Prevalence of left atrial thrombus in anticoagulated patients undergoing elective electrical cardioversion

Type of funding sources: None.

The prevalence of left atrial (LA) thrombus in patients with atrial fibrillation (AF) or atrial flutter (AFL) on guideline-directed anticoagulation is nor well known, moreover, evidence on the presence of left atrial thrombus with different anticoagulation therapies provides heterogeneous results.

Ambispective, observational, single-center study that consecutively included 271 patients undergoing elective electrical cardioversion (ECV) for AF or AFL >48 hours of onset. A transoesophageal echocardiogram (TOE) was performed in all patients within 24 hours prior to ECV. Patients with <3 weeks of anticoagulation and those in sinus rhythm on admission were excluded, and the clinical characteristics and presence of atrial thrombus were analyzed in 172 patients.

The main baseline characteristics are shown in Picture 1. A total of 66.5% of the patients were receiving treatment with direct oral anticoagulants (NOAC) dabigatran (15.9%); rivaroxaban (28.3%); apixaban (31.2%) and edoxaban (23.9%). The remaining 33.5% were anticoagulated with vitamin K antagonists (VKA). Eight thrombi were detected in the left atrial appendage (prevalence 4.7%), and on 2 occasions the presence of thrombus could not be ruled out, and CVE was also suspended. No statistically significant differences were observed between the prevalence of thrombus and the type of anticoagulant (NOAC vs VKA 4.5% vs 4.9%; p= 0.56) or between the different NOACs (p=0.61). Of the 8 patients with left atrial thrombus, anticoagulant treatment was modified in 3 of them. Control TOE was performed (median until new TOE 64 days), and resolution was verified in 3 cases (all under treatment with NOAC), of which 2 patients had maintained their previous anticoagulant treatment.

Anticoagulated patients scheduled for elective ECV present a prevalence of left atrial thrombus close to 5%. No differences were observed with respect to the anticoagulation treatment received.