What is double outlet right ventricle?

The human heart has four chambers. The top chambers, the right and left atria, receive blood that flows into the heart. The bottom chambers, the right and left ventricles, pump blood out of the heart. In a healthy heart, the right atrium receives blood that has traveled through the body and has little oxygen left in it. The right ventricle pumps blood out to the lungs through a large blood vessel called the pulmonary artery. The blood picks up oxygen in the lungs, travels back to the left side of the heart and is pumped out to the body through a large blood vessel called the aorta. Because the pulmonary artery and the aorta are the largest blood vessels in the body, doctors sometimes call them the great vessels or the great arteries.

Double outlet right ventricle (DORV) is a form of a congenital heart disease in which both great arteries are connected to the right ventricle instead of one great artery connected to each ventricle. 

Children born with a double outlet right ventricle heart defect almost always have another heart defect called a ventricular septal defect (VSD). A VSD is a hole in the septum, the wall that divides the right and left ventricle. In children with DORV, the VSD is actually helpful. Without the VSD, blood that traveled to the lungs and back to the left side of the heart would have no place to go, since the aorta isn’t attached to the left ventricle, and no oxygenated blood would reach the body.

The VSD allows oxygenated blood flowing into the left side of the heart to cross over to the right ventricle and be pumped out to the body through the aorta. However, because it’s a mix of the low oxygenated blood in the right ventricle and the highly oxygenated blood from the left ventricle, the blood isn’t as high in oxygen as it should be, and this causes a variety of problems.

The specific problems a child will experience depends on the type of DORV they have, which is classified according to the location of the VSD and how the great arteries are arranged.

In some cases, because more blood than normal is flowing into the right ventricle, too much blood is pumped to the lungs. Over time, this uncontrolled flow can damage the lungs and heart, and heart failure symptoms can result (similar to what happens with a simple VSD.

In other cases, children with DORV also have pulmonary stenosis, a problem with the valve that sends blood out of the heart to the pulmonary artery. These children may develop lower than normal oxygen levels, because there is less blood getting to the lungs (similar to what happens in tetralogy of Fallot).  

Another form of DORV results in blood flow patterns which may be similar to transposition of the great arteries. Abnormalities of the aortic arch and mitral valve can also occur.

Your Cardiac Center team at Children’s Hospital of Philadelphia (CHOP) will explain your child’s heart defect to you in detail.

Signs and symptoms of double outlet right ventricle

Double outlet right ventricle symptoms vary depending on how much oxygenated blood is reaching the body. In most cases, children will have symptoms in the first days or weeks of life, including:

• Blue or purple tint to lips, skin and nails (cyanosis)
• Poor eating and poor weight gain
• Rapid breathing or shortness of breath
• Excessive sweating, especially while feeding
• More sleepiness than normal
• Unresponsiveness or seeming “out of it”
• Heart murmur, or abnormal heart sound when a doctor listens with a stethoscope

Testing and diagnosis of DORV

In some cases, double outlet right ventricle is diagnosed while a child is still in the womb. The Fetal Heart Program at CHOP can monitor both you and your child throughout your pregnancy and create a plan for labor and care after the birth. CHOP has its own delivery unit for healthy mothers carrying babies with known birth defects. Here, newborns are cared for by pediatric cardiologists and specially trained cardiac nurses immediately following birth.

Several different tests are used to diagnose DORV after a baby is born. These include:

• Electrocardiogram (EKG or ECG), which is a record of the electrical activity of the heart
• Echocardiogram (also called echo or ultrasound), which is when sound waves create an image of the heart
• Chest X-ray
• Cardiac MRI, which is a 3D image that shows the heart's abnormalities

Sometimes, cardiac catheterization will be required. A thin, flexible tube (catheter) is inserted through a vein or artery in the leg and into the heart to provide detailed information about the structure and function of the heart and lungs.