An improved system and method for deploying medical electrical leads is disclosed. The system includes a guiding device such as a guidewire used to navigate the vascular system of a body. The guiding device includes a fixation member that can be deployed to maintain the guiding device at a desired location within the vascular system. The fixation member may be an inflatable device such as a balloon, or alternatively, may be an expandable device constructed of flexible fibers that has both an expanded and a contracted state. The system may further include a coupling member located adjacent to the guiding device. The coupling member may be a rail extending distally from a proximal end of the guiding device to a point proximal the fixation member. In an alternative embodiment of the invention, the coupling member is a channel included in the body of the guiding device adapted to slidably engage an electrode assembly. The coupling member is adapted to allow the electrode assembly to be slid to the distal end of the coupling member and deployed at a predetermined implant site. In one embodiment of the invention, the coupling member is movable with respect to the guiding device. This allows the coupling member to be re-positioned to multiple implant sites to deploy more than one electrode while the fixation mechanism remains stationary within a patient's vascular system. According to yet another aspect of the invention, the guiding device includes a lumen to delivery fluoro visible medium.