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Atrial Septal Defect (ASD)


Atrial septal defects (ASD) and Patent Foramen Ovale (PFO) are connections between the right and left side of the heart.

What are Atrial Septal Defect (ASD) and Patent Foramen Ovale (PFO)?

An ASD, often referred to as a “hole in the heart,” is an opening which allows oxygenated and deoxygenated blood to mix, called a shunt. It is the gradient of this shunt and the severity of symptoms which will determine the course of treatment. 


There are two types of holes in the heart: atrial septal defect (ASD) and patent foramen ovale (PFO). Both are holes in the wall of tissue between the left and right upper chambers of the heart, called the septum. The causes of the two conditions are very different.


Patients are born with ASDs, which occur when the septal tissue doesn’t form correctly between the two chambers. ASD holes can vary in size and the severity of abnormal blood flow often correlates with the size of hole.

Atrial septal defect condition

PFOs, on the other hand, are a remnant of an important function before birth. The foramen ovale is a hole between the two chambers of every growing baby’s heart. The hole has a purpose—it allows blood to bypass the lungs while the baby is in utero since the lungs aren’t functional and blood arrives at the heart already oxygenated by the placenta.


There is a flap of tissue that is held open by flow and when the baby is born and the pressures through the hole drop as blood is redistributed to the lungs, the flap closes. The foramen ovale completely seals shut in approximately 75 percent of people within several months after birth. When it retains some ability to reopen in certain circumstances, it’s called a PFO.

Some patients with a hole in their heart won’t experience symptoms; but for others, the conditions can negatively impact their quality of life.

Although the prevalence of PFO is about 25 percent in the general population, this increases to about 40 to 50 percent in patients who have stroke of unknown cause, referred to as cryptogenic stroke. This is especially true in patients who have had a stroke before age 55.


What are the symptoms of ASD and PFO?

Patients  may present with palpitations, shortness of breath, leg swelling, migraines or history of stroke.

Many strokes are caused by blood clots that block the arteries in the brain and cut off blood flow. In those with PFOs, small blood clots that would normally be absorbed by the lungs can flow through the hole, carrying out into the body.


If even a very small clot makes its way to the brain, it could lead to a stroke. According to the American Stroke Association, approximately 100,000 Americans suffer a PFO-related stroke each year.


What assessment do I need if I have ASD and PFO?

The first investigations to consider for the formal diagnosis is a bubble echo study to visualize whether microbubbles, which are injected into the blood supply, pass through the PFO. The Transesophageal Echo  is also used to accurately assess the hole (PFO/ASD).


What are the treatments for ASD and PFO?

These connections can be closed with minimally invasive techniques through a needle in the groin or with open heart surgery. The need to close the hole will be weighed up depending on current or future risks and symptoms.



What intervention/treatment does CardioCare offer for Atrial Septum Defect/PFO?


  • Minimally invasive placement of ASD / PFO Closure devices via catheter insertion through the groin 

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