Surgical management of the straddling mitral valve in the biventricular heart

Background. The straddling mitral valve in the biventricular heart is a rar e condition that may complicate biventricular repair. Methods. Treatment and outcomes in 5 consecutive patients who underwent pri mary repair between 1992 and 1997 were reviewed. Their ages at repair range d from 2 months to 8 years. Three patients had a double-outlet right ventri cle with a subaortic (n = 2) or subpulmonary (n = 1) ventricular septal def ect. Two patients had transposition of the great arteries [S,D,D], a ventri cular septal defect, and left ventricular outflow tract obstruction. The at tachments of the papillary muscles of the straddling mitral valves were loc ated on the right ventricular aspect of the ventricular septum. Four patien ts underwent baffle partitioning of the ventricular cavity. The baffle sutu re line was used to secure the chordae tendineae crossing the ventricular s eptal defect, or was intentionally omitted at the papillary muscle. The rig ht augmentation, an extracardiac conduit, or an arterial switch operation. One patient with transposition who had a giant papillary muscle to the stra ddling mitral valve associated with abnormal insertion of the tricuspid val ve on the conal septum underwent univentricular repair. Results. There were no early or late postoperative deaths. There was no mit ral valve dysfunction, left ventricular outflow tract obstruction, or heart block in the 4 patients who underwent biventricular repair. Conclusions. Although there are several exceptional situations in which ven tricular partitioning may result in early and late complications, a straddl ing mitral valve does not preclude biventricular repair. (C) 2000 by The So ciety of Thoracic Surgeons.