Original Article Radiofrequency Catheter Ablation of Atrial Fibrillation Guided by Spectral Mapping of Atrial Fibrillation Nests in Sinus Rhythm

Background: Two types of myocardia can be observed through the endocardial spectral mapping (SM) in sinus rhythm: the compact type with a smooth spectrum and the fibrillar type with a segmented spectrum (atrial fibrillation nests). During the atrial fibrillation (AF), the compact type has an organized activation and low frequency (passive), whereas the fibrillar type has a rather disorganized activation and high frequency (active/resonant), with both being activated by high-frequency sustained tachycardia- the background tachycardia (BT). Objective: To describe the treatment of AF by the ablation of the AF nests and BT. Methods: 1) Catheter ablation of the AF nests with RF [4/8mm-60º/30-40J/30s] guided by SM in sinus rhythm, outside the pulmonary vein; 2) atrial stimulation-300ppm; 3)Additional ablation of the AF nests if AF is induced; 4) Focal ablation if BT and/or Flutter is induced; 5)Clinical follow-up+ ECG+ Holter. Results: A total of 50±18 AF nests/patient were treated. After 11.3±8m, 81 patients (88%) did not present AF (28.3% with antiarrhythmic drugs). After the ablation of the AF nests, AF was not reinduced in 61 patients (71%) and BT was induced and treated in 24 patients (26%). There were two episodes of pericardial bleeding (1 treated clinically and 1 surgically), caused by sheaths that are no longer used. Conclusion: The SM in sinus rhythm can be used in the ablation of AF nests. During the AF, the AF nests present a reactive-resonant pattern and the compact myocardium is passive, stimulated by the high frequency of the BT. After th