PFO vs PDA: Difference and Comparison

PDA is a natural opening between the pulmonary artery and the heart’s aorta. It acts as a shunt in a newborn, transporting blood between the two vessels, then shuts after delivery.

PFO is a congenital abnormality of the wall that divides the heart’s right and left atria. It is sometimes referred to as a secundum ASD.

Key Takeaways

  1. PFO (patent foramen ovale) is a congenital heart condition where a small hole remains open between the left and right atria. In contrast, PDA (patent ductus arteriosus) involves an open blood vessel connecting the aorta and pulmonary artery.
  2. PFO is asymptomatic and doesn’t require treatment, but PDA can cause symptoms like shortness of breath and fatigue and may need medical intervention.
  3. PFO can lead to stroke or other complications if a blood clot passes through the hole, while PDA increases the risk of heart failure and other heart-related issues.


PFO is a condition where the foramen ovale, a small hole that normally exists between the two upper chambers of the heart in a fetus, fails to close completely after birth. PDA is a condition where a blood vessel that connects the pulmonary artery to the aorta in a fetus fails to close after birth.


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A patent foramen ovale (PFO) is a tiny aperture between the right and left atrium, the heart’s upper chambers. These chambers are normally separated by a thin membrane wall made composed of two connecting flaps.

There is no way for blood to circulate between them. A small amount of blood can travel between the atria through the flaps if a PFO occurs.

This isn’t a typical flow.

The fetus’s blood does not need to get to the lungs to be oxygenated before birth. The ductus arteriosus is a hole in the heart that permits blood to bypass circulation to the lungs.

When the infant is born, however, the blood must acquire oxygen in the lungs, and this hole is expected to close. If the ductus arteriosus remains open (or patent), blood may bypass this critical phase in circulation.

The patent ductus arteriosus is the name given to the open opening.

Comparison Table

Parameters of ComparisonPFOPDA
DefinitionOpening between the upper two chambers of an unborn baby’s heart.An artery that joins the two major arteries.
CausesGenetic, Down’s syndrome, or viral infections causes PFO.If mothers had German measles while pregnant.  
SymptomsNewborns with one mostly don’t display any signs or symptoms.Vary depending on the extent of the defect and whether the infant is full-term or preterm.  
TreatmentSurgically by making a tiny incision and then sewing the hole together.Intravenous (IV) indomethacin or ibuprofen
DiagnosisEchocardiogram is used to observe the PFO.A stethoscope is used to hear the heartbeat patterns.

What is PFO?

A flap-like aperture termed foramen ovale or fossa ovalis exists in the wall of the heart of a healthily developing fetus while within the uterus.

As the lungs are still not working, this helps to shunt blood between the two top chambers of the heart, known as the atria.

This foramen closes after birth when the lungs begin to function, which raises blood pressure in the left atrium, causing the foramen to close.

This foramen fails to seal entirely in around 25% of instances, resulting in a patent foramen ovale (PFO) condition.

Due to the non-closure of the aperture in PFO instances, there is elevated blood pressure in the patient’s chest when he coughs, sneezes, or strains for any activity.

This results in mixing oxygenated and deoxygenated blood from the heart’s right and left atrial chambers.

As a result, the blood in the left atrium is unfiltered since it does not travel via the lungs. As a result, small clots develop in the body’s circulation.

As a result, if this clot moves from the heart and lodges in the brain, there is a substantial risk of stroke.

Because microscopic blood clots elsewhere in the body might break free and travel to the heart via the blood, a PFO may raise the risk of strokes.

The lungs filter these small clots out of the blood. The clot might move from the right to the left atrium in a person with a PFO.

The clot then travels to the left ventricle, delivering it to the rest of the body or the brain, where it might harm organs more vulnerable to injury than the lungs.

A stroke occurs when a blood clot stops blood flow to a portion of the brain.

patent foramen ovale e1687145267197

What is PDA?

A Ductus arteriosus (DA) is a vital valve-like vascular opening in the developing fetus. It links the aorta arch to the right pulmonary artery.

Because the lungs are not functional and are squeezed in the growing baby, blood is circulated from the right pulmonary artery through DA, bypassing the lungs.

The DA obliterates and closes on its own after delivery with lung expansion.

This process begins within 12 hours of birth and lasts for up to three weeks. A PDA occurs when the ductus arteriosus fails to seal after birth.

The extent of the defect and whether the infant is full-term or preterm affect the symptoms of patent ductus arteriosus. A tiny PDA may show no symptoms and be unnoticed for a long period – even into adulthood.

A big PDA can cause early indications of heart failure.

The following are risk factors for developing a patent ductus arteriosus: A patent ductus arteriosus develops more frequently in prematurely born newborns than in full-term babies.

Other genetic disorders and family history A PDA is more likely if you have a family history of heart abnormalities or other genetic diseases like Down syndrome.

If one gets German measles (rubella) while pregnant, the kid is more likely to develop heart problems.

The rubella virus enters the baby’s circulatory system through the placenta and causes damage to blood vessels and organs, including the heart.

PDAs are more common in newborns born over 8,200 feet (2,499 meters) than in kids born at lower elevations.  Female children are twice as likely as a male children to engage in PDA.

patent ductus arteriosus

Main Differences Between PFO and PDA

  1. A foramen ovale is a normal opening between the upper two chambers of an unborn baby’s heart, whereas a PDA is an artery that joins the two major arteries that leave the heart, the aorta and the pulmonary artery.
  2. Genetic factors, Down’s syndrome, and viral infections are among the causes of PFO. PDA has an unclear cause. It is observed in preterm babies and in mothers who have had German measles while pregnant.
  3. Because a PFO seldom causes issues, most newborns with one don’t display any signs or symptoms. Many active people are unaware that they have a PFO, but the symptoms of a patent ductus arteriosus vary depending on the extent of the defect and whether the infant is full-term or preterm.
  4. While the preterm newborn with a large patent ductus arteriosus (PDA) is treated with intravenous (IV) indomethacin or ibuprofen, a PFO can be addressed surgically by making a tiny incision and then sewing the hole together.
  5. When PDA is detected in kids, a stethoscope is used to hear the heartbeat patterns, whereas an echocardiogram is used to observe the PFO.

Last Updated : 19 June, 2023

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