Double outlet right ventricle (DORV) is a very rare congenital heart defect in which both of the great arteries of the heart (the aorta and the pulmonary artery) are connected to the right ventricle instead of separate ventricles. The degree of the defect can vary.

DORV patients almost always have a ventricular septal defect (VSD), which is a hole in the wall (septum) between the two pumping chambers of the heart, the left and right ventricles. With DORV, the VSD actually helps patients because it allows oxygen-rich blood to pass from the left ventricle to the right, where it is pumped into the aorta and to the rest of the body. Circulation of oxygen-rich blood is accomplished with the VSD but only at great stress to the system. In addition, the oxygen levels in the blood are not as high as those found in patients with normal hearts.

Since DORV is a congenital heart defect, it is established during the fetal development – during the first eight weeks when the heart is formed. Congenital heart defects may be due to a genetic link, such as a chromosome abnormality or a gene defect. They also may be caused by exposure to environmental toxins. In most cases, however, heart defects, such as DORV, occur by chance with no definitive reason, as yet, for their occurrence.

The signs and symptoms of DORV usually appear in infancy. They will vary depending on the position and size of the VSD. The most common symptoms include a heart murmur, rapid breathing, fatigue and sweating. In addition, an infant or child may demonstrate a bluish-tint to the skin (cyanosis) and have poor weight gain. The signs and symptoms of DORV, however, may be similar to other medical conditions or heart problems. If a child demonstrates these symptoms, a physician should evaluate him or her.

An infant or child will likely be referred to a pediatric cardiologist for the definitive diagnosis of DORV. A physical examination and various tests, such as an echocardiogram, will be used to diagnose DORV defects.

Surgery is necessary to repair the heart defects from DORV. There are several surgical options and the specific treatment will be based on the extent of the condition and medical considerations of the child. The outlook for recovery for most patients undergoing treatment for DORV is very good. A pediatric cardiologist, however, must follow the patients to monitor the presence of any heart difficulties.  Although DORV may be corrected, it may not be cured and care by specialists dealing with congenital heart disease will be necessary indefinitely.

Double outlet right ventricle (DORV) is a very rare congenital heart defect in which both of the great arteries of the heart leave from the right ventricle. By contrast, in a healthy heart, both of the great vessels originate from separate ventricles. The degree of the defect from DORV can vary among patients.

The first great vessel is the pulmonary artery, which normally carries oxygen-poor blood from the right ventricle to the lungs to pick up oxygen. The second great vessel is the aorta, which normally carries oxygen-rich blood from the left ventricle to the rest of the body.

Under normal circumstances, this condition would be fatal because oxygen-rich blood from the lungs would not be pumped from the left ventricle into the body. However, most people born with DORV also have a ventricular septal defect (VSD), or a hole in the muscular wall (septum) that separates the right and left ventricles. Thus, blood travels along the following path:

• Oxygen-poor blood empties into the right ventricle from the body's veins and is pumped to the lungs via the pulmonary arteries. Some blood is also pumped through the aorta.
  
  
• After it picks up oxygen in the lungs, the blood returns to the left side of the heart through the pulmonary veins. Once there, it is pumped by the left ventricle through the VSD and into the right ventricle, where it now mixes with the oxygen-poor blood from the body. The VSD in this case is actually helpful because it allows oxygen-rich blood to reach the aorta.
  
  
• With each contraction of the right ventricle, some oxygen-poor blood is sent to the general circulation and some oxygen-rich blood is sent back to the lungs.
  
  
• Because of the closeness of the aorta to the VSD more of the oxygen-rich blood goes out to the body than out to the lungs. Usually the amount of oxygen in the arteries going to the body will be about two-thirds to three quarters of what it ought to be.

Obviously, this is a highly inefficient situation that places great stress on the heart and results in inadequate circulation of oxygen-rich blood to the body. The degree of the condition is related to the position of the great vessels, the size of the VSD, and any other associated conditions within the heart.

DORV is usually identified in early infancy but may be diagnosed in children who exhibit symptoms of the heart defect. Surgical intervention is the only means to deal with this condition and it is usually advised in infancy or early childhood shortly after the diagnosis is confirmed.  Sometimes the surgery requires stages to complete.

In the United States, congenital heart disease occurs in less than one percent of all newborns. DORV occurs in one out of every 10,000 live births, according to the National Institutes of Health (NIH). The death rate from surgery varies considerably based on the extent of the defects and additional complications. Overall, the 15-year survival rate for surgically treated patients is estimated to be from 89 to 96 percent, with more complex cases exhibiting a poorer chance of survival. However, mortality varies greatly among patients and can be best determined by the treating physicians.

