Left atrial appendage morphology and thromboembolic risk after catheter ablation for atrial fibrillation

BACKGROUND In patients with atrial fibrillation (AF), left atrial appendage (LAA) morphology has been suggested to modify risk of thromboembolic events (TEs). OBJECTIVE In this study, we tested the hypothesis that a TE after AF catheter ablation is associated with LAA characteristics. METHODS Of 2069 patients included in the Leipzig Heart Center AF Ablation Registry, 15 (0.7%) suffered a TE (excluding events within 30 days) during follow-up (ie, 3.078 patient-years). Those patients were matched for CHA(2)DS(2)-VASc criteria with 115 patients without TE, and computed tomography (n = 120) or magnetic resonance imaging (n = 10) data were also compared. LAA volume, morphology (cactus, chicken-wing, windsock, and cauliflower), and takeoff (higher/lower) in relation to the adjacent pulmonary vein were determined. RESULTS After patients were followed for a median period of 24 months, 67% of the patients remained in sinus rhythm. Patients with TE had a higher AF recurrence rate (73% vs 28%; P = .001) and a higher incidence of superior LAA takeoff (ie, higher than that of the left superior pulmonary vein; 80% vs 37%; P = .002), while LAA morphologies and other LAA characteristics were similar between groups. Multivariate Cox regression analysis revealed AF recurrence (hazard ratio 6.2; 95% confidence interval 2.0-19.6; P = .002) and superior LAA takeoff (hazard ratio 4.9; 95% confidence interval 1.4-17.4; P = .014) as TE predictors. There was a negative correlation between heart rate and LAA flow (r = -.22 cm/s per beat/min; P = .016), which was even more pronounced for the superior LAA takeoff (r = -.28 cm/s; P = .045). CONCLUSION AF recurrence and higher LAA takeoff are associated with thromboembolism after AF ablation, while LAA morphology is not. These results may have an implication for improved postablation management.