incorporated mehra et al 39 551 patent the combined implantable defibrillator pulse generator and electrode assembly 10 of fig1 includes an active electrode formed of the entire exterior surface 13 of the metallic pulse generator housing 9 by attaching the housing 9 internally to a defibrillation circuit output terminal optionally the major upper surface of the housing the surface intended to face toward the exterior of the patient 39 s body may be coated with insulation so that the exterior surface 13 is exposed on only the major lower surface of the housing the surface intended to face toward the interior of the patient 39 s body the defibrillator pulse generator housing 9 carries a connector block 11 into which the bifurcated connector 14 is inserted and mechanically and electrically coupled so that the other electrode 20 and the pace sense electrodes 24 and 26 may be coupled to the circuitry within the housing 9 in accordance with the invention the subcutaneous electrode surface area is increased and distributed over a wider area by coupling it to an electrode array formed in and exposed on one or both surfaces of the flexible electrode bearing pad 15 preferably the flexible pad 15 is permanently bonded to housing 9 around its periphery the active electrode is thereby formed as part or all of the pulse generator housing surface 13 and the electrode array formed in the flexible electrode pad 15 described hereafter the flexible electrode bearing pad 15 is relatively flat and is fabricated of a flexible biopcompatible material such as silicone rubber or polyurethane turning to fig2 one embodiment of the combined housing and electrode assembly 10 is depicted in greater detail the flexible electrode bearing pad 15 is attached around the edge of the.