Abstract: The present invention is directed to various systems for repairing tissue within the heart of a patient. The mitral valve repair system of the present invention comprises a guide catheter having a proximal end, a distal end, and at least one internal lumen formed therein, a therapy catheter capable of applying a suture to the tissue, and a fastener catheter capable of attaching a fastener to the suture. The therapy catheter and the fastener catheter are capable of traversing the internal lumen of the guide catheter. In addition, the present invention discloses various methods for repairing tissue within the heart of a patient.