LAUSR

Abstract Funding Acknowledgements Type of funding sources: None. Background Phase mapping using software of ExTRa Mapping is a new tool to clarify the localization of rotor in atrial fibrillation (AF), but the spatial distribution of rotor in right atrium (RA) and the effect of ablation is not clear compared with left atrium (LA). Purpose This study sought to investigate the spatial distribution of rotor in RA and the safety and effectiveness of RA rotor ablation after pulmonary vein isolation (PVI) in patients with persistent AF. Methods ExTRa mapping with a 20-polar Reflexion catheter in RA was performed in 2nd or 3rd ablation for recurrent AF after PVI in 16 patients with persistent AF (including 4 patients with long standing >1 year AF, 15 men, mean age 67±7.7years old, mean LAD 42±5.4mm, mean EF 57±11%). Rotor was defined as NPAs (non-passively activated areas) in which the percentage of the non-passively activated period in the recording time of 5 seconds is over 50%. RA was divided into 5 areas of crista terminalis (CT), septum (Sept), free wall of RA appendage (fRAA), septal side of RAA (sRAA), behind aorta (Ao), and distribution of NPAs was investigated. RA minimal ablation to NPAs was performed to avoid sinus node and phrenic nerve. The outcomes of AF recurrence were analyzed. Results NPAs in RA were observed in 15 of 16 cases, and 67% of cases in CT, 75% in Sept, 80% in fRAA, 20% in sRAA, and 43% in Ao. RA minimal ablation was performed in 21 NPAs in 8 patients to avoid sinus node and phrenic nerve. In a mean follow-up of 307±204 days, freedom from any atrial tachyarrhythmias without antiarrhythmic drugs was achieved in 9 of 16 patients (56%). In 4 (80%) of 5 patients in whom more than 75% area of NPAs were eliminated, sinus rhythm was maintained. There was no serious complication. Conclusion Rotor in RA existed relatively frequently in septum, fRAA and CT. RA rotor ablation was safe and could be a new strategy after PVI for persistent AF. Fig.1 Rotor ablation in RA Fig.2 freedom from AF or AT