Association between Normal Aging and Phasic Left Atrial Volume as Assessed by Real-Time Three-Dimensional Echocardiography

Background: Left atrial (LA) size is a good predictor of many cardiovascular outcomes, including atrial fibrillation, stroke and heart failure. Real-time 3D echocardiography (RT30E) may be a superior index for estimating LA volume, compared with traditional M-mode and 20 methods. In this study, we used RT3DE to evaluate phasic LA volumes and functions among different age groups of healthy Taiwanese subjects.Methods: Sixty-eight healthy volunteers were divided into three groups according to age. Group 1: under 40 years old (n = 20); group 2: 40-60 years old (n = 24); and group 3: over 60 years old (n = 24). RT3DE of LA volume was acquired from the apical view. Three phasic LA volumes, including maximal LA volume (LAVmax), minimal LA volume (LAVmin) and LA volume before atrial contraction (LAVpreA) were measured. These phasic LA volumes were used to calculate the emptying volume and emptying fraction at different phases of one heart cycle.Results: There were significantly positive correlations between age and LA volumes (p = 0.639 for LAVmax, p = 0.642 for LAVpreA, p = 0.661 for LAVmin; all p ＜ 0.001). Total LA empty volume (p ＜ 0.001) and active LA empty volume (p = 0.001) also positively correlated with age. In contrast, total, passive and active LA emptying fractions were not significantly different among the three age groups.Conclusion: Aging has a significant effect on phasic LA volumes, but phasic LA empty fractions remain unchanged in healthy Taiwanese adults.