Total Anomalous Pulmonary Venous Return in Children
Basics of Total Anomalous Pulmonary Venous Return
Total anomalous pulmonary venous return (TAPVR) is a heart disease that is present at birth (or “congenital”) in which none of the four veins that take blood from the lungs to the heart is attached to the left atrium (left upper chamber of the heart).
In a normal heart, oxygen-poor (blue) blood returns to the right atrium from the body, travels to the right ventricle, then is pumped through the pulmonary artery into the lungs, where it receives oxygen. Oxygen-rich (red) blood returns to the left atrium from the lungs through four pulmonary veins. It then passes into the left ventricle, and is pumped through the aorta out to the body.
In TAPVR, the four pulmonary veins are not connected to the left atrium, but elsewhere in the heart. While there are several possible places where the pulmonary veins can connect, the most common place is the superior vena cava, a blood vessel that brings oxygen-poor (blue) blood back to the right atrium.
In TAPVR, oxygen-rich (red) blood that should return to the left atrium, the left ventricle, the aorta, and then the body, instead mixes with the oxygen-poor (blue) blood flowing into the heart’s right side. Without a way for oxygen-rich (red) blood to be delivered to the body, life cannot be sustained.
TAPVR is associated with other heart defects that actually help an infant with total anomalous pulmonary venous return survive until surgical intervention is possible:
- An opening in the atrial or ventricular septum allows blood from one side to mix with blood from another, creating "purple" blood with an oxygen level somewhere between oxygen-poor (blue) and oxygen-rich (red) blood.
- Patent ductus arteriosus allows the mixture of oxygen-poor (blue) and oxygen-rich (red) blood through the connection between the aorta and pulmonary artery. The resulting "purple" blood is beneficial and provides at least a little oxygen to the body.
Fast Fact of Total Anomalous Pulmonary Venous Return
Total anomalous pulmonary venous return accounts for about 1 percent to 2 percent of all cases of congenital heart defects and occurs equally in boys and girls.
Causes of Total Anomalous Pulmonary Venous Return
The cause of total anomalous pulmonary venous return (TAPVR) is unknown.
Symptoms of Total Anomalous Pulmonary Venous Return
An obvious symptom of TAPVR is when a newborn becomes “cyanotic” (blue coloring of the skin, lips and nail beds) in the first days of life. The degree of cyanosis is related to the presence of other defects that allow blood to mix.
The infant may appear very sick and may have the following symptoms:
- Rapid breathing
- Labored breathing
- Rapid heart rate
- Cool, clammy skin
- Poor feeding
Because symptoms of total anomalous pulmonary venous may resemble other medical conditions or heart problems, it’s important to consult with a child's physician for a diagnosis.
Health Problems Associated with Total Anomalous Pulmonary Venous Return
For babies with this heart defect, the heart cannot supply oxygen-rich (red) blood to the body after birth. Without an additional heart defect (such as atrial or ventricular septal defect) that allows mixing of oxygen-poor (blue) and oxygen-rich (red) blood, infants with TAPVR will have a mixture of oxygen-rich (red) and oxygen-poor (blue) blood circulating through the right heart and back to the lungs — a situation that is fatal.
After birth, two fetal "shunts," or connections in the fetal circulation, remain open for a short while:
- The foramen ovale, an opening between the right atrium and left atrium, that allows some of the blood returning to the right atrium to flow into the left side of the heart, and out to the body.
- The ductus arteriosus, which connects the aorta to the pulmonary artery, allows some blood to mix between the two vessels, thus making it possible for more partially oxygenated blood to go to the body.
Once these two "shunts" close, a baby becomes very blue (“cyanotic”) unless there are other connections, such as an atrial or ventricular septal defect. Even with an additional heart defect that allows blood mixing, babies with TAPVR often still do not have enough oxygen in their bloodstream to meet their body's needs.
Another problem that occurs with TAPVR is that too much blood flows through the blood vessels in the lungs because pulmonary veins add extra blood back into circulation on the heart’s right side. This extra blood flow stresses the lungs and eventually damages them.
Tests, Procedures and Diagnosis of Total Anomalous Pulmonary Venous Return
The medical team diagnosing and treating a child with TAPVR may include a pediatric cardiologist and/or neonatologist. A pediatric cardiologist specializes in the diagnosis and treatment of congenital heart defects and heart problems that may develop later in childhood. A neonatologist specializes in illnesses affecting newborns, both premature and full-term.
Cyanosis and rapid breathing are red flags that a newborn suffers from a heart problem. The newborn’s physician may have also heard a heart murmur during a physical examination. A heart murmur is simply a noise caused by the turbulence of blood flowing through the openings that allow the blood to mix.
Diagnostic testing for congenital heart disease varies by a child's age and clinical condition and may include:
- Chest X-ray. This diagnostic test uses X-ray beams to produce images onto film of internal tissues, bones and organs.
- Electrocardiogram (ECG or EKG). This test records the electrical activity of the heart, shows abnormal rhythms (arrhythmias or dysrhythmias) and detects heart muscle stress.
- Echocardiogram (or “echo”). This procedure evaluates the structure and function of the heart by using sound waves recorded on an electronic sensor that produce a moving picture of the heart and heart valves.
- Cardiac catheterization. This invasive procedure gives very detailed information about the structures inside the heart. Under sedation, a small, thin, flexible tube (catheter) is inserted into a blood vessel in the groin, and gently guided to the inside of the heart. Blood pressure and oxygen measurements are taken in the four chambers of the heart, as well as the pulmonary artery and aorta. In addition, contrast dye is injected to more clearly visualize the structures inside the heart.
Treatment for Total Anomalous Pulmonary Venous Return
A child’s physician determines a specific treatment plan for TAPVR based on:
- A child's age, overall health and medical history
- Severity of the disease
- A child's tolerance for specific medications, procedures or therapies
- Expectations for the course of the disease
- Parents’ opinions or preferences
A child may be admitted to the intensive care unit (ICU) or special care nursery once symptoms are noted. Initially, a child may be placed on oxygen, and possibly even on a ventilator, to assist with breathing. IV medications may be given to help the heart and lungs function more efficiently.
- Medical management. Initial medical management may include oxygen, medications to increase blood pressure and treatments with prostaglandins, a medication used to keep the ductus arteriosus open.
- Interventional cardiac catheterization. This procedure can be used for both the diagnosis and initial treatment procedure for some heart defects. A cardiac catheterization procedure is usually performed to evaluate the heart defect(s) and amount of blood that is mixing. During cardiac catheterization, a procedure called balloon atrial septostomy may be performed to improve mixing of oxygen-rich (red) and oxygen-poor (blue) blood. During the procedure:
- A special catheter with a balloon in the tip is used to create an opening in the atrial septum (wall between the left and right atria).
- The catheter is guided through the foramen ovale—a small opening present in the atrial septum that closes shortly after birth—and into the left atrium.
- The balloon is inflated.
- The catheter is quickly pulled back through the hole, into the right atrium, enlarging the hole, and allowing blood to mix between the atria.
- An IV medication called prostaglandin E1 may be given to keep the ductus arteriosus from closing.
- Surgical repair. During an operation performed under general anesthesia, four pulmonary veins are reconnected to the left atrium, and any associated heart defects such as atrial septal defect, ventricular septal defect, patent foramen ovale, and/or patent ductus arteriosus are surgically closed.