An electrode assembly for an active implantable medical device comprising: an elongated, biocompatible, electrically non-conductive body, having a first portion and a second portion; one or more biocompatible, electrically conductive filaments inside the elongated non-conductive body between the first portion and the second portion; and one or more fluid passages along the elongated non-conductive body between the first potion and the second portion, wherein the one or more fluid passages allow a surrounding fluid of a patient to be in contact with the one or more conductive filaments. There is also disclosed a method of manufacturing.