Trabecular muscular ventricular septal defect

**Definition:** A congenital cardiac malformation in which there is a ventricular septal defect within the trabeculated component of the ventricular septum.

Additional information: the codes specifying defects within the trabecular part of the ventricular septum should not be used to code inlet or outlet muscular defects, as there are specific codes for these entities.

**Long definition:** A congenital cardiac malformation in which there is a ventricular septal defect within the apical component of the muscular ventricular septum. Defects within the muscular part of the ventricular septum that open to the inlet or the outlet of the right ventricle could also justifiably be considered to be within the apical part of the ventricular septum. More specific geographical codes, however, have been created for these latter variants. The code specifying defects within the trabecular part of the ventricular septum, therefore, should not be used to code the inlet or outlet muscular defects.