When assessing the right ventricle parameters in hypertensive patients we revealed lower values of the pulmonary artery index, the size and area of the right atrium, as well as the highest values of the RV velocity flow propagation, the rate of the tricuspid annulus early diastolic and systolic movement in Shor men compared with Caucasians. Shor women had the lowest values of early transtricuspid blood flow and the Et / At ratio. RV diastolic dysfunction was detected mainly in women, somewhat more often in Shor women. Accordingly, ethnicity was one of the factors associated with the RV diastolic dysfunction presence. Risk factors (smoking, obesity), blood pressure, gender, ethnicity, as well as LV parameters (impaired diastolic filling and an LV myocardial mass increase) were also associated with detection of RVDD.
Our previous study assessed the state of the right heart in healthy individuals of the Shor nationality . In that study, an increase in the dimensions of the pulmonary artery and right ventricle was found in Shor men and women compared to Caucasians. The indicators of the RV diastolic filling in the Shors were moderately better, which was manifested, in particular, by higher RV filling velocity in them. Participants of the present study were older and, therefore, both arterial hypertension and age influenced the state of the right heart, leveling out the initial ethnic differences in the LV structural parameters observed when comparing healthy individuals, and the right heart indicators in Shor women. It is possible that genetic factors influenced this dynamic of indicators during hypertension development. It was previously shown that different ethnic groups of rural Gornaya Shoriya residents had different genetic associations with LV hypertrophy. At the same time, LV hypertrophy among hypertensive patients was more prevalent in the Shor group than in the non-indigenous (Caucasian) group . In the previous study, no genetic associations with the state of the right ventricle were studied, however, in our study, there were no ethnic differences in the severity of LV hypertrophy. A possible reason for this is the influence of environmental factors: the shift from the traditional way of life of the Shors in rural areas to life in the city, greater availability of medical care, and an increase in the educational level. Examining healthy individuals in the MESA-Right Ventricle Study has shown that age, sex, and race are associated with significant differences in RV mass and volumes . The authors suggested that these differences could potentially explain distinct RV responses to cardiopulmonary disease ; however, in our study, on the contrary, we noted the leveling of the initial ethnic differences in RV parameters during the development of arterial hypertension.
Previous studies have shown that the level of physical activity , smoking  and the left ventricular hypertrophy [12, 24] affect the right ventricle. It was previously shown that healthy residents of highlands have small left heart and large right ventricle due to exposure to hypoxemia at high altitudes, and these changes did not depend on ethnicity . In the present study the RV dimensions are higher in Shor men than in non-indigenous men, which can be explained by a combination of several factors (high smoking frequency, genetic predisposition, and a decrease in daily activity due to changes in the traditional lifestyle is compensated, apparently, by the high prevalence of heavy physical labor among them).
We focused on the RV diastolic function since its development precedes systolic dysfunction both in experiment [26, 27] and during the disease’s development [10, 28], adversely affecting the prognosis at the same time [7, 29]. Our study confirmed the influence of the above factors on the presence of RVDD. The detection rate of RVDD was significantly lower than in a number of previous studies, where it was up to 45-60%. However, these studies examined patients with stable coronary artery disease before surgery  or with uncompensated hypertension . The more frequent RVDD detection in women turned out to be unexpected for us. In previous studies, on the contrary, there was a greater resistance of women to the RV dysfunction development compared to men . Perhaps this is characteristic of RV systolic dysfunction, but not of diastolic dysfunction. It also cannot be ruled out that the existing criteria for RV diastolic dysfunction may inaccurately reflect its presence in women, which apparently requires further research in this area.
Among the RVDD echocardiographic indicators, the velocity of RV filling to the greatest extent reflected its presence. This is probably a natural result. First, this indicator changes linearly with the increasing severity of RVDD, in contrast to the ratio of transtricuspid flow velocities. Secondly, assessing the filling flows of the right ventricle using 4D-MRI turned out to be the most informative in identifying initial changes in the right heart . It is proposed to continue the study of the 4D-MRI technique in assessing the RV diastole , but, apparently, it is impossible to leave out the echocardiographic assessment of the RV filling flows due to the greater availability of this examination technique.
We see the clinical significance of the study in the fact that, firstly, the leveling of most ethnic echocardiographic differences between Shors and Caucasians in the development of arterial hypertension shows that the clinical assessment may not take the influence of the patient's ethnicity into account. Secondly, the obtained data emphasize the complex interactions of genetic factors, environmental conditions, development of diseases, as well as a change in the traditional lifestyle of the Shors (moving from the middle mountains to the plains, reducing daily physical activity, changing diet), increasing the availability and quality of medical care for them for changes in the right heart. Revealing the diastolic function of the right ventricle predominantly in women among hypertensive patients requires additional study.
Several limitations should be mentioned. Subclinical coronary artery disease cannot be excluded in this study because coronary angiography was not performed. However, invasive diagnostics had not been indicated since this study included asymptomatic participants with no evidence of atherosclerotic lesions in other arterial regions. Another limitation is the relatively small number of included patients. This was due to the relatively small number of Shors living in urban settings. Nevertheless, we managed to obtain statistically significant results, which are desirable to confirm in larger studies. Finally, the assessment of right ventricular function was based on standard indicators of right ventricular systolic and diastolic function without the use of second-level methods (for example, strain assessment), which have been used in recent years, including in patients with arterial hypertension [24,30]. However, an international study has shown that new technologies such as global longitudinal strain and 3D echocardiography are rarely used to quantify right ventricular function in clinical setting (3% and 1%, respectively) . Therefore, the use of traditional RV indicators, in our opinion, at present can be justified, especially in an essentially screening study similar to ours. However, in the future, it is rational to conduct research using new technologies for assessing ethnic differences in RV function.