Adaptive frequency tracking of the baseline ECG identifies the site of atrial fibrillation termination by catheter ablation

► Modified ECG system was used (chest lead V6 placed in the patient's back). ► Contribution on the ECG of right/left atrial appendage activities was estimated. ► An adaptive harmonic frequency tracking algorithm was developed. ► Two innovative indices of organization were extracted. ► Promising indices to identify non-invasively the site of AF termination by catheter ablation.