Pulmonary venous (PV) velocities obtained by transthoracic echocardiography are used to assess diastolic function. The systolic/diastolic (S/D) PV velocity ratio is increased with impaired early diastolic filling and decreased with elevated mean left atrial pressure (LAP). Mitral stenosis (MS) is characterized by impaired filling and elevated LAP. We hypothesized that the S/D ratio would be increased in MS except in severe MS with high LAP, in which the S/D ratio would be decreased. Patients with isolated MS who underwent transthoracic echocardiography were studied. The PV S/D ratio was compared in mild ( n=18), moderate ( n=16), and severe ( n=7) MS. There was no characteristic PV pattern, with each category showing a wide range of S/D ratios (mild, S/D ratio=1.42 ±0.56; moderate, S/D ratio=1.19±0.59, and severe, S/D ratio=1.33±0.53) (mean±SD). Furthermore, there was no relationship between the S/D ratio and any index of severity of MS. There is no characteristic PV velocity pattern in MS.