A system for the treatment of conditions affecting the mitral valve, comprising an interventional device for deployment upon and/or along the mitral valve comprising: a proximal stabilizing structure having a first pair of arm members pivotably joined to a proximal engagement link , and wherein each arm member of the first pair of arm members is further pivotably joined to a respective joining member of a first pair of joining members , wherein each joining member of the first pair of joining members is pivotably coupled to an arm member of a second pair of arm members via a respective link of a first pair of links , wherein each arm member of the second pair of arm members is further coupled pivotably to a respective joining member of a second pair of joining members , and wherein each joining member of the second pair of joining members is further pivotably coupled to a middle engagement link ; and a distal stabilizing structure having a third pair of arm members , wherein each arm member of the third pair of arm members is pivotably coupled to a respective joining member of a third pair of joining members via a respective link of a second pair of links , wherein each joining member of the third pair of joining members is pivotably coupled to a respective arm member of a fourth pair of arm members pivotably joined to a distal engagement link , wherein each of the arm members of the third pair of arm members is further pivotably coupled to a respective joining member of a fourth pair of joining members , and wherein each joining member of the fourth pair of joining members is pivotably coupled to the middle engagement link ; wherein the distal and proximal stabilizing structures are pivotably coupled via the engagement link such that the distal and proximal stabilizing structures are configurable between an axially-elongated configuration and a laterally-elongated configuration. a proximal stabilizing structure having a first pair of arm members pivotably joined to a proximal engagement link , and wherein each arm member of the first pair of arm members is further pivotably joined to a respective joining member of a first pair of joining members , wherein each joining member of the first pair of joining members is pivotably coupled to an arm member of a second pair of arm members via a respective link of a first pair of links , wherein each arm member of the second pair of arm members is further coupled pivotably to a respective joining member of a second pair of joining members , and wherein each joining member of the second pair of joining members is further pivotably coupled to a middle engagement link ; and a distal stabilizing structure having a third pair of arm members , wherein each arm member of the third pair of arm members is pivotably coupled to a respective joining member of a third pair of joining members via a respective link of a second pair of links , wherein each joining member of the third pair of joining members is pivotably coupled to a respective arm member of a fourth pair of arm members pivotably joined to a distal engagement link , wherein each of the arm members of the third pair of arm members is further pivotably coupled to a respective joining member of a fourth pair of joining members , and wherein each joining member of the fourth pair of joining members is pivotably coupled to the middle engagement link ; wherein the distal and proximal stabilizing structures are pivotably coupled via the engagement link such that the distal and proximal stabilizing structures are configurable between an axially-elongated configuration and a laterally-elongated configuration. <EOS>