Transesophageal echocardiogram (TEE) was performed in 33 consecutive patients with both rheumatic mitral stenosis and chronic atrial fibrillation to evaluate tfae usefulness of this technique for the detection of left atrial thrombi, mitral regurgitation before percutaneous balloon mitral valvuloplasty and iatrogenic atrial septal defect after the procedure. TEE correctly identified thrombi in 10 (30%) patients and significant mitral regurgitation in 5 patients who underwent surgical intervention. The remaining 18 patients underwent percutaneous balloon mitral valvuloplasty without evidence of systemic embolic event and obtained adequate outcome. Transesophageal color doppler echocardiography demostrated left-o-ight shunting flow through atrial septum in 5 of 7(71%) patients 3 days after the procedure and repeated TEE in 2 of these 5 patients showed no shunting after 6 months. In conclusion, TEE plays a definite role in the selection of patients for balloon mitral valvuloplasty and assessment of iatroge Transesophageal echocardiogram (TEE) was performed in 33 consecutive patients with both rheumatic mitral stenosis and chronic atrial fibrillation to evaluate tfae usefulness of this technique for the detection of left atrial thrombi, mitral regurgitation before percutaneous balloon mitral valvuloplasty and iatrogenic atrial septal defect after the procedure The remaining 18 patients underwent percutaneous balloon mitral valvuloplasty without evidence of systemic embolic event and obtained adequate outcome. TEE correctly identified thrombi in 10 (30%) patients and significant mitral regurgitation in 5 patients who underwent surgical intervention. -o-ight shunting flow through atrial septum in 5 of 7 (71%) patients 3 days after the procedure and repeated TEE in 2 of these 5 patients showed no shunting after 6 months. In conclusion, TEE plays a definite role in the selection of patients for balloon mitral valvuloplasty and ass essment of iatroge