Left atrial appendage aneurysm

A 22-year-old male, with no past medical history of interest, consulted for recurrent dyspnea on exertion associated with dizziness lasting a few seconds, without syncope. He does not refer the sensation of palpitations.

The most relevant finding in the AP chest x-ray was a prominent left mediastinal border (Fig. 1).

Transesophageal echocardiogram (TEE) revealed a voluminous diffuse dilatation of the left atrial appendage that produced mass effect, with distortion of the nearby cardiac cavities (Fig. 2).

CT confirmed a left atrial appendage aneurysm with a maximum diameter of up to 10 cm and a neck of about 4 cm. There was no thrombus inside of it (Fig. 3). Coronary artery anatomy was normal (not shown).

Postsurgical PA and lateral chest x-ray showed changes of median sternotomy with aneurysmectomy and placement of a left atrial appendage closure device. A small left pleural effusion was also present (Fig. 4).

Background

Left atrial appendage (LAA) aneurysm (LAAA) is a rare condition characterized by a localized or diffuse dilatation of the LAA. The congenital form arises from dysplasia of the musculi pectinati and related atrial muscle bands. Acquired forms often occur in association with conditions leading to elevated left atrial pressure, including organic mitral valve diseases. LAAA has been seen in association with other congenital anomalies, such as atrial septal defect, ventricular septal defect, and Noonan syndrome [1]

It is seen in all ages, from infancy to the ninth decade of life. [2]

To date, about 150 cases of this entity have been described in the literature. [3]

Clinical Perspective

Patients with LAAA may be asymptomatic, or present with dyspnea, palpitations, or thromboembolic phenomenon. The condition may be detected incidentally during cardiac imaging [2].

Imaging Perspective

The usual findings on chest x-rays are cardiomegaly with a prominent upper left heart border. [2]

Transesophageal echocardiography (TEE) is superior to transthoracic echocardiography (TTE) for the detection of LAAA. TEE is also useful in the detection of intra-atrial or LAAA thrombi [1].

Cardiac computed tomography (CT) is a good choice for a better definition of anatomy, to delineate the structure of the LAAA, its compressive effect on the surrounding structures [1], and to evaluate the coronary artery anatomy. MRI can also be used to assess the surrounding structures and cardiac abnormalities. However, MRI has certain disadvantages, such as the need for regular heart rhythm. [3].

Outcome

Because LAAA predisposes patients to thromboembolism and atrial tachyarrhythmias, medical treatment with anticoagulation and antiarrhythmic drugs should be considered [1].

Most of the authors propose surgery (aneurysmectomy) as the main treatment modality for LAAA, regardless of the presence or absence of symptoms. A median sternotomy approach with or without cardiopulmonary bypass or minimal endoscopic techniques are both acceptable options [2].

Anticoagulation therapy is usually discontinued in patients after surgical treatment [1].

Take Home Message

Aneurysm of the left atrial appendage is rare and often an incidental diagnosis during cardiac imaging. It is important to recognize this entity, as it is associated with cardiovascular morbidity and mortality by predisposing to atrial tachyarrhythmia and thromboembolism. Surgical resection is the standard of treatment in the current literature. Medical management is directed at the treatment of thromboembolism and atrial tachyarrhythmia. [2]

Written informed patient consent for publication has been obtained.