[Surgical anatomy of the interventricular communications of the septal trabecula].

Muscular ventricular septal defects (VSD) are a special anatomical and surgical entity. They are observed in 85% of cases of multiple VSD. This study was based on the operative findings in 70 patients and 20 pathological specimens of muscular VSD. A surgical topographic classification is proposed, superior, intermediate and inferior, with a specific surgical approach for each of the three types. The superiorly situated muscular VSDs are approached through the right ventricle, the intermediate ones through the right atrium and the inferior through the right atrium or left ventricle. Section of the moderator band greatly facilitates the exposure of the intermediate and inferior segments of the septum through the tricuspid valve. Left ventriculotomies should be reserved for inferiorly situated muscular VSD with right ventricles of small volume.