A hermetic terminal assembly for an AIMD includes a shielded three-terminal flat-through EMI energy dissipating filter and a hermetically sealed feedthrough configured to be attachable to the ferrule or AIMD housing. The flat-through filter includes a first shield plate, an active electrode plate, and a second shield plate where the shield plates are electrically coupled to a metallization which in turn is coupled either to the ferrule or AIMD housing. The feedthrough includes an alumina substrate comprised of at least 96% alumina and a via hole with a substantially closed pore and substantially pure platinum fill. The platinum fill forms a tortuous and mutually conformal knitline or interface between the alumina substrate and the platinum fill, wherein the platinum fill is electrically coupled to at least one active electrode plate in non-conductive relationship to the at least one first and second shield plates.