A system for treating a heart includes a catheter that is advanceable into a chamber of the heart and that is repositionable within the chamber between a septal wall and an external wall to enable penetration of the septal and external walls via a needle that is disposed within a lumen of the catheter. A first guidewire is deliverable through the penetration of the septal wall so that a distal end of the first guidewire is disposed within another chamber of the heart. A second guidewire is deliverable through the penetration of the external wall so that a distal end of the second guidewire is disposed externally of the external wall. The first guidewire is connectable to the second guidewire to join or form a path within the chamber that extends between the septal wall and the external wall.
