Determinants of echocardiographic left atrial volume: implications for normalcy

The relative role of multiple determinants of left atrial volume index (LAVi) in athletes and non-athletes is not fully defined. Thus, we decided to prospectively assess the determinants of LAVi in healthy individuals and competitive athletes over a wide age range. Four hundred and eighteen healthy individuals (mean age 41.7 ± 15.6 years, range 16-84, 65% males, 38% competitive athletes) underwent Doppler echocardiography including assessment of LAVi by the biplane area-length method and of left ventricular (LV) diastolic function including the ratio of early diastolic peak LV inflow velocity to peak myocardial early diastolic velocity (E/e'). Mean LAVi was 32.2 ± 9.0 mL/m(2) in the pooled population. LAVi was larger in athletes than in non-athletes (38.9 ± 9.6 mL/m(2) vs. 28.4 ± 5.8 mL/m(2), P < 0.0001). In the pooled population a stepwise multiple linear regression analysis identified LV end-diastolic volume index (LVEDVi) (β = 0.378, P < 0.0001), LV mass index (LVMi) (β = 0.260, P < 0.0001), competitive sport activity (β = 0.258, P < 0.0001), and age (β = 0.222, P < 0.0001) as independent determinants of LAVi (model R(2) = 0.54, P < 0.0001). By separate analyses, although LVEDVi, age, and LVMi were predictors of LAVi in both groups, body mass index and the E/e' ratio were additional predictors of LAVi only in non-athletes. In healthy individuals LV size, competitive sport, age, and LV mass are independent determinants of LAVi. Body mass index and the E/e' ratio affect LAVi only in non-athletes. These findings may have practical implications when assessing normalcy of LA size in the clinical setting.