This invention relates to an implantable lead, which comprises a conductor an electrode assembly, arranged at a distal end of the lead, and comprising a housing defining an internal cavity a helical guide spring arranged in a proximal portion of the cavity and having several spaced turns, and a fixation assembly, which is rotatable relative to the housing, and which includes a shaft extending into the cavity from a proximal end of the housing and an extendable helical fixation element attached to the shaft at a distal end thereof and protruding beyond the distal end thereof. The fixation assembly has an interaction portion, which interacts with the helical guide spring for causing longitudinal movement of the fixation element when the shaft is rotated.
