Patent Foramen Ovale: Symptoms, Risks, and Treatment Options

A patent foramen ovale (PFO) is a small opening between the upper chambers of the heart that remains open after birth. Before birth, this opening is a normal part of fetal circulation because it allows blood to bypass the lungs while the baby develops. In most people, the opening naturally closes shortly after birth, but in some individuals, it stays open into adulthood. Many people with a patent foramen ovale never experience symptoms and may not know they have the condition unless it is discovered during testing for another reason.

Although a patent foramen ovale is usually harmless, it may be associated with certain health concerns in some people. The main concern is that a blood clot can occasionally pass through the opening and travel to the brain, potentially causing an ischemic stroke. Doctors may evaluate a PFO after an unexplained stroke, especially in younger adults without other clear risk factors. This article explains the symptoms, possible risks, diagnosis, and treatment options for patent foramen ovale, including when monitoring, medication, or a closure procedure may be considered.

What is a Patent Foramen Ovale (PFO)?

A Patent Foramen Ovale (PFO) is a small, tunnel-like opening between the heart’s two upper chambers (the right and left atria) that is a normal part of fetal circulation but fails to seal shut after birth. This remnant of the fetal circulatory system is not a congenital heart defect in the traditional sense but rather an anatomical variant present in a significant portion of the population.

While it often remains benign and undiscovered, it can, under specific circumstances, provide a pathway for blood to travel abnormally between the heart’s chambers, leading to potential health concerns. The structure of a PFO is distinct from an atrial septal defect (ASD), which is a true hole in the tissue of the atrial septum; a PFO is more like an unsealed flap or tunnel.

To understand better why a PFO exists, it is essential to first examine the role of its precursor, the foramen ovale, in the developing fetus.

Fetal Circulation and the Role of the Foramen Ovale

Before a baby is born, their lungs are filled with fluid and cannot exchange oxygen. Instead, the fetus relies completely on the mother’s placenta for oxygen and nutrients. Because sending large amounts of blood through the non-functioning fetal lungs is unnecessary and inefficient, the fetal cardiovascular system uses specialized pathways called shunts to redirect blood flow.

The Oxygenation Pathway

Highly oxygenated blood leaves the placenta and enters the fetus through the umbilical vein. It bypasses the liver via a small vessel called the ductus venosus and empties straight into the inferior vena cava, where it mixes slightly with deoxygenated blood returning from the lower body.

Shunting Inside the Heart

This oxygen-rich blood enters the right atrium of the pfo heart. Inside the chamber, a small tissue fold called the Eustachian valve acts like a directional flap, guiding the blood flow across a natural opening in the atrial wall—the foramen ovale.

This opening allows blood to slip directly from the right atrium into the left atrium, completely bypassing the pulmonary circuit (the lungs). From the left atrium, the oxygenated blood flows into the left ventricle and is pumped out through the aorta, ensuring the developing brain and vital organs receive a steady supply of oxygen.

Post-Natal Transition: How the Flap Seals

The moment a newborn takes their very first breath, the pressure balance inside the heart changes completely.

When air enters the lungs, the blood vessels inside them widen, causing the resistance in the pulmonary circuit to drop instantly. Blood pours into the lungs to collect oxygen and then drains back into the left atrium. This sudden rush of blood creates a high-pressure zone inside the left atrium.

At the same time, because the umbilical cord is clamped, less blood returns to the right atrium, dropping the pressure on the right side of the heart. This pressure shift forces the septum primum (a thin tissue flap) flat against the septum secundum (the thicker muscular wall), covering the opening like a one-way valve.

Over the first year of life, these two overlapping layers of tissue typically fuse completely solid in about 75% of people.

What is a PFO? Anatomical Variant vs. Congenital Defect

When answering what is a pfo, it is important to understand that it is a failure of this natural fusion process. If the two overlapping tissue layers do not grow together, the tunnel-like opening remains “patent,” meaning open.

