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

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

doi:10.3389/fcvm.2022.856749

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

Front Cardiovasc Med. 2022 May 23:9:856749. doi: 10.3389/fcvm.2022.856749. eCollection 2022.

Authors

Xu Chen¹, Bohan Liu¹, Yujiao Deng¹, Feifei Yang¹, Wenjun Wang¹, Xixiang Lin¹, Liheng Yu¹, Haitao Pu², Peifang Zhang², Zongren Li¹, Qin Zhong¹, Qian Jia¹, Yao Li¹, Xiao Wang¹, Wei Chen³, Daniel Burkhoff⁴, Kunlun He¹

Affiliations

¹ Beijing Key Laboratory for Precision Medicine of Chronic Heart Failure, Key Laboratory of Ministry of Industry and Information Technology of Biomedical Engineering and Translational Medicine, Translational Medicine Research Center, Medical Artificial Intelligence Research Center, Chinese PLA General Hospital, Beijing, China.
² BioMind Technology, Zhongguancun Medical Engineering Center, Beijing, China.
³ Department of Ultrasound Diagnosis, The Seventh Medical Center of Chinese PLA General Hospital, Beijing, China.
⁴ Cardiovascular Research Foundation, New York, NY, United States.

Abstract

Objective: 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.

Methods: Echocardiographic features of recently adapted Han migrant (3-12 months, n = 64) and highly adapted Han migrant (5-10 years, n = 71) residence in Tibet (4,300 m) using speckle tracking echocardiography were compared to those of age-matched native Tibetans (n = 75) and Han lowlanders living at 1,400 m (n = 60).

Results: Short-term acclimatized migrants showed increased estimated pulmonary artery systolic pressure (PASP) (32.6 ± 5.1 mmHg vs. 21.1 ± 4.2 mmHg, p < 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%, p < 0.05). While left ventricular ejection fraction (LVEF) was preserved, LV diameter (41.7 ± 3.1 mm vs. 49.7 ± 4.8 mm, p < 0.05) and LV longitudinal strain (-18.8 ± 3.2% vs. -22.9 ± 3.3%, p < 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, p < 0.05). In contrast, native Tibetans had slightly increased PASP (26.1 ± 3.4 mmHg vs. 21.1 ± 4.2 mmHg, p < 0.05) with minimally altered cardiac deformation compared to lowlanders.

Conclusion: Right ventricular systolic function is impaired in recent (<1 year) migrants to high altitudes but improved during the long-term dwelling. LV remodeling persists in long-term migrants (>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.

Keywords: cardiac physiology; cardiac responses; echocardiography; high altitude acclimatization; strain.