Bubble study


A patent foramen ovale (PFO) is a flaplike opening between the atrial septa primum and secundum at the location of the fossa ovalis that persists after 1 year of age. With increasing evidence being found that PFO is the culprit in paradoxical embolic events, the relative importance of the anomaly is being reevaluated.


  • Contrast echocardiography (Bubble Study): After obtaining optimal visualization of atrial septum on TTE or TEE, a bolus of agitated saline is injected to an antecubital vein. Subsequently, microbubbles appear in the right atrium. The study is positive for PFO if microbubbles appear in left atrium within 3 cardiac cycles of their appearance in the right atrium. Valsalva increases right atrial pressure and facilitates
  • 2D TEE with contrast provides superior visualization and is therefore preferred for detecting PFO. When clinically indicated, 2D TEE with contrast is strongly recommended if transthoracic echo is negative.