The transesophageal echocardiographic data of 62 patients with severe, rheumatic mitral stenosis, which was either isolated or associated with different degrees of mitral regurgitation were reviewed to study and compare their pulmonary venous flow patterns. Peak systolic and peak diastolic flow velocities and their respective time intervals were measured, and the presence or absence of systolic flow reversal (SFR) was noted. The venous flow velocities and time integrals were all below normal and the ratio between the systolic and diastolic velocities were all blunted. Systolic flow reversal was observed in some patients with severe mitral stenosis with or without mitral regurgitation, and was highly correlated with the presence of atrial fibrillation. Among patients with mitral regurgitation and in atrial fibrillation, flow reversal timing was shorter in patients with significant mitral regurgitation than in patients with mild or no mitral regurgitation.