We evaluated the resolution of left atrial spontaneous echocardiographic contrast (SEC) using transesophageal echocardiography (TEE) and transthoracic echocardiography (TTE) one day before and three days after percutaneous mitral balloon valvulotomy (PMV) in 56 consecutive patients with mitral stenosis. SEC was present in 43 patients (77%) before the procedure. We associated the following parameters with pre-procedure SEC; decreased forward (p=0.043) and backward (p=0.044) left atrial appendage (LAA) peak flow velocities, increased left atrial dimension (p=0.05), decreased mitral valve area (p=0.001), presence of atrial fibrillation (p=0.031), and increased pulmonary systolic pressure (p=0.01). In multivariate analysis, decreased forward LAA peak flow velocity (p=0.0724), and decreased mitral valve area (p=0.0026) were the significant independent predictors for the presence of pre-procedure SEC. On post-PMV transesophageal echocardiography, SEC was present in seven patients (13%). Analysis of this subgroup of patients showed them to be in the lowest quintile of the preprocedure forward LAA peak flow velocities. They also showed smaller percentage and absolute increase in backward LAA peak flow velocities after PMV. We suggest continued left atrial muscular dysfunction as an explanation for the persistence of SEC, despite the excellent hemodynamic improvement. We explain the dramatic decrease in SEC after PMV, on the basis of the youth of our patient population, the high success rates attained with PMV, and the physiopathologic mechanisms that may be in play in rheumatic mitral stenosis seen in developing countries.