What is a PFO in Medical Terms?

In medical terms, a patent foramen ovale (PFO) is classified as an anatomical variant rather than a true congenital heart defect. This distinction comes down to whether heart tissue is actually missing:

Hemodynamics of a PFO Heart Condition

In everyday life, a pfo heart condition is typically quiet and unnoticeable. Because the resting blood pressure in the left atrium remains slightly higher than the pressure in the right atrium, the natural pressure gradient keeps the tissue flaps pushed firmly together, preventing blood from crossing.

However, specific physiological actions can temporarily reverse this pressure balance. Activities that involve straining—such as a heavy cough, sneezing, vomiting, lifting weights, or straining during a bowel movement (known as a Valsalva maneuver)—cause a brief spike in right atrial pressure.

When the pressure on the right side exceeds the pressure on the left, it can push the unsealed flap open. This creates a temporary right-to-left shunt, allowing a small amount of deoxygenated blood to cross directly into the systemic circulation without passing through the lungs first.

What are the Symptoms of a Patent Foramen Ovale?

Most individuals with a Patent Foramen Ovale are asymptomatic and unaware of its presence; however, in a minority of cases, a PFO can be associated with specific medical conditions, including cryptogenic stroke, migraine with aura, and, in rare circumstances, shortness of breath.

A patent foramen ovale is fundamentally a silent condition. The unsealed flap itself does not have pain receptors, nor does it disrupt the heart’s natural electrical rhythm. Because of this, it does not cause direct physical symptoms like chest pain, palpitations, or chronic fatigue.

Instead, the clinical significance of this pfo heart condition comes down to its mechanics: under the right conditions, it acts as an open back door, allowing blood—and anything carried within it—to bypass the protective filtration system of the lungs.

The Right-to-Left Shunt: Bypassing the Pulmonary Filter

In a standard circulatory system, all venous blood returning from the body must pass through the right side of the heart and enter the lungs. The lungs act as a massive biological filter, trapping and neutralizing tiny blood clots, nitrogen bubbles, and inflammatory chemical compounds before the blood returns to the left side of the heart to be pumped out to the body.

When a patient has a patent foramen ovale (PFO), a transient spike in right-sided heart pressure can force the unsealed flap open. This creates a right-to-left shunt.

If a microscopic blood clot or bubble is floating in the bloodstream at that exact moment, it can slip straight through the pfo heart tunnel into the left atrium. From there, it enters the systemic arterial highway, where it can travel directly to the brain or other vital organs without ever being filtered by the lungs.

Clinical Conditions Scientifically Linked to a PFO

Because a PFO is hidden, it is rarely diagnosed through routine checkups. Instead, it is typically uncovered during a medical investigation after a patient experiences one of several specific complications.

Cryptogenic Stroke and TIA

The most serious medical risk associated with a PFO is a cryptogenic stroke—an ischemic stroke (a clot blocking a brain artery) that occurs without any identifiable cause, such as high blood pressure, arterial plaque, or an irregular heartbeat (atrial fibrillation). This happens through a process called a paradoxical embolism:

1. A tiny clot forms in the deep veins of the legs (a deep vein thrombosis).

2. The clot travels up to the right atrium of the heart.

3. A sudden strain (like a cough or sneeze) opens the PFO flap, allowing the clot to cross directly into the left atrium.

4. The left ventricle pumps the clot straight up into the carotid arteries and into the brain, blocking blood flow and causing a stroke or a temporary “mini-stroke” known as a Transient Ischemic Attack (TIA).

Migraine with Aura

Medical studies show a clear statistical link between PFOs and migraines, particularly migraine with aura (migraines preceded by visual distortions, flashing lights, or blind spots).

While researchers are still studying the exact cause, the leading theory is that microscopic blood clots or chemical triggers in the venous blood bypass the lung filter via the PFO. When these substances reach the brain’s blood vessels, they can irritate sensitive neurological tissue and trigger a migraine attack.

