Patent Foramen Ovale (PFO) – Understanding This Common Heart Defect

Introduction

Patent Foramen Ovale (PFO) is a common heart condition that many people have without even knowing it. It’s like having a tiny door between two rooms in your heart that didn’t close properly when you were born. This small opening is found between the upper left and right chambers of the heart, which doctors call the atria.

Millions of people around the world have PFO, and most of them don’t feel any different because of it. In fact, many people with PFO live their whole lives without ever finding out they have it. But it’s still important to know about PFO because sometimes it can cause problems.

PFO can be linked to certain health issues, like strokes and really bad headaches called migraines. That’s why doctors and scientists think it’s important to study and understand PFO better.

In this article, we’re going to explore PFO in detail. We’ll look at:

• What PFO looks like inside the heart
• Why some people are born with PFO
• How doctors find out if someone has PFO
• What kinds of problems PFO might cause
• How doctors can treat PFO if needed
• What people with PFO can do to stay healthy

By learning about PFO, we can better understand how our hearts work and how to take care of them. Even though it sounds scary, remember that most people with PFO live normal, healthy lives. But knowing about it can help us make good choices for our health.

What is a Patent Foramen Ovale (PFO)?

Anatomy and Embryology

A Patent Foramen Ovale, or PFO, is a common heart defect that begins during fetal development. In the womb, babies have a small opening between the upper chambers of their heart called the foramen ovale. This opening serves an important purpose before birth. It allows blood to bypass the lungs, which aren’t working yet, and sends oxygen-rich blood from the mother directly to the baby’s brain and other vital organs.

Normally, this opening closes shortly after birth when the baby starts breathing on its own. The increased pressure in the left side of the heart pushes a small flap of tissue called the septum primum against the septum secundum, sealing the opening. Over time, these layers usually fuse together completely.

However, in some people, this fusion doesn’t happen properly. When the foramen ovale remains open after birth, it’s called a Patent Foramen Ovale. The word “patent” means open or unobstructed.

PFO Formation

A PFO forms when the natural closure process of the foramen ovale doesn’t work as it should. There are several reasons why this might happen. Some people may have a genetic predisposition to PFOs, meaning it runs in their family. Environmental factors during pregnancy or shortly after birth might also play a role, though scientists are still studying these causes.

In a PFO, the flap-like opening between the heart’s upper chambers (atria) doesn’t seal properly. Instead of fusing shut, it remains loose like a swinging door. Most of the time, this flap stays closed due to the higher pressure in the left atrium. However, when someone with a PFO strains or coughs, the pressure in their chest can change. This pressure change can cause the flap to open briefly, allowing blood to flow between the atria.

It’s important to note that having a PFO is quite common. About one in four people have this condition, and many never experience any problems because of it.

PFO vs. ASD

While both Patent Foramen Ovale (PFO) and Atrial Septal Defect (ASD) involve openings between the heart’s upper chambers, they are different conditions. Understanding these differences can help patients and their families better grasp their situation.

An Atrial Septal Defect is a larger hole in the wall (septum) between the atria. Unlike a PFO, which is a remnant of normal fetal development, an ASD is a true defect. It occurs when the septal tissue doesn’t form properly during heart development. ASDs are usually bigger than PFOs and allow more blood to flow between the atria.

PFOs, on the other hand, are typically smaller. They’re more like a flap or valve that can open and close, rather than a constant opening. Because of their size and nature, PFOs often cause fewer symptoms than ASDs.

Doctors consider ASDs more serious because they can lead to more significant problems if left untreated. The larger opening in an ASD allows more blood to flow between the atria, which can strain the heart over time. PFOs, being smaller, usually allow less blood flow and often don’t require treatment unless they cause symptoms or are associated with other health issues.

Both conditions can be diagnosed using similar methods, such as echocardiograms or bubble studies. However, the treatment approaches may differ depending on the size of the opening and the symptoms it causes.

Causes and Risk Factors

Genetic Factors

The exact cause of Patent Foramen Ovale (PFO) is not fully understood, but scientists believe that genetic factors play a significant role. Some families have been observed to have a higher occurrence of PFO, which suggests there might be a genetic component to the condition. However, researchers have not yet identified specific genes that directly cause PFO. This lack of precise genetic markers makes it challenging to predict who might develop PFO based on family history alone. Despite this uncertainty, doctors often ask about family medical history when evaluating a patient for PFO, as it can provide valuable insights into potential risk factors.

