A delivery system for implanting a medical device into the body of a patient or subject and a method of use thereof. The delivery system includes a delivery catheter having a catheter lumen and an inner member extending therethrough. The inner member includes a distal tip portion, a proximal portion, and an intermediate portion, the intermediate portion being disposed adjacent to the distal end of the delivery catheter. A first sealing member, positioned near a distal end of the proximal portion, forms a fluid seal between the inner member and an inside surface of the delivery catheter. A second sealing member, positioned near a proximal end of the distal tip portion, forms a fluid seal between the inner member and an inside surface of the delivery catheter. The intermediate portion extends between the first seal and the second seal. In one embodiment, a medical device and a hydrating fluid are present in a device-containing region between the intermediate portion and the delivery catheter.