There are several different types of double outlet right ventricle (DORV). They are primarily classified according to the position of the ventricular septal defect (VSD) and its relationship to the great arteries. The position of the VSD is important because it tends to direct blood from the left ventricle, based on its position.The types of DORV and the associated symptoms include:

• DORV with subaortic VSD. A ventricular septal defect (VSD) occurs directly beneath the aorta. In this case, blood from the left ventricle is primarily directed into the aorta. Patients with this condition show the same symptoms as those with VSD, such as frequent chest colds and shortness of breath during physical activity. If pulmonic stenosis (a narrowed pulmonic valve and/or narrowing of the muscular region below the pulmonary valve, restricting blood flow to the lungs) is also present, there will likely be the same symptoms as tetralogy of Fallot, such as a bluish tint to the skin (cyanosis or blue baby in infants) and weakness during physical activity. There may also be shortness of breath and fatigue during nursing. This condition is generally treated when the person is about 6 months old.  However some centers advise intervention at an earlier age especially if there is a significant degree of pulmonary stenosis.  
  
  
• DORV with subpulmonary VSD or the Taussig-Bing complex. A VSD occurs directly beneath the pulmonary artery, meaning that blood from the left ventricle is generally directed into the pulmonary artery. Patients with this condition show the same symptoms as those who have transposition of the great arteries, such as bluish skin (cyanosis), fainting (syncope) and frequent chest colds. This condition is generally treated at birth or as soon as the diagnosis is established.
  
  
• DORV with doubly committed VSD. A VSD occurs in equal proximity to both great vessels, thus the blood from the left ventricle may be more equally committed to either the aorta or the pulmonary artery. The symptoms of this condition and the ideal age for treatment vary widely from person to person.
  
  
• DORV with non-committed VSD. A VSD occurs far away from the great vessels. Symptoms of this condition vary widely. This condition is generally treated between ages 3 to 5 years old

Testing is frequently performed on infants who are born with a bluish tint to their skin (Cyanosis or blue baby). Typically, these babies will be referred to a pediatric cardiologist, a physician who specializes in diagnosis and treatment of heart conditions in children. Initially, the cardiologist will obtain a detailed medical history of the patient and perform a physical examination.

The examination will focus on the child’s heart with particular attention to any detected Heart murmur. In addition, one or more of the following tests may be used to diagnose DORV:

• Echocardiogram. This is generally considered to be the definitive test to diagnose this condition. There are several components of this procedure. This test also shows the thickness, size and function of the heart, as well as the major arteries. It will also show the relationships of the blood vessels coming back to the heart (the veins), the valves in the heart, the walls between the chambers, and the vessels leading from the heart going to the lungs and body (the pulmonary artery and the aorta). A Doppler ultrasound may also be conducted to evaluate blood flow direction and speed. It will also help in determining the workload being placed on the heart chambers. It can measure how severe an area of narrowing may be. The last component is the color Doppler, which involves computer-generated color to the Doppler signal to give a movie-like quality to the blood flow. This is helpful in directing the person performing the study to understand how the blood travels through the heart. The entire test generally does not require sedation and has no recognized side effect or risk. There is no radiation exposure. The devices are portable and may be brought to outreach clinic settings and into the nursery.
  

  
  

• MRI (magnetic resonance imaging) and MRA (magnetic resonance angiography). A procedure that uses magnetic fields and a computer to produce high-resolution cross-sectional or three-dimensional images of the target area (e.g., the heart). A cardiac MRI/MRA can help evaluate the blood flow and function of the heart.  This test requires sedation since the patient cannot move during it.  A test of this nature in an infant is only performed at major medical centers with experience in dealing with infants.  The device is not portable.
  
  
• Cardiac catheterization. A more invasive procedure performed under sedation that provides detailed information about the inside of the heart. A thin, flexible tube (catheter) is inserted into a blood vessel, typically in the groin, and threaded up into the heart to obtain diagnostic information.  Pediatric cardiac catheterizations are only done at major centers and only by pediatric cardiologists.  This test is generally not necessary in the diagnosis of DORV.

Treatment of double outlet right ventricle (DORV) depends on a number of factors, including the type of defect and the extent of condition. A patient’s overall health and tolerance for procedures and therapies will also determine the course of treatment.

Typically, some form of surgery is used to correct the defects from DORV. Although the surgical procedures vary, they all share the same basic goal: connecting the left ventricle to the aorta while keeping the pulmonary artery connected with the right ventricle.

