We present a case of a 36-year-old woman with highly symptomatic persistent atrial fibrillation (AF) refractory to sotalol, flecainide, and external direct current (DC) cardioversion. The patient underwent biatrial mapping and ablation procedure for AF. Both atria were characterized by refractory properties which were much shorter than reported previously. Global fibrillatory activity was present with a median cycle length of 120 ms (range: 62-143). Extensive map-guided ablation sets had to be delivered to both left and right sides before effective DC cardioversion enabled sinus rhythm (SR) restoration. The patient remained in SR at 9 months of follow-up.