Background: Current catheter ablation of atrial fibrillation (AF) is focused on the elimination of pulmonary vein (PV) potentials. Tailored approach based on complex fractionated electrograms (CFE) has been proposed. Objective: We hypothesized that the electrogram-guided ablation (EGA) in addition to the anatomical PV antral isolation has an additive effect achieving end-point of the procedure. Methods: Patients with symptomatic, drug-refractory AF (paroxysmal, 50, persistent, 29 pts) were included. After circumferential PV isolation (CPVI), EGA was continued in the left/right atrium targeting CFEs if AF was inducible in paroxysmal AF or persisted in persistent AF. End-point of the procedure was non-inducibility of AF in patients with paroxysmal AF (PAF) and termination into sinus rhythm in patients with persistent AF (PeAF). Results: 1. In PAF, CPVI alone rendered AF non-inducible in 25 of 50 patients (50%) while CPVI converted inducible AF into inducible AFL in 4 of 50 patients (8%). After EGA, AF became non-inducible in additional 10 patients (20%), while only atrial flutters were inducible in 6 patients (12%). AF remained inducible in 5 patients (10%) after this combined ablation procedures. 2. In PeAF, CPVI restored sinus rhythm in none of the 0/29 pts. After EGA, AF converted directly into sinus rhythm in 2 (7%) and into AFLs in 17 patients (58%), while AF persisted in 10 patients (35%). Conclusion: EGA targeting CFEs after CPVI rendered inducible AF into AFL in patients with PAF, or converted of AF into AFL in patients with PeAF. EGA showed an additive effect in addition to CPVI alone achieving end-point of the procedure.