Abstract: A catheter system allows for percutaneous intervention on the fast-moving structures inside the heart. The device consists of a steerable catheter sheath, an actuated, multi-degree of freedom moving catheter, and a catheter end effector, such as a fixation device. An actuator controls the motion of the catheter guide-wire in the catheter sheath to follow the motion of the target tissue. A control system controls the actuator and compensates for mechanical characteristics of the system including friction and backlash. A 3-D imaging system can be used to view the motion of the target tissue and the catheter end effector and produce 3-D imaging data. The 3-D imaging data can be used by the control system to track the target tissue and accurately position the end effector with respect to the moving target tissue allowing a clinician to repair the target tissue while it is moving.