Normal Values of Left Atrial Size and Function and the Impact of Age: Results of the World Alliance Societies of Echocardiography Study.

BACKGROUND: Left atrial (LA) evaluation includes volumetric and functional parameters with an abundance of diagnostic and prognostic implications. Solid normal reference ranges are compulsory for accurate interpretation in individual patients, but previous studies have yielded mixed conclusions regarding the effects of age, sex, and/or race. The present report from the World Alliance Societies of Echocardiography study focuses on two-dimensional (2D) and three-dimensional (3D) measures of LA structure and function, with subgroup analysis by age, sex, and race. METHODS: Transthoracic 2D and 3D echocardiographic images were obtained in 1,765 healthy individuals (901 men, 864 women) evenly distributed among age subgroups: 18 to 40 years (n = 745), 41 to 65 years (n = 618), and >65 years (n = 402); the racial distribution was 38.4% white, 39.9% Asian, and 9.7% black. Images were analyzed using dedicated LA analysis software to measure LA volumes and phasic function from 3D volume and 2D strain curves. RESULTS: Three-dimensional maximum and minimum LA volumes adjusted for body surface area were nearly identical for men and women, but women demonstrated higher 3D total and passive emptying fractions (EFs). Two-dimensional reservoir strain was similar for both sexes. Age was associated with an incremental rise in LA volumes alongside characteristic shifts in functional indices. Total 2D EF and reservoir and conduit strain varied inversely with age, counteracted by higher booster strain, with a greater magnitude of effect in women. Active 3D EF was significantly higher, while total and passive EFs decreased with age. Interracial differences were noted in LA volumes, without substantial differences in functional indices. CONCLUSION: Although similar normal values for LA volumes and strain can be applied to both sexes, meaningful differences in LA size occur with aging. Indices of function also shift with age, with a compensatory rise in booster function, which may serve to counteract observed lower total and passive EFs. Defining age-associated normal values may help differentiate age-associated "healthy" LA aging from pathologic processes.

Two-Dimensional Echocardiographic Right Ventricular Size and Systolic Function Measurements Stratified by Sex, Age, and Ethnicity: Results of the World Alliance of Societies of Echocardiography Study.

BACKGROUND: Echocardiographic assessment of right ventricular (RV) systolic function is an important component of clinical decision making. Although professional societies have worked to define normal ranges of RV size and function, their guidelines have not included the impacts of age, sex, and ethnicity on these parameters, as they have for the left ventricle. The World Alliance of Societies of Echocardiography study was designed to investigate the effects of age, sex, and ethnicity on all cardiac chambers. The aim of this study was to explore whether these differences exist for RV systolic parameters. METHODS: Adequate two-dimensional RV-focused views for the measurement of systolic parameters, including fractional area change and global and free wall longitudinal strain, were available in 1,913 subjects (mean age, 47 ± 17 years; 51% men). Basal and mid-RV dimensions, length, tricuspid annular peak systolic excursion, tissue Doppler S' velocity, and myocardial performance index were also measured. Subjects were grouped by age (<40, 41-65, and >65 years), with results also stratified by sex and ethnicity (Asian, black, or white) and analyzed using vendor-independent software. Differences among groups were evaluated using analysis of variance. RESULTS: Women had smaller absolute and indexed RV areas and absolute RV dimensions and higher magnitudes of fractional area change, free wall strain, and global longitudinal strain compared to men. With respect to age, most of the statistically significant differences were noted between the <40- and >65-year age groups, with RV areas and lengths smaller in older age groups and RV functional parameters (S', fractional area change, tricuspid annular plane systolic excursion, global longitudinal strain, free wall strain, and myocardial performance index) showing minimal decreases or no changes with age. Although there were no meaningful differences in functional parameters among ethnic groups, RV size was smallest in Asians. CONCLUSIONS: These findings suggest that although two-dimensional RV parameters are age and sex dependent, association with race is less apparent, excepting that the Asian population appears to have smaller chamber sizes compared with whites and blacks.

Normal Values of Cardiac Output and Stroke Volume According to Measurement Technique, Age, Sex, and Ethnicity: Results of the World Alliance of Societies of Echocardiography Study.

