Patent foramen ovale

• Flap-like opening between the atrial septa primum and secundum
• Occurs at fossa ovalis
• Persists beyond 1 year of age
• Inter-atrial communication allows right-to-left cardiac shunting
• Most patients with isolated PFO are asymptomatic
  • But there is increasing evidence that PFO is the culprit in paradoxical embolic events

• Stroke or TIA of undefined etiology
  • Consider in young, healthy patients without risk factors for stroke
• Migraine or migraine-like symptoms
• Neurologic decompression sickness (seen in scuba divers)
• Acute myocardial infarction
• Systemic embolism, such as renal infarction
• Fat embolism
• Paradoxical embolism caused by right atrial tumors that increase right atrial pressure
• Left-sided valve disease in carcinoid syndrome

• Echocardiography: color flow Doppler imaging
  • Small "flame" of color signal may be seen in middle region of atrial septum
• Contrast echocardiography (Bubble Study)
  • Bolus of agitated saline injected to antecubital vein
  • Microbubbles appear in right atrium
    • Study positive for PFO if microbubbles appear in left atrium within 3 cardiac cycles of their appearance in right atrium
  • Valsalva increases right atrial pressure and facilitates right-to-left shunting if present
• 2D TEE with contrast provides superior visualization and is preferred
  • Obtain 2E TEE with constrast if suspicion is high and TTE is negative

• Most patients with incidental or isolated PFO receive no treatment
• Treatment more common when PFO associated with unexplained neurologic event, but no consensus for treatment exists

• Congenital Heart Disease
• Missile embolism

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