We present a case of double outlet right ventricle (DORV), with subaortic ventricular septal defect (VSD).

Our ultrasound revealed the following findings:

• Images 1 and 2: At 11 weeks of pregnancy, the cardiac ultrasound examination is limited, however some elements can be examined such as location in the thorax and cardiac axis. Color doppler is used to assess anterograde chamber filling and anterograde blood ejection through the output vessels. In these images, cardiac location and axis are normal. Image 1 shows a 4-chamber view with two ventricles with anterograde filling. Image 2 shows the outflow tracts. The expected pattern would be a "V-shaped" image representing the ductus arteriosus joining the aorta. Instead, here there is one big vessel with anterograde flow.

• Video 1, and images 3-13: (CIV = VSD, AP=PA. BIF=bifurcation) At 21 weeks of pregnancy, cardiac examination shows levocardy and situs solitus. Atrioventricular concordance, well balanced LV and RV, normal atrioventricular valves. Perimembranous subaortic VSD, left-to-right shunt. Malposition of the great arteries with both vessels arising from the right ventricle. Dextroposed aorta and left-sided aortic arch, smaller pulmonary trunk with normal left pulmonary artery and right pulmonary artery. Both great arteries have anterograde flow without stenosis, anterograde ductus arteriosus, indicating this is not a ductus-dependent condition at birth. That is the description of a double outlet right ventricle, with subaortic VSD (the so called Fallot type). There is also a persistent left superior vena cava draining into the enlarged coronary sinus. The thymus is present (absence of thymus may suggest a 22q1.1 microdeletion, DiGeorge Syndrome).

In DORV (double outlet right ventricle), both great arteries arise entirely or predominantly from the right ventricle. Several types of DORV exist according to the location of the VSD, the spatial relationship of the great arteries and whether or not there is an outflow obstruction. Pulmonary stenosis is the most common associated cardiac anomaly. Chromosomal anomalies are found in some fetuses (12% up to 40%) such as Trisomy 18, Trisomy 13 and 22q1.1 microdeletion (DiGeorge Syndrome). The primary differential diagnosis is Tetralogy of Fallot and transposition of the great arteries. Subpulmonic VSD and aortic coarctation are associated with suboptimal postsurgical outcomes in DORV.

References

Alfred Abuhamad, Rabih Chaoui. A Practical Guide to Fetal Echocardiography. (2019) ISBN: 9780781797573