Ventricular septal defect haemodynamically insignificant

**Definition:** A congenital cardiac malformation in which there is one or more small, clinically insignificant ventricular septal defect(s) in the absence of flow-related cardiac chamber dilation or abnormal elevation of pulmonary arterial pressure.

Additional information: though restrictive ventricular septal defect is listed as a synonym of haemodynamically insignificant VSD, it should be recognised that some pressure restrictive ventricular septal defects will lead to flow-related chamber dilation, and thus would be haemodynamically significant. In such instances, the term haemodynamically insignificant ventricular septal defect should not be coded.