Diagnosis of lipomatous hypertrophy of the atrial septum by two-dimensional echocardiography

Abstract

Originally described in 1964, lipomatous hypertrophy of the atrial septum currently remains a diagnosis established primarily at autopsy. Clinical interest in this disorder has centered on the reported association with supraventricular arrhythmias and sudden death. Because two-dimensional echocardiography allows detailed assessment of atrial septal configuration, we reviewed two-dimensional echocardiographic reports obtained over a 1 year period and identified 17 patients who had features consistent with lipomatous hypertrophy of the atrial septum. Nine were men and the average age was 70 years. Autopsy confirmation of the echographic findings was possible in one patient. In nine patients, ideal body weight was exceeded by 10% or more. The atrial septum viewed from the subcostal transducer position showed a distinctive echo-dense globular thickening sparing the valve of the fossa ovalis. The resultant tomographic image of the atrial septum had a characteristic dumbbell appearance. The mean thickness of the atrial septum was 21 mm (range 15 to 29). Seven patients had supraventricular arrhythmias, and eight had P wave abnormalities. The two-dimensional echocardiographic features described are distinctive and suggest that this technique is the procedure of choice not only for establishing the diagnosis of lipomatous hypertrophy of the atrial septum but also for providing a means for prospective follow-up of patients with this little known entity.

A case of lipomatous hypertrophy of the interatrial septum detected via transthoracic 2-dimensional echocardiography

“…2 This clinical entity is a disorder characterized by excessive accumulation of adipose tissue within the interatrial septum, resulting in a globular thickening of the interatrial septum. 3,4 Infiltration of adipose cells between atrial myocytes with a small amount of interstitial fibrosis, or a mixture of fat and cardiac myocytes were described as the microscopic findings as shown in the present case. 5 Burke and Virmani 5 reported that lipomatous hypertrophy is a rare lesion, and approximately 200 cases have been reported.…”

“…Several authors 4,10 have emphasized the usefulness of 2-dimensional echocardiography, both transthoracic and transesophageal for detecting lipomatous hypertrophy of the interatrial septum. However, the 2-dimensional echocardiographic appearance of lipomatous hypertrophy of the interatrial septum may not be specific enough to establish this diagnosis.…”

“…Particularly, it must be dif- ferentiated from other left atrial masses-including atrial myxoma, thrombi, or cardiac amyloidosis-and often this differential diagnosis may be difficult. Fyke et al 4 described guidelines for making an echocardiographic diagnosis of lipomatous hypertrophy of the interatrial septum, namely (1) presence of the characteristic bilobed appearance of the atrial septum when the beam is directed through the region of the fossa ovalis, (2) a thickness posterosuperior or anteroinferior to the valve of the fossa ovalis of 15 mm or more, and (3) absence of any other, more likely explanation for septal thickening.…”

Left Atrial Anatomy Revisited

“…On cross-sectional echocardiography, the septum appears like a "dumbbell." 35 Even in hearts without so-called "septal hypertrophy," transgression through the rim can hinder needle penetration, and, being a thicker structure, can restrict maneuverability after crossing and also increase the risk of exiting the heart, dissecting into the fatty tissue plane, and causing hemopericardium. At particular risk is the anterior rim of the fossa, which is in close anatomic relationship with the aortic mound.…”

Lipomatous hypertrophy of the atrial septum: Diagnosis with fat suppressed MR imaging

“…it consists histopathologically of varying proportions of mature adipose tissue, fibrosis, inflammation, and fetal fat cells, the presence of which is a hallmark of lipomatous hypertrophy of the atrial septum (2-4). This condition, albeit mostly benign, has been associated with atrial arrhythmias, congestive right-sided heart failure, atherosclerotic coronary artery disease, and sudden death (2,5). In most cases, these unencapsulated lipomas extend from the coronary sinus to just above the level of the aortic root with relative sparing of the fossa ovalis, which results in a typical dumbell configuration on computed tomography and echocardiography (1.6).…”