1365Which patients develop recurrent atrial tachycardia but not atrial fibrillation after catheter ablation for atrial fibrillation?

Background: Although it has been considered that ablation gap contributes to atrial tachycardia (AT) recurrence after radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF), the underlying mechanism of AT recurrence after RFCA for atrial fibrillation AF is yet unclear. Objective: The purpose of this study is to investigate the association of the degree of atrial remodeling and recurrence pattern after AF ablation without the effect of antiarrhythmic drugs. Methods: Among 2047 patients who underwent AF ablation, 501 patients (351 [70.1%] men) who experienced recurrence after RFCA, excluding recurrence with the effect of antiarrhythmic drugs, were included in this study. Among these patients, 333 (66.5%) were diagnosed with paroxysmal AF. Circumferential pulmonary vein isolation (CPVI) was performed in 257 patients, while additional linear ablation after CPVI was performed in the remaining 244 patients. Results: 1. During a mean follow-up of 43.2±24.2 months, 42.5% of the recurring atrial arrhythmias were AT, and the proportion of AT recurrence was not different between the CPVI only (44.7%) and additional linear ablation groups (40.2%, p=0.321). 2. Absence of hypertension (OR 0.529, 95% CI 0.313–0.893, p=0.017), small left atrial (LA) volume index (OR 0.979, 95% CI 0.965–0.990, p=0.002), high LA voltage (OR 1.892, 95% CI 1.171–3.058, p=0.009), and early recurrence within 3 months (OR 2.060, 95% CI 1.205–3.523, p=0.008) were independently associated with AT recurrence, whereas additional linear ablation (p=0.300) and number of ablation lines (p=0.352) were not. 3. Among 97 patients who underwent a redo-procedure, bidirectional block states of previous linear ablation (p=0.288) were not significantly different between those with AT recurrence and those with AF recurrence. Conclusion: The degree of LA remodeling is significantly associated with AT recurrence after AF ablation, irrespective of potential ablation gaps in the linear lesion.