Oesophageal temporary pacing of the heart is an established treatment in heart block and several catheters are licenced for this purpose with minimal procedural risks. Due to the position of the oesophagus, pacing from the oesophagus could sense and pace the posterior left atrium. If the posterior wall could be demonstrated to be electrically isolated with oesophageal pacing then invasive electrophysiological study such as the second stage of a hybrid AF ablation would be unnecessary.~This would save patients from undergoing invasive left atrial mapping and exposure to the consequent risks of the procedure.
Patients undergoing hybrid AF ablation second stage catheter ablation have the posterior left atrium mapped to see it if is electrically isolated. This is done via a standard electrophysiogical study in accordance with routine clinical practice.~Investigators propose to check left atrium posterior wall isolation via oesophageal pacing and compare this to findings from invasive study