[Transesophageal echocardiography and risk factors for embolism]

Echocardiography is the main diagnostic tool for thromboembolic risk evaluation in patients with atrial fibrillation (AF). Transthoracic echocardiography (TTE) has low sensitivity and specificity in thrombus detection, especially in left atrium appendage; on the other hand the transesophageal approach (TEE) provides information about thrombi located anywhere. In recent years, large trials on thromboembolic risk in AF have given strong value to echocardiographic risk factors such as left atrial enlargement and left ventricular dysfunction, well detected by TTE. Transesophaged echocardiography can be considered the best technique to study factors even more closely correlated to thromboembolic risk, such as spontaneous echocontrast or left atrium appendage abnormalities both anatomical (enlargement and malformations) or functional (low peak velocity). Preliminary data from new trials, like SPAF III and FASTER, confirm this fact. On the other hand, TEE permits the study of thoracic aorta and atheromasic lesions, which can be considered additional direct (ulcerated plaques) or generic thrombotic risks.