Combined pacemaker substrate and electrical interconnect and method of assembly

A pacemaker having a single integrated interconnect structure is disclosed which combines the functions of a flexible interconnect cable and a protective lid for a hybrid substrate. The integrated interconnect structure is a molded three-dimensional part having a lid portion and a feedthrough portion. An electronic substrate can be mounted onto the integrated interconnect structure wherein electrical conductors formed within the integrated interconnect structure connect the electronic substrate to the battery terminals and to the pacemaker feedthroughs. In one embodiment, the integrated interconnect structure may be adapted to have additional electronic circuitry mounted directly onto a flat inner cavity within the lid portion, thereby enabling electronic components to be easily added or modified without complicating the assembly operations of the pacemaker.