Catheter ablation is an effective therapeutic strategy for paroxysmal atrial fibrillation (AF) as well as persistent AF [1,2]. Sinus node dysfunction (SND) and AF are associated with each other [3]. Concealed SND sometimes manifests after restoration of sinus rhythm by catheter ablation and requires pacemaker implantation [[4], [5], [6]]. In terms of the relationship between atrioventricular conduction disturbances (AVCD) and AF, previous studies demonstrated that atrioventricular block was associated with incident AF [[7], [8], [9], [10]]. In surgical AF ablation, both SND and AVCD have been reported as causes of postoperative pacemaker implantation [11]. However, the presence of potential AVCD in patients with persistent AF has not been adequately studied because the accurate assessment of atrioventricular conduction during AF is difficult. In this study, we investigated the relationship between pre-ablation heart rate and concomitant AVCD after ablation in persistent AF, and we searched for predictors of AVCD.