Giant Aneurysm of the Left Atrial Appendage Detected by Real-Time 3-Dimensional Echocardiography

A 29-year-old woman presented with a 5-month history of exertional palpitations and shortness of breath. In a supine position, the patient experienced an abrupt heart-rate increase from 100 to 180 beats/min (in sinus rhythm, as confirmed by electrocardiography) and an abrupt blood-pressure decrease from 90/60 to 78/50 mmHg. Upon 2-dimensional (2-D) echocardiographic examination, we detected, between the left ventricle and the pericardium, a huge sac that communicated with the left atrium through an orifice (diameter, 2 cm) (Fig. 1). Real-time 3--dimensional (3-D) echocardiography showed an aneurysmal extension of the left atrial appendage (LAA)—connected with the left atrium via an orifice (diameter, 3.1 cm) and located anterior to, and to the left of, the left ventricle (Fig. 2A). Surgery confirmed the diagnosis of a giant (22 × 15 × 15 cm) elliptical aneurysm (Fig. 2B), which connected to the LAA via a 3-cm orifice; no thrombus was found within. The aneurysm was surgically resected, and the patient recovered without recurrence of symptoms.

Fig. 1 Two-dimensional echocardiography shows a normal-sized RA and RV, but a narrowed LV chamber. A huge, elliptical and thin wall sac is wedged between the LV and the pericardium; it communicates with a normal-sized LA. LA = left atrium; LV = left ventricle; RA = right atrium; RV = right ventricle

Fig. 2 A) A real-time 3-dimensional echocardiogram acquired from the apical transducer position shows an aneurysm that occupies the upper-right section of the image and communicates with the LA via the orifice just above the level of the mitral annulus. B) Intraoperative photograph shows the giant aneurysm to the left of the MPA and the LV pushed to the right by the aneurysm. In the intraoperative photograph, the patient's head is below the bottom of the image. LA = left atrium; LV = left ventricle; MPA = main pulmonary artery; MV = mitral valve; RAA = right atrial appendage; RV = right ventricle; asterisk = the lower border of the aneurysm

Comment

Left atrial appendage aneurysm, caused by dysplasia of the atrial muscle, is a rare congenital heart disease.¹ Life-threatening systemic embolism² and supraventricular tachycardias are the most frequently reported complications. However, never before to our knowledge has such a huge aneurysm of the LAA been reported. Because of the limitations of its acoustic windows and cross-sectional views, 2-D echocardiography failed to show the entire structure of the aneurysm. Although 3-D echocardiography was helpful in establishing the huge structure as an extension of the true LAA, the inherent limitations of the currently available 3-D technology still made difficult our attempt to include the entire structure for analysis. Because the orifice diameter measured by 3-D echocardiography (3.1 cm) was much closer to the surgical finding (3 cm) than that measured by means of 2-D (2 cm), we conclude that 3-D was better in delineating the spatial relationship between the LAA aneurysm and the adjacent structures, and in helping us to reach surgical decisions.