Right atrial appendage thrombosis after percutaneous left atrial appendage occlusion: a case report.

Left atrial appendage occlusion (LAAO) is an established alternative stroke-prevention strategy for patients with atrial fibrillation (AF) who have contraindications to long-term oral anticoagulation. However, LAAO addresses only left-sided thromboembolism and does not eliminate the risk of thrombus formation in other cardiac chambers. We present the case of a 72-year-old man with dilated cardiomyopathy and persistent AF who developed right atrial appendage (RAA) thrombosis one year after percutaneous LAAO with an Amplatzer Cardiac Plug (ACP). The patient had initially undergone LAAO due to intracerebral hemorrhage during oral anticoagulant therapy. He presented to the emergency department with decompensated heart failure. Transthoracic echocardiography revealed a mobile mass (30 mm × 19 mm) in the right atrium, and contrast-enhanced cardiac computed tomography confirmed a filling defect within the RAA, consistent with RAA thrombus. Anticoagulation with rivaroxaban 15 mg once daily was initiated, and follow-up imaging at two weeks demonstrated complete resolution of the mobile thrombus. This case highlights the potential for RAA thrombosis in patients with AF following LAAO, particularly in the presence of heart failure and enlarged cardiac chambers. Clinicians should remain vigilant for right-sided intracardiac thrombi in this population, even after successful LAAO, and the decision to discontinue anticoagulation after LAAO should be carefully individualized.