The present invention is directed to systems, devices and methods fortrans-septally delivering carbon dioxide through a minimally invasive cathetertocreate a gaseous pocket or emphysema between the posterior wall of the leftatrium and the esophagus during cardiac ablation of the left atrium. Thispocket ofgas expanded tissue serves to thermally insulate and separate the esophagusfrom the left atrium during ablation to prevent the formation of an atrial-esophagealfistula. The system comprises a control system to precisely deliver the gas toadesired location through a needle-based catheter assembly.
