[Contribution of transesophageal echocardiography in the investigation of the atrium in systemic embolism]

Abstract

Transesophageal echocardiography (TEE) is a semi-invasive examination that provides better images of the atrium than classical transthoracic echocardiography (TTE) due to the anatomical positioning of the captor and the high frequency Doppler apparatus used. We used TEE and TTE to evaluate the incidence of the cardiac origin of emboli in 46 patients with unexplained stroke or transient ischemic attack (TIA): 23 had documented heart disease (mean age 60 years) and 23 had no cardiac disease (mean age 43 years). Among those with existing heart disease, 4% of the anomalies certainly or probably responsible for the emboli in addition to the underlying cardiopathy were detected by TTE versus 37% by TEE (as compared to values reported in the literature: 25% by TTE and 51% by TEE). In particular, 4 abnormalities were better visualized by TEE: left atrial thrombus, especially those located in the auricle (5 TEE versus 1 TTE); spontaneous contrast showing the swirl of blood stagnating in the dilated left atria of patients with mitral valve disease seen in 7-39% of the TIA by TEE as compared to less than 1% by TTE (3 TEE versus 0 TTE); aneurysm of the interauricular septum (AIAS) observed in 5-16% of the TIA by TEE as opposed to 0-1% by TTE (4 TEE versus 1 TTE); patent foramen ovale (PFO) was noted more frequently following injection of a contrast medium when visualized by TEE (19-22%) than by TTE (6-8%) and can explain the passage of a paradoxical embolus (1 TEE versus 0 TTE). The incidences of left atrial thrombus, AIAS and PFO are well correlated with systemic emboli, especially in young adults having experienced an unexplained TIA without underlying cardiopathy. TEE is an easy-to-use and well tolerated technique for detecting the cardiac origin of emboli in unexplained stroke. Whether to opt for a medical or surgical treatment to avoid recurrences is discussed.