A prosthetic valve delivery system comprising a prosthetic valve having a self-expanding frame having a superior end, an inferior end, and a midsection therebetween, wherein the frame has an expanded configuration and a collapsed configuration, the collapsed configuration adapted to be delivered to a patient's heart, and the expanded configuration adapted to anchor the self-expanding frame in the patient's heart, wherein the frame comprises: a self-expanding atrial skirt adjacent the superior end, wherein the atrial skirt forms a flanged region after self-expansion thereof, the flanged region configured to anchor the self-expanding frame to an atrial surface of the heart, and wherein the flanged region comprises an edge of the flange; a self-expanding ventricular skirt adjacent the inferior end, wherein the ventricular skirt anchors the self-expanding frame to a ventricular surface of the heart after self-expansion thereof; and a first self-expanding tab adjacent the inferior end and coupled with the ventricular skirt, the first self-expanding tab having a tip and a base; the delivery system comprising an outer sheath to constrain the prosthetic valve, wherein the first self-expanding tab is configured to radially self -expand when unconstrained, and wherein a receptacle adapted for receiving a valve leaflet is formed by an area bounded by an outer surface of the atrial skirt, an outer surface of the ventricular skirt, and an inner surface of the first tab, and wherein a window is defined by a gap between the edge of the flange and the tip of the first tab, characterised in that the outer sheath has a cammed inner surface adjacent a distal end thereof, such that retraction of the outer sheath causes the gap to be maximized when the tip of the first tab is unconstrained and a base of the first tab is at least partially constrained and the gap to be minimized when tip of the first tab is unconstrained and the base of the first tab is also unconstrained. a self-expanding atrial skirt adjacent the superior end, wherein the atrial skirt forms a flanged region after self-expansion thereof, the flanged region configured to anchor the self-expanding frame to an atrial surface of the heart, and wherein the flanged region comprises an edge of the flange; a self-expanding ventricular skirt adjacent the inferior end, wherein the ventricular skirt anchors the self-expanding frame to a ventricular surface of the heart after self-expansion thereof; and a first self-expanding tab adjacent the inferior end and coupled with the ventricular skirt, the first self-expanding tab having a tip and a base; wherein the first self-expanding tab is configured to radially self -expand when unconstrained, and wherein a receptacle adapted for receiving a valve leaflet is formed by an area bounded by an outer surface of the atrial skirt, an outer surface of the ventricular skirt, and an inner surface of the first tab, and wherein a window is defined by a gap between the edge of the flange and the tip of the first tab, characterised in that the outer sheath has a cammed inner surface adjacent a distal end thereof, such that retraction of the outer sheath causes the gap to be maximized when the tip of the first tab is unconstrained and a base of the first tab is at least partially constrained and the gap to be minimized when tip of the first tab is unconstrained and the base of the first tab is also unconstrained.