Introduction: Thrombus in left atrial appendage (LAA) is an important cause of cerebral thromboembolism. The prevalence and management of LAA thrombi associated with novel oral anticoagulants (NOAC) remain to be clarified. NOACs are superior to warfarin in preventing stroke or systemic embolism, causes less bleeding and results in lower mortality in patient with atrial fibrillation. In literature, there aren’t too many reports of resolution of LAA thrombus with NOACs. (1, 2) The gold standard for the diagnosis of LAA thrombi remains transesophageal echocardiography (TEE). In patients diagnosed with LAA thrombi, the optimal duration of therapy is uncertain.

Case report: We present a 59-year-old male patient with persistent atrial fibrillation associated with left atrial thrombus. Initial treatment was with rivaroxaban 20 mg once a day for thirty days. Despite the fact that he was on rivaroxaban thirty days before, we decided to perform TEE, which revealed the formation of a small thrombus (12x10 mm) in the LAA. Thirty days of dabigatran treatment showed complete thrombus resolution. Finally, cardioversion with 120 J was performed successfully without signs of cardiac embolism and the patient was discharged in good medical condition under continued anticoagulant treatment with dabigatran 150 mg twice a day.

Conclusion: In this case, we selected dabigatran after rivaroxaban. To our knowledge, this is the first documented case of LAA thrombus resolution under dabigatran therapy after unsuccessful rivaroxaban 20 mg once a day therapy. Therefore, dabigatran could be considered to have an important role in rhythm control strategies in similar cases. It requires further investigation in a larger population.