[Spontaneous left atrial echo contrast in trans-esophageal echocardiography].
Left atrial spontaneous contrasts (LASC) are found almost exclusively with transesophageal echocardiography (TEE), usually in patients with mitral stenosis or mitral prosthetic valves. The prevalence of LASC was examined in 143 consecutive patients undergoing TEE and transthoracic echocardiography (TEE). LASC of variable intensity were observed in 31 patients (22%) with TEE, in contrast to none with TTE. There was a significant correlation between the presence of LASC and atrial fibrillation (p less than 0.001), left atrial dilatation (p less than 0.005) and presence of mitral valve prosthesis or mitral stenosis (p less than 0.02). In 48% of patients with LASC the mitral valve was entirely normal. Multivariance analysis showed atrial fibrillation and left atrial dilatation to be independent predictors for the presence of LASC. There were significantly more ischemic strokes in patients with LASC (35% vs 12% in patients without LASC). LASC are a frequent observation with TEE. As sensitivity of the echocardiography instruments steadily improves, LASC are also found in increasing numbers of patients with minimal structural change of the heart. LASC may indicate the presence of microthrombi and thus be involved in the pathogenesis of thromboembolic complications; their clinical relevance and prognostic significance needs to be further investigated.