Decompression Sickness (“The Bends”)

For recreational and professional scuba divers, a PFO introduces a unique, severe hazard. As a diver ascends from a deep dive, dissolved nitrogen in their tissues naturally forms tiny micro-bubbles in the veins.

In a standard heart, these bubbles travel to the lungs and are exhaled safely. However, in a diver with a PFO, a sudden change in pressure can shunt these nitrogen bubbles directly into the arterial bloodstream. Once in the arteries, the bubbles can travel to the brain or spinal cord, causing severe neurological decompression sickness even if the diver followed a standard, safe ascent profile.

Rare Structural Manifestations: Platypnea-Orthodeoxia Syndrome

While a PFO does not typically cause respiratory symptoms, it can cause severe shortness of breath and fatigue in a rare condition known as Platypnea-Orthodeoxia Syndrome (POS).

[Mechanics of Platypnea-Orthodeoxia]
                │
[1. Vertical Posture] ── Patient stands up; gravity shifts internal organs.
                │
[2. Anatomical Distortion] ── An enlarged aorta or lung disease reshapes the right atrium.
                │
[3. Targeted Blood Shunting] ── Deoxygenated blood is channeled straight at the PFO tunnel.
                │
[4. Systemic Hypoxemia] ── Low-oxygen blood floods the body, causing shortness of breath.

POS is a unique syndrome where a patient experiences significant shortness of breath (platypnea) and a drop in blood oxygen levels (orthodeoxia) only when they are sitting or standing upright. The symptoms disappear completely the moment the patient lies flat.

For this syndrome to occur, a patient must have a PFO combined with a secondary physical change, such as an enlarged aorta (an aortic aneurysm), a shifted diaphragm, or certain lung diseases.

When the patient stands up, gravity causes these surrounding structures to physically distort or compress the right atrium. This change in shape acts like a funnel, directing deoxygenated blood from the lower body straight through the PFO flap into the left side of the heart. The sudden mixing of low-oxygen blood lowers the body’s overall oxygen saturation, leading to sudden breathlessness and fatigue that quickly resolves once the patient lies back down.

Advanced Cardiovascular Diagnostic Procedures

When evaluating a patient for a suspected right-to-left shunt, cardiologists rely on specialized imaging techniques rather than standard chest X-rays or EKGs.

Transthoracic Echocardiogram (TTE) with Bubble Study: This is the initial, non-invasive screening tool. An ultrasound probe is placed on the outside of the chest while an IV line is used to inject a solution of agitated sterile saline (which contains microscopic, harmless micro-bubbles) into the patient’s arm. The cardiologist monitors the ultrasound screen to see if any bubbles cross from the right atrium directly into the left atrium within three cardiac cycles, confirming a shunt.

Transesophageal Echocardiogram (TEE): If the TTE results are unclear, a TEE is performed. The patient is sedated, and a specialized, thin ultrasound probe is passed down the esophagus, which sits directly behind the heart. This technique eliminates interference from the ribs and lungs, providing high-resolution images of the atrial wall so doctors can clearly evaluate the structure of the PFO tunnel.

Transcranial Doppler (TCD): A neurological ultrasound that looks at blood flow in the brain’s arteries during a bubble study. If micro-bubbles are detected in the brain after being injected into the arm, it confirms that a right-to-left shunt is actively allowing material to reach the cerebral circulation.

Diagnostic Evaluation Checklist

If a patient presents with a cryptogenic stroke or unexplained neurological symptoms, a comprehensive diagnostic evaluation for a PFO generally includes the following steps:

• [ ] Clinical History Review: Documenting any recent history of unexplained strokes, frequent migraines with aura, or dive-related decompression sickness.

• [ ] Physical Valsalva Testing: Observing changes in symptoms or murmurs when the patient strains or coughs.

• [ ] Surface TTE with Saline Contrast: Performing an initial bedside ultrasound paired with a micro-bubble injection to screen for a shunt.

