A delivery device for percutaneously deploying a prosthetic valve includes a sheath, an inner shaft, and a release assembly. The release assembly is disposed between the sheath and the inner shaft, and includes a retraction member, a release member, and a retention member. The retraction member can self-retract in length from an extended condition to a retracted condition. The release member can self-expand from a compressed condition to an expanded condition. The retention member is distal the release member. In a delivery state, the sheath end is distal the retention member, the release member is in the compressed condition and the retraction member in the extended condition to retain the prosthesis. In a deployment state, the sheath end is positioned to permit the release member to self-transition to the expanded condition, allowing the retraction member to self-transition to the retracted condition and release the prosthesis.