Abstract: An improved electrode sealing arrangement for use on lead assemblies to be coupled to an implantable pulse generator to form a cardiac pacer apparatus. The conductive portion of the lead includes a terminal pin which is both rigid and durable, and which is arranged to be clamped between a set screw and a terminal post. The improved sealing means includes a generally closed cylindrical resilient segment which is arranged generally coaxially of the lead conductor, with a resilient peripheral sleeve extending outwardly of the cylindrical segment and having a raised resilient ring extending continuously about the outer periphery of the peripheral sleeve. The raised resilient ring is disposed axially outwardly from the distal end of the terminal pin, so as to provide an axial displacement between the terminal pin and the resilient sealing ring.