954-3 Usefulness of Contrast Transesophageal Echocardiography in Identification of Increased Risk of Cardiogenic Embolism in Nonvalvular Atrial Fibrillation

Anatomical and functional informations about the left atrial appendage (LAA) obtained by transesophageal echocardiography (TEE) are contributory to evaluate a risk of cardiogenic embolism (CE) in nonvalvular atrial fibrillation (NVAF). This study was designed to further characterize a subgroup of NVAF pts with an increased risk of CE with the use of contrast TEE. In 33 NVAF pts, 15 were complicated by CE and 18 were not. Twelve agematched healthy subjects were studied as control. Albunex0.1 ml/kg was injected intravenously and the contrast echo enhancement in the left atrium was recorded by TEE on a video tape. Non opacified area in LAA (Ao) and LAA area were measured in end-systole, and the ratio of Ao to LAA area (Ao ratio) was obtained as a mean of 5 consecutive measurements.ResultsIn healthy subjects, the contrast agent produced complete opacification of LAA, thus Ao ratio was 0%. While, Ao ratio was 52±9% and 31±6% in NVAF with CE and without CE, respectively (p<0.001). Ao ratio over 40% was 80% sensitive and 78% specific for identifying CE group, and the positive predictive value was 75%.ConclusionIn NVAF, the echo contrast agent did not opacify LAA entirely. Non opacified area of transpulmonary contrast agent in LAA as measured by TEE, probably reflecting the extent of blood stagnation in LAA more directly, may be a new useful index for identification of a subgroup of NVAF pts with an increased risk of C