Devices and methods for improving the function of a valve (e.g., mitral valve) by positioning a spacing filling device outside and adjacent the heart wall such that the device applies an inward force against the heart wall acting on the valve. A substantially equal and opposite force may be provided by securing the device to the heart wall, and/or a substantially equal and opposite outward force may be applied against anatomical structure outside the heart wall. The inward force is sufficient to change the function of the valve, and may increase coaptation of the leaflets, for example. The space filling device may be implanted by a surgical approach, a transthoracic approach, or a transluminal approach, for example. The space filling portion may be delivered utilizing a delivery catheter navigated via the selected approach, and the space filling portion may be expandable between a smaller delivery configuration and a larger deployed configuration.