Although treatment of atrial fibrillation (AF) classically focuses on eliminating the pulmonary vein (PV) triggers, isolation of PVs is associated with limited success rates in patients with persistent AF. The role of the left atrial appendage (LAA) as both trigger and driver in arrhythmogenesis of AF was previously demonstrated. In the present case, fractionation mapping software of Ensite system was firstly tested to detect critical substrate during AF. Focusing on the width and continuity of fractionation pattern, the LAA was accepted as main driver for maintenance of AF. Ablation in fractionated electrograms around the LAA caused acute AF termination. After isolation of the LAA, no AF was inducible with atrial stimulation with and without isoproterenol infusion. Fractionation mapping may be used to detect potential importance of the LAA in AF continuity.