Abstracts of the 26th World Congress on Ultrasound in Obstetrics and Gynecology, Rome, Italy, 24-28 September 2016

Objectives: On the long axis view of the fetal left ventricle the presence of a perimembranous defects is often suspected but a true subaortic ventricular septal defect (VSD) is postnatally confirmed only in a small number of these cases. The aim of this study was to assess if the systematic use of the short axis view of the heart may improve the antenatal prediction of VSD in fetuses with suspected findings at 5 chamber view. Methods: Cases where an isolated subaortic VSD was suspected on the five chamber view of the fetal heart were subsequently assessed using the short axis scanning plane. On this plane the presence of a defect across the ventricular septum between the aortic wall and the tricuspid valve was searched upon (see figure). Postnatal assessment was performed in all fetuses within 2 weeks from birth at our Paediatric Cardiology Unit. Results: Overall a subaortic VSD was suspected on the long axis view in 18 fetuses and confirmed on the short axis in 12 patients. At postnatal follow up a subaortic VSD was diagnosed in 10 cases, and in all of these the VSD had been antenatally documented in both the long and the short axis view. Only two cases with abnormal findings at long and short axis view were not confirmed at postnatal assessment whereas all the 8 cases with a suspected VSD at the five chamber view only turned out to be false positive. Conclusions: The short axis view of the fetal heart seems useful in confirming the presence of a perimembranous VSD suspected on the 5 chamber view.