LETTER TO THE EDITOR

doi:10.1093/eurheartj/ehn290 Long-term survival in patients undergoing cardiac resynchronization therapy: the importance of atrio-ventricular junction ablation in patients with permanent atrial fibrillation We read with interest the article by Gasparini et al.1 on the effect of cardiac resynchroniza-tion therapy (CRT) in patients with permanent atrial fibrillation (AF). In this registry study of patients with AF undergoing CRT, atrioventri-cular junction (AVJ) ablation 2 months after implantation was associated with a prognostic advantage over rate-slowing drugs. This study has emerged in the context of our findings of a similar mortality and morbidity outcome in non-ablated patients with AF and patients with sinus rhythm undergoing CRT.2 One important difference between Gasparini’s study and ours is the use of ventricular-triggered pacing. While in Gasparini’s study this pacing mode was used when available, it was employed in all the patients included in our study. Although ventricular-triggered pacing produces fused beats rather than true biventricular pacing, it could conceivably be superior to the ventri-cular demand mode. We eagerly await the findings of randomized trials of AVJ ablation in patients with AF undergoing CRT. We wonder whether, on the basis of the findings from our observational study, such random-ized trials should also address the effects of the ventricular-triggered mode