Pulmonary vein flow patterns measured with transesophageal echocardiography have been used recently to assess the severity of mitral valve regurgitation. This study was designed to determine whether regurgitant jet direction selectively influences the pattern of flow in right and left pulmonary veins. Thirty-seven patients undergoing mitral valve repair or replacement for severe valvular regurgitation were studied intraoperatively with biplane transesophageal echocardiography. Regurgitant jets were classified by color flow mapping as central or wall, with the latter further classified as septal, lateral, anterior, or posterior in the two orthogonal scan planes. Pulmonary vein flow patterns were measured with pulsed wave Doppler ultrasonography and categorized as showing normal, blunted, or reversed systolic flow. Right and left pulmonary vein flow patterns were identical in the majority of patients studied (78%). Eight patients had discordant flow patterns. In seven of eight patients, the more abnormal pattern was seen in the right pulmonary vein, despite the fact that the regurgitant jets were directed centrally in four of these seven patients. Since discordant pulmonary vein flow patterns occurred in 5 of 15 patients (33%) with central jets, but in only 3 of 22 patients (14%) with eccentric wall jets, it is unlikely that mitral regurgitation jet direction per se causes predictable and selective unilateral alteration in pulmonary vein flow patterns.