AUTHOR=Chen Xu , Liu Bohan , Deng Yujiao , Yang Feifei , Wang Wenjun , Lin Xixiang , Yu Liheng , Pu Haitao , Zhang Peifang , Li Zongren , Zhong Qin , Jia Qian , Li Yao , Wang Xiao , Chen Wei , Burkhoff Daniel , He Kunlun 

TITLE=Cardiac Adaptation to Prolonged High Altitude Migration Assessed by Speckle Tracking Echocardiography

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2022.856749

DOI=10.3389/fcvm.2022.856749

ISSN=2297-055X

ABSTRACT=<sec><title>Objective</title><p>Exposure to high altitudes represents physiological stress that leads to significant changes in cardiovascular properties. However, long-term cardiovascular adaptions to high altitude migration of lowlanders have not been described. Accordingly, we measured changes in cardiovascular properties following prolonged hypoxic exposure in acclimatized Han migrants and Tibetans.</p></sec><sec><title>Methods</title><p>Echocardiographic features of recently adapted Han migrant (3–12 months, <italic>n</italic> = 64) and highly adapted Han migrant (5–10 years, <italic>n</italic> = 71) residence in Tibet (4,300 m) using speckle tracking echocardiography were compared to those of age-matched native Tibetans (<italic>n</italic> = 75) and Han lowlanders living at 1,400 m (<italic>n</italic> = 60).</p></sec><sec><title>Results</title><p>Short-term acclimatized migrants showed increased estimated pulmonary artery systolic pressure (PASP) (32.6 ± 5.1 mmHg vs. 21.1 ± 4.2 mmHg, <italic>p</italic> &lt; 0.05), enlarged right ventricles (RVs), and decreased fractional area change (FAC) with decreased RV longitudinal strain (−20 ± 2.8% vs. −25.5 ± 3.9%, <italic>p</italic> &lt; 0.05). While left ventricular ejection fraction (LVEF) was preserved, LV diameter (41.7 ± 3.1 mm vs. 49.7 ± 4.8 mm, <italic>p</italic> &lt; 0.05) and LV longitudinal strain (−18.8 ± 3.2% vs. −22.9 ± 3.3%, <italic>p</italic> &lt; 0.05) decreased. Compared with recent migrants, longer-term migrants had recovered RV structure and functions with slightly improved RV and LV longitudinal strain, though still lower than lowlander controls; LV size remained small with increased mass index (68.3 ± 12.7 vs. 59.3 ± 9.6, <italic>p</italic> &lt; 0.05). In contrast, native Tibetans had slightly increased PASP (26.1 ± 3.4 mmHg vs. 21.1 ± 4.2 mmHg, <italic>p</italic> &lt; 0.05) with minimally altered cardiac deformation compared to lowlanders.</p></sec><sec><title>Conclusion</title><p>Right ventricular systolic function is impaired in recent (&lt;1 year) migrants to high altitudes but improved during the long-term dwelling. LV remodeling persists in long-term migrants (&gt;5 years) but without impairment of LV systolic or diastolic function. In contrast, cardiac size, structure, and function of native Tibetans are more similar to those of lowland dwelling Hans.</p></sec>