Environmental Factors

Currently, there are no known environmental factors that contribute to the development of PFO. Unlike some other medical conditions that can be influenced by exposure to certain substances or lifestyle choices, PFO is primarily considered a remnant of normal fetal heart development that persists into adulthood. During pregnancy, all babies have an opening between the upper chambers of the heart called the foramen ovale. This opening typically closes shortly after birth, but in some individuals, it remains open, resulting in a PFO. The reasons why this closure doesn’t occur in some people are still not fully understood, but it does not appear to be related to external environmental factors.

Other Medical Conditions

PFO can sometimes be associated with other heart defects or conditions, which may increase the risk of complications. One such condition is an atrial septal aneurysm, where a portion of the wall between the heart’s upper chambers bulges. This bulging can make the PFO larger or more likely to allow blood to pass through. Another related condition is the Chiari network, which is a web-like structure in the right atrium of the heart that can direct more blood flow towards the PFO. These associated conditions can make the PFO more significant and may require additional medical attention. Doctors often look for these related conditions when diagnosing and treating PFO to ensure comprehensive care. It’s important for patients with PFO to be aware of these potential associated conditions and discuss them with their healthcare provider.

Symptoms and Diagnosis

Common Symptoms

Most people with Patent Foramen Ovale (PFO) do not experience any noticeable symptoms. However, some individuals may develop health issues related to the abnormal blood flow between the heart’s atria. These symptoms can include:

1. Migraines: Some people with PFO may experience frequent or severe migraines, particularly those with visual disturbances or auras.

2. Strokes: In rare cases, PFO can lead to a higher risk of stroke, especially in younger adults who have no other apparent risk factors.

3. Respiratory issues: Difficulty breathing or shortness of breath may occur, particularly during physical activity or when lying down.

4. Fatigue: Some individuals with PFO may feel unusually tired or lacking in energy.

5. Heart palpitations: Occasionally, people with PFO may experience a fluttering or racing heartbeat.

It’s important to note that these symptoms can be subtle and may not be immediately linked to PFO. Many people with PFO live their entire lives without knowing they have the condition.

Diagnostic Tests

Diagnosing PFO typically involves several tests to confirm the presence of the defect and assess its impact on heart function. These tests include:

1. Echocardiogram: This non-invasive test uses sound waves to create images of the heart. It can show the structure of the heart and how blood flows through its chambers. There are two types of echocardiograms used in PFO diagnosis:

a. Transthoracic echocardiogram (TTE): This is the standard echocardiogram performed on the chest.

b. Transesophageal echocardiogram (TEE): This provides a more detailed view of the heart by inserting a small probe into the esophagus.

1. Bubble test: Also known as a contrast echocardiogram, this test involves injecting a saline solution with tiny air bubbles into a vein while performing an echocardiogram. If a PFO is present, the bubbles can be seen passing from the right to the left atrium.

2. Transcranial Doppler (TCD): This ultrasound test can detect bubbles in the arteries of the brain, which may indicate the presence of a PFO.

3. Cardiac MRI: In some cases, a magnetic resonance imaging (MRI) scan of the heart may be used to provide detailed images of the heart’s structure.

4. Cardiac catheterization: This invasive procedure involves inserting a thin tube into a blood vessel and guiding it to the heart to measure pressures and blood flow.

Differential Diagnosis

PFO must be differentiated from other heart conditions to ensure appropriate treatment. Some conditions that may have similar symptoms or characteristics include:

1. Atrial Septal Defect (ASD): This is a larger hole in the heart’s atrial septum that allows more significant blood flow between the atria.

2. Ventricular Septal Defect (VSD): This is a hole in the wall between the heart’s lower chambers (ventricles).

3. Mitral valve prolapse: This condition affects the valve between the left atrium and left ventricle.

4. Other causes of stroke or migraine: These may include hypertension, blood clotting disorders, or other cardiovascular issues.

To distinguish PFO from these conditions, doctors will consider:

1. Medical history: A thorough review of the patient’s symptoms, family history, and risk factors.

2. Physical examination: Listening to the heart and lungs, checking blood pressure, and assessing overall health.

3. Diagnostic tests: As mentioned earlier, various imaging tests can help visualize the heart’s structure and function.

4. Age and health status: PFO is more commonly diagnosed in younger adults with unexplained strokes, while other heart defects may be detected earlier in life.

By carefully evaluating all of these factors, healthcare providers can accurately diagnose PFO and develop an appropriate treatment plan for each patient.

