Background:The mitral annulus (MA) is a dynamic structure which integrates the left atrium and left ventricle (LV). However, the geometric change of the MA during systole and its impact on the left atrial filling has not been well defined
Methods: 51 patients (LVEF = 37.4짹13.5%) who underwent real-time 3D echocardiography were enrolled. Those who had significant mitral regurgitation, regional wall motion abnormality or atrial fibrillation were excluded. Pulmonary venous (PV) systolic inflow velocity was measured by 2D Doppler echocardiography. Fractional changes of antero-posterior dimension of mitral annulus (MAD) and left atrial volume (LAV) during systole as well as LV ejection fraction were assessed using multi-planar reconstructive mode of 3D image analysis software (TomTec, Co. Germany).
Results: The MA showed antero-posterior directional enlargement during systole. Fractional change of MAD during systole was significantly related to LV ejection fraction (r = 0.63, P < 0.01). Fractional change of MAD also showed significant correlations with that of LAV (r = 0.79, P < 0.01) and PV systolic inflow velocity (r = 0.56, P < 0.01).
Conclusion: The MA showed the antero-posterior enlargement during systole, which was dependent on LV systolic function. The systolic MA motion seems to have a bridge role providing interactive relationship between LV and LA function during systole and ultimately contributing to LA filling.