The patent foramen ovale is a small hole in the heart. The hole is located between the two upper chambers of the heart, called the right and left atria (see Figure 1 and Figure 2). The patent foramen ovale allows blood to flow between these two chambers.
Before birth, when the fetus is developing inside the mother's womb, the presence of this hole between the right and left atria is a normal phenomenon, because it enables blood to flow through the heart in the correct direction. (Blood flow through the heart before birth is different from the blood's path after birth).
After birth, this communication between the right and left atria is not necessary. In most newborns, this hole closes shortly after birth. In some newborns, however, it remains open. This phenomenon is called patent foramen ovale and is very common. About 1 in 4 people has a patent foramen ovale. The etiology of patent foramen ovale remains unknown.
Most people with a patent foramen ovale do not experience any problems or symptoms. Some people may discover it during an exam for another reason.
In some cases, a patent foramen ovale can cause problems, such as a stroke, which is the death of part of the brain due to a blockage in blood flow. This can affect speech, mental function, and limb mobility.
A patent foramen ovale can cause a stroke in the following ways: A blood clot can form in a vein in the lower extremities. The clot can travel through the bloodstream to the heart. If someone has a patent foramen ovale, the clot can travel into the left atrium. From there, it can enter the left ventricle and then the systemic circulation and end up in another organ in the body, including the brain, causing a stroke.
The test used to diagnose patent foramen ovale is an echocardiogram, which uses ultrasound to create images of the heart while it is beating.
During the echocardiogram, your doctor may perform a bubble test. Specifically, they will administer stirred saline (0.9% saline solution) intravenously and monitor the path of the bubbles through your heart using the echocardiogram.
Patients with a stroke for which no other cause has been found (cryptogenic stroke) are usually tested for patent foramen ovale.
Treatment for patent foramen ovale depends on whether it is causing symptoms or not. If the patent foramen ovale is not causing symptoms, no treatment is needed. In patients with a stroke that may be caused by a patent foramen ovale, the doctor may recommend:
- Medication, such as aspirin or other drugs that inhibit blood clotting.
- Percutaneous or surgical closure of the patent foramen ovale.
In people with a patent foramen ovale, the doctor may recommend methods to prevent thrombosis in the lower extremities, such as:
- Avoid sitting or standing still for long periods of time.
- To quit smoking.
- Change positions when sitting, and move their legs frequently.
- Stand up and walk around every 1-2 hours, even on long trips by car, plane or train.
- Avoid straining during bowel movements, coughing, and lifting or pushing heavy objects. All of the above increase blood flow from the right to the left atrium, and therefore the possibility of a clot moving in the same direction.
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