title: Catheter ablation of persistent atrial fibrillation: The importance of substrate modification.
abstract: Accumulating data have shown that elimination of atrial fibrillation (AF) sources should be the goal in persistent AF ablation. Pulmonary vein isolation, linear lesions and complex fractionated atrial electrograms (CFAEs) ablation have shown limited efficacy in patients with persistent AF. A combined approach using voltage, CFAEs and dominant frequency (DF) mapping may be helpful for the identification of AF sources and subsequent focal substrate modification. The fibrillatory activity is maintained by intramural reentry centered on fibrotic patches. Voltage mapping may assist in the identification of fibrotic areas. Stable rotors display the higher DF and possibly drive AF. Furthermore, the single rotor is usually consistent with organized AF electrograms without fractionation. It is therefore quite possible that rotors are located at relatively "healthy islands" within the patchy fibrosis. This is supported by the fact that high DF sites have been negatively correlated to the amount of fibrosis. CFAEs are located in areas adjacent to high DF. In conclusion, patchy fibrotic areas displaying the maximum DF along with high organization index and the lower fractionation index are potential targets of ablation. Prospective studies are required to validate the efficacy of substrate modification in left atrial ablation outcomes.
authors: Konstantinos P Letsas, Michael Efremidis, Nikolaos P Sgouros, Konstantinos Vlachos, Dimitrios Asvestas, Antonios Sideris, Second Department of Cardiology, Laboratory of Cardiac Electrophysiology, Evangelismos General Hospital of Athens, 10676 Athens, Greece.
authors: Konstantinos P
authors: KP
authors: Letsas
authors: Konstantinos P Letsas, Michael Efremidis, Nikolaos P Sgouros, Konstantinos Vlachos, Dimitrios Asvestas, Antonios Sideris, Second Department of Cardiology, Laboratory of Cardiac Electrophysiology, Evangelismos General Hospital of Athens, 10676 Athens, Greece.
authors: Michael
authors: M
authors: Efremidis
authors: Konstantinos P Letsas, Michael Efremidis, Nikolaos P Sgouros, Konstantinos Vlachos, Dimitrios Asvestas, Antonios Sideris, Second Department of Cardiology, Laboratory of Cardiac Electrophysiology, Evangelismos General Hospital of Athens, 10676 Athens, Greece.
authors: Nikolaos P
authors: NP
authors: Sgouros
authors: Konstantinos P Letsas, Michael Efremidis, Nikolaos P Sgouros, Konstantinos Vlachos, Dimitrios Asvestas, Antonios Sideris, Second Department of Cardiology, Laboratory of Cardiac Electrophysiology, Evangelismos General Hospital of Athens, 10676 Athens, Greece.
authors: Konstantinos
authors: K
authors: Vlachos
authors: Konstantinos P Letsas, Michael Efremidis, Nikolaos P Sgouros, Konstantinos Vlachos, Dimitrios Asvestas, Antonios Sideris, Second Department of Cardiology, Laboratory of Cardiac Electrophysiology, Evangelismos General Hospital of Athens, 10676 Athens, Greece.
authors: Dimitrios
authors: D
authors: Asvestas
authors: Konstantinos P Letsas, Michael Efremidis, Nikolaos P Sgouros, Konstantinos Vlachos, Dimitrios Asvestas, Antonios Sideris, Second Department of Cardiology, Laboratory of Cardiac Electrophysiology, Evangelismos General Hospital of Athens, 10676 Athens, Greece.
authors: Antonios
authors: A
authors: Sideris
keywords: Ablation; Atrial fibrillation; Dominant frequency; Persistent; Substrate