A prosthetic heart valve device for treating a native heart valve having a native annulus and native leaflets, comprising: a valve support having an upstream region and a downstream region relative to blood flow direction through a native heart valve of a human heart, the upstream region being configured to support a prosthetic valve , the prosthetic valve having a plurality of leaflets and having an undeformed shape in which the leaflets coapt sufficiently to prevent backflow through the prosthetic valve; an anchoring member arranged around the valve support and including an outwardly-facing fixation portion having an engagement surface configured to engage tissue at an implant site on or below the native annulus, the fixation portion having a first cross-sectional shape in an unbiased condition and being deformable into a second cross-sectional shape to adapt to a shape of the tissue at the implant site in a deployed state; and a connection structure interconnecting the fixation portion to the valve support , the fixation portion extending from the connection structure at a transition zone, and the transition zone being configured to be positioned at a subannular location below the native annulus and to allow the fixation portion to deflect angularly relative to the connection structure; characterized in that the tissue fixation portion of the anchoring member is mechanically isolated from the upstream region of the valve support such that the upstream region of the valve support maintains the undeformed shape if the anchoring member has been deformed into the second cross-sectional shape by distorting forces exerted by the tissue at the implant site during each cardiac cycle. a valve support having an upstream region and a downstream region relative to blood flow direction through a native heart valve of a human heart, the upstream region being configured to support a prosthetic valve , the prosthetic valve having a plurality of leaflets and having an undeformed shape in which the leaflets coapt sufficiently to prevent backflow through the prosthetic valve; an anchoring member arranged around the valve support and including an outwardly-facing fixation portion having an engagement surface configured to engage tissue at an implant site on or below the native annulus, the fixation portion having a first cross-sectional shape in an unbiased condition and being deformable into a second cross-sectional shape to adapt to a shape of the tissue at the implant site in a deployed state; and a connection structure interconnecting the fixation portion to the valve support , the fixation portion extending from the connection structure at a transition zone, and the transition zone being configured to be positioned at a subannular location below the native annulus and to allow the fixation portion to deflect angularly relative to the connection structure; characterized in that the tissue fixation portion of the anchoring member is mechanically isolated from the upstream region of the valve support such that the upstream region of the valve support maintains the undeformed shape if the anchoring member has been deformed into the second cross-sectional shape by distorting forces exerted by the tissue at the implant site during each cardiac cycle. <EOS>