Partial Anomalous Pulmonary Venous Return: A Rare Congenital Heart Defect

Partial anomalous pulmonary venous return (PAPVR), also known as partial anomalous pulmonary venous connection (PAPVC) is a congenital heart defect in which some blood vessels carrying oxygen-rich blood from the lungs do not connect to the heart correctly. Instead, they may connect to the right side of the heart instead of the left, or they may connect to another blood vessel.

PAPVR is rare; it is only present in 0.4–0.7% of the population. The heart or blood vessels do not form correctly as the infant develops in the womb.

Normal, healthy heart function

A healthy heart has four chambers. The two on the top are called the atria, and the two on the bottom are called ventricles. Arteries bring blood away from the heart, and veins carry blood back to the heart. The circulatory system is like a one-way, figure-8 street. Oxygenated blood from the lungs and deoxygenated blood from the body never mix. When the circulatory system is functioning normally:

  1. Blood enters the lungs via the pulmonary arteries and picks up oxygen.
  2. The blood returns to the heart via the pulmonary veins and enters the left side of the heart.
  3. The left side of the heart pumps the blood out to the brain and the body, delivering oxygen and picking up carbon dioxide to be expelled by the lungs.
  4. The blood returns to the right side of the heart via the veins.
  5. The right side of the heart pumps the blood into the lungs via the pulmonary arteries to begin the cycle again.

The defect

In PAPVR, one or more, but not all, of the veins coming from the heart do not connect to the left atria of the heart. There are many different variations of this defect, and the veins may connect to:

  • The right atria
  • The superior or inferior vena cava (the veins that return blood from the body)
  • The coronary arteries (the arteries that bring blood to the heart muscle)
  • The brachiocephalic veins (the veins that bring blood back to the heart from the arms and brain)
  • The portal vein (the vein that brings blood from the stomach to the liver and other digestive organs)
  • The hepatic veins, (the veins that bring blood from the liver to the heart)
  • A combination of these locations

PAPVR is found equally in males and females.

When first diagnosed in adulthood, the abnormality most often occurs in the veins coming from the left side of the lungs.

When diagnosed in childhood, it is more common to see the abnormality in the vein leaving the right lung. This may be because more symptoms are associated with right-sided anomalies, and the symptoms become evident earlier in life.

Symptoms

PAPVR frequently has no symptoms, and the condition is often discovered incidentally during examinations for other reasons. If symptoms develop, they typically occur because oxygen-rich blood is pumped back to the lungs instead of out to the body. The severity of the symptoms may differ from person to person, depending on how much oxygen the cells and tissues of the body are receiving and how much extra blood reaches the lungs.

Symptoms may include:

  • Pulmonary hypertension (high blood pressure in the lungs)
  • Difficulty breathing
  • Chest pain
  • Heart palpitations
  • Heart arrhythmias
  • Rapid heart rate
  • Heart murmur
  • Right-sided heart failure
  • Enlarged right side of the heart

Children may also become tired quickly during strenuous exercise or develop cyanosis, a bluish hue to the lips, nails, and skin.

For women, PAPVR symptoms, such as atrial fibrillation, will often appear for the first time during pregnancy. The mother is usually able to complete the pregnancy and deliver a healthy baby.

Often PAPVR will not be the only heart defect present.

Atrial septal defects are the most common heart defects associated with PAPVR. An atrial septal defect is a hole in the wall that divides the two top chambers of the heart, the atria. This hole allows oxygen-rich blood from the heart and oxygen-depleted blood from the body to mix in the atria, allowing blood with very little oxygen to reach the cells and tissues of the body.

Diagnosis

A doctor or other healthcare professional often discovers PAPVR by accident while running tests for a different medical condition. Doctors may detect PAPVR via:

  • Chest x-ray
  • CT scan
  • MRI
  • Echocardiography
  • Transthoracic echocardiography

Treatment

Surgeons will generally only repair PAPVR if the defect is causing symptoms or if it occurs along with other congenital heart defects that need surgical correction. Adults who did not have surgery to repair the defect as children may need surgery if they develop right-sided heart enlargement.

If surgery is needed, the surgeon will construct a tunnel to reattach the vein to the left side of the heart and put a patch on the atrial septal defect, if present.

Medication may also be prescribed to manage symptoms.

Complications

Certain conditions caused by PAPVR could lead to complications.

Higher than normal pressure in the lungs can cause mild to severe pulmonary hypertension. This condition may appear from early childhood to adulthood but only occurs in rare cases.

If an unrepaired heart defect leads to a heavier workload for your heart, you may develop Eisenmenger syndrome. Eisenmenger syndrome is a progressive heart condition that may occur when a congenital heart defect is present but not corrected in childhood.

If you have surgery to correct PAPVR, you may develop an obstruction in one of the new connections.

You may experience frequent chest infections.

You may develop heart arrhythmias, such as atrial fibrillation (Afib). The older you are when surgery occurs to repair the defect, the higher the chance you will develop Afib.

Key takeaways

PAPVR is a heart defect that is present at birth. One or more blood vessels are not connected to the left side of the heart as they should be. The condition may not ever cause symptoms. However, surgery may be necessary if the blood flow changes create severe enough symptoms.

If you or your child has been diagnosed with PAPVR, follow up with a cardiologist regularly to monitor the condition.

Most people with PAPVR will not have activity restrictions. However, talk to your doctor before beginning a new exercise if you have difficulty breathing while exercising or have been diagnosed with pulmonary hypertension, a blockage of your repaired vein, or a heart arrhythmia.

If you have been diagnosed with PAPVR and are pregnant or plan to become pregnant, talk to your cardiologist about your risks and any treatments that may be necessary.

Resources:

Radiopaedia. Secundum Atrial Septal Defect.

Johns Hopkins Children's Hospital. Partial Anomalous Pulmonary Venous Return.

Pulmonary Circulation. Partial anomalous pulmonary venous return presenting with adult-onset pulmonary hypertension.

Radiology Case Reports. Partial anomalous pulmonary venous return with secundum atrial septal defect: A case report.

Radiopaedia. Partial Anomalous Pulmonary Venous Return.

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