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Patent foramen ovale
By Mayo Clinic staffOriginal Article: http://www.mayoclinic.com/health/patent-foramen-ovale/DS00728
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Definition
A patent foramen ovale (PFO) is a hole in the heart that didn't close the way it should after birth. The condition is relatively common.
During fetal development, a small flap-like opening — the foramen ovale (foh-RAY-mun oh-VAY-lee) — is usually present between the right and left upper chambers of the heart. It normally closes within the first or second year of life. When the foramen ovale doesn't close, it's called a patent foramen ovale.
Most people with a patent foramen ovale never know they have it. A patent foramen ovale is often discovered during tests for other problems. Learning that you have a patent foramen ovale is understandably worrisome, but most people never need treatment for this condition.
Symptoms
Most people with a patent foramen ovale don't know they have it, because it's usually a hidden condition that doesn't create signs or symptoms.
Rarely, an infant with a patent foramen ovale might have bluish skin (cyanosis) when crying or straining, such as when passing stool. When an infant with a patent foramen ovale has cyanosis, he or she usually has other heart defects.
Causes
It's unclear what causes the foramen ovale to stay open in some people, though genetics may play a role.
An overview of normal heart function in a child or adult is helpful in understanding the role of the foramen ovale before birth.
Normal heart function
Your heart has four pumping chambers that circulate your blood:
- The right atrium, the upper right chamber, receives oxygen-poor blood from your body and pumps it into the right ventricle through the tricuspid valve.
- The right ventricle, the lower right chamber, pumps the blood through a large vessel called the pulmonary artery and into the lungs, where the blood is resupplied with oxygen and carbon dioxide is removed from the blood. The blood is pumped through the pulmonary valve, which closes when the right ventricle relaxes between beats.
- The left atrium, the upper left chamber, receives the oxygen-rich blood from the lungs through the pulmonary veins and pumps it into the left ventricle through the mitral valve.
- The left ventricle, the lower left chamber, pumps the oxygen-rich blood through a large vessel called the aorta and on to the rest of the body. The blood passes through the aortic valve, which also closes when the left ventricle relaxes.
Baby's heart in the womb
Because a baby in the womb isn't breathing, the lungs aren't functioning yet. The heart needs to bypass the lungs and use a different route to circulate oxygen-rich blood from the mother to the baby's body.
The umbilical cord delivers oxygen-rich blood to the baby's right atrium. Most of this blood travels through the foramen ovale and into the left atrium. From there the blood goes to the left ventricle, which pumps it throughout the body. Blood also travels from the right atrium to the right ventricle, which also pumps blood to the body via another bypass system.
Newborn baby's heart
When a baby's lungs begin functioning, the circulation through the heart changes. Now the oxygen-rich blood comes from the lungs and enters the left atrium. At this point, blood circulation follows the normal circulatory route.
The pressure of the blood pumping through the heart usually forces the foramen ovale closed. In most people, the opening fuses shut, usually sometime within the first or second year of life.
Complications
In most people, a patent foramen ovale doesn't cause complications. The disorder has been associated with other conditions, such as stroke and migraine, but it's unknown whether or not patent foramen ovale is a potential cause of these conditions. Possible complications linked to patent foramen ovale include:
Stroke
Stroke is an interruption or reduction of blood supply to a part of the brain. Patent foramen ovale has been associated with an increased risk of stroke, especially strokes with no known cause that occur in people under 55 years old. Yet, most people with a patent foramen ovale will never have a stroke.
Migraine with aura
Migraines with aura are very painful headaches accompanied by sensations such as shimmering spots, blurred vision and blind spots. There is some evidence of a link between patent foramen ovale and migraine with aura, because some people's migraines get better after surgery to close a patent foramen ovale.
Preparing for your appointment
In most cases, a patent foramen ovale is discovered during imaging tests to examine other heart conditions or to look for causes of stroke. Your doctor may also suspect a heart defect, such as a patent foramen ovale, if he or she hears an unusual sound (heart murmur) when listening to your heart.
After a patent foramen ovale has been diagnosed, you'll likely have numerous questions for your doctor. Some questions you may want to ask include:
- What caused this to happen to me or to my child?
- How dangerous is this condition?
- What treatments are available, and which do you recommend?
- What are the risks of a procedure to close the patent foramen ovale?
- Is surgery the only option, or are there any alternatives approaches that might work, such as medication?
- I have other health conditions. How can I best manage these conditions together?
- Do I or my child need to restrict activity in any way?
- Could I have passed this condition to my child?
- Are there any brochures or other printed material that I can take home with me? What websites do you recommend visiting?
Tests and diagnosis
A heart specialist (cardiologist) can detect a patent foramen ovale with one of the following tests:
Echocardiogram
An echocardiogram shows the structure and function of your heart. The standard form of this test is called a transthoracic echocardiogram.