One approach is called intraventricular repair. During this operation, the surgeon creates a tunnel from the ventricular septal defect connecting the left ventricle to the aorta. This allows blood to flow from the left ventricle to the aorta. This surgery cannot be done if any of the following complications are present:

• There is not enough room to make a tunnel without blocking one of the heart’s critical valves. In some cases, the intraventricular repair can still be done but with a slight modification called LeCompte procedure.
  
  
• The valves are not functioning properly.
  
  
• The left ventricle is not large enough to handle, by itself, the pumping of all oxygen–rich blood.

Another surgical procedure is called the arterial switch operation (ASO). This surgery involves two steps. In the first step, a tunnel is created from the VSD to the pulmonary artery. At that point, the heart is wired completely backwards because the left ventricle is now connected to the pulmonary artery, and the right ventricle is connected to the aorta – the reverse of the normal heart.  In the second step, the two great arteries are disconnected and reconnected to the correct ventricles. The coronary arteries are transferred to the newly positioned aorta for proper blood supply to the heart. Based on tests conducted before surgery, the surgeon may correct other heart conditions during surgery.

Other options include the Fontan procedure and the Rastelli procedure.

Because the surgeries for DORV vary so widely, the success is dependent on a number of factors. The death rate from surgery varies considerably based on the extent of the defects and additional complications. Overall, the 15-year survival rate for surgically treated patients is estimated to be from 89 to 96 percent, with more complex cases exhibiting a poorer chance of survival. However, mortality varies greatly among patients and can be best determined by the treating physicians.

In rare cases, patients may develop some narrowing between the heart valves. Regular follow-up care by a pediatric cardiologist is recommended for monitoring of the patients heart health. Patients with corrected DORV typically need to take preventive antibiotics before undergoing certain dental or surgical procedures for life.  Some patients may require medications to be taken for a period of time or for life depending on the results of the surgery and any residual defects.

Residual defects, out-growing synthetic material, devices used in the repair or valve leakage may require further surgical procedures in later years.

Even rarer than DORV is double outlet left ventricle (DOLV) – a condition in which the aorta and the pulmonary artery exit from the left ventricle. The result of this condition is that the right ventricle cannot pump blood directly to the pulmonary artery and out to the lungs.

In addition, DOLV patients tend to have a ventricular septal defect (VSD) and pulmonic stenosis. The life-saving presence of the VSD (a hole in the wall between the ventricles) allows blood to travel through the VSD from the right ventricle and into the left, out the pulmonary artery and to the lungs. As a result, circulation is accomplished but only with great pressure on the heart and circulatory system.

An echocardiogram and possibly a cardiac catheterization and angiogram will be done to confirm the diagnosis of DOLV and to assess whether the patient is a good candidate for surgery. If so, the goals of surgery usually include closing the VSD and creating a passageway between the right ventricle and the pulmonary artery. This passageway allows blood to travel from the right ventricle through the pulmonary artery and to the lungs.

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients (or parents) may wish to ask their doctor the following questions about double outlet right ventricle (DORV):

1. How will I recognize DORV in my child?
   
   
2. Can the condition be detected in my child during pregnancy?
   
   
3. What tests will be used to diagnose DORV?
   
   
4. What type of DORV does my child have?
   
   
5. Are there any additional heart defects?
   
   
6. What type of surgery will be used to correct the defects?
   
   
7. Can the complete repair be accomplished as the initial procedure or will it be staged?
   
   
8. Will there be residual defects or anticipated concerns that will probably require surgery or interventional catheterization in later years?
   
   
9. What is the medical center’s experience and surgical results with patients with this defect?
   
   
10. When should my child undergo this surgery?
    
    
11. What are the risks associated with this surgery?
    
    
12. What will be involved with the recovery from surgery?
    
    
13. What is the prognosis following treatment for DORV?
    
    
14. How will DORV affect my child later in life?
    
    
15. What is life like with teenagers and young adults with surgical correction of DORV?
    
    
16. What restrictions would be anticipated in adult years?  If the patient is a female, what does this mean with respect to concerns of family planning?
    
    
17. What are the treatment options besides surgery?
    
    
18. How will my child’s heart be monitored?
    
    
19. Am I at risk for having another child with DORV?
    
    
20. If a fetal echocardiogram is suggested, how early in the pregnancy can the test be done?
    
    
21. If DORV has been diagnosed on a fetal echocardiogram, will I have to deliver the baby at a specialized center?
    
    

22. Are there any genetic or chromosome defects associated with DORV and will my child be checked for them?