Coronary venous pacing lead and anchoring screw system

A system implantable in a coronary venous system, for stimulating a left heart chamber by a generator of an active implantable medical device, comprising:

• a stimulation lead having a distal end, a proximal end and a lead body having a sheath of a deformable material, said stimulation lead having a lead head at the distal end, with at least one stimulation electrode adapted to come into contact with a region facing an epicardial wall of a target vein of a patient's coronary network, and said stimulation lead having at the proximal end means for coupling to a generator of the active implantable medical device, and
• a removable guide catheter comprising a hollow tube having a proximal end and a distal end, both ends being open and having a lumen for receiving the stimulation lead for movement translationally within the guide catheter between a retracted position and a deployed position, at the retracted position the lead head being positioned at a guide catheter lumen distal end, and at the deployed position the lead head with the at least one stimulation electrode extending from said catheter lumen distal end,
• wherein the hollow tube of the guide catheter is elastically deformable and relatively more rigid than the sheath of the lead body,
• wherein the stimulation lead is a screw lead, having an anchoring screw axially extending along the lead head configured to penetrate the patient's epicardial tissue in response to a screw motion imparted to the lead head;
• wherein the sheath of the lead body is not pre-shaped at the distal end of the stimulation lead, and wherein the hollow tube of the guide catheter is a single pre-shaped tube with, in absence of a stress, first and second curvatures inscribed in two separate surfaces, said first and second curvatures self-orienting the distal end of the guide catheter tube in the target vein with the lead head in the retracted position, and configured to maintain an axis of the anchoring screw towards the epicardial wall of the target vein during a combined motion of screwing and moving the lead head to the deployed position
• wherein the anchoring screw comprises an end portion that is configured to penetrate the patient's epicardial tissue and a tip active electrically conductive region extending through an electrically isolated intermediary part.