With this test, a technician spreads gel on your chest and then presses a device called a transducer against the skin over the heart. The transducer emits high-pitched sound waves and records the sound wave echoes as they reflect off internal structures in the heart. A computer converts the echoes into moving images on a monitor. Variations of this procedure may be used to identify patent foramen ovale:
- Color-flow Doppler. When sound waves bounce off blood cells moving through your heart, they change pitch. These characteristic changes (Doppler signals) and computerized colorization of these signals can help your doctor examine the speed and direction of blood flow in your heart. If you have a patent foramen ovale, a color-flow Doppler echocardiogram could detect the flow of blood between the right atrium and left atrium.
- Saline contrast study (bubble study). With this approach a sterile salt solution is shaken until tiny bubbles form and then is injected into a vein. The bubbles travel to the right side of your heart and appear on the echocardiogram. If there's no hole between the left atrium and right atrium, the bubbles will simply be filtered out in the lungs. If you have a patent foramen ovale, some bubbles will appear on the left side of the heart.
Transesophageal echocardiogram
This test uses a small transducer on a tube inserted down the esophagus, the part of the digestive tract that runs from the throat to the stomach. Because the esophagus lies close to the heart, having the transducer placed there provides a detailed image of the heart and blood flow through the heart. The use of a transesophageal echocardiogram makes it easier to see a patent foramen ovale by either color-flow Doppler or a saline contrast study.
Treatments and drugs
Most people with a patent foramen ovale don't need treatment. In certain circumstances, however, your doctor will recommend that you or your child have a procedure to close the patent foramen ovale.
Reasons for closure
If a patent foramen ovale is found when an echocardiogram is done for other reasons, a procedure to close the opening usually isn't performed. Procedures to close the opening in the heart may be used in the following circumstances:
- If your child is undergoing surgery to correct a congenital heart defect and your child also has a patent foramen ovale, the surgeon may close the opening when making other repairs to the heart.
- In adults having other types of heart surgery, a patent foramen ovale may be closed at the time of the operation.
- Closure of a patent foramen ovale may be done to treat low blood oxygen levels resulting from right-to-left blood flow across the patent foramen ovale.
Closure of a patent foramen ovale to prevent stroke or to treat migraines is controversial right now and is being studied in clinical trials. Closure of the patent foramen ovale is sometimes recommended for individuals with recurrent strokes when no other cause has been found.
Surgical and other procedures for closure
Procedures to close patent foramen ovale include:
- Device closure. Using cardiac catheterization, doctors can insert a device that plugs the patent foramen ovale. In this procedure, the device is on the end of a long flexible tube (catheter). The doctor inserts the device-tipped catheter into a vein in the groin and guides the device into place with the imaging assistance of an echocardiogram. Although complications are uncommon with this procedure, a tear to the heart or aorta or the development of irregular heartbeats are possible consequences.
- Surgical repair. A surgeon can close the patent foramen ovale by opening up the heart and stitching shut the flap-like opening. This can sometimes be done with the use of robotic techniques and a very small incision. Since the development of the device closure procedure, surgery isn't as commonly used. If you or your child is undergoing surgery to correct another heart problem, your doctor may recommend that you have the patent foramen ovale corrected surgically at the same time.
Stroke prevention
Medications can be used to try to reduce the risk of blood clots crossing a patent foramen ovale. However, the benefit of anti-platelet therapy such as aspirin or clopidogrel (Plavix) and other blood thinners, such as warfarin (Coumadin), in treating a patent foramen ovale isn't clear.
Clinical trials
Some professional organizations have encouraged doctors to talk to those with a patent foramen ovale about participating in clinical trials addressing the many unanswered questions about patent foramen ovale, stroke and migraine. Your doctor may suggest this option to you and provide information about trials in your area.
Lifestyle and home remedies
If you know you have a patent foramen ovale, but don't have symptoms, you probably won't have any restrictions on your activities.
But, be sure to consult your doctor before undertaking activities that might limit your levels of oxygen, such as scuba diving or mountain climbing. People with a patent foramen ovale may be more likely to get decompression sickness when scuba diving or a life-threatening form of altitude sickness called high-altitude pulmonary edema when mountain climbing.
Coping and support
Learning that you or your child has a patent foramen ovale can be frightening. While your doctor can provide you with medical advice and information about the disorder, you may find it helpful to talk to other people who've been in the same situation. Support groups include Mended Hearts for people who have survived heart disease and Mended Little Hearts for parents of children with congenital heart problems. Call the American Heart Association at 800-AHA-USA1 (800-242-8721) and ask for Mended Hearts support or visit its website. Mended Hearts can also be reached on weekdays at 888-HEART99 (888-432-7899). You can also ask your doctor or your child's doctor if he or she knows of any support groups in your area.
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