Abstract
Introduction: The risk of developing left atrial (LA) thrombi
after initial catheter ablation for atrial fibrillation (AF) and
requirements for imaging evaluation for thrombi screening at repeat
ablation is unclear. This study aimed to
assess the occurrence of thrombus
development and frequency of any imaging study evaluating thrombus
formation during repeat ablation for AF.
Methods: Of 2,066 patients undergoing initial catheter ablation
for AF with uninterrupted oral anticoagulation, 615 patients underwent
repeat ablation after 258.0 (105.0-882.0) days. We investigated which
factors were associated with safety outcomes and requirements for
thrombi screening.
Results: All patients underwent at least one imaging
examination to screen for thrombi in the first session, but the
examination rate decreased to 476 patients (77%) before the repeat
procedure. The frequency of imaging evaluations was 5.0%, 11%, 21%,
84%, and 91% for transesophageal echocardiography and 18%, 33%,
49%, 98%, and 99% for any imaging modality at repeat ablation
performed ≤60 days, ≤90 days, ≤180 days, >180 days, and
>1 year after the initial procedure, respectively.
Three patients (0.5%) developed
LA thrombi at repeat ablation due to identifiable causes, and no
patients had thromboembolic events when no imaging evaluation was
performed. Multivariate analysis revealed that
repeat ablation >180
days, non-paroxysmal atrial arrhythmias, and lower left ventricular
ejection fraction were predictors of the risk of thrombus development.
Conclusions: The risk development of thrombus at repeat
ablation for AF was low. There needs to be a risk stratification for the
requirement of imaging screening for thrombi at repeat ablation for AF.
Keywords: catheter ablation; atrial fibrillation; repeat
session; transesophageal echocardiography; thrombus.