device 15 are inserted into the patient utilizing a catheter system 50 which is a meter or more long as is necessary to extend from an incision in the patient through the vascular system to the various locations where the components of the medical device 15 are to be implanted the catheter system 50 has a proximal end that remains outside the patient to which the physician has access to manipulate the elements of the catheter system and has a distal end that is inserted into the patient and which contains the medical device components the distal end section of the catheter system 50 is illustrated in fig3 to which continuing reference is made the catheter system comprises a conventional guide wire 52 over which an assembly 51 of several catheters and sheaths are coaxially inserted those catheters and sheaths are made of a flexible biologically compatible material commonly used for medical catheters a first or inner catheter 54 has a tubular construction with a lumen 55 through which the guide wire 52 extends see also the cross section through this region of the catheter system 50 in fig4 a first component such as the second electrode 21 of the medical device is positioned around the end of the first catheter 54 with a first inner sheath 56 around the first component to maintain it.