Increasing evidence supports the theory that the cardiac autonomic nervous system plays a pivotal role in triggering and maintaining atrial fibrillation. We describe a case of extreme bradycardia during catheter ablation of atrial fibrillation in a 67-year-old man. Interestingly, despite numerous radiofrequency applications, we could not abolish the vagal reflex. Our case underlines the need to look for more specific and reproducible end points when performing this procedure.