Remodeling Disparity between Left Atrium and Appendage Relates to Recurrence after Atrial Fibrillation Ablation

Hypothesis: Different alterations of volume between left atrium (LA) and appendage (LAA) can predict clinical outcome of ablation of atrial fibrillation (AF). Methods: Among 386 consecutive patients (37% non-paroxysmal AF), 284 patients with LAD<45mm and 102 with LAD>45mm were assessed. LA diameter (LAD) was measured by transthoracic echocardiography, and volumes of LA and LAA were calculated by 3-D CT scan. Results: During mean 22±16 months, rate of freedom from recurrence was higher in LAD<45mm compared with LAD>45mm (80.3% vs 61.8%, p<0.001). In patients with LAD<45mm, LAD and LAA volume were significantly greater in patients with recurrence compared with those without recurrence (40.1 ± 3.9 vs 37.8±4.4mm, p<0.001; 12.8±12.2 vs 9.3±4.0ml, p=0.042), whereas there was no significant difference in LA volume. In patients with LAD>45mm, LAA volume was significantly larger in patients with recurrence than those without recurrence (15.5±8.9 vs 11.8±5.6ml, p=0.024), however, there was no difference in LAD and LA volume. In patients with LAD<45;mm, LAD was associated with higher recurrence rate (OR 1.127; 95%CI 1.031-1.232; p=0.008), whereas in patients with LAD>45mm, LAA volume independently predicted recurrence after AF ablation (OR 1.094; 95%CI 1.003-1.194; p=0.044). Conclusions: Larger LAA volume predicts recurrence after ablation of AF in patients with enlarged LA. These finding suggests that LAA is an important substrate of AF in remodeled LA.