Membranes of Left Atrial Appendage: Real Appearance or “Pitfall”

Abstract

The membranes of left atrial appendage (LAA) cavity are very rare entity. To date, only five cases of a membrane involving LAA have been described. In this report, we describe two different cases: in Case 1, we show image of a "real" nonobstructive membrane within the body of LAA, but in Case 2 we show a linear image, mimicking a membrane within the body of LAA. It really is a "pitfall" of transesophageal echocardiography (TEE).

A Rare Case of Non-obstructive Membrane of the Body of Left Atrial Appendage Incidentally Found in Asymptomatic Adult Woman

“…The most likely explanation of the origin of these membranes would appear to be a congenital anatomic variation [1-3]. In five reports [1, 2], non-obstructive membranes located in the body of the LAA have been described and in two cases [4, 5] obstructive membranes at the opening of the LAA, causing functional stenosis have been reported. Similar to previous reports [1, 2], we described a case that has a thin mobile membrane-like structure at the body the LAA.…”

“…In five reports [1, 2], non-obstructive membranes located in the body of the LAA have been described and in two cases [4, 5] obstructive membranes at the opening of the LAA, causing functional stenosis have been reported. Similar to previous reports [1, 2], we described a case that has a thin mobile membrane-like structure at the body the LAA. It does not cause an obstruction at the LAA opening as demonstrated by absence of velocity step-up on pulse-wave Doppler of the LAA and by a lack of turbulence with color flow Doppler.…”

“…It does not cause an obstruction at the LAA opening as demonstrated by absence of velocity step-up on pulse-wave Doppler of the LAA and by a lack of turbulence with color flow Doppler. The different diagnosis of linear structures within LAA cavity may include prominent pectinate muscles, side lobe artifacts, partial resorption of prior LAA thrombi and localized pericardial effusion [1, 2]. The clinical significance of this membrane has not been known [2].…”

Misleading aspect of left atrial appendage membrane: an incidental echocardiographic finding

“…LAA membranes are discovered incidentally most of the time, and a consensus has yet to emerge as to their clinical significance (3,4).…”

“…The origin of membranes involving the LAA is not clear. The most likely explanation for the origin of these membranes would appear to be a congenital anatomic variation (3).…”