Mechanism of Regular Atrial Tachyarrhythmias During Combined Pulomonary Vein Isolation and Complex Fractionated Electrogram Ablation in Patients With Atrial Fibrillation

Background Atrial tachyarrhythmias (ATA) frequently develop during catheter ablation of atrial fibrillation (AF), but the mechanism of ATA during combined pulmonary vein isolation (PVI) and complex fractionated electrogram-guided ablation (CFEA) has not been reported. Methods and results This study involved 105 patients with symptomatic, drug-refractory AF. After PVI, CFEA was performed in the left/right atrium if AF remained inducible in paroxysmal AF (PAF) or persisted in persistent AF (PeAF). For the 70 PAF patients, PVI alone rendered AF non-inducible in 29 patients (41.4%), and converted inducible AF into inducible atrial flutter (AFl) in 10 patients (14.3%). For the remaining 31 PAF patients, additional CFEA rendered AF non-inducible in 11 patients (15.7%), whereas only AFl was inducible in 11 patients (15.7%). For 35 PeAF patients, PVI and CFEA converted AF into sinus rhythm in 2 (5.7%) and into AFl in 21 (60.0%) patients, while AF persisted in 12 patients (34.3%). The mechanism of ATA was focal (20/114, 17.5%), roof-dependent (20/114, 17.5%), peri-mitral (33/114, 28.9%), cavotricuspid isthmus-dependent (34/114, 29.8%) AFl or unknown (7/114, 6.1%). Successful ablation was achieved in 93/114 (81.6%) tachycardias. Conclusions The major mechanism of ATA during the combined approach of PVI and CFEA is macroreentry around large anatomic obstacles such as the pulmonary vein or the mitral or tricuspid annuli.