Introduction
Catheter ablation is an effective
treatment for suppressing atrial fibrillation (AF) and has a high
success rate.1, 2 With the recent development of
ablation technology and mapping devices and growing indications of
catheter ablation in patients with AF, most patients are recurrence-free
from AF after the initial catheter ablation procedure.
However, the success rate is not
absolute, and some patients have a recurrence after the initial
ablation. These patients are often
scheduled to undergo repeat sessions for recurrent AF when associated
with intolerable symptoms and frequent occurrence.
Transesophageal echocardiography (TEE) is the gold standard for
evaluating left atrial (LA) thrombi before AF ablation, and a recent
expert consensus report recommended the necessity of excluding the
possibility of LA thrombi before the initial AF catheter
ablation.3 Nonetheless, the relevance of evaluating
the presence of thrombi at repeat sessions due to recurrence remains
unclear. After the first session, although patients have a recurrence,
the burden and duration of AF may significantly decrease, and these
patients usually continue oral anticoagulants following the procedure,
which could indicate that the thrombi are unlikely to develop in those
patients after the first session.4It is unclear whether imaging
examination to screen for LA thrombi is necessary at repeat sessions,
especially in patients at low risk and in early repeat ablation. Since
TEE is associated with the risk of aspiration pneumonia and pharyngeal
perforation, although with a very low prevalence, it is important to
avoid unnecessary examinations which impose a burden on the patient and
cause discomfort before the repeat ablation.
To test this hypothesis, the present study was conducted to assess the
occurrence of thrombi at repeat ablation for AF recurrence after the
first session and the frequency of any imaging study, including TEE and
contrast-enhanced computed tomography (CT) imaging, for thrombi
screening before the repeat procedure in a large cohort study. We
investigated which factors and time to repeat ablation were associated
with safety outcomes regarding thrombi development during AF repeat
ablation and with the requirement for invasive imaging studies for
evaluating thrombi development.