HEART & BLOOD Cardiovascular System • Aortic aneurysm • High blood pressure (hypertension) • High blood cholesterol • Thrombophlebitis • Rheumatic fever • Varicose veins • Heart arrhythmias • Atrial fibrillation • Endocarditis • Aortic valve stenosis • Aortic valve regurgitation • Mitral valve stenosis • Mitral valve regurgitation • Pulmonary hypertension • Raynaud's disease • Long QT syndrome • Mitral valve prolapse • Pericarditis • Cardiomyopathy • Myocarditis • Arteriosclerosis / Atherosclerosis • Peripheral arterial disease (PAD) • Low blood pressure (hypotension) • Aortic dissection • Lymphedema • Pulmonary valve stenosis • Ventricular septal defect (VSD) • Tetralogy of Fallot • Coarctation of the aorta • Atrial septal defect (ASD) • Patent ductus arteriosus (PDA) • Left ventricular hypertrophy • Bundle branch block • Heart murmurs • Patent foramen ovale • Transposition of the great arteries • Hypoplastic left heart syndrome • Sudden cardiac arrest • Prehypertension • Tricuspid atresia • Ebstein's anomaly • Buerger's disease

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In normal fetal development, a small, flap-like opening develops in the wall (septum) between the right and left upper chambers of the heart (right atrium and left atrium). This opening occurs naturally before birth and usually closes within weeks or months after a baby is born.

However, in at least one out of four people, this opening persists throughout life and is called patent foramen ovale (PA-tunt fo-RA-mun o-VA-le), or PFO. The opening that occurs in patent foramen ovale may allow blood to flow from the heart's right atrium to the left atrium and vice versa.

Most people with patent foramen ovale don't know they have the condition. That's because patent foramen ovale usually doesn't cause any signs or symptoms. Most people with patent foramen ovale don't need treatment, although closing the opening with a device is an option.

A patent foramen ovale usually doesn't cause any signs or symptoms.

Rarely, an infant with patent foramen ovale may exhibit bluish skin (cyanosis) when crying or straining, such as when passing stool. This is ordinarily true only if the patent foramen ovale is associated with other congenital heart defects.

Patent foramen ovale is a congenital defect, meaning it's present at birth.

However, before birth, patent foramen ovale is actually a necessary part of fetal development. Because the fetus receives oxygen from the mother's circulation, it doesn't need to pump blood to the lungs. Instead, the flap-like opening in the septum allows oxygenated blood to flow from the fetus's right atrium to the left atrium and circulate throughout the body. In this way, the patent foramen ovale acts as a form of bypass, preventing blood from unnecessarily going to the lungs before birth.

After a baby is born, the heart doesn't need this opening anymore. After birth, the baby cries or takes a deep breath, which expands the lungs and results in blood flowing into the lungs from the right side of the heart. The blood coming into the right atrium is sent down to the heart's lower right chamber (right ventricle) and then on to the lungs, where it is replenished with oxygen before returning to the left atrium. A flap closes the opening in the majority of infants.

It's not known why the foramen ovale remains open (patent) in one out of four people. However, experts believe that hereditary and genetic factors may play a role.

Patent foramen ovale may be associated with other cardiac defects, including:

• Atrial septal aneurysm (ASA). This condition occurs when the heart's inner wall (septum) has extra tissue that bulges into either the right or left atrium.
• Atrial septal defect (ASD). Similar to patent foramen ovale, an atrial septal defect is a hole in the wall between the two upper chambers of the heart.
• Ebstein's anomaly. This is a defect of the tricuspid valve, which controls blood flow between the heart's right atrium and right ventricle. In Ebstein's anomaly, the valve is malformed and positioned lower than normal into the ventricle instead of remaining between the atrium and the ventricle.
• Complex congenital heart disease, particularly cyanotic defects. In many complex congenital heart defects, a patent foramen ovale or other shunt is necessary for survival. These babies are blue (cyanotic) because the unoxygenated blood isn't sent to the lungs to take on oxygen.

A patent foramen ovale usually doesn't cause any signs or symptoms that would signal you to contact your doctor.

However, because infants with a PFO may exhibit signs, call your doctor if your baby develops bluish skin (cyanosis) when crying or straining, such as when passing stool. More often that not, this cyanosis is observed in newborns by the doctors and nurses before the baby goes home — and, at that point, more tests are done.

Patent foramen ovale is generally a harmless condition, usually discovered by accident not in infancy but later in life when a doctor orders imaging tests for an unrelated reason, such as for a heart murmur.

Alternatively, your doctor may suspect a patent foramen ovale if you experience a stroke or transient ischemic attack (TIA). A stroke occurs when the blood supply to a part of your brain is interrupted or severely reduced — often due to a blood clot. A transient ischemic attack, often called a ministroke, exhibits many of the signs of stroke, but usually lasts less than one hour. Patent foramen ovale is a rare cause of stroke.

Sometimes a patent foramen ovale is diagnosed due to low blood oxygen levels. This most commonly occurs if you have severe lung disease, such as emphysema or pulmonary fibrosis, which can cause an increase in right heart pressure. If you have a patent foramen ovale, unoxygenated blood can cross from the right atrium to the left side of your heart, further aggravating the diminished oxygenation of the blood and leading your doctor to suspect a patent foramen ovale.

