Apêndice atrial esquerdo: imagem ecocardiográfica transtorácica tridimensional em tempo real

Abstract

1-4 . This fact becomes especially relevant when anatomical observation translates into prognostic clinical implications, such as in the identification of images of thrombi in the left atrium or left atrial appendage. In most clinical situations, the investigation of intra-atrial images of thrombi with the use of two-dimensional transthoracic echocardiography does not allow anatomical information reliable enough for a diagnostic definition. Use of multiplane bidimensional transesophagic echocardiography enabled additional diagnostic information for discrimination of intra-atrial masses caused by the use of transducers with a greater ultrasound emission frequency, at a greater proximity to the structure of interest, providing images with a better quality of structural definition. Nevertheless, this semi-invasive echocardiographic modality does not yet allow structural from all anatomic planes of observation (a primary limitation for structural identification based on frontal and transversal cardiac planes, with observation point in atrioventricular, pulmonary, and aortic valve rings). Real-time three-dimensional transthoracic echocardiography is an advancement in anatomical analysis because it allows a rotation of heart structures based on three primary planes of structural definition (infero-superior plane, mid-lateral plane, and depth or elevation plane), as well as a structural composition based on the analysis of composite planes or diagonal planes. Image acquisition is made in real-time, and the final image may be obtained by the projection of interest to the clinician or surgeon. In the case shown, we observe the two-dimensional transthoracic echocardiographic analysis of the left atrial appendage (Figure 1), and the real-time three-dimensional transthoracic image of the left atrial appendage from different observation planes (Figures 2A, 2B and 2C), as from the frontal plane (en face). Currently, transesophagic echocardiography is still the most appropriate echocardiographic technique for visualization of the left atrial appendage and investigation of intracavitary thrombi, as it shows evidence based on analyses with a large number of patients. Further studies are needed for a definition of the diagnostic and prognostic impact of the anatomical findings obtained by the use of real-time threedimensional transthoracic echocardiography.