• [ ] High-Resolution TEE: Passing an internal probe down the esophagus to visually inspect the overlap of the septum primum and secundum.

• [ ] Transcranial Doppler Tracking: Scanning the brain’s blood vessels during a bubble study to confirm whether shunted material is reaching the cerebral circulation.

What is the Stroke Risk associated with a Patent Foramen Ovale?

While a patent foramen ovale is a common and usually benign anatomical variant in the general population, its presence changes from a quiet trait to a significant medical consideration in young to middle-aged adults (typically under age 60) who suffer an unexplained ischemic stroke.

When a stroke occurs without a clear cause—such as high blood pressure, arterial plaque buildup, or an irregular heart rhythm like atrial fibrillation—it is classified as a cryptogenic stroke. In these cases, a pfo heart condition is frequently identified as the hidden mechanism behind the event.

The Anatomy of a Paradoxical Embolism

To understand what is a pfo stroke risk, it helps to track the exact chain of events that transforms a common venous clot into a neurological emergency. This specific pathway is known as a paradoxical embolism.

[1. Source: Venous System]    ──► A clot (DVT) forms in the deep veins of the legs or pelvis.
                                       │
                                       ▼
[2. Route: To the Heart]       ──► The clot travels up the vena cava into the Right Atrium.
                                       │
                                       ▼
[3. The Paradoxical Shunt]     ──► A strain (cough/sneeze) spikes pressure, forcing the PFO flap open.
                                   The clot slips from the Right Atrium directly to the Left Atrium.
                                       │
                                       ▼
[4. Destination: The Brain]    ──► The Left Ventricle pumps the clot into the systemic arteries.
                                   It lodges in a cerebral artery, causing a Cryptogenic Stroke.

In a standard heart, any venous clot that breaks free travels to the right side of the heart, which pumps it directly into the lungs. The lungs possess an extensive, microscopic capillary network that acts as a natural filter, trapping the clot. While this can cause a respiratory issue known as a pulmonary embolism (PE), the clot cannot reach the brain.

However, in an individual with a pfo heart, a sudden physical strain (like a heavy cough or lifting something heavy) temporarily raises the pressure in the right atrium. If a micro-clot arrives at the heart at that exact split second, the pressure pushes the unsealed tissue flap open. The clot travels through the PFO tunnel, bypassing the lung filter entirely, and enters the left side of the heart. From there, it is pumped straight out into the systemic arterial highway, where it can travel up into the brain, block blood flow, and cause an ischemic stroke.

Anatomical Risk Factors: High-Risk PFO Features

Not all PFOs carry the same level of risk. Cardiologists use high-resolution imaging, such as a transesophageal echocardiogram (TEE), to inspect the exact shape, size, and movement of the unsealed flap. Several distinct anatomical features dramatically increase the likelihood of a clot crossing over.

Atrial Septal Aneurysm (ASA)

This is the single strongest anatomical predictor of a PFO-related stroke. An atrial septal aneurysm is a redundant, floppy, and hypermobile section of the tissue wall between the heart’s upper chambers. Instead of being a firm wall, this section of tissue bulges and swings back and forth with every heartbeat. This continuous whipping motion acts like a mechanical funnel, actively catching floating blood clots and directing them straight into the PFO opening.

Large Shunt Size

The physical size of the opening dictates what can pass through it. During a diagnostic bubble study, doctors grade the size of the shunt based on how many micro-bubbles cross into the left side of the heart. A large PFO allows a higher volume of blood to move between the chambers and can accommodate larger, more dangerous blood clots that can cause extensive neurological damage.

Long PFO Tunnel

A long, narrow tunnel structure creates a unique hazard. Rather than just being an open window, a long tunnel can act as a resting place where a tiny clot can get temporarily caught or slowed down. If the tunnel holds a micro-clot, a subsequent pressure spike can instantly propel it forward into the left atrium.

