An implantable device for occluding a septal defect has interleaved frame sections that allow flexibility to conform to a variety of defect geometries and provide reliable occlusion during endothelialization. Left and right frames connect to opposite ends of a floating connection post. The device is resiliently deformable and is biased into a natural state wherein, in situ in a variety of defect geometries, the device applies a sandwiching force to the tissue surrounding the defect that is relatively uniform across its diameter, improving stability and promoting occlusion.