A pacing lead having a lead body comprising a hollow sheath by a first lumen and an extension body extending from the lead body, the extension body having a proximal end and a distal end, the distal end having an active lead region. The extension is traversed by a second lumen, the second lumen communicating with the first lumen of the lead body so as to receive a guide wire for the implantation of the lead. The extension has an outside diameter of between 1 and 3 French. The extension distal end comprises at least one electrically isolated peripheral conductor electrically insulated except for at least two denuded areas on an outer surface of the conductor to contact a wall of a target vein, so as to form a network of stimulation electrodes electrically connected together. The lead body proximal end includes an electrical connection for the peripheral conductor.