Clinical and Hypercoagulable Risk Multipliers

While the structure of the pfo in the heart provides the pathway, the stroke risk rises substantially if a patient’s blood is inherently more prone to forming the clots that travel through that pathway.

• Thrombophilia (Hypercoagulable States): Underlying genetic or acquired blood disorders make the blood much stickier and more prone to clotting. Common examples include the Factor V Leiden mutation, prothrombin gene mutations, or antiphospholipid syndrome.

• A Personal History of DVT: A patient who has an established medical history of forming deep vein blood clots has a proven source for a potential paradoxical embolism, making a PFO a much higher clinical risk.

• Situational Stasis: Temporary life events can sharply increase clot formation. Prolonged physical immobility—such as sitting on a long-haul flight, bed rest during a prolonged illness, or recovering from major orthopedic or pelvic surgeries—slows down venous blood flow, creating the perfect environment for a blood clot to form.

Summary of High-Risk PFO Criteria

When a medical team evaluates a patient after a cryptogenic stroke, they use the following checklist to determine if the PFO was the highly probable cause of the stroke, which heavily influences whether the patient needs a procedural intervention:

What are the Closure Options for a Patent Foramen Ovale?

The primary closure options for a Patent Foramen Ovale, which are almost exclusively considered for patients who have already experienced a PFO-attributable stroke, consist of two main strategies: long-term medical management with anti-clotting medications or a minimally invasive percutaneous (catheter-based) procedure to permanently seal the opening with a closure device.

The decision of whether to close a PFO is a complex one, made by a multidisciplinary “heart-brain team” including a neurologist and an interventional cardiologist. The goal of either approach is the same: to prevent a recurrent stroke. Simple discovery of an asymptomatic PFO does not warrant intervention. The debate between medication and closure centers on balancing the long-term risks of bleeding and medication adherence against the upfront procedural risks and long-term benefits of a definitive structural repair.

To understand the best course of action, it is important to detail the primary treatments available after a PFO-related stroke has occurred.

What are the primary treatments for a PFO after a stroke?

The two primary treatments for a PFO after a presumed PFO-mediated cryptogenic stroke are long-term medical therapy with antiplatelet or anticoagulant drugs, and percutaneous PFO closure, a procedure where a device is implanted via a catheter to permanently seal the PFO. The choice between these pathways depends on a careful evaluation of the patient’s age, the characteristics of their stroke, the anatomy of their PFO, and their personal preferences and lifestyle.

• Medical Therapy: This has historically been the standard approach and remains a valid option for many patients. The goal is not to close the PFO but to reduce the body’s ability to form the clots that could pass through it.

* Antiplatelet Agents: Drugs like aspirin and clopidogrel work by making platelets less sticky, thereby inhibiting the formation of blood clots. This is often the first-line medical treatment and is effective at reducing the risk of many types of stroke.

* Anticoagulants: Medications like warfarin or the newer direct oral anticoagulants (DOACs) are more potent “blood thinners” that interfere with the clotting cascade. They are generally more effective at preventing clots originating in the venous system (like DVTs) but also carry a higher risk of serious bleeding compared to antiplatelets. They may be preferred if the patient has another reason to be on an anticoagulant, such as a known clotting disorder.

• Percutaneous PFO Closure: This is a minimally invasive, non-surgical procedure designed to provide a definitive, structural fix.

* The Procedure: It is performed in a cardiac catheterization lab. A catheter is inserted into a large vein, typically in the groin, and advanced under X-ray and ultrasound guidance to the heart. A collapsible closure device, consisting of two discs or umbrellas connected by a short waist, is passed through the PFO tunnel. One disc is deployed in the left atrium and the second in the right atrium. The device is then cinched together, effectively sandwiching the septum and sealing the opening.

* Recovery and Long-Term Outcome: The patient’s own heart tissue gradually grows over the device over the next three to six months, incorporating it into the septal wall. Patients are typically discharged home the same or the next day and are prescribed a course of antiplatelet medication for a period after the procedure.

When is PFO closure recommended over medication?

