The patient population will include symptomatic persistent AF patients (N=50). The total of fifty patients will be studied to determine:~The values and limitations of ECGI in identifying atrial fibrillation (AF) triggers, AF initiators and AF perpetuators as targets sites for catheter ablations in patients with persistent AF.~The mechanisms of residual atrial tachycardia/flutter (Res-AT/AFl) after AF substrate ablations by targeting complex fractionated atrial electrograms (CFAE).~If there is a relationship between primary CFAE sites and driver sites or other distinct patterns from the ECGI mapping system.~The rate of AF termination to sinus rhythm after ablation at target sites identified by ECGI
To determine the values and limitations of ECGI in guiding ablation and risk stratification in patients with persistent atrial fibrillation.