This invention provides an antimicrobial annuloplasty rings, and methods for making the same, wherein the annuloplasty rings have a desired degree of initial rigidity to facilitate ease of handling during implantation but which becomes flexible some time after implantation. The annuloplasty ring contains a relatively rigid insert enclosed by a fabric sheath, the insert being at least partly comprised of a biodegradable material. Following surgical implantation of the annuloplasty ring, the rigid insert component of the ring, upon exposure to blood and / or other physiological fluids, undergoes a controlled biodegradation which decreases its rigidity, thereby increasing the flexibility of the implanted annuloplasty ring. Furthermore, at least some portion of the annuloplasty ring of the invention has incorporated therein one or more antimicrobial agents in a manner which reduces the likelihood of device infection following implantation.