Figure 92a

Top: Active fixation lead with a porous electrode and an electrically inert screw. Surrounding the electrode is a silicone rubber collar impregnated with dexamethasone sodium phosphate (steroid). (Courtesy Telectronics Pacing Systems.)
Bottom: Active fixation lead with an electrically active screw. There is a steroid eluting collar surrounding the screw. (Courtesy Medtronics, Inc.)

Mond, H.G., MD, Permanent Cardiac Pacemakers: Techniques of Implantation, Testing, and Surveillance, Hurst's The Heart, 8th ed., p 815-841 (modified)