The mechanism and re-ablation of recurrent atrial arrhythmias after ablation of atrial fibrillation using electroanatomic mapping system and double LASSO technique

Objective To investigate the possible mechanism and re-ablation of recurrent atrial arrhythmias after atrial fibrillation(AF) ablation by utilizing the Carto system and double LASSO technique.Methods A total of 77 AF patients were enrolled and among them,56 with paroxysmal AF and 21 with persistent AF.Eight-F Swartz long sheaths were positioned in the left atrium by transseptal technique.One to two LASSO catheters were placed in the ipsilateral pulmonary veins(PV).The anatomy of the left atrium and PV was established using the Carto system.PV selective venography was carried out to identify the PV ostium.Continuous circular lesions(CCL) were made at the left atrium at 0.5 to 1.0 cm outside the PV ostium.Irrigated radiofrequecy energy was delivered in all the patients.The end point of the CCL was defined as absence of all PV spikes documented with LASSO catheters within the ipsilateral PVs.Results A repeat ablation was performed in 14 patients who experienced highly symptomatic atrial tachyarrhythmia.During the repeat procedures,conduction gaps in the previous CCL were found in 13 out of the 14 patients,and a typical atrial flutter was found in the other patient which was eliminated by ablation of the tricuspid isthmus.During the second procedure,pulmonary vein tachycardia was demonstrated in 7 patients.The pulmonary vein tachycardia activated the LA via the conduction gaps.All conduction gaps were successfully ablated by irrigated RF applications.After the second procedure,12 out of the 14 patients were free of AF during 3 to 30 months of follow-up.Conclusion Continuous circular lesions(CCL) in the left atrium utilizing the Carto system and double LASSO technique had a high success.In patients with recurrent atrial tachyarrhythmia after CCLs,recovered PV conduction is a main cause for the recurrence.