Patent Foramen Ovale

Patent foramen ovale (PFO) is a congenital heart defect characterized by the persistence of a small opening between the two atria (upper chambers) of the heart, which is normally present during fetal development but should close shortly after birth. The foramen ovale is a natural opening that allows oxygenated blood to bypass the developing lungs in the fetus. When it remains open after birth, it is referred to as a patent foramen ovale.

 

Types

Patent foramen ovale can be classified into two types based on the size and nature of the opening:

  • Small PFO: In this type, the opening is relatively small and may not cause significant blood flow between the atria.
  • Large PFO: A larger opening may allow more significant shunting of blood between the atria, which can be associated with a higher risk of complications.

 

Causes

Patent foramen ovale is a congenital condition, meaning it is present at birth. During fetal development, the foramen ovale allows blood to bypass the lungs, as they are not yet functioning, and oxygen is received from the mother. After birth, the pressure changes in the heart and lungs should close the foramen ovale. In some individuals, the foramen ovale may fail to close completely, leading to a patent foramen ovale.

 

Symptoms

Most individuals with a patent foramen ovale do not experience any symptoms, and the condition may go undiagnosed for many years. However, in some cases, a PFO can be associated with certain health conditions, and it may contribute to the following symptoms:

  • Paradoxical embolism: In rare cases, a blood clot from the veins may cross the PFO and travel to the brain, causing a stroke.
  • Migraine with aura: Some studies have suggested a possible association between PFO and migraines, particularly those with visual or sensory disturbances (auras).
  • Decompression illness: Scuba divers may be at risk of decompression sickness due to bubbles crossing the PFO.

 

 

Risk Factors

The exact factors contributing to a patent foramen ovale are not fully understood. However, certain risk factors may increase the likelihood of a PFO causing complications, such as strokes or migraines with aura:

  • Previous history of stroke or transient ischemic attack (TIA)
  • Family history of stroke or cardiovascular diseases
  • Having certain medical conditions, such as atrial septal aneurysm or deep vein thrombosis
  • Engaging in activities associated with increased risk of decompression illness (e.g., scuba diving)

 

Diagnosis

The diagnosis of patent foramen ovale involves a combination of medical history review, physical examination, and diagnostic tests, including:

  • Echocardiography: This ultrasound test provides detailed images of the heart, allowing visualization of the atrial septum and detecting the presence and size of PFO.
  • Transesophageal echocardiography (TEE): In some cases, a more specialized echocardiography may be performed, where a probe is inserted into the esophagus to obtain better images of the atrial septum.
  • Cardiac catheterization: In rare cases, a catheter may be inserted into the heart to measure pressures and obtain more detailed information about the PFO.

 

Treatment

In many cases, a patent foramen ovale may not require treatment, especially if it is small and not causing any symptoms. However, if a PFO is associated with a history of stroke or TIA, recurrent migraines with aura, or decompression illness in scuba divers, treatment options may include:

  • Medications: Anticoagulant medications may be prescribed to prevent blood clot formation and reduce the risk of stroke or other embolic events.
  • Closure devices: In certain cases, a PFO closure device may be inserted to seal the opening between the atria. This can be done through minimally invasive procedures, such as transcatheter closure.

 

When to Consult a Physician

If you have a known history of stroke, TIA, or recurrent migraines with aura, or if you are a scuba diver with a history of decompression illness, it is essential to consult a physician for evaluation and appropriate management. A cardiologist can assess the risk factors and discuss the potential benefits and risks of PFO closure or other treatment options. If you experience any symptoms of a stroke or neurological disturbances, seek immediate medical attention, as these may be signs of a paradoxical embolism related to the PFO.