Differences in mitral valve geometry between atrial and ventricular functional mitral regurgitation in patients with atrial fibrillation: a 3D transoesophageal echocardiography study

This study investigated geometric differences in mitral valve apparatus between atrial functional mitral regurgitation (A-FMR) and functional mitral regurgitation (FMR) with left ventricular (LV) dysfunction in patients with atrial fibrillation (AF) using 3D transoesophageal echocardiography (TOE).

In total, 135 moderate or greater FMR patients with persistent AF or atrial flutter underwent 3D TOE. Fifty-six patients had A-FMR, defined as preserved LV ejection fraction (LVEF) of ≥50% and normal LV wall motion. Seventy-nine patients had ventricular FMR (V-FMR), defined as LV dysfunction (LVEF of <50%) or LV wall motion abnormality. To evaluate mitral leaflet coaptation, the coapted area was calculated as follows: total leaflet area (TLA) in end-diastole − closed leaflet area in mid-systole. Although annular area (AA) did not significantly differ between the two groups, TLA was significantly smaller in A-FMR than in V-FMR (P = 0.005). TLA/AA, indicating the degree of the leaflet remodelling, was significantly smaller in A-FMR than in V-FMR (P < 0.001). A-FMR had significantly smaller posterior mitral leaflet tethering height and angle measured at three anteroposterior planes (lateral, central, and medial) than V-FMR (all P < 0.001). However, vena contracta width (VCW) measured on long-axis view on TOE and coapted area, which correlated with VCW (r = −0.464, P < 0.001), were similar between the two groups.

Mitral leaflet remodelling may be less in A-FMR compared with V-FMR. However, leaflet tethering was smaller in A-FMR than in V-FMR, and this may result in a similar degree of mitral leaflet coaptation and mitral regurgitation severity.