Abstract: The invention discloses an occluder for a structural heart defect, comprising a tubular interlaced structure having a pitch that varies along an axial length of the occluder; a proximal element; a distal element; and an intermediate element extending between the proximal element and the distal element. According to one aspect, at least one transition section of the pitch, from a first pitch to a second pitch, is located closer to the intermediate element of the occluder than an outer circumference of at least one of the proximal elements and the distal element when the occluder is in a relaxed state. According to another aspect, the occluder is extendible from the relaxed state to an axially extended state wherein the load to extension ratio, measured in N/mm, provided by the occluder is less than about 0.75 when extended at least 2 mm.