Introduction

The importance of pulmonary vein ectopy in the initiation and maintenance of atrial fibrillation (AF) is well recognised (1) resulting in pulmonary vein isolation (PVI) forming a key component of AF ablation procedures. The success rates of PVI alone are variable, and it has been observed that persistent AF ablation success rates (40-70%) are lower than paroxysmal AF success rates (60-70%) (2). The variability in reported outcomes may reflect variation in definitions of success, intensity of monitoring and the impact of non-pulmonary vein triggers or substrates for AF. Numerous strategies comprising substrate ablation beyond PVI have been investigated with variable degrees of success (3) iterating the requirement for better, more targeted ablation approaches. This editorial discusses the Determinant of Successful Radiofrequency Catheter Ablation of Atrial Fibrillation (DECAAF) II trial which aimed to assess the impact of PVI plus MRI-guided atrial fibrosis ablation versus PVI alone in persistent AF.