Aims: Electrographic flow (EGF) mapping is a method to detect action potential sources within the atria. In a double-blinded retrospective study we evaluated whether sources detected by EGF are related to procedural outcome. Methods: EGF maps were retrospectively generated using the Ablamap® software from unipolar data recorded with a 64-pole basket catheter from patients who previously underwent focal impulse and rotor modulation-guided ablation. We analyzed patient outcomes based on source activity (SAC) and variability. Freedom from atrial fibrillation (AF) was defined as no recurrence of AF, atypical flutter or atrial tachycardia at the follow-up visits. Results: EGF maps were from 123 atria in 64 patients with persistent or long-standing persistent AF. Procedural outcome correlation with SAC peaked at >26%. S-type EGF signature (source-dependent AF) is characterized by stable sources with SAC > 26% and C-type (source-independent AF) is characterized by sources with SAC ≤ 26%. Cases with AF recurrence at 3-, 6-, or 12-month follow-up showed a median final SAC 34%; while AF-free patients had sources with significantly lower median final SAC 21% (p =.0006). Patients with final SAC and Variability above both thresholds had 94% recurrence, while recurrence was only 36% for patients with leading source SAC and variability below threshold (p =.0001). S-type EGF signature post-ablation was associated with an AF recurrence rate 88.5% versus 38.1% with C-type EGF signature. Conclusions: EGF mapping enables the visualization of active AF sources. Sources with SAC > 26% appear relevant and their presence post-ablation correlates with high rates of AF recurrence.