Apparatus, comprising: (i) a catheter (64); (ii) an implant (100), comprising a flexible longitudinal member (102), and a linking member (104) that extends from a first linking site (106a) of the longitudinal member to a second linking site (106b) of the longitudinal member, the implant having: (a) a delivery state in which the longitudinal member is coaxial with the catheter, and at least a portion of the linking member is disposed alongside the longitudinal member, and (b) an implanted state in which a first distance between the first linking site and the second linking site, measured along the longitudinal member, is greater than a second distance between the first linking site and the second linking site, measured along the linking member; and (iii) a plurality of tissue anchors (46), slidable through the catheter and with respect to the longitudinal member. Other embodiments are also described.