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 (1).

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 (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.

The clinical manifestations of DORV range from severe cyanosis (with the Taussig-Bing anomaly or any VSD type with pulmonary stenosis) to congestive heart failure and pulmonary hypertension (with a subaortic VSD and no pulmonary outflow obstruction).

Physical examination may reveal a single loud second heart sound (S2) with pulmonary hypertension, a systolic ejection murmur at the base due to pulmonary stenosis, cyanosis with clubbing, and, if a coarctation is present, decreased femoral pulses.

• Chest x-ray and ECG

• Echocardiography

• MRI and CT

• Cardiac catheterization

The ECG consistently shows right ventricular hypertrophy with right axis. If the pulmonary outflow and pulmonary valve are unobstructed, the chest x-ray shows cardiomegaly and increased pulmonary vascularity. Conversely, in the presence of pulmonary stenosis, heart size may be normal and pulmonary vascular markings normal or decreased.

Echocardiography demonstrates the anatomy well, showing the size and location of the VSD, arrangement of the aortic and pulmonary arteries, and the presence or degree of pulmonary stenosis, either below or at the valve level.

MRI or CT is valuable in planning surgical intervention by providing details of the spatial relationships of the VSD and great vessels.

Cardiac catheterization may have a role in defining the hemodynamics, including any gradient across the VSD, pulmonary artery pressure, and vascular resistance.

• Medications to treat cyanosis and heart failure

• Surgery

During the newborn period, prostaglandins may be needed for severe cyanosis if critical pulmonary stenosis is present. If pulmonary blood flow is greatly increased, heart failure treatment is required. However, surgical intervention is invariably required.

In the most common variety of DORV with a subaortic VSD, a complete repair is possible with closure of the VSD in such a way as to direct left ventricular outflow to the aorta with an intracardiac patch. Pulmonary stenosis, if present, needs to be relieved.

In the Taussig-Bing anomaly, the repair is more complex and involves an arterial switch along with closure of the VSD, directing the left ventricular outflow to the aorta. In cases in which the VSD is uncommitted to either great vessel, surgical correction is more difficult and may require a palliative procedure, such as an aortopulmonary shunt (see photo Modified Blalock-Taussig-Thomas Shunt) or staged procedures to a Fontan operation.

• In double outlet right ventricle (DORV), both the aorta and pulmonary valve connect to the right ventricle.

• DORV has a wide spectrum of anatomy and physiology depending on the size and location of the ventricular septal defect (VSD) and the presence and degree of pulmonic stenosis.

• Diagnosis is with chest x-ray, MRI, CT, ECG, echocardiography, and cardiac catheterization.

• During the newborn period, prostaglandins might be needed for severe cyanosis; heart failure treatment may also be needed.

• Surgery is inevitably required; in the most common type, complete repair is possible.

The following English-language resources may be useful. Please note that THE MANUAL is not responsible for the content of these resources.

1. American Heart Association: Common Heart Defects: Provides overview of common congenital heart defects for parents and caregivers

2. American Heart Association: Infective Endocarditis: Provides an overview of infective endocarditis, including summarizing prophylactic antibiotic use, for patients and caregivers