Factors Related to Ventricular Size and Valvular Regurgitation in Healthy Tibetans in Lhasa

BACKGROUND Lhasa is the main residence of Tibetans and one of the highest cities in the world. Its unique geography and ethnic population provide the chance to investigate the interactions among high altitude, ethnicity, and cardiac adaptation. Meanwhile, echocardiographic data about healthy Tibetans on a large scale are not available. This study aimed to analyze physiological factors related to ventricular size and valvular function in healthy Tibetans in Lhasa. METHODS A representative sample of residents in Tibet was recruited using a multistage cluster random sampling method. Two-dimensional echocardiographic measurements and Doppler evaluation for valvular function were performed. Healthy Tibetans in Lhasa constituted the study population. Associations between physiological parameters and ventricular dimensions in healthy Tibetans were analyzed by canonical correlation analysis. Factors related to valvular regurgitations were determined by logistic regression analysis. RESULTS The 454 healthy Tibetans (340 females and 114 male) in Lhasa were included in the final analysis. Canonical correlation analysis revealed that weight was positively correlated with the proximal right ventricular outflow diameter and the basal left ventricular linear dimension in both genders. Weight and pulse were negatively related to mild tricuspid regurgitation. Age was a positive factor for pulmonary and aortic regurgitations. The same was found between systolic blood pressure and mitral regurgitation. CONCLUSIONS Weight is associated with ventricular size and valvular regurgitation in healthy Tibetans. It should be of more concern in research of high altitude population.