A method of implanting a collapsible prosthetic heart valve is disclosed. The prosthetic heart valve includes three biological leaflets mounted within a self-expanding tubular leaflet frame formed of nitinol. The method comprises loading a collapsed prosthetic heart valve into a distal end of a delivery tube. The distal end of the delivery tube is inserted into a vasculature of a patient and positioned proximal to an aortic valve. The prosthetic heart valve is expelled into an annulus of the aortic valve and allowed to self-expand to a first diameter. A balloon is then inflated within the prosthetic heart valve for expanding the prosthetic heart valve to a second diameter, wherein the second diameter is larger than the first diameter, thereby securely implanting the prosthetic heart valve within the annulus of the aortic valve.