month of HA exposure, while systolic function decreased after one year. Notably, these functional changes were not significantly influenced by altitude differences. Dilation of the pulmonary artery and a progressive increase in pulmonary artery systolic pressure were observed with both increasing exposure time and altitude. Additionally, decreased diameter of the inferior vena cava and reduced bicuspid and tricuspid blood flow velocity indicated reduced blood flow following migration to HA.
Conclusions
One year of migration to HA is associated with decreased blood volume and enhanced hypoxic pulmonary vasoconstriction. These factors contribute to reduced cardiac chamber size and slight declines in bi-ventricular function.