A delivery apparatus for implanting a radially compressible and expandable prosthetic heart valve in a native heart valve of the heart includes a handle portion and an elongated shaft extending from and movable relative to the handle portion. The shaft includes a proximal end portion coupled to the handle portion and a distal end portion configured to mount a prosthetic heart valve in a radially compressed state. The handle portion includes a control member movable longitudinally with respect to the handle portion, the control member engaging a gear assembly operable to convert longitudinal motion of the control member to rotational motion of the gear assembly. The gear assembly engages the elongated shaft such that rotational motion of the gear assembly causes corresponding longitudinal motion of the elongated shaft relative to the handle portion.