Left ventricular diastolic function is strongly correlated with active emptying of the left atrium: a novel analysis using three-dimensional echocardiography

BACKGROUND Increased left atrial (LA) dimensions are known to be a risk factor in predicting cardiovascular events and mortality and to be one key diagnostic tool to assess diastolic dysfunction. Currently, LA measurements are usually conducted using 2D-echocardiography, although there are well-known limitations. Real-time 3D-echocardiography is able to overcome these limitations, furthermore being a valid measurement tool compared to reference standards (e.g. cardiac magnetic resonance imaging). We investigated LA function and volume and their association to left ventricular (LV) diastolic function, using newly designed and validated software for 3D-echocardiographic analysis. This software is the first to allow for a sophisticated analysis of both passive and active LA emptying. METHODS We analyzed 2D- and 3D-echocardiographic measurements of LA volume and function in 56 subjects and compared the results between patients with normal LV diastolic function (NDF) (n = 30, 52 ± 15 years, BMI 24.7 ± 2.6 kg/m2) and patients in which diastolic dysfunction (DDF) was suspected (n = 26, 65 ± 9 years, BMI 26.7 ± 3.7 kg/m2). RESULTS Volumes during LA active emptying were significantly smaller in DDF compared to NDF (active atrial stroke volume (ASV): 3.0 (0.1-4.5) vs. 5.5 (2.7-7.8) ml, p = 0.005; True-EF: 7.3(0.1-11.5) vs. 16.2 (8.1-25.4) %, p = 0.002). Furthermore, ASV showed a stronger association to E/e'mean than all other measured LA volumes (β = - 0.35, p = 0.008). Neither total stroke LA volume, nor maximum or minimum LA volume differed significantly between the groups. CONCLUSIONS Diastolic LV dysfunction results in a reduction in active LA emptying, which is more strongly associated with LV filling pressure than other previously investigated LA parameters.