US Patent 7618410 Devices and methods for access through a tissue wall

A method of accessing the pericardial space comprises providing a primary catheter having an inflatable balloon, inserting the primary catheter into the vascular system, forwarding the primary catheter through the vascular system to an atrial appendage, inflating the balloon to engage the wall of the appendage sufficient to separate opposing wall portions of the appendage between the cardiac tissue and the pericardium. The inflated balloon increases the distance of the pericardium from the cardiac tissue to permit easier access into the pericardial space via the appendage. The inflated balloon further can be configured to create a seal of the balloon exterior surface relative to an inner wall of the appendage adjacent to an apex of the appendage. The balloon seal isolates a portion of the interior of the appendage adjacent the apex allowing the removal of blood from the isolated portion. This prevents cross-contamination of fluid between the pericardial space and the appendage. An implantable valve positionable in the apex of the appendage permits repeatable access into the pericardial space.