Complications and Associated Conditions

Stroke and Embolic Events

One of the most significant complications of Patent Foramen Ovale (PFO) is the increased risk of stroke. Blood clots can form in the veins of the body and travel through the PFO to the left atrium of the heart. From there, these clots can be pumped to the brain, causing an ischemic stroke. This risk is particularly high in individuals who have had unexplained strokes or mini-strokes, also known as transient ischemic attacks (TIAs).

People with PFO may be more likely to experience “cryptogenic strokes,” which are strokes with no clear cause. In some cases, doctors may recommend closing the PFO through a minimally invasive procedure to reduce the risk of future strokes. However, this decision is made on a case-by-case basis, considering factors such as the patient’s age, overall health, and history of stroke or TIA.

Migraines and Other Neurological Issues

There is a potential link between PFO and migraines, especially migraines with aura. The exact mechanism is not fully understood, but researchers believe that the abnormal blood flow through the PFO may contribute to these neurological symptoms. Some studies suggest that closing the PFO might help reduce the frequency and severity of migraines in certain patients, although more research is needed to confirm this connection.

In addition to migraines, PFO has been associated with other neurological issues, such as:

• Transient global amnesia: A temporary loss of memory that usually resolves within 24 hours
• Decompression sickness: A condition that can affect divers when they ascend too quickly from deep waters
• Sleep apnea: A sleep disorder characterized by pauses in breathing during sleep

While these associations exist, it’s important to note that not everyone with PFO will experience these neurological issues, and having these conditions doesn’t necessarily mean a person has PFO.

Respiratory Issues

In rare cases, PFO can lead to respiratory complications, such as platypnea-orthodeoxia syndrome. This condition is characterized by a decrease in blood oxygen levels when a person sits up or stands. While lying down, oxygen levels may be normal, but they drop when the person changes position. This happens because the PFO allows deoxygenated blood to bypass the lungs and enter the body’s circulation directly.

Platypnea-orthodeoxia syndrome is rare but can be significant for individuals affected by it. Symptoms may include:

• Shortness of breath when sitting or standing
• Dizziness or lightheadedness upon changing positions
• Blue discoloration of the skin (cyanosis) in severe cases

Treatment for this condition often involves closing the PFO to prevent the abnormal blood flow. In some cases, other heart defects may also need to be addressed to fully resolve the symptoms.

Treatment Options

Closure Devices

One of the most common and effective treatments for Patent Foramen Ovale (PFO) is the use of closure devices. These small, umbrella-like implants are designed to seal the opening between the two upper chambers of the heart. The Amplatzer PFO Occluder is a popular choice among doctors. This device is made of a flexible metal mesh and is inserted through a catheter, which is a thin tube. The doctor guides the catheter through a vein in the leg up to the heart. Once in place, the device is deployed to cover the hole. Over time, heart tissue grows over the device, permanently sealing the opening. This procedure is minimally invasive, meaning it doesn’t require open-heart surgery. Patients usually recover quickly and can often go home the same day or the day after the procedure. Closure devices are often preferred because they have fewer risks and a shorter recovery time compared to traditional surgery.

Surgical Closure

While closure devices are the first choice for many patients, sometimes surgery is necessary. This is especially true if the PFO is very large or if there are other heart defects that need to be fixed at the same time. In the past, fixing a PFO always meant open-heart surgery. Now, this is rarely needed unless it’s part of a bigger heart operation. During surgical closure, the doctor makes a cut in the chest to reach the heart. They then stitch or patch the hole closed. This method is very effective but has a longer recovery time than using a closure device. Patients usually stay in the hospital for several days after surgery and take a few weeks to fully recover.

Medical Therapy

Not everyone with a PFO needs to have it closed. For some people, especially those without symptoms or complications, doctors may recommend medical therapy instead. This means using medicines to manage symptoms and prevent problems. One common worry with PFO is blood clots. To help prevent these, doctors might prescribe anticoagulant medications, also known as blood thinners. These drugs make it harder for clots to form. For patients who have migraines linked to their PFO, anti-migraine medications can help reduce headaches and other symptoms. Some patients might also be advised to take antibiotics before certain medical procedures to prevent infections. The choice of medical therapy depends on each person’s specific situation and risk factors. Doctors will closely monitor patients on medical therapy to make sure the treatment is working well.

Lifestyle Changes and Prevention

Healthy Lifestyle Habits

Maintaining a healthy lifestyle is crucial for reducing the risk of complications associated with PFO. Regular exercise is important and can include activities like walking, swimming, or cycling for at least 30 minutes a day, five days a week. A balanced diet rich in fruits, vegetables, whole grains, and lean proteins helps keep your heart healthy. It’s also important to limit foods high in saturated fats, salt, and added sugars.

