Bilateral atrial appendage thrombus formation in a patient with atrial fibrillation

Abstract

A 60-year-old Japanese man without obvious past medical history was referred to our hospital because of dyspnea. An electrocardiogram revealed atrial fibrillation (AF) without ST-T change, and a chest X-ray showed mild pulmonary congestion and bilateral pleural effusion. Two-dimensional transthoracic echocardiography (2D TTE) on admission showed markedly reduced left ventricular systolic function (LVEF) of 19 % and enlarged heart chambers ( Fig. 1a, b). We detected a left atrial appendage thrombus (Fig. 1c). 2D transesophageal echocardiography (2D TEE) was additionally performed to prepare for electrical cardioversion, and incidentally identified mobile thrombi in both the left atrial appendage (LAA) and right atrial appendage (RAA) ( Fig. 2a-d). The patient underwent emergency prophylactic surgical resection of bilateral thrombi in order to prevent systemic and pulmonary embolism. The surgical procedure removed both LAA and RAA with thrombi. In addition, the ''Maze'' procedure was performed for the treatment of atrial fibrillation. Pathological findings showed a mixture of old and freshly organized thrombus in the LAA. On the other hand, the RAA thrombus mainly consisted of fresh thrombus (Fig. 3).In the present case, we were able to visualize both left and right appendage thrombi using 3D TEE. This is the first report of 3D TEE images of bilateral atrial thrombi.Thrombus formation in LAA is a common complication in patients with AF, and its incidence is quoted as 12-15 %. In contrast, the formation of a RAA thrombus is relatively rare, at 0.8-6 % [1-4], and few cases of bilateral appendage thrombosis have been reported [1]. In our case, the size of the RAA thrombus (3.39 9 2.01 cm) was larger than that of the LAA thrombus (2.53 9 1.26 cm), and this finding coincides with the previous report [1]. In addition, LV systolic dysfunction (reduced LVEF) is a risk factor for LV and LAA thrombus formation. A previous report suggested that LV end-diastolic diameter was correlated with LAA thrombus formation [5]. On the other hand, moderate to severe mitral regurgitation (MR) has been recognized as a negative predictor for the development of a left atrial thrombus [6,7]. The severity of MR was mild in our case.We should pay attention to thrombus formation in not only the left but also the right atrial appendage, especially in patients with AF and reduced LV systolic function. Recently, real-time three-dimensional (3D) TEE has been a & Koichiro Imai