A delivery device for a collapsible prosthetic heart valve may include an operating handle and a catheter assembly. The handle may include a housing, a piston cylinder, a piston longitudinally slidable within the piston cylinder, the piston and the piston cylinder together defining at least one pressure chamber, a deployment actuator coupled to the housing and rotatable relative thereto, and a pneumatic switch adapted to provide a pressurized fluid to the pressure chamber to apply a longitudinal force to the piston. The catheter assembly may include a first shaft around which a valve-receiving compartment is defined, the first shaft being operatively connected to the housing, and a distal sheath operatively connected to the piston, the distal sheath being moveable between a closed condition covering the compartment and an open condition uncovering the compartment. Longitudinal movement of the piston may move the distal sheath between the closed and open conditions.