Prevalence of left atrial appendage thrombus and spontaneous echo contrast on transesophageal echocardiography in patients scheduled for pulmonary vein isolation

Background

To avoid causing a thromboembolic event in patients undergoing catheter ablation for atrial fibrillation (AF), patients are treated with oral anticoagulants (OAC) prior to the procedure. Despite being on anticoagulants, some patients develop a left atrial appendage thrombus (LAAT). To exclude the presence of LAAT, transesophageal ultrasound (TEE) is performed in all patients prior to the procedure. We hypothesized continuous treatment with anticoagulants would result in a low prevalence of LAAT, in patients with low CHA₂DS₂-VASc score.

Method

Medical records of consecutive patients planned to undergo AF ablation at Lund University Hospital during the years 2018–2020 were reviewed retrospectively. Examination protocols from transesophageal and transthoracic echocardiography were examined for LAAT and spontaneous echo contrast (SEC). Patients with LAAT and SEC were compared to patients without using Mann–Whitney U-test and Pearson Chi-squared analysis to test for correlation.

Results

Of 553 patients, three patients (0.54%) had LAAT, and 18 (3.25%) had spontaneous contrast (SEC). Patients with LAAT or SEC had a higher CHA₂DS₂-VASc score, more often presented in AF at TEE and less often had a normal sized left atrium.

Conclusion

There is a low prevalence of LAAT and SEC in patients with AF scheduled for pulmonary vein isolation. Patients with SEC or LAAT tend to have paroxysmal AF less often and more often presented in AF at admission. No patients with CHA₂DS₂-VASc 0, paroxysmal AF, normal sized left atrium and sinus rhythm at TEE were found to have LAAT or SEC.