PFO closure is now generally recommended over medical therapy alone for carefully selected younger patients, typically under the age of 60, who have suffered a cryptogenic ischemic stroke that is attributed to the PFO, especially when high-risk anatomical features are present. This recommendation is strongly supported by the results of several landmark randomized controlled trials that demonstrated the superiority of closure in preventing recurrent strokes in this specific population. The decision is not automatic and requires a thorough evaluation to ensure that the benefits of the procedure outweigh its risks.

The comparison between closure and medication hinges on several key criteria:

Patient Profile: The ideal candidate for PFO closure is a younger, active individual (under 60) who has had a confirmed stroke visible on an MRI and in whom a comprehensive workup has failed to find any other cause. In older patients, other stroke causes like atrial fibrillation or atherosclerosis become much more common, making the PFO less likely to be the culprit.

High-Risk PFO Anatomy: The strongest evidence for closure is in patients whose PFOs have high-risk features. The presence of a large right-to-left shunt or a coexisting atrial septal aneurysm (ASA) significantly strengthens the case for closure, as these features were common among the patients who benefited most in the clinical trials. The RoPE (Risk of Paradoxical Embolism) score is a clinical tool used to estimate the likelihood that a PFO was responsible for a stroke, and a high score favors closure.

Evidence from Clinical Trials: Pivotal trials like RESPECT, REDUCE, and CLOSE compared PFO closure combined with antiplatelet therapy against antiplatelet therapy alone. These studies conclusively showed that over a period of approximately five years, PFO closure led to a significant relative risk reduction (over 50% in some studies) in recurrent ischemic strokes compared to medication. While the absolute risk of recurrent stroke was low in both groups, the benefit of closure was clear and statistically significant.

Risk-Benefit Discussion: The recommendation for closure involves a shared decision-making process. The small but real risks of the closure procedure (such as bleeding at the catheter site, device dislodgement, or a post-procedural risk of developing atrial fibrillation) must be weighed against the long-term cumulative risk of another stroke and the lifelong risks and inconvenience of medical therapy, including the risk of bleeding. For many young stroke survivors, the prospect of definitively reducing their future stroke risk makes closure a highly preferred option.

Key considerations for diagnosing and managing a PFO

Evaluating and managing a patent foramen ovale involves carefully reviewing cardiac anatomy, patient lifestyle, and systemic risks. Since the unsealed flap is usually harmless, clinical intervention is tightly focused on preventing recurrent complications rather than treating day-to-day symptoms.

Definitive Diagnosis and Structural Distinction

To determine if a patent foramen ovale is the source of a right-to-left shunt, cardiologists rely on specific contrast-enhanced imaging. These tests help distinguish it from other conditions, such as an atrial septal defect.

Transthoracic Echocardiogram (TTE) with Bubble Study

As a frontline non-invasive check, a TTE visualizes the heart through the chest wall. During the ultrasound, a small amount of agitated sterile saline is injected into an arm vein, creating micro-bubbles.

The physician tracks these bubbles as they enter the right atrium. If a patent foramen ovale is present, bubbles can be seen slipping into the left atrium—especially if the patient performs a Valsalva maneuver (straining to briefly raise right-sided heart pressure).

Transesophageal Echocardiogram (TEE)

Considered the gold standard for anatomical evaluation, a TEE involves passing a thin ultrasound probe down the esophagus. Because the esophagus sits directly behind the heart, this approach provides clear images of the tissue wall without interference from the ribs or lungs.

A TEE allows the cardiologist to measure the exact length of the tunnel and look for high-risk features like an atrial septal aneurysm.

Transcranial Doppler (TCD)

A TCD uses ultrasound on the side of the head to measure blood flow in the brain’s arteries during a saline bubble injection. While it does not image the heart directly, catching micro-bubbles in the brain confirms that a right-to-left shunt is actively allowing material to enter the brain’s circulation.

