A method of reducing regurgitation between native leaflets of an atrioventricular heart valve includes advancing a delivery catheter through a sheath, wherein the delivery catheter has a valve leaflet coaptation element mounted over a distal end portion. The coaptation element is positioned within the heart valve and is permitted to radially expand from a compressed configuration to an enlarged configuration for filling a gap between the native leaflets of the heart valve. After deployment, the position of the coaptation element is fixed relative to the heart valve, thereby reducing regurgitation between the native leaflets of the heart valve and improving heart function.