Reference values and correlates of right atrial volume in healthy adults by two-dimensional echocardiography

BACKGROUND: Right atrial (RA) volume is an important parameter in the evaluation of patients with pulmonary hypertension. Aim of this study was to define reference ranges for RA volume by two-dimensional echocardiography (2DE) in healthy adults. METHODS: A total of 596 healthy subjects [mean age 45.7 ± 14.6 years, range 18-88 years; 60.1% women] underwent a transthoracic echocardiography. In addition, a meta-analysis was performed of published studies measuring RA volume in healthy subjects, using 2DE single plane area-length (A-L) and/or method of disks (MOD) at end-systole in apical four-chamber view. RESULTS: In our cohort, RA volume was higher in men than women but did not vary with age. Body surface area (BSA), stroke volume (SV), and tricuspid annular plane systolic excursion (TAPSE) were the only independent variables associated with RA volume (β coefficient 0.569, 0.123, and 0.131, respectively; all P < .001). In the pooled analysis, normalized RA volume was 25.7 ± 7.0 mL/m2 in men and 21.2 ± 5.8 mL/m2 in women for A-L, 21.6 ± 5.6 mL/m2 in men and 18.2 ± 5.4 mL/m2 in women for MOD (all P values < .0001). The upper limit was about 36 mL/m2 in men and 31 mL/m2 in women for A-L and 31 mL/m2 in men and 27 mL/m2 in women for MOD. CONCLUSIONS: RA volume was found to be higher in men but not influenced by age. It was mainly correlated with larger BSA, indices of preload (SV) and RV longitudinal function (TAPSE). A statistically significant difference was found between A-L and MOD.