An implantable lead includes a distal portion carrying a tissue stimulating electrode, at least a portion of its outer surface being adapted to stimulate cardiac tissue, wherein the electrode is covered by a pliable, electrically conductive sheath. The sheath is made of an electrically conductive material that does not rely on porosity for electrical charge transfer. The sheath is constructed and arranged to minimize or eliminate tissue ingrowth while passing sufficient electrical energy to stimulate the tissue.