An electrode assembly for implantation around an elongate biological structure such as, for example, a blood vessel, includes at least one belt mechanism for securing the electrode assembly around the outer surface of the elongate biological structure. Each of the at least one belt mechanism includes a strap and a buckle. The assembly has a length that is sufficient to permit wrapping it around the outer surface of the elongate biological structure. The buckle can be attached to, or integrally formed in, the base, and functions to retain a portion of the strap when the strap is engaged with the buckle.