The present invention is directed to systems, devices and methods for trans-septally delivering carbon dioxide through a minimally invasive catheter to create a gaseous pocket or emphysema between the posterior wall of the left atrium and the esophagus during cardiac ablation of the left atrium. This pocket of gas expanded tissue serves to thermally insulate and separate the esophagus from the left atrium during ablation to prevent the formation of an atrial-esophageal fistula. The system comprises a control system to precisely deliver the gas to a desired location through a needle-based catheter assembly.
