A case with sudden onset of position-dependent hypoxemia caused by reopening of foramen ovale

SummaryWe report a case of a 68-year-old woman with sudden onset of position-dependant hypoxemia after recovering from pulmonary embolism. Transesophageal echocardiography (TEE) and cardiac catheterization revealed the presence of patent foramen ovale (PFO) and right-to-left shunting with no evidence of the right-to-left pressure gradient especially in the right lateral decubitus position. Surgical closure of the PFO was performed because the right-to-left shunting caused position-dependent severe hypoxemia. At operation, it was noted that the patient's enlarged aortic root pressed the heart inferiorly and compressed the upper part of the right atrium. A large Eustachian valve, which is an embryonic remnant of the right valve of the sinus venosus, was observed in the right atrium. Preceding pulmonary embolism could lead to a temporal elevation of the right heart and pulmonary arterial pressures and it caused the reopening of the closed foramen ovale. To the best of our knowledge, this is the first case of reopening of the foramen ovale causing sudden onset of position-dependent hypoxemia.