BACKGROUND: Assessment of cardiac output (CO) and stroke volume (SV) is essential to understand cardiac function and hemodynamics. These parameters can be examined using three echocardiographic techniques (pulsed-wave Doppler, two-dimensional [2D], and three-dimensional [3D]). Whether these methods can be used interchangeably is unclear. The influence of age, sex, and ethnicity on CO and SV has also not been examined in depth. In this report from the World Alliance of Societies of Echocardiography Normal Values Study, the authors compare CO and SV in healthy adults according to age, sex, ethnicity, and measurement techniques. METHODS: A total of 1,450 adult subjects (53% men) free of heart, lung, and kidney disease were prospectively enrolled in 15 countries, with even distributions among age groups and sex. Subjects were divided into three age groups (young, 18-40 years; middle aged, 41-65 years; and old, >65 years) and three main racial groups (whites, blacks, and Asians). CO and SV were indexed (cardiac index [CI] and SV index [SVI], respectively) to body surface area and height and measured using three echocardiographic methods: Doppler, 2D, and 3D. Images were analyzed at two core laboratories (one each for 2D and 3D). RESULTS: CI and SVI were significantly lower by 2D compared with both Doppler and 3D methods in both sexes. SVI was significantly lower in women than men by all three methods, while CI differed only by 2D. SVI decreased with aging by all three techniques, whereas CI declined only with 2D and 3D. CO and SV were smallest in Asians and largest in whites, and the differences persisted after normalization for body surface area. CONCLUSIONS: The present results provide normal reference values for CO and SV, which differ by age, sex, and race. Furthermore, CI and SVI measurements by the different echocardiographic techniques are not interchangeable. All these factors need to be taken into account when evaluating cardiac function and hemodynamics in individual patients.

Normal Values of Right Atrial Size and Function According to Age, Sex, and Ethnicity: Results of the World Alliance Societies of Echocardiography Study.

BACKGROUND: The World Alliance Societies of Echocardiography study is a multicenter, international, prospective, cross-sectional study whose aims were to evaluate healthy adult individuals to establish age- and sex-normative values of echocardiographic parameters and to determine whether differences exist among people from different countries and of different ethnicities. The present report focuses on two-dimensional (2D) and three-dimensional (3D) right atrial (RA) size and function. METHODS: Transthoracic 2D and 3D echocardiographic images were obtained in 2,008 healthy adult individuals evenly distributed among subgroups according to sex (1,033 men, 975 women) and age 18 to 40 years (n = 854), 41 to 65 years (n = 653), and >65 years (n = 501). For ethnicity, 34.9% were white, 41.6% Asian, and 9.7% black. Images were analyzed in a core laboratory according to current American Society of Echocardiography/European Association of Cardiovascular Imaging guidelines. RA measurements included 2D dimensions, 2D and 3D RA volumes (RAVs) indexed to body surface area (BSA), emptying fraction (EmF), and global longitudinal strain, including total/reservoir, passive/conduit, and active/contractile phases. Differences among age and sex categories and among countries were also examined. RESULTS: RAVs were larger in men (even after BSA indexing), while 3D total EmF and global longitudinal strain magnitudes were higher in women. For both sexes, there were no significant age-related differences in 2D RAV measurements, but 3D RAV values differed minimally with age, remaining significant after BSA indexing. RA total EmF and reservoir strain and passive EmF and conduit strain magnitude were lower in older groups for both sexes. Interestingly, whereas RA active EmF increased with age, contractile strain magnitude decreased. Considerable geographic variations were identified: Asians of both sexes had significantly lower BSA than non-Asians, and their 2D and 3D end-systolic RAVs were significantly smaller even after BSA indexing. Of note, 2D end-systolic RAVs in this group were considerably lower than normal values provided in the current guidelines. CONCLUSIONS: There is significant sex, age, and geographic variability in normal RA size and function parameters. Current guideline-recommended normal ranges for RA size and function parameters should be adjusted geographically on the basis of the results of this study.

