Oesophageal Pacing to Check Left Atrial Posterior Wall Isolation

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