pediatrics
Double Outlet Right Ventricle
Pathophysiology of Double Outlet Right Ventricle
DORV has a wide spectrum of anatomy and physiology depending on the size and location of the ventricular septal defect (VSD), which is invariably present, and the presence and degree of Pulmonic Stenosis ( AO = aorta; LA = left atrium; LV = left ventricle; PA = pulmonary artery; RA = right atrium; RV = right ventricle; VSD = ventricular septal defect. Because both great vessels arise from one ventricle, there is some degree of mixing of desaturated systemic venous blood and highly saturated pulmonary venous return that enters the right ventricle via flow through the left atrium, left ventricle, and VSD. However, the degree of systemic arterial desaturation is greatly affected by streaming of flow across the ventricular defect and the presence of obstruction to the pulmonary artery. If the defect is subaortic, the VSD shunt goes to both the aorta and the pulmonary artery, resulting in an effective large left-to-right shunt. The physiology and clinical findings are nearly identical to that of a large VSD. If pulmonic stenosis occurs with the subaortic VSD, more desaturated blood in the right ventricle is directed to the aorta, leading to cyanosis and a clinical picture similar to Tetralogy of Fallot . If the VSD is subpulmonic, the highly saturated blood from the left ventricle flows predominantly to the pulmonary artery and the desaturated blood in the right ventricle goes primarily to the aorta, resulting in moderate to severe cyanosis and the same physiology as Transposition of the Great Arteries (TGA) (d-TGA). When the VSD is subpulmonic and the pulmonary valve is immediately adjacent to the defect or partially overrides the VSD, the defect is known as a Taussig-Bing anomaly. The last major variant of VSD location is a muscular defect that is not committed to either great vessel. The clinical findings fall in the middle of the spectrum between the other types of VSD with both excessive pulmonary blood flow and systemic desaturation. A variety of other congenital defects can be associated with DORV, but the most common is Coarctation of the Aorta with a Taussig-Bing anomaly. 1.Yim D, Dragulescu A, Ide H, et al: Essential modifiers of double outlet right ventricle: Revisit with endocardial surface images and 3-dimensional print models.Circ Cardiovasc Imaging11(3):e006891, 2018. doi:10.1161/CIRCIMAGING.117.006891 