Distinguishing a PFO from an Atrial Septal Defect (ASD)

It is structurally important to separate a patent foramen ovale from an atrial septal defect:

• Patent Foramen Ovale: A potential, tunnel-like flap formed by overlapping layers of tissue that failed to grow together completely after birth. It typically stays closed and only allows brief, intermittent blood shunting during pressure spikes.

• Atrial Septal Defect: A permanent congenital defect where a portion of the tissue wall is entirely missing, leaving a literal hole. This structural absence leads to continuous blood shunting—usually from the high-pressure left atrium to the right atrium—which can cause right-sided heart strain over time.

Management Pathways: Medical Therapy vs. Transcatheter Closure

When a patent foramen ovale is linked to an otherwise unexplained stroke, the medical team must choose between long-term medication or a structural closure procedure to reduce the risk of a recurrence.

Medical Therapy

For many patients, especially those with standard, low-risk anatomy, daily medication is the preferred path. This approach focuses on preventing the blood clots that could travel through the shunt:

• Antiplatelet Medications: Daily low-dose aspirin or clopidogrel is used to keep blood cells from sticking together, reducing the risk of a stroke.

• Anticoagulants: Stronger blood thinners, such as warfarin or direct oral anticoagulants, may be used if the patient has a known underlying blood-clotting disorder.

Percutaneous Transcatheter PFO Closure

For patients who experience a recurrent stroke despite taking medication, or those with high-risk anatomical features, a minimally invasive structural repair is often recommended.

A structural heart interventionalist inserts a thin catheter through a vein in the groin and guides it up to the heart. They place a small, double-disc closure device directly into the tunnel. The device expands to clamp the overlapping tissue layers together, closing the tunnel completely. Over the following months, the body’s natural lining grows over the device to seal it permanently.

Post-Procedural Recovery Timeline

Recovery after a transcatheter closure procedure is generally swift, moving through predictable steps focused on healing the entry site and preventing clots on the new device.

Days 1 to 2 (Immediate Post-Procedure): Most patients stay overnight for observation and return home within 24 hours. The focus is on letting the groin access site heal to prevent bleeding.

Weeks 1 to 2 (Activity Modification): Patients can resume light daily walks and desk work within a few days. However, they must avoid heavy lifting (over 10 pounds) and strenuous workouts for up to two weeks to ensure the closure device stays securely in place while early tissue healing begins.

Months 1 to 6 (Endothelialization & Medication): The patient takes dual antiplatelet therapy (typically aspirin combined with clopidogrel) for one to six months. This prevents blood clots from forming on the metal surface of the device before the heart’s natural tissue can completely grow over it. At the one-month mark, a follow-up TTE with a bubble study is performed to check the device’s position and look for any remaining leaks.

Year 1 and Beyond (Long-Term Maintenance): A final imaging check is typically done between 6 and 12 months to confirm the tunnel is fully sealed. After the initial recovery phase, patients usually stop taking the second antiplatelet medication but remain on a daily low-dose aspirin indefinitely.

Special Precautions and Scuba Diving Risks

For individuals with an open patent foramen ovale, specific high-pressure environments introduce distinct physical risks that require careful management.

The Mechanics of “The Bends” in Scuba Diving

During a dive, the increased underwater pressure causes nitrogen gas to dissolve into the body’s tissues. As the diver ascends toward the surface, this nitrogen slowly comes out of solution and forms tiny bubbles in the veins.

In a standard circulatory system, these bubbles travel safely to the lungs, where they are filtered out and exhaled without causing harm.

However, if a diver has a patent foramen ovale, physical exertion or equalization techniques during ascent can cause a brief pressure spike in the right atrium. This pressure can open the unsealed flap, allowing nitrogen bubbles to bypass the lung filter entirely and cross directly into the arterial bloodstream.

Once in the arteries, these bubbles can travel to the brain or spinal cord, causing an arterial gas embolism. This can lead to severe neurological decompression sickness, resulting in symptoms like sudden dizziness, altered mental status, or paralysis.

