Incidence of Late Thromboembolic Events After Catheter Ablation of Atrial Fibrillation

Background: A low incidence of thromboembolic events after successful catheter ablation of atrial fibrillation (AF) during a mid-term follow-up period was recently reported. However, because the incidence of such events over the long term is unknown, we investigated the late incidence of thromboembolic events after catheter ablation. Methods and Results: Patients with paroxysmal and persistent AF undergoing catheter ablation and being followed up for at least 24 months formed the study group (n=524); 82 patients (16%) had CHADS(2.) scores of at least 2. Mean follow-up was 44 13 months. Warfarin was discontinued in 400 (93%) of 429 patients (82% of 524 patients) without AF recurrence. None of the patients without AF recurrence suffered thromboembolic events, whereas 3 of 95 patients (3%) with AF recurrence did (P<0.001). One of the 3 was a late AF recurrence occurring >12 months after catheter ablation. There were 2 nonfatal major hemorrhagic events in patients with AF recurrence who continued on warfarin, but no hemorrhagic events were observed in patients free from AF (P=0.002). Conclusions: Maintenance of sinus rhythm after catheter ablation of AF was associated with a lower incidence of thromboembolic events during long-term follow-up >3 years. This result suggests that catheter ablation reduces thromboembolic events if patients continue anticoagulation regardless of the ablation outcome. (Circ J 2011; 75: 2343-2349)