[Two-dimensional echocardiographic observation of ruptured chordae tendineae of the mitral valve: Its localization and uneven development of papillary muscles (author's transl)].

Twenty-three cases with ruptured chordae tendineae (RCT) of the mitral valve and 9 normal control cases were studied by two-dimensional echocardiography. Mitral valve replacement (MVR) was performed in 13 of the 23 cases. The preoperative diagnosis of RCT was proven accurately at operation in all except 2 cases with bacterial endocarditis. Whether RCT occurred in the antero-lateral or in the postero-medial commissural side could be determined perfectly. RCT was observed in the postero-medial side more often than in the anterolateral side, i.e., postero-medial side in 16 (9 operated) and antero-lateral side in 5 (2 operated). This tendency has also been noted in other Japanese reports regardless of the cause of RCT. In the short axis view at the level of the papillary muscles, the area of the posterior papillary muscles was smaller than the area of the anterior papillary muscles in the RCT cases. It is speculated that the smaller size of the posterior papillary muscles has a certain relation with the more frequent RCT in the postero-medial commissural side.