Normal Values of Echocardiographic Right Ventricular Size and Systolic Function Measurements in a Healthy Japanese Population ― Subanalysis of the WASE Study ―

Background: Although accurate assessment of right ventricular (RV) morphology and function is clinically important, data regarding reference values for echocardiographic measurements of the right ventricle in the Japanese population are limited. Methods and Results: The World Alliance Society of Echocardiography (WASE) Normal Values Study was conducted to examine normal echocardiographic values in 15 countries. Using the WASE study database, we analyzed 2-dimensional echocardiographic parameters of RV size and systolic function in 192 healthy Japanese individuals and compared them with those obtained from 153 healthy American individuals. In the Japanese population, the absolute values of RV dimensions were smaller for women than men, although the difference disappeared after the data were adjusted for body surface area. RV dimensions, RV length and RV area were smaller in the elderly, but age did not affect RV systolic function. The absolute value, but not the adjusted value, of RV size tended to be smaller in Japanese than American individuals for both sexes. For men, RV systolic function parameters were lower in the Japanese population. This trend was not seen in women. Conclusions: The present study identified normal reference values for RV size and systolic function in a healthy Japanese population. Sex, age, and race had a significant impact on RV size; however, this trend was weak for RV systolic function.