The present invention relates to an apparatus for treating a defective heart valve in a patient, comprising:a prosthetic valve comprising an expandable stent portion and a valvular structure supported within the stent portion；a balloon catheter comprising an elongated shaft and a balloon connected to a distal end portion of the shaft；a guide catheter comprising an elongated shaft extending over the balloon catheter shaft, the shaft of the guide catheter comprising a steerable section, the guide catheter further comprising an adjustment mechanism operatively coupled to the steerable section, the adjustment mechanism configured to adjust the curvature of the steerable section and the portion of the balloon catheter shaft extending through the steerable section； anda tapered nose piece positioned distal to the balloon for providing atraumatic tracking through tortuous vasculature；wherein the balloon catheter is advanceable relative to the prosthetic valve for sliding the balloon into the prosthetic valve and wherein the balloon is inflatable for deploying the prosthetic valve at an implantation site in the patient's body.
