An improved implantable electrode for delivery of electrical stimulation pulses or signals to an organ such as the heart from an electrical pulse generator. The electrode is normally exposed to the organ to be stimulated and is, in turn, electrically coupled to a conductive lead extending from the pulse generator, with the electrode being a body which substantially completely envelopes the lead. The electrode comprises a plurality of electrically conductive metallic filaments compressed together to form a generally fibrous body which may in certain instances be pliant or flexible in nature. The filaments preferably have a mean, effective diameter less than about 100 microns and form from about 3% to 30% of the total volume of the fibrous member, and preferably from 5% to 20%. In one embodiment, the filaments are retained as a bundle within a metallic grid enclosure.