This is a prospective study done to describe the pulmonary venous flow pattern of the left upper pulmonary vein by transesophageal pulse wave Doppler in patients with mitral stenosis with Left Atrial Appendage thrombus, spontaneous echo contrast and absence of spontaneous echocontrast nor thrombus. From January to August, 2000, a total of 55 patients were examined. Majority of the patients have Severe Mitral Stenosis with or without mild mitral regurgitation, with 0.73 ems' in NYHA Functional Class II and in Atrial Fibrillation. All have dilated LA, normal Ejection Fraction, mild Pulmonary Hypertension with normal LV dimension. Parameters noted were as follows: systolic, diastolic and systolic reversal flow velocities and velocity time integral, diastolic time and Pressure Half Time as well as systolic and diastolic time integrals. Except for 8 patients who show a normal pulmonary venous flow pattern, defined as systolic over diastolic velocity ratio of 2: 1. The rest showed a blunted pulmonary venous flow pattern.' Among the 3 groups studied, Group I, composed of patients with LAA thrombus, showed the highest systolic velocity whether in Atrial Fibrillation of in Sinus Rhythm. Those with AF have the lowest systolic flow velocity integral isovolurnic relaxationtime with markedly prolonged distolic time integral. On the other hand, those in Sinus Rhythm have a significantly low diastolic velocity but a high systolic over diastolic velocity compared to those without thrombus nor spontaneous echo contrast.