The disclosure relates to a multipolar, detection/stimulation endovascular lead intended to be implanted in the coronary venous network. The lead comprises a lead body with in proximal portion a connector to a cardiac pacemaker/defibrillator generator, and in a distal portion a first branch and a second branch extending beyond a bifurcation. The distal ends of the branches are free ends carrying an array of electrodes connected to the connector. Each of the branches comprises at its free end an outlet in the distal direction, able to receive an implantation guide wire inserted therein and to guide the implantation guide wire in an axial direction parallel to the main axis of the lead body.