1. The instant invention relates to transseptal access systems and methods for accessing the left atrium (52) from the right atrium (48) by crossing the interatrial septum (50).

2. The diastolic transseptal pressure gradient correlated inversely with the eccentric index.

3. Objective To evaluate the relationship of transseptal pressure and QP /QS.

4. In particular, the instant invention is directed toward medical devices used with catheter assemblies in cardiology procedures that require transseptal puncture(s).

5. Methods: A new self- manufactured LAA occluder was implanted into the LAA through a transseptal catheter in 20 dogs.

6. The puncture device is adjustable from a position within the dilator to a position extending beyond the end of the dilator when necessary for use in transseptal procedures.