Effects of Age and Gender on Left Atrial Ejection Force and Volume from Real-Time Three-Dimensional Echocardiography

Introduction: This study was carried out to (i) provide the methodology for determining left atrial (LA) volume, emptying fraction and ejection force (LAEF), from real-time 3-dimensional echocardiography (RT3DE), and (ii) evaluate the effects of age and gender on LA volume and LAEF in a wide age range of healthy participants. Materials and Methods: RT3DE was performed in 102 healthy participants (age range, 20 to 80 years). From full-volume data sets, LA endocardial borders were automatically traced and LA volumes were determined. LAEF was calculated as 1/3xmitral annular area x (blood density) x (peak velocity of A wave)2 according to Newton's law of motion and hydrodynamics; wherein the mitral annular area (MVA) is traced using RT3DE and A is the peak Doppler-derived blood velocity at atrial systole with the sample volume placed at the mitral annulus level. Results: ANOVA analysis revealed that LA volume indices were significantly correlated with age (r = 0.366, P <0.0001 for maximal volume index and r = 0.288, P <0.005 for minimal volume index). LAEF was also significantly positively correlated with age (r = 0.49, P<0.0001). The LA emptying fraction was maintained across ages. LA volume indices and LAEF did not differ significantly with gender. Conclusion: Our data can be used as normal reference values for LA volumes and LAEF. We have demonstrated that age is positively related to LA volume indices and LAEF, which suggests that age-dependent cut-off values should be considered in those with heart disease.