This implant (1) is formed by a helically wound wire (2). According to the invention, it has dimensions such that it is able to be screwed into the wall of the annulus (103) and/or into the cardiac wall (101) adjoining this annulus (103) such that a portion of said annulus (103) and/or of said wall (101) is located in the perimeter of the implant (1) and it comprises at least one first coil able, during said screwing of the implant (1), to insert itself into said wall while having a first dimension and at least one second coil having a second dimension, or adopting this second dimension after implantation, said second dimension being smaller than the first dimension such that the implant (1), once inserted, enables contraction of said wall portion located in the perimeter of this implant (1).