Transesophageal echocardiography in atrial fibrillation. A new paradigm

Transesophageal echocardiography (TEE) has contributed to our understanding of the patho-physiology of the thromboembolic sequelae of atrial fibrillation. This imaging modality has demonstrated thrombus formation within the left atrial appendage, as well as allowing for assessment of dynamic indices of left atrial appendage function. Studies using TEE have introduced the concept of post conversion "stunning", suggesting an increased milieu for thrombus formation after restoration of sinus rhythm. The detailed assessment of the atrium allowed for by TEE gave rise to the concept of TEE guided cardioversion, bypassing the traditional practice of prolonged anticoagulation prior to cardioversion. The only randomized trial of this practice, the multicenter ACUTE trial, has demonstrated that this strategy is a safe one with less bleeding, and appears to be a strong alternative to the conventional approach. There is some suggestion that TEE may play a role in further risk stratification of patients with chronic atrial fibrillation, but more data is needed on this potential utility of TEE. Treatment strategies for atrial fibrillation are continuing to evolve, and TEE has played a role and will likely continue to play a role in this development.