Abstract: A small diameter, unipolar or bipolar, atrial or ventricular transvenous or epimyocardial pacing lead with a porous, platinized, steroid eluting cathode electrode exhibiting an effective surface area in the range of 0.1 to 4.0 mm.sup.2, preferably 0.6 to 3.0 mm.sup.2, provides low stimulation thresholds in the range of 0.5 volts, 0.5 milliseconds, very high pacing impedance (800 to 2,000 .OMEGA.), relatively low polarization, good to excellent sensing, and adequately low source impedance. The high pacing impedance prolongs the longevity of pacing pulse generators and allows for the miniaturization of their components. The low thresholds allow large safety factors at low applied voltages, which also contribute to increased battery longevity.

Abstract: A large surface electrode optimized for use as a subcutaneous defibrillation electrode. The electrode includes an insulative electrode pad carrying a large surface electrode. Both the upper and lower surfaces of the electrode pad are covered by a fabric mesh to reduce fluid build-up at the site of implantation. The defibrillation electrode is spaced at least 0.5" from the external periphery of the pad.