Comparison of two and three dimensional transthoracic versus transesophageal echocardiography in evaluation of anatomy and pathology of left atrial apendage.

Objective: Our objective was the comparison of combined utility of two-dimensional (2D) transthoracic echocardiography (TTE) and three-dimensional (3D) TTE versus 2D and 3D transesophageal echocardiography (TEE) in evaluation of anatomy of the left atrium appendage (LAA) and for clot formation in LAA.

Background: 2DTEE as semi-invasive method has been for a long time used to visualize the LAA. Improved echocardiography technology has increasingly improved visualization of LAA by 2DTTE and 3DTTE in many patients and decreased the need for TEE performance.

Methods: We compared combined 2DTTE and 3DTTE with 2DTEE and 3DTEE in evaluating the LAA for anatomical features and thrombus. Eighty-six patients underwent 2DTTE, 3DTTE, 2DTEE and 3DTEE.

Results: LAA could be visualized in all patients. 31 % of patients had one lobe, 43% had 2 lobes and 26% had > 2 lobes. Of 86 patients studied, 79 had no thrombus and 7 had thrombus in the LAA by all modalities. Six patients, 3 with atrial fibrillation (AF), and 4 in sinus rhythm (SR) had a suspected thrombus by 2DTEE. Only in one patient 3DTEE cropping has been needed to clearly show thrombus which was suspected in short axis view on 2DTEE as rounded echo dense mass.

Conclusions: Our preliminary study suggests that combined 2DTTE and 3DTTE has comparable accuracy to TEE in evaluating the LAA anatomy and pathology in terms of thrombus. Only in inappropriate (obese) patients 2TTE, but not 3DTTE, may misdiagnose pectinate musculature as thrombus.