Abstract: An insulated, corrosion-resistant heart pacer is described which incorporates a novel tantalum output means, said output means having disposed on at least the exterior surfaces thereof an anodically-formed substantially continuous Ta.sub.2 O.sub.5 insulating layer. The output means of the pacer or other medical electronic device comprises a tantalum centerpin disposed through a hermetically sealed titanium case, which centerpin is welded to a tantalum feed wire, the combination providing a device in which the Ta.sub.2 O.sub.5 insulating layer reduces the electrical leakage from the tantalum conductor to the titanium case, and whereby the insulating layer disposed thereon further protects the pacer from electrolysis and electrochemical corrosion. An alternate embodiment of the present invention provides tantalum conduit means for electrically connecting an energy source to logic circuitry which is disposed within a hermetically sealed titanium case.