Abstract: An apparatus for performing a transesophageal cardiovascular procedure includes an elongated tubular main access device having a first lumen with an open proximal end and a distal side opening, and a second lumen with a rigid outer wall and a collapsible inner wall. The second lumen is adapted to receive an elongated probe or surgical device. The apparatus further includes an inflatable sealing means on the outside of the main access device above and below the side opening, and a first fluid conduit extending along the main access device for inflating the sealing means so that when the main access device is inserted into a patient's esophagus and the sealing means are inflated. The portion of the esophagus opposite the side opening is isolated from the remainder of the esophagus above and below the side opening.