Introduction: The 2012 HRS/EHRA/ECAS guidelines
encourage pre-procedural transesophageal echocardiography (TEE) prior to
ablation for atrial fibrillation (AF), but acknowledge a lack of consensus in
patients maintained on therapeutic warfarin before,
during and after the procedure. This is partly because the incidence of left atrial
appendage (LAA) thrombus is so low, that it is hard to draw clear conclusion regarding
the characteristics of patients who develop thrombus. We hypothesize that the presence of low LAA emptying velocities, which predisposes
to thrombus, and/or thrombus itself can be predicted in patients undergoing
ablation, based upon clinical characteristics and transthoracic
Methods: In this multicentre study, we
undertook TTE and transesophageal echocardiograms (TEE) in 586 patients (age
59.9±0.4 years old, 64.5% male) undergoing catheter ablation for AF who were anticoagulated on warfarin (target international
normalized ratio 2–3.5) for ≥3 consecutive weeks prior to procedure and
maintained on warfarin for the procedure.
Results: Low peak LAA emptying
velocities (<40cm/s) were identified in 111 (24.7%) patients and LAA
thrombus was identified in 3 patients (0.5%) despite having therapeutic INRs.
The 3 patients with thrombus had LAA emptying velocities of 23, 29 and 31 cm/s.
None of the remaining patients had a peri-procedural stroke. Patients with peak
LAA emptying velocities <40cm/s or thrombus on TEE had significantly (p<0.05)
higher CHA2DS2-VASc scores (1.7± 0.1 v’s 1.4±0.1), and
were more likely to have impaired LVSF (odds ratio [95% CI]: 2.66 [1.52-4.66]),
a LA diameter >4.6cm on TTE (2.40
[2.13-5.41]), or persistent AF (2.60
[1.63-4.14]) compared to those with a higher LAA velocity without thrombus.
Conclusion: In patients on
uninterrupted warfarin therapy, a CHA2DS2-VASc score ≥1
or LA diameter >4.6cm on TTE identifies 91.5% of those
at risk of developing thrombus with LAA emptying velocity of
<40 cm/s and 100% of those with thrombus in
Credits: Neil Herring; Stephen P. Page; Mohammed Ahmed; Melanie R. Burg; Ross J. Hunter; Mark J. Earley; Simon C. Sporton; James D. Newton; Nikant K. Sabharwal; Saul G. Myerson; Yaver Bashir; Tim R Betts; Richard J. Schilling; Kim Rajappan