1. A method for producing a patient-specific implantable pacemaker electrode, comprising the steps of: using an electronic 3D representation of the coronary sinus vessel tree of a patient in whom a pacemaker electrode is to be implanted, said 3D representation including an indication of an implantation site in the coronary sinus vessel tree for the electrode, segmenting the 3D representation of the coronary sinus vessel tree to visually indicate the interior surface of the coronary sinus vessel tree and a representative line from an opening of the coronary sinus vessel tree to the implantation site; generating a computerized model of said electrode; conducting a computerized virtual implantation of said electrode through said 3D representation of said coronary sinus vessel tree to said implantation site using at least said model and said internal surface and said representative line; from said virtual implantation, making an implantation determination as to whether an electrode conforming to said model can be guided to and implanted at said implantation site in a medically acceptable manner; if said implantation determination is positive, producing an actual electrode conforming to said model; and if said implantation determination is negative, iteratively modifying said model and repeating said virtual implantation until a positive implantation determination is achieved, with a last-modified model, and producing an actual electrode conforming to said last-modified model.