Left Atrial Arrhythmia Substrate Identification After Confirmed durABLE Pulmonary Vein Isolation

Catheter ablation using cryoballoon pulmonary vein isolation. Utilisation of a 'cold balloon' (Cryoenergy or cryoballoon ablation) to freeze the bases of the 4 pulmonary veins to achieve electrical isolation.

Catheter ablation using radiofrequency energy to achieve pulmonary vein isolation. Radiofrequency energy is delivered through the tip of a catheter to make tiny burns (ablation lesions) around the outlines of the 4 pulmonary veins at their bases

All participants will receive a repeat electrophysiological study 2 months after the index procedure during which radiofrequency catheter ablation guided by ultra-high density mapping will be used to identify regions of reconnection that need re-isolation; other tests will be carried out including testing for arrhythmia inducibility

The left atrial posterior wall will be isolated in Group 2 participants (those who received radiofrequency ablation at the index procedure) during the repeat electrophysiological study in 2 months