Left Ventricular Diastolic Function in Healthy Adult Individuals: Results of the World Alliance Societies of Echocardiography Normal Values Study.

BACKGROUND: The World Alliance Societies of Echocardiography (WASE) study was conducted to describe echocardiographic normal values in adults and to compare races and nationalities using a uniform acquisition and measurement protocol. This report focuses on left ventricular (LV) diastolic function. METHODS: WASE is an international, cross-sectional study. Participants were enrolled with equal distribution according to age and gender. Echocardiograms were analyzed in a core laboratory based on the latest American Society of Echocardiography/European Association of Cardiovascular Imaging guidelines. Left ventricular diastolic function was assessed by E, E/A, e' velocities, E/e', left atrial volume index (LAVI), and tricuspid regurgitation velocity. Determination of LV diastolic function was made using the algorithm proposed by the guidelines. RESULTS: A total of 2,008 subjects from 15 countries were enrolled. The majority were of white or Asian race (42.8%, 41.8%, respectively). E and E/e' were higher in female patients, while LAVI was similar in both genders. Consistent increase in E/e' and decrease in E/A, E, and e' were found as age increased. The upper limit of normal for LAVI was higher in WASE compared with the guidelines. The lower limits of normal for e' were smaller in elder groups than those in the guidelines, while the upper limits of normal for E/e' were below the guideline values. These findings suggest that the cutoff value for LAVI should be shifted upward and age-specific cutoff values for e' should be considered. In WASE, <93.6% of patients were classified as normal LV diastolic function using the guidelines' algorithm, and the proportion increased to 97.4% when applying the revised cutoff values for LAVI obtained in our study. CONCLUSIONS: Guideline-recommended normal values for e' velocities and LAVI should be reconsidered. The algorithm for the determination of LV diastolic function proposed by the guidelines is useful, but adjustments to LAVI could further improve it.

Similarities and Differences in Left Ventricular Size and Function among Races and Nationalities: Results of the World Alliance Societies of Echocardiography Normal Values Study.

BACKGROUND: The World Alliance Societies of Echocardiography (WASE) Normal Values Study evaluates individuals from multiple countries and races with the aim of describing normative values that could be applied to the global community worldwide and to determine differences and similarities among people from different countries and races. The present report focuses specifically on two-dimensional (2D) left ventricular (LV) dimensions, volumes, and systolic function. METHODS: The WASE Normal Values Study is a multicenter international, observational, prospective, cross-sectional study of healthy adult individuals. Participants recruited in each country were evenly distributed among six predetermined subgroups according to age and gender. Comprehensive 2D transthoracic echocardiograms were acquired and analyzed following strict protocols based on recent American Society of Echocardiography and European Association of Cardiovascular Imaging guidelines. Analysis was performed at the WASE 2D core laboratory and included 2D LV dimensions, LV volumes, and LV ejection fraction (LVEF) by the biplane Simpson method and global longitudinal strain (GLS). RESULTS: Two thousand eight subjects were enrolled in 15 countries. The median age was 45 years (interquartile range, 32-65 years), 42.8% were white, 41.8% were Asian, and 9.7% were black. LV dimensions and volumes were larger in male subjects, while LVEF and GLS were higher in female subjects. Global WASE normal ranges for LV dimensions were smaller than those in the guidelines, but the upper limits of normal for LV volumes and the lower limits of normal for LVEF were higher in the WASE study. Significant intercountry variation was identified for all LV parameters reflecting LV size (dimensions, mass, and volumes) even after indexing to body surface area, with LV end-diastolic and end-systolic volumes having the highest variation. The largest volumes were noted in Australia, while the smallest were measured in India for both genders. This finding suggests that in addition to gender and body surface area, specific country should be considered when evaluating LV volumes. Intercountry variation for LVEF and GLS was smaller but still statistically significant (P < .05 for all). CONCLUSIONS: LV dimensions and volumes are larger in men, while LVEF and GLS are higher in women. Current guideline-recommended normal ranges for LV volumes and LVEF should be adjusted. Intercountry variability is significant for LV volumes, and therefore nationality should be considered for defining ranges of normality.