The following tests may be performed as part of the work-up for PFO:

• Chest X-ray. In this test, a tiny burst of radiation passes through your body to produce an image on a piece of film or a digital plate. This test is used to assess your heart size and to look for any suggestion of more complex heart disease or pulmonary disease. The chest X-ray can't diagnose PFO.
• Electrocardiogram (ECG). This test records the electrical signals produced by your heart. It may show increased voltage from the right atrium, which suggests enlargement.
• Echocardiogram. This test uses ultrasound imaging to view the heart and is used to screen for patent foramen ovale.
• Transesophageal echocardiography. This test involves swallowing a flexible tube with a recording device that captures ultrasound images. This is the best test for detecting a patent foramen ovale.
• Cardiac catheterization. In this test, a soft, flexible tube (catheter) is inserted into a blood vessel in your groin area then guided to your heart where it can collect pressures from the various chambers of your heart and images after the injection of a contrast medium.

The relationship between patent foramen ovale and stroke is controversial, in part because PFO is fairly common.

In theory, because a patent foramen ovale has the potential to allow blood to flow from the heart's right atrium to the left atrium — thus bypassing the lungs, which filter the blood — the opening may allow small blood clots to move into the left side of your heart and then be pumped to your body. If a blood clot travels to your brain, it can lead to a stroke or a transient ischemic attack (TIA), which occurs when the blood supply to part of your brain is interrupted, depriving brain tissue of oxygen and nutrients.

Blood clots can also block other blood vessels. For example, if a blood clot passes through a patent foramen ovale and lodges in one of the arteries supplying your heart (coronary artery), then a heart attack can occur. Or, the clot can go to an arm or a leg.

The risk of stroke may be higher if you also have an increased risk of developing blood clots, whether due to a medical condition, poor circulation or inactivity. Risk may also be higher if you have an atrial septal aneurysm, a condition in which the wall between your heart's upper chambers (atrial septum) is floppy and more mobile than usual.

Research ongoing
The relationship between patent foramen ovale and stroke is an area of active clinical research, including studies, to determine if closing the PFO will reduce the risk of future strokes. Research also continues to determine if patent foramen ovale may be associated with migraines and decompression sickness in divers.

Most people with patent foramen ovale don't need treatment. This is because a PFO rarely causes adverse symptoms or complications. The possibility that you have a PFO may not emerge until you're being assessed for another health condition.

If you have symptoms that suggest you may have had a stroke, the first step for your doctor will be to determine if you've had a stroke or if there's another cause of your symptoms. If you have had a stroke, the second step is to determine the cause — including looking for a patent foramen ovale. Your doctor will look for other causes of stroke as well, such as blockage of the carotid arteries and conditions that cause blood clotting.

Your doctor may recommend treatment of a PFO if you've had a stroke that may be related to the PFO. The ideal treatment isn't known; studies to find one are under way. Treatment may consist of blood-thinning (anticoagulant) medications, such as warfarin (Coumadin) or anti-platelet agents, such as aspirin or clopidogrel (Plavix), to help prevent a future stroke.

Closing the patent foramen ovale is another option. Doctors most commonly use a procedure called device closure. Current guidelines suggest that device closure is best reserved for people at high risk, such as those who've had recurrent stroke while taking warfarin. Open-heart surgery is a second option for closing the PFO.

Device closure
Device closure is a nonsurgical procedure that uses a special kind of implanted device designed to close the PFO. It doesn't require open-heart surgery and can usually be performed with little discomfort.

During the procedure, a soft, flexible, hollow tube (catheter) is inserted into a blood vessel in your groin area. The catheter is then guided to your heart. Once it's inside your heart, your doctor can measure the PFO to determine the correct size of the device needed.

The device itself is then inserted through the catheter, and placed through the opening in the septum so that disks on the device sit on each side of the PFO. Once the device is situated correctly, it's left in place and the catheter is removed. The disks on each side of the septum fit together snugly, holding the device in place. In a few months, tissue grows over the device.

Usually, an ultrasound of the heart (echocardiogram, or ECG) is done during the catheterization procedure in order to better see the PFO. This may be done by passing a tube either through your esophagus (transesophageal echocardiogram) or through a blood vessel on the other side of your groin area (intracardiac echocardiogram).

Following the procedure
You can usually go home the same day or the day after device closure of a patent foramen ovale. You'll be restricted from driving the first day, and from certain physical activities for the first two weeks or so after the procedure. For the first year after the device has been planted, your doctor will recommend that you take antibiotics when you go to the dentist to prevent infection.

Most people take aspirin or other anti-platelet agents for at least six months after the procedure. If you've been taking warfarin, you may need to continue it for the first six months or so. Be sure you talk to your doctor about specific recommendations for your condition. You'll need periodic follow-up visits with your doctor and echocardiograms to check the device.

Complications from device closure include problems due to bleeding — usually at the site where the catheter entered, or bleeding into the lining of the heart. An irregular heart rhythm may occur, especially early after the device has been implanted. Make sure you tell your doctor if you experience palpitations or rapid heartbeat. Life-threatening problems, including infection and dislodgement of the device, are rare but can occur.

Surgical closure of PFO
A patent foramen ovale can also be closed by a heart surgeon. The operation is usually straightforward, but involves the risk and recovery time of open-heart surgery. If an atrial septal aneurysm is present, your surgeon can remove that tissue at the time of PFO closure. Some people undergoing heart surgery for other reasons, such as valve replacement, have a PFO closed at the same time.

The risks of surgery include bleeding and infection, although the risk is very low if PFO is the only problem. Most people stay in the hospital about five days after surgery and are be back to full activity within six weeks.