A method of delivering a collapsible prosthetic heart valve may include providing a delivery device having a catheter assembly and an operating handle. The catheter assembly may include a compartment adapted to receive the valve and a slidable distal sheath. The operating handle may include a housing and first and second lead screws each movable in first and second opposite longitudinal directions. The method may include loading the valve into the compartment and covering the compartment and the valve with proximal and distal segments of the distal sheath. The method may include inserting the catheter assembly into the patient, and partially deploying the valve by moving the first lead screw in the first longitudinal direction. The method may include fully deploying the valve by simultaneously continuing movement of the first lead screw in the first longitudinal direction and moving the second lead screw in the second longitudinal direction.