Avoiding smoking is essential, as it can damage blood vessels and increase the risk of blood clots. If you currently smoke, talk to your doctor about ways to quit. Limiting alcohol consumption is also important. For those who choose to drink, it’s recommended to do so in moderation, which means up to one drink per day for women and up to two drinks per day for men.

Maintaining a healthy weight is another key factor in reducing the risk of complications. Being overweight or obese can put extra strain on your heart and increase the risk of blood clots. If you need to lose weight, consider working with a nutritionist or your healthcare provider to create a safe and effective weight loss plan.

Stress management is also an important part of a healthy lifestyle. High levels of stress can contribute to heart problems and increase the risk of complications. Try activities like meditation, yoga, or deep breathing exercises to help manage stress.

Preventive Measures

Regular check-ups with a healthcare provider are essential, especially if you have a history of unexplained strokes or migraines. During these check-ups, your doctor can monitor your heart health and check for any changes or complications related to your PFO.

If you have been diagnosed with PFO, it’s important to follow your doctor’s recommendations for treatment and follow-up care. This may include taking medications as prescribed, attending regular appointments, and undergoing any recommended tests or procedures.

Be aware of the signs and symptoms of stroke, which can include sudden weakness or numbness on one side of the body, difficulty speaking, or vision problems. If you experience any of these symptoms, seek medical attention immediately.

For those who have PFO and plan to travel, especially by air, it’s important to discuss any potential risks with your doctor. They may recommend measures to prevent blood clots during long flights, such as wearing compression stockings or taking breaks to walk around.

If you have PFO and are planning to become pregnant, it’s important to discuss this with your healthcare provider. They can help you understand any potential risks and develop a plan to manage your condition during pregnancy.

Staying informed about your condition is another important preventive measure. Keep up-to-date with the latest information about PFO and its management. Don’t hesitate to ask your healthcare provider questions about your condition or treatment options.

Conclusion

Patent Foramen Ovale (PFO) is a heart condition that many people are born with, affecting about 1 in 4 individuals. While it often doesn’t cause any problems, it’s important to understand this common heart defect. PFO occurs when a small opening between the upper chambers of the heart doesn’t close properly after birth.

For most people with PFO, there are no noticeable symptoms. However, in some cases, it can lead to serious health issues. These problems might include strokes, migraines, or difficulty breathing. That’s why it’s crucial to be aware of PFO and its potential effects on your health.

Knowing about PFO can help you recognize possible signs that something might be wrong. If you experience unexplained symptoms like shortness of breath, chest pain, or frequent headaches, it’s important to talk to a doctor. They can check if PFO might be the cause and suggest the best ways to manage it.

Even if you have PFO, you can still live a healthy and active life. Eating a balanced diet, exercising regularly, and avoiding smoking are great ways to keep your heart strong. These healthy habits can help reduce the risk of complications from PFO.

For some people with PFO, doctors might recommend treatments like medication or a simple procedure to close the opening. But for many, no treatment is needed at all. The key is to stay informed about your condition and work closely with your healthcare team.

By understanding PFO and taking care of your overall heart health, you can lower your chances of having problems related to this common heart defect. Remember, knowledge is power when it comes to your health, and staying informed about PFO is an important step in taking care of your heart.

References

1. American Heart Association. Patent Foramen Ovale (PFO). https://www.heart.org/en/health-topics/congenital-heart-defects/about-congenital-heart-defects/patent-foramen-ovale-pfo. Accessed May 7, 2021.
2. Cleveland Clinic. Patent Foramen Ovale (PFO): Symptoms, Causes & Treatment. https://my.clevelandclinic.org/health/diseases/17326-patent-foramen-ovale-pfo. Accessed May 7, 2021.
3. Mayo Clinic. Patent foramen ovale – Symptoms & causes. https://www.mayoclinic.org/diseases-conditions/patent-foramen-ovale/symptoms-causes/syc-20353487. Accessed May 7, 2021.
4. Penn Medicine. Patent Foramen Ovale (PFO) – Symptoms and Causes. https://www.pennmedicine.org/for-patients-and-visitors/patient-information/conditions-treated-a-to-z/patent-foramen-ovale. Accessed May 7, 2021.
5. StatPearls. Patent Foramen Ovale. https://www.ncbi.nlm.nih.gov/books/NBK493151/. Accessed May 7, 2021.