Safety Protocol for Divers with a Confirmed PFO

If a diver has a confirmed patent foramen ovale and chooses to dive without undergoing a structural closure procedure, they must follow a highly conservative diving profile to limit nitrogen buildup:

• Depth and Time Limits: Avoid deep dives and strictly limit total underwater bottom time.

• Ascent Profile Changes: Perform exceptionally slow ascents, incorporate prolonged safety stops, and avoid making multiple dives on the same day.

• Specialist Consultation: Divers should seek a comprehensive medical evaluation from a physician trained in dive medicine alongside their cardiologist to determine if a transcatheter closure is necessary to safely return to diving.

Conclusion

A patent foramen ovale is a common heart condition that often causes no symptoms and does not require treatment in many people. However, in certain situations, it may increase the risk of complications such as stroke, especially when blood clots can pass through the opening and reach the brain. Treatment decisions depend on factors such as previous stroke history, overall health, and individual risk factors. Regular medical evaluation can help determine whether monitoring, medications, or a PFO closure procedure is the most appropriate approach.

Read more: 8+ Warning Ruptured Spleen Signs That Need Emergency Care

Frequently Asked Questions

1. What is a patent foramen ovale?

A patent foramen ovale is a small flap-like opening between the right and left atria, which are the upper chambers of the heart. This opening is normal before birth because it helps blood circulate without passing through the developing lungs. After birth, it usually closes as pressure changes inside the heart, but it remains open in some people. Most individuals with a PFO do not have symptoms or require treatment.

2. What symptoms can a patent foramen ovale cause?

Most people with a patent foramen ovale have no noticeable symptoms. The condition is often discovered accidentally during an echocardiogram or heart evaluation for another issue. In some cases, a PFO may be associated with unexplained stroke, migraine with aura, or low oxygen levels, although the relationship between these conditions is complex. Doctors usually consider the entire medical history before deciding whether a PFO is contributing to symptoms.

3. Can a patent foramen ovale cause a stroke?

A patent foramen ovale may increase stroke risk in some people because it can allow a blood clot from the veins to pass into the arterial circulation and travel to the brain. This process is called a paradoxical embolism. However, many people with PFO never experience a stroke, and other factors such as high blood pressure, irregular heart rhythm, or artery disease may also contribute. Doctors typically investigate other possible causes before linking a stroke to a PFO.

4. How is a patent foramen ovale diagnosed?

A patent foramen ovale is usually diagnosed through an echocardiogram, which uses sound waves to create images of the heart. Doctors may use a specialized test called a bubble study, where tiny air bubbles are injected into a vein to see whether they cross through the opening. Other imaging methods, such as transesophageal echocardiography, may provide more detailed views. The choice of testing depends on the patient’s symptoms and medical history.

5. Does a patent foramen ovale need treatment?

Many people with a patent foramen ovale do not need treatment if they have no symptoms or complications. Doctors may recommend observation and routine follow-up in these cases. If someone has had an unexplained stroke that may be related to the PFO, treatment options can include blood-thinning medications or a catheter-based closure procedure. The best approach depends on the person’s risk factors and overall health.

6. What happens during patent foramen ovale closure?

A patent foramen ovale closure is a minimally invasive procedure that uses a catheter inserted through a blood vessel, usually in the groin, to place a small device over the opening. The device acts as a barrier that allows heart tissue to grow over it and permanently close the passage. The procedure usually does not require open-heart surgery and is performed under imaging guidance. After closure, patients typically need follow-up care and medication for a period of time to reduce clot risk.

Sources

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Cleveland Clinic. Patent Foramen Ovale (PFO). 
National Heart, Lung, and Blood Institute. Congenital Heart Defects. 
MedlinePlus. Patent Foramen Ovale. 
American College of Cardiology. Patent Foramen Ovale and Cryptogenic Stroke. 
National Organization for Rare Disorders. Patent Foramen Ovale.