An implantable medical electrical lead includes an electrode assembly in which an electrical junction between a first conductor and an inner surface of a first electrode of the assembly is wedged within a first channel of at least one core member of the assembly, around which the first electrode extends. The at least one core member is formed from an insulating material, and the first channel may be one of a plurality of longitudinally extending channels arrayed around a circumference of a central lumen of the assembly, which is defined by the at least one core member. The first conductor extends along a length of the assembly, for example, defined between the first electrode and a second electrode thereof, in a helical path that travels around the central lumen.