What is a patent foramen ovale (PFO)?

Patent foramen ovales (PFOs) and atrial septal defects are basically holes in the dividing section between the top chambers of the heart. These can be a problem because they can allow clots to pass through the top chambers of the heart, go from the right atrium to the left atrium, and out, up into the brain or perhaps to other parts of the body. These blood clots can cause strokes. Further, people with these conditions are also at a higher risk for heart rhythm problems.

There's an option to close these holes in the catheterization lab through a minimally invasive surgery with a long tube that can go up into the right side of the heart. It can go across the hole and insert a plug-like device. In addition to long-term benefits, people also feel better quickly.

Fetuses have a normal opening (called a foramen ovale) between the left and right atria (upper chambers) of the heart. But if this opening fails to close naturally soon after birth, the result is an open (patent) foramen ovale, or PFO. Most of the time, this defect doesn't cause significant health problems and doesn't require treatment. When a PFO is serious enough to cause problems, healthcare providers may recommend a procedure to close the hole.

Dr. Bijoy K. Khandheria, MD
Cardiologist (Heart Specialist)

The heart has four chambers—two atria and two ventricles. Foramen ovale is a hole in the wall between the two atrial (upper) chambers that allows oxygenated blood to travel through the heart before birth. The hole allows oxygen-enriched blood from the mother to cross from the right to the left side of the baby’s heart, bypassing the baby's lungs. Normally, the hole closes at birth when increased blood pressure on the left side of the heart forces the opening to close. The hole remains open (patent) through adulthood in one out of four individuals, causing blood to be diverted from the right atrium to the left atrium—skipping the lungs where it would receive oxygen.

The human heart is divided into four chambers: the upper chambers, the left and right atria, and the lower chambers, the left and right ventricles. Patent foramen ovale (PFO) is an opening between the two upper chambers of the heart. The wall between the two upper chambers actually consists of two walls, and the PFO is a channel between those two walls.

The PFO is a legacy left over from when a person is a fetus in the womb. A fetus does not breathe, so there is no need for blood to pass from the heart to the lungs to pick up oxygen. Instead the blood travels through the PFO from the right side of the heart to the left side of the heart where it then moves through a large artery called the aorta and then to the rest of the body. When a baby is born, the pressure in the left upper chamber becomes higher than the pressure in the right upper chamber, and it pushes the two walls together, closing the channel. However, in 25 percent of people the channel is not sealed off tightly.

Most people with an open PFO never experience any adverse effects. Very rarely, a person may have a stroke because a blood clot passes through the channel and then travels to the brain. Additionally, one theory is that an open PFO may be a cause of severe migraine headaches in some sufferers. Research and clinical trials are investigating whether closing the PFO in some patients or the use of blood-thinning medications or other medications can help treat these conditions.

Patent foramen ovale (PFO) is an intracardiac defects, or "holes in the heart." It is an abnormal openings in the wall (septum) that separates the two atria, or upper chambers, of the heart. PFO results when a normal opening in the septum fails to close after birth. PFO can cause strokes by allowing clots and air to enter the left side of the heart.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.