Quantitative real-time three-dimensional echocardiography provides new insight into the mechanisms of mitral valve regurgitation post-repair of atrioventricular septal defect.

BACKGROUND: Mechanisms of mitral valve regurgitation after atrioventricular septal defect repair are unclear.

METHODS: To gain further insight into mitral valve regurgitation, real-time three-dimensional echocardiography was performed in 53 patients after atrioventricular septal defect repair (30 partial and 23 complete) and 40 controls. Mitral valve {x, y, z} coordinates from the annulus, leaflet surface, papillary muscle, and chordal attachments were recorded. Vena contracta area of the regurgitant jet(s) and volume of leaflet prolapse and tethering were measured.

RESULTS: Twenty-three patients had mild (group 1) and 30 moderate (group 2) mitral valve regurgitation. Patients in both groups 1 and 2 had more circular annuli than controls. Annular area was greater in group 2 than in group 1 and controls (P < .01). Group 2 had more frequent segmental prolapse in the superior-mural leaflet segment. The anterolateral papillary muscle was more laterally displaced in group 2 than in controls and group 1 at end-diastole (P = .01 and P = .05) and formed a more acute angle with the mitral valve annulus than in controls or group 1 (P = .01).

CONCLUSIONS: In patients with atrioventricular septal defects, significant mitral valve regurgitation is associated with leaflet prolapse, larger annular area, and lateral papillary muscle displacement.