Description

A 57-year-old female patient presented to our emergency department with irregular palpitations for more than 48 h. She had a history of hypothyroidism on treatment without any other cardiovascular risk factors. An ECG performed at admission revealed atrial fibrillation with rapid ventricular response. She was referred to our echocardiography laboratory for study. The transthoracic echocardiogram demonstrated a structurally normal heart. With a goal of electrical cardioversion, the patient underwent transesophageal echocardiogram (TEE), which revealed a 4 mm image of medium echogenicity, coating the entire left atrium and left atrial appendage (figure 1A–C).

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Figure 1

(A–C) Image of medium echogenicity coating the entire left atrium and left atrial appendage (arrows).

Considering the clinical context, a rather atypical left atrial thrombus was considered the most likely diagnosis and the patient was put on oral anticoagulation with vitamin K antagonist. Two months later, a novel TEE was performed and the thrombus had partially disappeared (figure 2). Thrombophilia was subsequently excluded.

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Figure 2

Control transesophageal echocardiogram revealing the thrombus disappearance.

Thrombus formation in patients with non-valvular AF results from stagnant blood in the atria,1 combined with other physiological derangements such as progressive atrial dilation and abnormal platelet activation and changes in coagulation factors, contributing to an increased propensity for blood clot formation. This particular shape of thrombus coating the entire left atrium and left atrial appendage has never been reported before, and thus represents an extremely rare form of presentation. Physicians should be aware of the potential high variability of thrombus shape and location.