A system for treating mitral valve regurgitation comprises a tensioning device slidably received within a delivery catheter. The tensioning device includes a tether linking proximal an anchoring member and a distal anchoring member. At least one of the anchoring members includes an elastic portion that flexes in response to a heartbeat when the tensioning device is positioned across a chamber of a heart. The tether includes at least one locking member initially positioned between the anchoring members. A method for treating mitral valve regurgitation comprises piercing a first wall of a chamber of a heart, engaging a distal anchoring member with a second wall of the heart chamber, engaging a proximal anchoring member with the first wall, and pulling a locking member affixed to a tether linking the anchoring members from an initial position between the two anchoring members to a locked position proximal the proximal anchoring member.