OBJECTIVE: This study examined the geometric changes of the mitral valve (MV) after repair using conventional and three-dimensional echocardiography. DESIGN: Prospective evaluation of consecutive patients undergoing mitral valve repair. TYPE OF HOSPITAL: Tertiary care university hospital. PARTICIPANTS: Fifty consecutive patients scheduled for elective repair of the mitral valve for regurgitant disease. INTERVENTIONS: Intraoperative transesophageal echocardiography. MEASUREMENTS: Assessments of valve area (MVA) were performed using two-dimensional planimetry (2D-Plan), pressure half-time (PHT), and three-dimensional planimetry (3D-Plan). In addition, the direction of ventricular inflow was assessed from the three-dimensional imaging. MAIN RESULTS: Good correlations (r = 0.83) and agreement (-0.08 +/- 0.43 cm(2)) were seen between the MVA measured with 3D-Plan and PHT, and were better than either compared to 2D-Plan. MVAs were smaller after repair of functional disease repaired with an annuloplasty ring. After repair, ventricular inflow was directed toward the lateral ventricular wall. Subgroup analysis showed that the change in inflow angle was not different after repair of functional disease (168 to 171 degrees) as compared to those presenting with degenerative disease (168 to 148 degrees; p0.0001). CONCLUSIONS: Three-dimensional imaging provides caregivers with a unique ability to assess changes in valve function after mitral valve repair.