Abstract: Systems, devices, and methods for reducing regurgitation through an atrioventricular heart valve: i.e., the mitral valve and the tricuspid valve. The device includes a flexible anchor rail anchored in the tissue of the ventricle and an offset coaptation element on a catheter that rides over the anchor rail and is positionable between the valve leaflets. The proximal end of the coaptation catheter is fixed subcutaneously adjacent the subclavian vein. The coaptation element includes an inert covering over a foam interior, and is radially offset on the catheter so that the foam body projects away from the septal side of the valve to reduce or minimize deformation from contact with the septal wall of the ventricle. Markers on the coaptation element facilitate positioning in the desired rotational orientation during delivery and implant.