A transseptal cannula having a flexible cannula body, a left atrial anchor coupled to the distal end of the flexible cannula body, and a right atrial anchor operable to be attached to the left atrial anchor in vivo. The left and right atrial anchors are implanted and deployed separately. Delivery of the transseptal cannula to a heart tissue can include a low profile coaxial balloon catheter comprising a tube body including an inner member and an outer member surrounding the inner member and thereby creating an inflation channel between the inner and outer members, a hub coupled to the proximal portion of the tube body and including a fluid space in fluid communication with the inflation channel and a balloon coupled to the distal portion of the tube body, wherein the balloon is in fluid communication with the inflation channel. The hub of the coaxial balloon catheter is constructed with a low profile so that other surgical devices can be directed over the coaxial hub without deflating and removing the balloon.
