Abstract: A feedthrough filter capacitor assembly and related installation method are provided for shielding a conductive terminal pin or lead of the type used, for example, in an implantable medical device such as a heart pacemaker or defibrillator, against passage of external interference signals. The feedthrough assembly includes a terminal pin subassembly having at least one terminal pin supported within a cylindrical conductive ferrule by a hermetically sealed insulator ring. The ferrule is adapted for mounting onto a conductive pacemaker housing, as by welding or brazing, to support the terminal pin for feedthrough passage to the housing interior. A co-axial filter capacitor is mounted at an inboard side of the pacemaker housing, with capacitor electrode plate sets coupled respectively to the pacemaker housing and to the terminal pin by a conductive adhesive or the like.